React NativeAccessibility #
Native App Accessibility (iOS and Android) #
Both iOS and Android provide APIs for making apps accessible to people with disabilities. In addition, both platforms provide bundled assistive technologies, like the screen readers VoiceOver (iOS) and TalkBack (Android) for the visually impaired. Similarly, in React Native we have included APIs designed to provide developers with support for making apps more accessible. Take note, iOS and Android differ slightly in their approaches, and thus the React Native implementations may vary by platform.
In addition to this documentation, you might find this blog post about React Native accessibility to be useful.
Making Apps Accessible #
Accessibility properties #
accessible (iOS, Android) #
When true, indicates that the view is an accessibility element. When a view is an accessibility element, it groups its children into a single selectable component. By default, all touchable elements are accessible.
On Android, ‘accessible={true}’ property for a react-native View will be translated into native ‘focusable={true}’.
Accessibility #
Native App Accessibility (iOS and Android) #
Both iOS and Android provide APIs for making apps accessible to people with disabilities. In addition, both platforms provide bundled assistive technologies, like the screen readers VoiceOver (iOS) and TalkBack (Android) for the visually impaired. Similarly, in React Native we have included APIs designed to provide developers with support for making apps more accessible. Take note, iOS and Android differ slightly in their approaches, and thus the React Native implementations may vary by platform.
In addition to this documentation, you might find this blog post about React Native accessibility to be useful.
Making Apps Accessible #
Accessibility properties #
accessible (iOS, Android) #
When true, indicates that the view is an accessibility element. When a view is an accessibility element, it groups its children into a single selectable component. By default, all touchable elements are accessible.
On Android, ‘accessible={true}’ property for a react-native View will be translated into native ‘focusable={true}’.
In the above example, we can't get accessibility focus separately on 'text one' and 'text two'. Instead we get focus on a parent view with 'accessible' property.
accessibilityLabel (iOS, Android) #
When a view is marked as accessible, it is a good practice to set an accessibilityLabel on the view, so that people who use VoiceOver know what element they have selected. VoiceOver will read this string when a user selects the associated element.
To use, set the accessibilityLabel property to a custom string on your View:
B contains a child view C a
<CustomRadioButton
accessibleComponentType={this.state.radioButton}
- onPress={this._onPress}/>In the above example we've created a custom radio button that now behaves like a native one. More specifically, TalkBack now correctly announces changes to the radio button selection.
Testing VoiceOver Support (iOS) #
To enable VoiceOver, go to the Settings app on your iOS device. Tap General, then Accessibility. There you will find many tools that people use to use to make their devices more usable, such as bolder text, increased contrast, and VoiceOver.
To enable VoiceOver, tap on VoiceOver under "Vision" and toggle the switch that appears at the top.
At the very bottom of the Accessibility settings, there is an "Accessibility Shortcut". You can use this to toggle VoiceOver by triple clicking the Home button.
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AccessibilityInfo #
Sometimes it's useful to know whether or not the device has a screen reader that is currently active. The +
AccessibilityInfo #
Sometimes it's useful to know whether or not the device has a screen reader that is currently active. The
AccessibilityInfo API is designed for this purpose. You can use it to query the current state of the
screen reader as well as to register to be notified when the state of the screen reader changes.
Here's a small example illustrating how to use AccessibilityInfo:
ActionSheetIOS #
Methods #
static showActionSheetWithOptions(options, callback) #
Display an iOS action sheet. The options object must contain one or more
+
ActionSheetIOS #
Methods #
static showActionSheetWithOptions(options, callback) #
Display an iOS action sheet. The options object must contain one or more
of:
options(array of strings) - a list of button titles (required)cancelButtonIndex(int) - index of cancel button inoptionsdestructiveButtonIndex(int) - index of destructive button inoptionstitle(string) - a title to show above the action sheetmessage(string) - a message to show below the title
static showShareActionSheetWithOptions(options, failureCallback, successCallback) #
Display the iOS share sheet. The options object should contain
one or both of message and url and can additionally have
a subject or excludedActivityTypes:
url(string) - a URL to sharemessage(string) - a message to sharesubject(string) - a subject for the messageexcludedActivityTypes(array) - the activities to exclude from the ActionSheet
NOTE: if url points to a local file, or is a base64-encoded
diff --git a/releases/next/docs/activityindicator.html b/releases/next/docs/activityindicator.html
index a2842490584..213f28a79c5 100644
--- a/releases/next/docs/activityindicator.html
+++ b/releases/next/docs/activityindicator.html
@@ -1,4 +1,4 @@
-
ActivityIndicator #
Displays a circular loading indicator.
Props #
animating?: bool #
Whether to show the indicator (true, the default) or hide it (false).
color?: [object Object] #
The foreground color of the spinner (default is gray).
size?: [object Object], [object Object] #
Size of the indicator (default is 'small'). +
ActivityIndicator #
Displays a circular loading indicator.
Props #
animating?: bool #
Whether to show the indicator (true, the default) or hide it (false).
color?: [object Object] #
The foreground color of the spinner (default is gray).
size?: [object Object], [object Object] #
Size of the indicator (default is 'small'). Passing a number to the size prop is only supported on Android.
ioshidesWhenStopped?: bool #
Whether the indicator should hide when not animating (true by default).
You can edit the content above on GitHub and send us a pull request!
Examples # | Edit on GitHub |
AdSupportIOS #
Methods #
You can edit the content above on GitHub and send us a pull request!
Examples # | Edit on GitHub |
AdSupportIOS #
Methods #
You can edit the content above on GitHub and send us a pull request!
Examples # | Edit on GitHub |
Alert #
Launches an alert dialog with the specified title and message.
Optionally provide a list of buttons. Tapping any button will fire the +
Alert #
Launches an alert dialog with the specified title and message.
Optionally provide a list of buttons. Tapping any button will fire the respective onPress callback and dismiss the alert. By default, the only button will be an 'OK' button.
