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<html><head><meta charset="utf-8"/><meta http-equiv="X-UA-Compatible" content="IE=edge, chrome=1"/><title>Direct Manipulation · React Native</title><meta name="viewport" content="width=device-width"/><meta name="generator" content="Docusaurus"/><meta property="og:title" content="Direct Manipulation · React Native"/><meta property="og:type" content="website"/><meta property="og:url" content="https://facebook.github.io/react-native/index.html"/><meta property="og:description" content="It is sometimes necessary to make changes directly to a component without using"/><link rel="shortcut icon" href="/react-native/img/favicon.png"/><link rel="stylesheet" href="https://cdn.jsdelivr.net/docsearch.js/1/docsearch.min.css"/><link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.12.0/styles/solarized-dark.min.css"/><link rel="alternate" type="application/atom+xml" href="https://facebook.github.io/blog/atom.xml" title="React Native Blog ATOM Feed"/><link rel="alternate" 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</script></nav></div><div class="container mainContainer"><div class="wrapper"><div class="post"><header class="postHeader"><a class="edit-page-link button" href="https://github.com/facebook/react-native-website/blob/master/website/versioned_docs/version-0.5/direct-manipulation.md" target="_blank">Edit</a><h1>Direct Manipulation</h1></header><article><div><span><p>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 apps. <code>setNativeProps</code> is the React Native
equivalent to setting properties directly on a DOM node.</p>
<blockquote>
<p>Use setNativeProps when frequent re-rendering creates a performance bottleneck</p>
<p>Direct manipulation will not be a tool that you reach for frequently; you will
typically only be using it for creating continuous animations to avoid the
overhead of rendering the component hierarchy and reconciling many views.
<code>setNativeProps</code> is imperative and stores state in the native layer (DOM,
UIView, etc.) and not within your React components, which makes your code more
difficult to reason about. Before you use it, try to solve your problem with
<code>setState</code> and
<a href="http://facebook.github.io/react/advanced-performance.md#shouldcomponentupdate-in-action">shouldComponentUpdate</a>.</p>
</blockquote>
<h2><a class="anchor" aria-hidden="true" name="setnativeprops-with-touchableopacity"></a><a href="#setnativeprops-with-touchableopacity" aria-hidden="true" class="hash-link" ><svg aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>setNativeProps with TouchableOpacity</h2>
<p><a href="https://github.com/facebook/react-native/blob/master/Libraries/Components/Touchable/TouchableOpacity.js">TouchableOpacity</a>
uses <code>setNativeProps</code> internally to update the opacity of its child component:</p>
<pre><code class="hljs css javascript">setOpacityTo(value) {
<span class="hljs-comment">// Redacted: animation related code</span>
<span class="hljs-keyword">this</span>.refs[CHILD_REF].setNativeProps({
<span class="hljs-attr">opacity</span>: value
});
},
</code></pre>
<p>This allows us to write the following code and know that the child will have its
opacity updated in response to taps, without the child having any knowledge of
that fact or requiring any changes to its implementation:</p>
<pre><code class="hljs css javascript">&lt;TouchableOpacity onPress={this._handlePress}&gt;
&lt;View style={styles.button}&gt;
&lt;Text&gt;Press me!&lt;/Text&gt;
&lt;/View&gt;
&lt;/TouchableOpacity&gt;;
</code></pre>
<p>Let's imagine that <code>setNativeProps</code> was not available. One way that we might
implement it with that constraint is to store the opacity value in the state,
then update that value whenever <code>onPress</code> is fired:</p>
<pre><code class="hljs css javascript"><span class="hljs-keyword">constructor</span>(props) {
<span class="hljs-keyword">super</span>(props);
<span class="hljs-keyword">this</span>.state = { <span class="hljs-attr">myButtonOpacity</span>: <span class="hljs-number">1</span>, };
}
render() {
<span class="hljs-keyword">return</span> (
<span class="xml"><span class="hljs-tag">&lt;<span class="hljs-name">TouchableOpacity</span> <span class="hljs-attr">onPress</span>=<span class="hljs-string">{()</span> =&gt;</span> this.setState({myButtonOpacity: 0.5})}
onPressOut={() =&gt; this.setState({myButtonOpacity: 1})}&gt;
