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https://github.com/facebook/react-native.git
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Spencer Ahrens
5ec382d1be
Summary:
Automatically provides and subscribes to dimension updates - super easy usage:
```
function MyComponent(props: Props) {
const {width, height, scale, fontScale} = useWindowDimensions();
return <Text ...
};
```
Only window for now - it's what people want 99% of the time, so we'll just shovel out a pit of success for them...
There are still cases where `Dimensions` is needed outside of React component render functions, like in GraphQL variables, so we need to keep the existing module.
Reviewed By: zackargyle
Differential Revision: D16525189
fbshipit-source-id: 0a049fb3be8d92888a8a69e3898d337b93422a09
36 lines
1.0 KiB
JavaScript
36 lines
1.0 KiB
JavaScript
/**
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @format
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* @flow strict-local
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*/
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'use strict';
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import Dimensions from './Dimensions';
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import {type DisplayMetrics} from './NativeDeviceInfo';
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import * as React from 'react';
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export default function useWindowDimensions(): DisplayMetrics {
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const dims = Dimensions.get('window'); // always read the latest value
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const forceUpdate = React.useState()[1];
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const initialDims = React.useState(dims)[0];
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React.useEffect(() => {
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Dimensions.addEventListener('change', forceUpdate);
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const latestDims = Dimensions.get('window');
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if (latestDims !== initialDims) {
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// We missed an update between calling `get` in render and
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// `addEventListener` in this handler...
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forceUpdate();
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}
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return () => {
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Dimensions.removeEventListener('change', forceUpdate);
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};
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}, [forceUpdate, initialDims]);
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return dims;
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}
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