This is an API that works both on iOS and Android and can show static alerts. To show an alert that prompts the user to enter some information, diff --git a/releases/next/docs/alertios.html b/releases/next/docs/alertios.html index 91c68510365..dca15c67af0 100644 --- a/releases/next/docs/alertios.html +++ b/releases/next/docs/alertios.html @@ -1,4 +1,4 @@ -
AlertIOS #
AlertIOS provides functionality to create an iOS alert dialog with a
+
AlertIOS #
AlertIOS provides functionality to create an iOS alert dialog with a
message or create a prompt for user input.
Creating an iOS alert:
Building React Native from source #
You will need to build React Native from source if you want to work on a new feature/bug fix, try out the latest features which are not released yet, or maintain your own fork with patches that cannot be merged to the core.
Prerequisites #
Assuming you have the Android SDK installed, run android to open the Android SDK Manager.
Make sure you have the following installed:
- Android SDK version 23 (compileSdkVersion in
build.gradle) - SDK build tools version 23.0.1 (buildToolsVersion in
build.gradle) - Android Support Repository >= 17 (for Android Support Library)
- Android NDK (download links and installation instructions below)
Point Gradle to your Android SDK: #
Step 1: Set environment variables through your local shell.
Note: Files may vary based on shell flavor. See below for examples from common shells.
- bash:
.bash_profileor.bashrc - zsh:
.zprofileor.zshrc - ksh:
.profileor$ENV
Example:
Building React Native from source #
You will need to build React Native from source if you want to work on a new feature/bug fix, try out the latest features which are not released yet, or maintain your own fork with patches that cannot be merged to the core.
Prerequisites #
Assuming you have the Android SDK installed, run android to open the Android SDK Manager.
Make sure you have the following installed:
- Android SDK version 23 (compileSdkVersion in
build.gradle) - SDK build tools version 23.0.1 (buildToolsVersion in
build.gradle) - Android Support Repository >= 17 (for Android Support Library)
- Android NDK (download links and installation instructions below)
Point Gradle to your Android SDK: #
Step 1: Set environment variables through your local shell.
Note: Files may vary based on shell flavor. See below for examples from common shells.
- bash:
.bash_profileor.bashrc - zsh:
.zprofileor.zshrc - ksh:
.profileor$ENV
Example:
Step 2: Create a local.properties file in the android directory of your react-native app with the following contents:
Example:
Download links for Android NDK #
- Mac OS (64-bit) - http://dl.google.com/android/repository/android-ndk-r10e-darwin-x86_64.zip
- Linux (64-bit) - http://dl.google.com/android/repository/android-ndk-r10e-linux-x86_64.zip
- Windows (64-bit) - http://dl.google.com/android/repository/android-ndk-r10e-windows-x86_64.zip
- Windows (32-bit) - http://dl.google.com/android/repository/android-ndk-r10e-windows-x86.zip
You can find further instructions on the official page.
Building the source #
1. Installing the fork #
First, you need to install react-native from your fork. For example, to install the master branch from the official repo, run the following:
Alternatively, you can clone the repo to your node_modules directory and run npm install inside the cloned repo.
2. Adding gradle dependencies #
Add gradle-download-task as dependency in android/build.gradle:
Profiling Android UI Performance #
We try our best to deliver buttery-smooth UI performance by default, but sometimes that just isn't possible. Remember, Android supports 10k+ different phones and is generalized to support software rendering: the framework architecture and need to generalize across many hardware targets unfortunately means you get less for free relative to iOS. But sometimes, there are things you can improve (and many times it's not native code's fault at all!).
The first step for debugging this jank is to answer the fundamental question of where your time is being spent during each 16ms frame. For that, we'll be using a standard Android profiling tool called systrace. But first...
Make sure that JS dev mode is OFF!
You should see
__DEV__ === false, development-level warning are OFF, performance optimizations are ONin your application logs (which you can view usingadb logcat)
Profiling with Systrace #
Systrace is a standard Android marker-based profiling tool (and is installed when you install the Android platform-tools package). Profiled code blocks are surrounded by markers start/end markers which are then visualized in a colorful chart format. Both the Android SDK and React Native framework provide standard markers that you can visualize.
Collecting a trace #
NOTE:
Systrace support was added in react-native
v0.15. You will need to build with that version to collect a trace.
First, connect a device that exhibits the stuttering you want to investigate to your computer via USB and get it to the point right before the navigation/animation you want to profile. Run systrace as follows
A quick breakdown of this command:
timeis the length of time the trace will be collected in secondssched,gfx, andvieware the android SDK tags (collections of markers) we care about:schedgives you information about what's running on each core of your phone,gfxgives you graphics info such as frame boundaries, andviewgives you information about measure, layout, and draw passes-a <your_package_name>enables app-specific markers, specifically the ones built into the React Native framework.your_package_namecan be found in theAndroidManifest.xmlof your app and looks likecom.example.app
Once the trace starts collecting, perform the animation or interaction you care about. At the end of the trace, systrace will give you a link to the trace which you can open in your browser.
Reading the trace #
After opening the trace in your browser (preferably Chrome), you should see something like this:
If your trace .html file isn't opening correctly, check your browser console for the following:
Since Object.observe was deprecated in recent browsers, you may have to open the file from the Google Chrome Tracing tool. You can do so by:
- Opening tab in chrome chrome://tracing
- Selecting load
- Selecting the html file generated from the previous command.
HINT: Use the WASD keys to strafe and zoom
Enable VSync highlighting #
The first thing you should do is highlight the 16ms frame boundaries if you haven't already done that. Check this checkbox at the top right of the screen:
You should see zebra stripes as in the screenshot above. If you don't, try profiling on a different device: Samsung has been known to have issues displaying vsyncs while the Nexus series is generally pretty reliable.
Find your process #
Scroll until you see (part of) the name of your package. In this case, I was profiling com.facebook.adsmanager, which shows up as book.adsmanager because of silly thread name limits in the kernel.
On the left side, you'll see a set of threads which correspond to the timeline rows on the right. There are three/four threads we care about for our purposes: the UI thread (which has your package name or the name UI Thread), mqt_js and mqt_native_modules. If you're running on Android 5+, we also care about the Render Thread.