<span class="hljs-tag">&lt;<span class="hljs-name">View</span> <span class="hljs-attr">style</span>=<span class="hljs-string">{[styles.button,</span> {<span class="hljs-attr">opacity:</span> <span class="hljs-attr">this.state.myButtonOpacity</span>}]}&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">Text</span>&gt;</span>Press me!<span class="hljs-tag">&lt;/<span class="hljs-name">Text</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">View</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">TouchableOpacity</span>&gt;</span></span>
)
}
</code></pre>
<p>This is computationally intensive compared to the original example - React needs
to re-render the component hierarchy each time the opacity changes, even though
other properties of the view and its children haven't changed. Usually this
overhead isn't a concern but when performing continuous animations and
responding to gestures, judiciously optimizing your components can improve your
animations' fidelity.</p>
<p>If you look at the implementation of <code>setNativeProps</code> in
<a href="https://github.com/facebook/react/blob/master/src/renderers/native/NativeMethodsMixin.js">NativeMethodsMixin.js</a>
you will notice that it is a wrapper around <code>RCTUIManager.updateView</code> - this is
the exact same function call that results from re-rendering - see
<a href="https://github.com/facebook/react/blob/master/src/renderers/native/ReactNativeBaseComponent.js">receiveComponent in ReactNativeBaseComponent.js</a>.</p>
<h2><a class="anchor" aria-hidden="true" name="composite-components-and-setnativeprops"></a><a href="#composite-components-and-setnativeprops" aria-hidden="true" class="hash-link" ><svg aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Composite components and setNativeProps</h2>
<p>Composite components are not backed by a native view, so you cannot call
<code>setNativeProps</code> on them. Consider this example:</p>
<div class="snack-player"><div class="mobile-friendly-snack" style="display: none"><pre><code class="hljs css javascript"><span class="hljs-keyword">import</span> React <span class="hljs-keyword">from</span> <span class="hljs-string">'react'</span>;
<span class="hljs-keyword">import</span> { Text, TouchableOpacity, View } <span class="hljs-keyword">from</span> <span class="hljs-string">'react-native'</span>;
<span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">MyButton</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">React</span>.<span class="hljs-title">Component</span> </span>{
render() {
<span class="hljs-keyword">return</span> (
<span class="xml"><span class="hljs-tag">&lt;<span class="hljs-name">View</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">Text</span>&gt;</span>{this.props.label}<span class="hljs-tag">&lt;/<span class="hljs-name">Text</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">View</span>&gt;</span></span>
)
}
}
<span class="hljs-keyword">export</span> <span class="hljs-keyword">default</span> <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">App</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">React</span>.<span class="hljs-title">Component</span> </span>{
render() {
<span class="hljs-keyword">return</span> (
<span class="xml"><span class="hljs-tag">&lt;<span class="hljs-name">TouchableOpacity</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">MyButton</span> <span class="hljs-attr">label</span>=<span class="hljs-string">"Press me!"</span> /&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">TouchableOpacity</span>&gt;</span>
)
}
}
</span></code></pre></div><div class="desktop-friendly-snack" style="margin-top: 15px; margin-bottom: 15px"><div
data-snack-name="setNativeProps with Composite Components"
data-snack-description="Example usage"
data-snack-code="import%20React%20from%20'react'%3B%0Aimport%20%7B%20Text%2C%20TouchableOpacity%2C%20View%20%7D%20from%20'react-native'%3B%0A%0Aclass%20MyButton%20extends%20React.Component%20%7B%0A%20%20render()%20%7B%0A%20%20%20%20return%20(%0A%20%20%20%20%20%20%3CView%3E%0A%20%20%20%20%20%20%20%20%3CText%3E%7Bthis.props.label%7D%3C%2FText%3E%0A%20%20%20%20%20%20%3C%2FView%3E%0A%20%20%20%20)%0A%20%20%7D%0A%7D%0A%0Aexport%20default%20class%20App%20extends%20React.Component%20%7B%0A%20%20render()%20%7B%0A%20%20%20%20return%20(%0A%20%20%20%20%20%20%3CTouchableOpacity%3E%0A%20%20%20%20%20%20%20%20%3CMyButton%20label%3D%22Press%20me!%22%20%2F%3E%0A%20%20%20%20%20%20%3C%2FTouchableOpacity%3E%0A%20%20%20%20)%0A%20%20%7D%0A%7D%0A"
data-snack-platform="ios"
data-snack-preview="true"
data-snack-sdk-version="23.0.0"
style="
overflow: hidden;
background: #fafafa;
border: 1px solid rgba(0,0,0,.16);
border-radius: 4px;
height: 514px;
width: 880px;
"
></div></div></div><p>If you run this you will immediately see this error: <code>Touchable child must either be native or forward setNativeProps to a native component</code>. This occurs