UI Thread #
This is where standard android measure/layout/draw happens. The thread name on the right will be your package name (in my case book.adsmanager) or UI Thread. The events that you see on this thread should look something like this and have to do with Choreographer, traversals, and DispatchUI:
JS Thread #
This is where JS is executed. The thread name will be either mqt_js or <...> depending on how cooperative the kernel on your device is being. To identify it if it doesn't have a name, look for things like JSCall, Bridge.executeJSCall, etc:
Native Modules Thread #
This is where native module calls (e.g. the UIManager) are executed. The thread name will be either mqt_native_modules or <...>. To identify it in the latter case, look for things like NativeCall, callJavaModuleMethod, and onBatchComplete:
Bonus: Render Thread #
If you're using Android L (5.0) and up, you will also have a render thread in your application. This thread generates the actual OpenGL commands used to draw your UI. The thread name will be either RenderThread or <...>. To identify it in the latter case, look for things like DrawFrame and queueBuffer:
Identifying a culprit #
A smooth animation should look something like the following:
Each change in color is a frame -- remember that in order to display a frame, all our UI work needs to be done by the end of that 16ms period. Notice that no thread is working close to the frame boundary. An application rendering like this is rendering at 60FPS.
If you noticed chop, however, you might see something like this:
Notice that the JS thread is executing basically all the time, and across frame boundaries! This app is not rendering at 60FPS. In this case, the problem lies in JS.
You might also see something like this:
In this case, the UI and render threads are the ones that have work crossing frame boundaries. The UI that we're trying to render on each frame is requiring too much work to be done. In this case, the problem lies in the native views being rendered.
At this point, you'll have some very helpful information to inform your next steps.
JS Issues #
If you identified a JS problem, look for clues in the specific JS that you're executing. In the scenario above, we see RCTEventEmitter being called multiple times per frame. Here's a zoom-in of the JS thread from the trace above:
This doesn't seem right. Why is it being called so often? Are they actually different events? The answers to these questions will probably depend on your product code. And many times, you'll want to look into shouldComponentUpdate.
TODO: Add more tools for profiling JS
Native UI Issues #
If you identified a native UI problem, there are usually two scenarios:
- the UI you're trying to draw each frame involves to much work on the GPU, or
- You're constructing new UI during the animation/interaction (e.g. loading in new content during a scroll).
Too much GPU work #
In the first scenario, you'll see a trace that has the UI thread and/or Render Thread looking like this:
Notice the long amount of time spent in DrawFrame that crosses frame boundaries. This is time spent waiting for the GPU to drain its command buffer from the previous frame.
To mitigate this, you should:
- investigate using
renderToHardwareTextureAndroidfor complex, static content that is being animated/transformed (e.g. theNavigatorslide/alpha animations) - make sure that you are not using
needsOffscreenAlphaCompositing, which is disabled by default, as it greatly increases the per-frame load on the GPU in most cases.
If these don't help and you want to dig deeper into what the GPU is actually doing, you can check out Tracer for OpenGL ES.
Creating new views on the UI thread #
In the second scenario, you'll see something more like this:
Notice that first the JS thread thinks for a bit, then you see some work done on the native modules thread, followed by an expensive traversal on the UI thread.
There isn't an easy way to mitigate this unless you're able to postpone creating new UI until after the interaction, or you are able to simplify the UI you're creating. The react native team is working on a infrastructure level solution for this that will allow new UI to be created and configured off the main thread, allowing the interaction to continue smoothly.
Still stuck? #
If you are confused or stuck, please post ask on Stack Overflow with the react-native tag. If you are unable to get a response there, or find an issue with a core component, please File a Github issue.
You can edit the content above on GitHub and send us a pull request!
Redirecting...
Click here if you are not redirected. \ No newline at end of file diff --git a/releases/next/docs/animated.html b/releases/next/docs/animated.html index c316cac9821..d6cc528c974 100644 --- a/releases/next/docs/animated.html +++ b/releases/next/docs/animated.html @@ -1,4 +1,4 @@ -Animated #
The Animated library is designed to make animations fluid, powerful, and
+
Animated #
The Animated library is designed to make animations fluid, powerful, and
easy to build and maintain. Animated focuses on declarative relationships
between inputs and outputs, with configurable transforms in between, and
simple start/stop methods to control time-based animation execution.
The simplest workflow for creating an animation is to to create an diff --git a/releases/next/docs/animations.html b/releases/next/docs/animations.html index fbfc2a5bd83..ee7980eb20e 100644 --- a/releases/next/docs/animations.html +++ b/releases/next/docs/animations.html @@ -1,4 +1,4 @@ -
Animations #
Animations are very important to create a great user experience. +
Animations #
Animations are very important to create a great user experience. Stationary objects must overcome inertia as they start moving. Objects in motion have momentum and rarely come to a stop immediately. Animations allow you to convey physically believable motion in your interface.
React Native provides two complementary animation systems: @@ -275,7 +275,7 @@ computationally intensive work until after animations are complete, using the InteractionManager. You can monitor the frame rate by using the In-App Developer Menu "FPS -Monitor" tool.
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AppRegistry #
AppRegistry is the JS entry point to running all React Native apps. App
+
AppRegistry #
AppRegistry is the JS entry point to running all React Native apps. App
root components should register themselves with
AppRegistry.registerComponent, then the native system can load the bundle
for the app and then actually run the app when it's ready by invoking
diff --git a/releases/next/docs/appstate.html b/releases/next/docs/appstate.html
index e21974dd985..f01b22ef7af 100644
--- a/releases/next/docs/appstate.html
+++ b/releases/next/docs/appstate.html
@@ -1,4 +1,4 @@
-
AppState #
AppState can tell you if the app is in the foreground or background,
+
AppState #
AppState can tell you if the app is in the foreground or background,
and notify you when the state changes.
AppState is frequently used to determine the intent and proper behavior when handling push notifications.
App States #
active- The app is running in the foregroundbackground- The app is running in the background. The user is either in another app or on the home screeninactive- This is a state that occurs when transitioning between diff --git a/releases/next/docs/asyncstorage.html b/releases/next/docs/asyncstorage.html index 35ddd41150f..8d73cf7b9b4 100644 --- a/releases/next/docs/asyncstorage.html +++ b/releases/next/docs/asyncstorage.html @@ -1,4 +1,4 @@ -AsyncStorage AsyncStorage #
AsyncStorageis a simple, unencrypted, asynchronous, persistent, key-value storage +AsyncStorage AsyncStorage #
AsyncStorageis a simple, unencrypted, asynchronous, persistent, key-value storage system that is global to the app. It should be used instead of LocalStorage.It is recommended that you use an abstraction on top of
AsyncStorageinstead ofAsyncStoragedirectly for anything more than light usage since it operates globally.On iOS,
AsyncStorageis backed by native code that stores small values in a diff --git a/releases/next/docs/backandroid.html b/releases/next/docs/backandroid.html index 060b1007958..e51b10460a6 100644 --- a/releases/next/docs/backandroid.html +++ b/releases/next/docs/backandroid.html @@ -1,4 +1,4 @@ -BackAndroid BackAndroid #
Detect hardware back button presses, and programmatically invoke the default back button +
BackAndroid BackAndroid #
Detect hardware back button presses, and programmatically invoke the default back button functionality to exit the app if there are no listeners or if none of the listeners return true. The event subscriptions are called in reverse order (i.e. last registered subscription first), and if one subscription returns true then subscriptions registered earlier will not be called.
Example:
BackAndroid.addEventListener('hardwareBackPress', function() { diff --git a/releases/next/docs/button.html b/releases/next/docs/button.html index 4d663800ad0..a0d92f658d8 100644 --- a/releases/next/docs/button.html +++ b/releases/next/docs/button.html @@ -1,4 +1,4 @@ -Button Button #
A basic button component that should render nicely on any platform. Supports +
Button Button #
A basic button component that should render nicely on any platform. Supports a minimal level of customization.
If this button doesn't look right for your app, you can build your own diff --git a/releases/next/docs/cameraroll.html b/releases/next/docs/cameraroll.html index 50adf59f3ad..e661e486c38 100644 --- a/releases/next/docs/cameraroll.html +++ b/releases/next/docs/cameraroll.html @@ -1,4 +1,4 @@ -
CameraRoll CameraRoll #
CameraRollprovides access to the local camera roll / gallery. +CameraRoll CameraRoll #
CameraRollprovides access to the local camera roll / gallery. Before using this you must link theRCTCameraRolllibrary. You can refer to Linking for help.Permissions #
The user's permission is required in order to access the Camera Roll on devices running iOS 10 or later. Fill out the
NSCameraUsageDescriptionkey in yourInfo.plistwith a string that describes how your diff --git a/releases/next/docs/clipboard.html b/releases/next/docs/clipboard.html index 635bf8ef16a..1bad07ab173 100644 --- a/releases/next/docs/clipboard.html +++ b/releases/next/docs/clipboard.html @@ -1,4 +1,4 @@ -Clipboard Clipboard #
Clipboardgives you an interface for setting and getting content from Clipboard on both iOS and AndroidMethods #
static getString() #
Get content of string type, this method returns a
Promise, so you can use following code to get clipboard contentasync _getContent() { +Clipboard Clipboard #
Clipboardgives you an interface for setting and getting content from Clipboard on both iOS and AndroidMethods #
static getString() #
Get content of string type, this method returns a
Promise, so you can use following code to get clipboard contentasync _getContent() { var content = await Clipboard.getString(); }static setString(content) #
Set content of string type. You can use following code to set clipboard content
_setContent() { Clipboard.setString('hello world'); diff --git a/releases/next/docs/colors.html b/releases/next/docs/colors.html index b535a90d64a..32034b72a18 100644 --- a/releases/next/docs/colors.html +++ b/releases/next/docs/colors.html @@ -1,4 +1,4 @@ -Colors Colors #
The following formats are supported:
'#f0f'(#rgb)'#f0fc'(#rgba)'#ff00ff'(#rrggbb)'#ff00ff00'(#rrggbbaa)'rgb(255, 255, 255)''rgba(255, 255, 255, 1.0)''hsl(360, 100%, 100%)''hsla(360, 100%, 100%, 1.0)''transparent''red'0xff00ff00(0xrrggbbaa)
For the named colors, React Native follows the CSS3 specification:
- aliceblue (#f0f8ff)
- antiquewhite (#faebd7)
- aqua (#00ffff)
- aquamarine (#7fffd4)
- azure (#f0ffff)
- beige (#f5f5dc)
- bisque (#ffe4c4)
- black (#000000)
- blanchedalmond (#ffebcd)
- blue (#0000ff)
- blueviolet (#8a2be2)
- brown (#a52a2a)
- burlywood (#deb887)
- cadetblue (#5f9ea0)
- chartreuse (#7fff00)
- chocolate (#d2691e)
- coral (#ff7f50)
- cornflowerblue (#6495ed)
- cornsilk (#fff8dc)
- crimson (#dc143c)
- cyan (#00ffff)
- darkblue (#00008b)
- darkcyan (#008b8b)
- darkgoldenrod (#b8860b)
- darkgray (#a9a9a9)
- darkgreen (#006400)
- darkgrey (#a9a9a9)
- darkkhaki (#bdb76b)
- darkmagenta (#8b008b)
- darkolivegreen (#556b2f)
- darkorange (#ff8c00)
- darkorchid (#9932cc)
- darkred (#8b0000)
- darksalmon (#e9967a)
- darkseagreen (#8fbc8f)
- darkslateblue (#483d8b)
- darkslategray (#2f4f4f)
- darkslategrey (#2f4f4f)
- darkturquoise (#00ced1)
- darkviolet (#9400d3)
- deeppink (#ff1493)
- deepskyblue (#00bfff)