because <code>MyButton</code> isn't directly backed by a native view whose opacity should
be set. You can think about it like this: if you define a component with
<code>createReactClass</code> you would not expect to be able to set a style prop on it and
have that work - you would need to pass the style prop down to a child, unless
you are wrapping a native component. Similarly, we are going to forward
<code>setNativeProps</code> to a native-backed child component.</p>
<h4><a class="anchor" aria-hidden="true" name="forward-setnativeprops-to-a-child"></a><a href="#forward-setnativeprops-to-a-child" aria-hidden="true" class="hash-link" ><svg aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Forward setNativeProps to a child</h4>
<p>All we need to do is provide a <code>setNativeProps</code> method on our component that
calls <code>setNativeProps</code> on the appropriate child with the given arguments.</p>
<div class="snack-player"><div class="mobile-friendly-snack" style="display: none"><pre><code class="hljs css javascript"><span class="hljs-keyword">import</span> React <span class="hljs-keyword">from</span> <span class="hljs-string">'react'</span>;
<span class="hljs-keyword">import</span> { Text, TouchableOpacity, View } <span class="hljs-keyword">from</span> <span class="hljs-string">'react-native'</span>;
<span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">MyButton</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">React</span>.<span class="hljs-title">Component</span> </span>{
setNativeProps = <span class="hljs-function">(<span class="hljs-params">nativeProps</span>) =&gt;</span> {
<span class="hljs-keyword">this</span>._root.setNativeProps(nativeProps);
}
render() {
<span class="hljs-keyword">return</span> (
<span class="xml"><span class="hljs-tag">&lt;<span class="hljs-name">View</span> <span class="hljs-attr">ref</span>=<span class="hljs-string">{component</span> =&gt;</span> this._root = component} {...this.props}&gt;
<span class="hljs-tag">&lt;<span class="hljs-name">Text</span>&gt;</span>{this.props.label}<span class="hljs-tag">&lt;/<span class="hljs-name">Text</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">View</span>&gt;</span></span>
)
}
}
<span class="hljs-keyword">export</span> <span class="hljs-keyword">default</span> <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">App</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">React</span>.<span class="hljs-title">Component</span> </span>{
render() {
<span class="hljs-keyword">return</span> (
<span class="xml"><span class="hljs-tag">&lt;<span class="hljs-name">TouchableOpacity</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">MyButton</span> <span class="hljs-attr">label</span>=<span class="hljs-string">"Press me!"</span> /&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">TouchableOpacity</span>&gt;</span>
)
}
}
</span></code></pre></div><div class="desktop-friendly-snack" style="margin-top: 15px; margin-bottom: 15px"><div
data-snack-name="Forwarding setNativeProps"
data-snack-description="Example usage"
data-snack-code="import%20React%20from%20'react'%3B%0Aimport%20%7B%20Text%2C%20TouchableOpacity%2C%20View%20%7D%20from%20'react-native'%3B%0A%0Aclass%20MyButton%20extends%20React.Component%20%7B%0A%20%20setNativeProps%20%3D%20(nativeProps)%20%3D%3E%20%7B%0A%20%20%20%20this._root.setNativeProps(nativeProps)%3B%0A%20%20%7D%0A%0A%20%20render()%20%7B%0A%20%20%20%20return%20(%0A%20%20%20%20%20%20%3CView%20ref%3D%7Bcomponent%20%3D%3E%20this._root%20%3D%20component%7D%20%7B...this.props%7D%3E%0A%20%20%20%20%20%20%20%20%3CText%3E%7Bthis.props.label%7D%3C%2FText%3E%0A%20%20%20%20%20%20%3C%2FView%3E%0A%20%20%20%20)%0A%20%20%7D%0A%7D%0A%0Aexport%20default%20class%20App%20extends%20React.Component%20%7B%0A%20%20render()%20%7B%0A%20%20%20%20return%20(%0A%20%20%20%20%20%20%3CTouchableOpacity%3E%0A%20%20%20%20%20%20%20%20%3CMyButton%20label%3D%22Press%20me!%22%20%2F%3E%0A%20%20%20%20%20%20%3C%2FTouchableOpacity%3E%0A%20%20%20%20)%0A%20%20%7D%0A%7D%0A"
data-snack-platform="ios"
data-snack-preview="true"
data-snack-sdk-version="23.0.0"
style="
overflow: hidden;
background: #fafafa;
border: 1px solid rgba(0,0,0,.16);
border-radius: 4px;
height: 514px;
width: 880px;
"
></div></div></div><p>You can now use <code>MyButton</code> inside of <code>TouchableOpacity</code>! A sidenote for clarity:
we used the
<a href="https://facebook.github.io/react/more-about-refs.md#the-ref-callback-attribute">ref callback</a>
syntax here, rather than the traditional string-based ref.</p>
<p>You may have noticed that we passed all of the props down to the child view