- dimgray (#696969)
- dimgrey (#696969)
- dodgerblue (#1e90ff)
- firebrick (#b22222)
- floralwhite (#fffaf0)
- forestgreen (#228b22)
- fuchsia (#ff00ff)
- gainsboro (#dcdcdc)
- ghostwhite (#f8f8ff)
- gold (#ffd700)
- goldenrod (#daa520)
- gray (#808080)
- green (#008000)
- greenyellow (#adff2f)
- grey (#808080)
- honeydew (#f0fff0)
- hotpink (#ff69b4)
- indianred (#cd5c5c)
- indigo (#4b0082)
- ivory (#fffff0)
- khaki (#f0e68c)
- lavender (#e6e6fa)
- lavenderblush (#fff0f5)
- lawngreen (#7cfc00)
- lemonchiffon (#fffacd)
- lightblue (#add8e6)
- lightcoral (#f08080)
- lightcyan (#e0ffff)
- lightgoldenrodyellow (#fafad2)
- lightgray (#d3d3d3)
- lightgreen (#90ee90)
- lightgrey (#d3d3d3)
- lightpink (#ffb6c1)
- lightsalmon (#ffa07a)
- lightseagreen (#20b2aa)
- lightskyblue (#87cefa)
- lightslategray (#778899)
- lightslategrey (#778899)
- lightsteelblue (#b0c4de)
- lightyellow (#ffffe0)
- lime (#00ff00)
- limegreen (#32cd32)
- linen (#faf0e6)
- magenta (#ff00ff)
- maroon (#800000)
- mediumaquamarine (#66cdaa)
- mediumblue (#0000cd)
- mediumorchid (#ba55d3)
- mediumpurple (#9370db)
- mediumseagreen (#3cb371)
- mediumslateblue (#7b68ee)
- mediumspringgreen (#00fa9a)
- mediumturquoise (#48d1cc)
- mediumvioletred (#c71585)
- midnightblue (#191970)
- mintcream (#f5fffa)
- mistyrose (#ffe4e1)
- moccasin (#ffe4b5)
- navajowhite (#ffdead)
- navy (#000080)
- oldlace (#fdf5e6)
- olive (#808000)
- olivedrab (#6b8e23)
- orange (#ffa500)
- orangered (#ff4500)
- orchid (#da70d6)
- palegoldenrod (#eee8aa)
- palegreen (#98fb98)
- paleturquoise (#afeeee)
- palevioletred (#db7093)
- papayawhip (#ffefd5)
- peachpuff (#ffdab9)
- peru (#cd853f)
- pink (#ffc0cb)
- plum (#dda0dd)
- powderblue (#b0e0e6)
- purple (#800080)
- rebeccapurple (#663399)
- red (#ff0000)
- rosybrown (#bc8f8f)
- royalblue (#4169e1)
- saddlebrown (#8b4513)
- salmon (#fa8072)
- sandybrown (#f4a460)
- seagreen (#2e8b57)
- seashell (#fff5ee)
- sienna (#a0522d)
- silver (#c0c0c0)
- skyblue (#87ceeb)
- slateblue (#6a5acd)
- slategray (#708090)
- slategrey (#708090)
- snow (#fffafa)
- springgreen (#00ff7f)
- steelblue (#4682b4)
- tan (#d2b48c)
- teal (#008080)
- thistle (#d8bfd8)
- tomato (#ff6347)
- turquoise (#40e0d0)
- violet (#ee82ee)
- wheat (#f5deb3)
- white (#ffffff)
- whitesmoke (#f5f5f5)
- yellow (#ffff00)
- yellowgreen (#9acd32)
You can edit the content above on GitHub and send us a pull request!
Colors #
The following formats are supported:
'#f0f'(#rgb)'#f0fc'(#rgba)'#ff00ff'(#rrggbb)'#ff00ff00'(#rrggbbaa)'rgb(255, 255, 255)''rgba(255, 255, 255, 1.0)''hsl(360, 100%, 100%)''hsla(360, 100%, 100%, 1.0)''transparent''red'0xff00ff00(0xrrggbbaa)
For the named colors, React Native follows the CSS3 specification:
- aliceblue (#f0f8ff)
- antiquewhite (#faebd7)
- aqua (#00ffff)
- aquamarine (#7fffd4)
- azure (#f0ffff)
- beige (#f5f5dc)
- bisque (#ffe4c4)
- black (#000000)
- blanchedalmond (#ffebcd)
- blue (#0000ff)
- blueviolet (#8a2be2)
- brown (#a52a2a)
- burlywood (#deb887)
- cadetblue (#5f9ea0)
- chartreuse (#7fff00)
- chocolate (#d2691e)
- coral (#ff7f50)
- cornflowerblue (#6495ed)
- cornsilk (#fff8dc)
- crimson (#dc143c)
- cyan (#00ffff)
- darkblue (#00008b)
- darkcyan (#008b8b)
- darkgoldenrod (#b8860b)
- darkgray (#a9a9a9)
- darkgreen (#006400)
- darkgrey (#a9a9a9)
- darkkhaki (#bdb76b)
- darkmagenta (#8b008b)
- darkolivegreen (#556b2f)
- darkorange (#ff8c00)
- darkorchid (#9932cc)
- darkred (#8b0000)
- darksalmon (#e9967a)
- darkseagreen (#8fbc8f)
- darkslateblue (#483d8b)
- darkslategray (#2f4f4f)
- darkslategrey (#2f4f4f)
- darkturquoise (#00ced1)
- darkviolet (#9400d3)
- deeppink (#ff1493)
- deepskyblue (#00bfff)
- dimgray (#696969)
- dimgrey (#696969)
- dodgerblue (#1e90ff)
- firebrick (#b22222)
- floralwhite (#fffaf0)
- forestgreen (#228b22)
- fuchsia (#ff00ff)
- gainsboro (#dcdcdc)
- ghostwhite (#f8f8ff)
- gold (#ffd700)
- goldenrod (#daa520)
- gray (#808080)
- green (#008000)
- greenyellow (#adff2f)
- grey (#808080)
- honeydew (#f0fff0)
- hotpink (#ff69b4)
- indianred (#cd5c5c)
- indigo (#4b0082)
- ivory (#fffff0)
- khaki (#f0e68c)
- lavender (#e6e6fa)
- lavenderblush (#fff0f5)
- lawngreen (#7cfc00)
- lemonchiffon (#fffacd)
- lightblue (#add8e6)
- lightcoral (#f08080)
- lightcyan (#e0ffff)
- lightgoldenrodyellow (#fafad2)
- lightgray (#d3d3d3)
- lightgreen (#90ee90)
- lightgrey (#d3d3d3)
- lightpink (#ffb6c1)
- lightsalmon (#ffa07a)
- lightseagreen (#20b2aa)
- lightskyblue (#87cefa)
- lightslategray (#778899)
- lightslategrey (#778899)
- lightsteelblue (#b0c4de)
- lightyellow (#ffffe0)
- lime (#00ff00)
- limegreen (#32cd32)
- linen (#faf0e6)
- magenta (#ff00ff)
- maroon (#800000)
- mediumaquamarine (#66cdaa)
- mediumblue (#0000cd)
- mediumorchid (#ba55d3)
- mediumpurple (#9370db)
- mediumseagreen (#3cb371)
- mediumslateblue (#7b68ee)
- mediumspringgreen (#00fa9a)
- mediumturquoise (#48d1cc)
- mediumvioletred (#c71585)
- midnightblue (#191970)
- mintcream (#f5fffa)
- mistyrose (#ffe4e1)
- moccasin (#ffe4b5)
- navajowhite (#ffdead)
- navy (#000080)
- oldlace (#fdf5e6)
- olive (#808000)
- olivedrab (#6b8e23)
- orange (#ffa500)
- orangered (#ff4500)
- orchid (#da70d6)
- palegoldenrod (#eee8aa)
- palegreen (#98fb98)
- paleturquoise (#afeeee)
- palevioletred (#db7093)
- papayawhip (#ffefd5)
- peachpuff (#ffdab9)
- peru (#cd853f)
- pink (#ffc0cb)
- plum (#dda0dd)
- powderblue (#b0e0e6)
- purple (#800080)
- rebeccapurple (#663399)
- red (#ff0000)
- rosybrown (#bc8f8f)
- royalblue (#4169e1)
- saddlebrown (#8b4513)
- salmon (#fa8072)
- sandybrown (#f4a460)
- seagreen (#2e8b57)
- seashell (#fff5ee)
- sienna (#a0522d)
- silver (#c0c0c0)
- skyblue (#87ceeb)
- slateblue (#6a5acd)
- slategray (#708090)
- slategrey (#708090)
- snow (#fffafa)
- springgreen (#00ff7f)
- steelblue (#4682b4)
- tan (#d2b48c)
- teal (#008080)
- thistle (#d8bfd8)
- tomato (#ff6347)
- turquoise (#40e0d0)
- violet (#ee82ee)
- wheat (#f5deb3)
- white (#ffffff)
- whitesmoke (#f5f5f5)
- yellow (#ffff00)
- yellowgreen (#9acd32)
You can edit the content above on GitHub and send us a pull request!
Communication between native and React Native #
In Integrating with Existing Apps guide and Native UI Components guide we learn how to embed React Native in a native component and vice versa. When we mix native and React Native components, we'll eventually find a need to communicate between these two worlds. Some ways to achieve that have been already mentioned in other guides. This article summarizes available techniques.
Introduction #
React Native is inspired by React, so the basic idea of the information flow is similar. The flow in React is one-directional. We maintain a hierarchy of components, in which each component depends only on its parent and its own internal state. We do this with properties: data is passed from a parent to its children in a top-down manner. If an ancestor component relies on the state of its descendant, one should pass down a callback to be used by the descendant to update the ancestor.
The same concept applies to React Native. As long as we are building our application purely within the framework, we can drive our app with properties and callbacks. But, when we mix React Native and native components, we need some special, cross-language mechanisms that would allow us to pass information between them.
Properties #
Properties are the simplest way of cross-component communication. So we need a way to pass properties both from native to React Native, and from React Native to native.
Passing properties from native to React Native #
In order to embed a React Native view in a native component, we use
RCTRootView.RCTRootViewis aUIViewthat holds a React Native app. It also provides an interface between native side and the hosted app.RCTRootViewhas an initializer that allows you to pass arbitrary properties down to the React Native app. TheinitialPropertiesparameter has to be an instance ofNSDictionary. The dictionary is internally converted into a JSON object that the top-level JS component can reference.NSArray *imageList = @[@"http://foo.com/bar1.png", +Communication between native and React Native Communication between native and React Native #
In Integrating with Existing Apps guide and Native UI Components guide we learn how to embed React Native in a native component and vice versa. When we mix native and React Native components, we'll eventually find a need to communicate between these two worlds. Some ways to achieve that have been already mentioned in other guides. This article summarizes available techniques.
Introduction #
React Native is inspired by React, so the basic idea of the information flow is similar. The flow in React is one-directional. We maintain a hierarchy of components, in which each component depends only on its parent and its own internal state. We do this with properties: data is passed from a parent to its children in a top-down manner. If an ancestor component relies on the state of its descendant, one should pass down a callback to be used by the descendant to update the ancestor.
The same concept applies to React Native. As long as we are building our application purely within the framework, we can drive our app with properties and callbacks. But, when we mix React Native and native components, we need some special, cross-language mechanisms that would allow us to pass information between them.
Properties #
Properties are the simplest way of cross-component communication. So we need a way to pass properties both from native to React Native, and from React Native to native.
Passing properties from native to React Native #
In order to embed a React Native view in a native component, we use
RCTRootView.RCTRootViewis aUIViewthat holds a React Native app. It also provides an interface between native side and the hosted app.RCTRootViewhas an initializer that allows you to pass arbitrary properties down to the React Native app. TheinitialPropertiesparameter has to be an instance ofNSDictionary. The dictionary is internally converted into a JSON object that the top-level JS component can reference.NSArray *imageList = @[@"http://foo.com/bar1.png", @"http://foo.com/bar2.png"]; NSDictionary *props = @{@"images" : imageList}; @@ -74,7 +74,7 @@ Making a dimension flexible in both JS and native leads to undefined behavior. F newFrame.size = rootView.intrinsicContentSize; rootView.frame = newFrame; -}In the example we have a
FlexibleSizeExampleViewview that holds a root view. We create the root view, initialize it and set the delegate. The delegate will handle size updates. Then, we set the root view's size flexibility toRCTRootViewSizeFlexibilityHeight, which means thatrootViewDidChangeIntrinsicSize:method will be called every time the React Native content changes its height. Finally, we set the root view's width and position. Note that we set there height as well, but it has no effect as we made the height RN-dependent.You can checkout full source code of the example here.