using <code>{...this.props}</code>. The reason for this is that <code>TouchableOpacity</code> is
actually a composite component, and so in addition to depending on
<code>setNativeProps</code> on its child, it also requires that the child perform touch
handling. To do this, it passes on
<a href="/react-native/docs/view.html#onmoveshouldsetresponder">various props</a> that call back to the
<code>TouchableOpacity</code> component. <code>TouchableHighlight</code>, in contrast, is backed by a
native view and only requires that we implement <code>setNativeProps</code>.</p>
<h2><a class="anchor" aria-hidden="true" name="setnativeprops-to-clear-textinput-value"></a><a href="#setnativeprops-to-clear-textinput-value" aria-hidden="true" class="hash-link" ><svg aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>setNativeProps to clear TextInput value</h2>
<p>Another very common use case of <code>setNativeProps</code> is to clear the value of a
TextInput. The <code>controlled</code> prop of TextInput can sometimes drop characters when
the <code>bufferDelay</code> is low and the user types very quickly. Some developers prefer
to skip this prop entirely and instead use <code>setNativeProps</code> to directly
manipulate the TextInput value when necessary. For example, the following code
demonstrates clearing the input when you tap a button:</p>
<div class="snack-player"><div class="mobile-friendly-snack" style="display: none"><pre><code class="hljs css javascript"><span class="hljs-keyword">import</span> React <span class="hljs-keyword">from</span> <span class="hljs-string">'react'</span>;
<span class="hljs-keyword">import</span> { TextInput, Text, TouchableOpacity, View } <span class="hljs-keyword">from</span> <span class="hljs-string">'react-native'</span>;
<span class="hljs-keyword">export</span> <span class="hljs-keyword">default</span> <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">App</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">React</span>.<span class="hljs-title">Component</span> </span>{
clearText = <span class="hljs-function"><span class="hljs-params">()</span> =&gt;</span> {
<span class="hljs-keyword">this</span>._textInput.setNativeProps({<span class="hljs-attr">text</span>: <span class="hljs-string">''</span>});
}
render() {
<span class="hljs-keyword">return</span> (
<span class="xml"><span class="hljs-tag">&lt;<span class="hljs-name">View</span> <span class="hljs-attr">style</span>=<span class="hljs-string">{{flex:</span> <span class="hljs-attr">1</span>}}&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">TextInput</span>
<span class="hljs-attr">ref</span>=<span class="hljs-string">{component</span> =&gt;</span> this._textInput = component}
style={{height: 50, flex: 1, marginHorizontal: 20, borderWidth: 1, borderColor: '#ccc'}}
/&gt;
<span class="hljs-tag">&lt;<span class="hljs-name">TouchableOpacity</span> <span class="hljs-attr">onPress</span>=<span class="hljs-string">{this.clearText}</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">Text</span>&gt;</span>Clear text<span class="hljs-tag">&lt;/<span class="hljs-name">Text</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">TouchableOpacity</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">View</span>&gt;</span>
);
}
}
</span></code></pre></div><div class="desktop-friendly-snack" style="margin-top: 15px; margin-bottom: 15px"><div
data-snack-name="Clear text"
data-snack-description="Example usage"
data-snack-code="import%20React%20from%20'react'%3B%0Aimport%20%7B%20TextInput%2C%20Text%2C%20TouchableOpacity%2C%20View%20%7D%20from%20'react-native'%3B%0A%0Aexport%20default%20class%20App%20extends%20React.Component%20%7B%0A%20%20clearText%20%3D%20()%20%3D%3E%20%7B%0A%20%20%20%20this._textInput.setNativeProps(%7Btext%3A%20''%7D)%3B%0A%20%20%7D%0A%0A%20%20render()%20%7B%0A%20%20%20%20return%20(%0A%20%20%20%20%20%20%3CView%20style%3D%7B%7Bflex%3A%201%7D%7D%3E%0A%20%20%20%20%20%20%20%20%3CTextInput%0A%20%20%20%20%20%20%20%20%20%20ref%3D%7Bcomponent%20%3D%3E%20this._textInput%20%3D%20component%7D%0A%20%20%20%20%20%20%20%20%20%20style%3D%7B%7Bheight%3A%2050%2C%20flex%3A%201%2C%20marginHorizontal%3A%2020%2C%20borderWidth%3A%201%2C%20borderColor%3A%20'%23ccc'%7D%7D%0A%20%20%20%20%20%20%20%20%2F%3E%0A%20%20%20%20%20%20%20%20%3CTouchableOpacity%20onPress%3D%7Bthis.clearText%7D%3E%0A%20%20%20%20%20%20%20%20%20%20%3CText%3EClear%20text%3C%2FText%3E%0A%20%20%20%20%20%20%20%20%3C%2FTouchableOpacity%3E%0A%20%20%20%20%20%20%3C%2FView%3E%0A%20%20%20%20)%3B%0A%20%20%7D%0A%7D%0A"
data-snack-platform="ios"
data-snack-preview="true"
data-snack-sdk-version="23.0.0"