It's fine to change root view's size flexibility mode dynamically. Changing flexibility mode of a root view will schedule a layout recalculation and the delegate
rootViewDidChangeIntrinsicSize:method will be called once the content size is known.Note: React Native layout calculation is performed on a special thread, while native UI view updates are done on the main thread. This may cause temporary UI inconsistencies between native and React Native. This is a known problem and our team is working on synchronizing UI updates coming from different sources.
Note: React Native does not perform any layout calculations until the root view becomes a subview of some other views. If you want to hide React Native view until its dimensions are known, add the root view as a subview and make it initially hidden (use
UIView'shiddenproperty). Then change its visibility in the delegate method.You can edit the content above on GitHub and send us a pull request!
DatePickerAndroid #
Opens the standard Android date picker dialog.
Example #
try { +DatePickerAndroid DatePickerAndroid #
Opens the standard Android date picker dialog.
Example #
try { const {action, year, month, day} = await DatePickerAndroid.open({ // Use `new Date()` for current date. // May 25 2020. Month 0 is January. diff --git a/releases/next/docs/datepickerios.html b/releases/next/docs/datepickerios.html index 4cc88f80122..050d9ccde2b 100644 --- a/releases/next/docs/datepickerios.html +++ b/releases/next/docs/datepickerios.html @@ -1,4 +1,4 @@ -DatePickerIOS DatePickerIOS #
Use
DatePickerIOSto render a date/time picker (selector) on iOS. This is +DatePickerIOS DatePickerIOS #
Use
DatePickerIOSto render a date/time picker (selector) on iOS. This is a controlled component, so you must hook in to theonDateChangecallback and update thedateprop in order for the component to update, otherwise the user's change will be reverted immediately to reflectprops.dateas the diff --git a/releases/next/docs/debugging.html b/releases/next/docs/debugging.html index 0fbc0208241..46bc25a9653 100644 --- a/releases/next/docs/debugging.html +++ b/releases/next/docs/debugging.html @@ -1,4 +1,4 @@ -Debugging Debugging #
Accessing the In-App Developer Menu #
You can access the developer menu by shaking your device or by selecting "Shake Gesture" inside the Hardware menu in the iOS Simulator. You can also use the
Command⌘+Dkeyboard shortcut when your app is running in the iPhone Simulator, orCommand⌘+Mwhen running in an Android emulator.
The Developer Menu is disabled in release (production) builds.
Reloading JavaScript #
Instead of recompiling your app every time you make a change, you can reload your app's JavaScript code instantly. To do so, select "Reload" from the Developer Menu. You can also press
Command⌘+Rin the iOS Simulator, or pressRtwice on Android emulators.If the
Command⌘+Rkeyboard shortcut does not seem to reload the iOS Simulator, go to the Hardware menu, select Keyboard, and make sure that "Connect Hardware Keyboard" is checked.Automatic reloading #
You can speed up your development times by having your app reload automatically any time your code changes. Automatic reloading can be enabled by selecting "Enable Live Reload" from the Developer Menu.
You may even go a step further and keep your app running as new versions of your files are injected into the JavaScript bundle automatically by enabling Hot Reloading from the Developer Menu. This will allow you to persist the app's state through reloads.
There are some instances where hot reloading cannot be implemented perfectly. If you run into any issues, use a full reload to reset your app.
You will need to rebuild your app for changes to take effect in certain situations:
- You have added new resources to your native app's bundle, such as an image in
Images.xcassetson iOS or theres/drawablefolder on Android. - You have modified native code (Objective-C/Swift on iOS or Java/C++ on Android).
In-app Errors and Warnings #
Errors and warnings are displayed inside your app in development builds.
Errors #
In-app errors are displayed in a full screen alert with a red background inside your app. This screen is known as a RedBox. You can use
console.error()to manually trigger one.Warnings #
Warnings will be displayed on screen with a yellow background. These alerts are known as YellowBoxes. Click on the alerts to show more information or to dismiss them.
As with a RedBox, you can use
console.warn()to trigger a YellowBox.YellowBoxes can be disabled during development by using
console.disableYellowBox = true;. Specific warnings can be ignored programmatically by setting an array of prefixes that should be ignored:console.ignoredYellowBox = ['Warning: ...'];.In CI/Xcode, YellowBoxes can also be disabled by setting the
IS_TESTINGenvironment variable.RedBoxes and YellowBoxes are automatically disabled in release (production) builds.
Accessing console logs #
You can display the console logs for an iOS or Android app by using the following commands in a terminal while the app is running:
$ react-native log-ios +Debugging Debugging #
Accessing the In-App Developer Menu #
You can access the developer menu by shaking your device or by selecting "Shake Gesture" inside the Hardware menu in the iOS Simulator. You can also use the
Command⌘+Dkeyboard shortcut when your app is running in the iPhone Simulator, orCommand⌘+Mwhen running in an Android emulator.The Developer Menu is disabled in release (production) builds.
Reloading JavaScript #
Instead of recompiling your app every time you make a change, you can reload your app's JavaScript code instantly. To do so, select "Reload" from the Developer Menu. You can also press
Command⌘+Rin the iOS Simulator, or pressRtwice on Android emulators.If the
Command⌘+Rkeyboard shortcut does not seem to reload the iOS Simulator, go to the Hardware menu, select Keyboard, and make sure that "Connect Hardware Keyboard" is checked.Automatic reloading #
You can speed up your development times by having your app reload automatically any time your code changes. Automatic reloading can be enabled by selecting "Enable Live Reload" from the Developer Menu.
You may even go a step further and keep your app running as new versions of your files are injected into the JavaScript bundle automatically by enabling Hot Reloading from the Developer Menu. This will allow you to persist the app's state through reloads.
There are some instances where hot reloading cannot be implemented perfectly. If you run into any issues, use a full reload to reset your app.
You will need to rebuild your app for changes to take effect in certain situations:
- You have added new resources to your native app's bundle, such as an image in
Images.xcassetson iOS or theres/drawablefolder on Android. - You have modified native code (Objective-C/Swift on iOS or Java/C++ on Android).
In-app Errors and Warnings #
Errors and warnings are displayed inside your app in development builds.
Errors #
In-app errors are displayed in a full screen alert with a red background inside your app. This screen is known as a RedBox. You can use
console.error()to manually trigger one.Warnings #
Warnings will be displayed on screen with a yellow background. These alerts are known as YellowBoxes. Click on the alerts to show more information or to dismiss them.
As with a RedBox, you can use
console.warn()to trigger a YellowBox.YellowBoxes can be disabled during development by using
console.disableYellowBox = true;. Specific warnings can be ignored programmatically by setting an array of prefixes that should be ignored:console.ignoredYellowBox = ['Warning: ...'];.In CI/Xcode, YellowBoxes can also be disabled by setting the
IS_TESTINGenvironment variable.RedBoxes and YellowBoxes are automatically disabled in release (production) builds.
Accessing console logs #
You can display the console logs for an iOS or Android app by using the following commands in a terminal while the app is running:
$ react-native log-ios $ react-native log-androidYou may also access these through
Debug → Open System Log...in the iOS Simulator or by runningadb logcat *:S ReactNative:V ReactNativeJS:Vin a terminal while an Android app is running on a device or emulator.Chrome Developer Tools #
To debug the JavaScript code in Chrome, select "Debug JS Remotely" from the Developer Menu. This will open a new tab at http://localhost:8081/debugger-ui.
Select
Tools → Developer Toolsfrom the Chrome Menu to open the Developer Tools. You may also access the DevTools using keyboard shortcuts (Command⌘+Option⌥+Ion Mac,Ctrl+Shift+Ion Windows). You may also want to enable Pause On Caught Exceptions for a better debugging experience.It is currently not possible to use the "React" tab in the Chrome Developer Tools to inspect app widgets. You can use Nuclide's "React Native Inspector" as a workaround.
Debugging on a device with Chrome Developer Tools #
On iOS devices, open the file
RCTWebSocketExecutor.mand change "localhost" to the IP address of your computer, then select "Debug JS Remotely" from the Developer Menu.On Android 5.0+ devices connected via USB, you can use the
adbcommand line tool to setup port forwarding from the device to your computer:adb reverse tcp:8081 tcp:8081Alternatively, select "Dev Settings" from the Developer Menu, then update the "Debug server host for device" setting to match the IP address of your computer.
If you run into any issues, it may be possible that one of your Chrome extensions is interacting in unexpected ways with the debugger. Try disabling all of your extensions and re-enabling them one-by-one until you find the problematic extension.
Debugging using a custom JavaScript debugger #
To use a custom JavaScript debugger in place of Chrome Developer Tools, set the
REACT_DEBUGGERenvironment variable to a command that will start your custom debugger. You can then select "Debug JS Remotely" from the Developer Menu to start debugging.The debugger will receive a list of all project roots, separated by a space. For example, if you set
REACT_DEBUGGER="node /path/to/launchDebugger.js --port 2345 --type ReactNative", then the commandnode /path/to/launchDebugger.js --port 2345 --type ReactNative /path/to/reactNative/appwill be used to start your debugger.Custom debugger commands executed this way should be short-lived processes, and they shouldn't produce more than 200 kilobytes of output.
Debugging with Stetho on Android #
In
android/app/build.gradle, add these lines in thedependenciessection:compile 'com.facebook.stetho:stetho:1.3.1' compile 'com.facebook.stetho:stetho-okhttp3:1.3.1'In
android/app/src/main/java/com/{yourAppName}/MainApplication.java, add the following imports:import com.facebook.react.modules.network.ReactCookieJarContainer; import com.facebook.stetho.Stetho; @@ -16,7 +16,7 @@ import java.util.addNetworkInterceptor(new StethoInterceptor()) .build(); OkHttpClientProvider.replaceOkHttpClient(client); -}Run
react-native run-androidIn a new chrome tab, open :
chrome://inspect, click on 'Inspect device' (the one followed by "Powered by Stetho")
Debugging native code #
When working with native code (e.g. when writing native modules) you can launch the app from Android Studio or Xcode and take advantage of the debugging features (setup breakpoints, etc.) as you would in case of building a standard native app.
Performance Monitor #
You can enable a performance overlay to help you debug performance problems by selecting "Perf Monitor" in the Developer Menu.
You can edit the content above on GitHub and send us a pull request!
Dimensions #
Methods #
static set(dims) #
This should only be called from native code by sending the +
Dimensions Dimensions #
Methods #
static set(dims) #
This should only be called from native code by sending the didUpdateDimensions event.
@param {object} dims Simple string-keyed object of dimensions to set
static get(dim) #
Initial dimensions are set before
runApplicationis called so they should be available before any other require's are run, but may be updated later.Note: Although dimensions are available immediately, they may change (e.g due to device rotation) so any rendering logic or styles that depend on diff --git a/releases/next/docs/direct-manipulation.html b/releases/next/docs/direct-manipulation.html index f46bd5e991d..2aacf63e43f 100644 --- a/releases/next/docs/direct-manipulation.html +++ b/releases/next/docs/direct-manipulation.html @@ -1,4 +1,4 @@ -
Direct Manipulation Direct Manipulation #
It is sometimes necessary to make changes directly to a component +
Direct Manipulation Direct Manipulation #
It is sometimes necessary to make changes directly to a component without using state/props to trigger a re-render of the entire subtree. When using React in the browser for example, you sometimes need to directly modify a DOM node, and the same is true for views in mobile @@ -136,7 +136,7 @@ the jerky animation each 250ms when
setStatetriggers a re-render.<shouldComponentUpdateyou can avoid the unnecessary overhead involved in reconciling unchanged component subtrees, to the point where it may be performant enough to -usesetStateinstead ofsetNativeProps.You can edit the content above on GitHub and send us a pull request!
DrawerLayoutAndroid #
React component that wraps the platform
DrawerLayout(Android only). The +DrawerLayoutAndroid DrawerLayoutAndroid #
React component that wraps the platform
DrawerLayout(Android only). The Drawer (typically used for navigation) is rendered withrenderNavigationViewand direct children are the main view (where your content goes). The navigation view is initially not visible on the screen, but can be pulled in from the diff --git a/releases/next/docs/easing.html b/releases/next/docs/easing.html index 4a17a019938..6ee3ca427e7 100644 --- a/releases/next/docs/easing.html +++ b/releases/next/docs/easing.html @@ -1,4 +1,4 @@ -Easing