style="
overflow: hidden;
background: #fafafa;
border: 1px solid rgba(0,0,0,.16);
border-radius: 4px;
height: 514px;
width: 880px;
"
></div></div></div><h2><a class="anchor" aria-hidden="true" name="avoiding-conflicts-with-the-render-function"></a><a href="#avoiding-conflicts-with-the-render-function" aria-hidden="true" class="hash-link" ><svg aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Avoiding conflicts with the render function</h2>
<p>If you update a property that is also managed by the render function, you might
end up with some unpredictable and confusing bugs because anytime the component
re-renders and that property changes, whatever value was previously set from
<code>setNativeProps</code> will be completely ignored and overridden.</p>
<h2><a class="anchor" aria-hidden="true" name="setnativeprops-shouldcomponentupdate"></a><a href="#setnativeprops-shouldcomponentupdate" aria-hidden="true" class="hash-link" ><svg aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>setNativeProps &amp; shouldComponentUpdate</h2>
<p>By
<a href="https://facebook.github.io/react/advanced-performance.md#avoiding-reconciling-the-dom">intelligently applying <code>shouldComponentUpdate</code></a>
you can avoid the unnecessary overhead involved in reconciling unchanged
component subtrees, to the point where it may be performant enough to use
<code>setState</code> instead of <code>setNativeProps</code>.</p>
<h2><a class="anchor" aria-hidden="true" name="other-native-methods"></a><a href="#other-native-methods" aria-hidden="true" class="hash-link" ><svg aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Other native methods</h2>
<p>The methods described here are available on most of the default components
provided by React Native. Note, however, that they are <em>not</em> available on
composite components that aren't directly backed by a native view. This will
generally include most components that you define in your own app.</p>
<h3><a class="anchor" aria-hidden="true" name="measurecallback"></a><a href="#measurecallback" aria-hidden="true" class="hash-link" ><svg aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>measure(callback)</h3>
<p>Determines the location on screen, width, and height of the given view and
returns the values via an async callback. If successful, the callback will be
called with the following arguments:</p>
<ul>
<li>x</li>
<li>y</li>
<li>width</li>
<li>height</li>
<li>pageX</li>
<li>pageY</li>
</ul>
<p>Note that these measurements are not available until after the rendering has
been completed in native. If you need the measurements as soon as possible,
consider using the <a href="/react-native/docs/view.html#onlayout"><code>onLayout</code> prop</a> instead.</p>
<h3><a class="anchor" aria-hidden="true" name="measureinwindowcallback"></a><a href="#measureinwindowcallback" aria-hidden="true" class="hash-link" ><svg aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>measureInWindow(callback)</h3>
<p>Determines the location of the given view in the window and returns the values
via an async callback. If the React root view is embedded in another native
view, this will give you the absolute coordinates. If successful, the callback
will be called with the following arguments:</p>
<ul>
<li>x</li>
<li>y</li>
<li>width</li>
<li>height</li>
</ul>
<h3><a class="anchor" aria-hidden="true" name="measurelayoutrelativetonativenode-onsuccess-onfail"></a><a href="#measurelayoutrelativetonativenode-onsuccess-onfail" aria-hidden="true" class="hash-link" ><svg aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>measureLayout(relativeToNativeNode, onSuccess, onFail)</h3>
<p>Like <code>measure()</code>, but measures the view relative an ancestor, specified as
<code>relativeToNativeNode</code>. This means that the returned x, y are relative to the
origin x, y of the ancestor view.</p>
<p>As always, to obtain a native node handle for a component, you can use
<code>ReactNative.findNodeHandle(component)</code>.</p>
<h3><a class="anchor" aria-hidden="true" name="focus"></a><a href="#focus" aria-hidden="true" class="hash-link" ><svg aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>focus()</h3>
<p>Requests focus for the given input or view. The exact behavior triggered will
depend on the platform and type of view.</p>
<h3><a class="anchor" aria-hidden="true" name="blur"></a><a href="#blur" aria-hidden="true" class="hash-link" ><svg aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>blur()</h3>
<p>Removes focus from an input or view. This is the opposite of <code>focus()</code>.</p>
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