154 lines
4.1 KiB
JavaScript
154 lines
4.1 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
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*/
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'use strict';
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var React = require('react');
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var ReactNative = require('react-native');
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var {Image, LayoutAnimation, StyleSheet, Text, View} = ReactNative;
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import type {ViewLayout, ViewLayoutEvent} from 'ViewPropTypes';
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type State = {
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containerStyle?: {|width: number|},
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extraText?: string,
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imageLayout?: ViewLayout,
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textLayout?: ViewLayout,
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viewLayout?: ViewLayout,
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viewStyle: {|margin: number|},
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};
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class LayoutEventExample extends React.Component<{}, State> {
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state: State = {
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viewStyle: {
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margin: 20,
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},
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};
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animateViewLayout = () => {
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LayoutAnimation.configureNext(LayoutAnimation.Presets.spring, () => {
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console.log('layout animation done.');
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this.addWrapText();
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});
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this.setState({
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viewStyle: {
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margin: this.state.viewStyle.margin > 20 ? 20 : 60,
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},
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});
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};
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addWrapText = () => {
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this.setState(
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{extraText: ' And a bunch more text to wrap around a few lines.'},
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this.changeContainer,
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);
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};
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changeContainer = () => {
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this.setState({containerStyle: {width: 280}});
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};
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onViewLayout = (e: ViewLayoutEvent) => {
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console.log('received view layout event\n', e.nativeEvent);
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this.setState({viewLayout: e.nativeEvent.layout});
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};
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onTextLayout = (e: ViewLayoutEvent) => {
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console.log('received text layout event\n', e.nativeEvent);
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this.setState({textLayout: e.nativeEvent.layout});
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};
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onImageLayout = (e: ViewLayoutEvent) => {
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console.log('received image layout event\n', e.nativeEvent);
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this.setState({imageLayout: e.nativeEvent.layout});
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};
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render() {
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var viewStyle = [styles.view, this.state.viewStyle];
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var textLayout = this.state.textLayout || {width: '?', height: '?'};
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var imageLayout = this.state.imageLayout || {x: '?', y: '?'};
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return (
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<View style={this.state.containerStyle}>
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<Text>
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layout events are called on mount and whenever layout is recalculated.
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Note that the layout event will typically be received{' '}
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<Text style={styles.italicText}>before</Text> the layout has updated
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on screen, especially when using layout animations.{' '}
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<Text style={styles.pressText} onPress={this.animateViewLayout}>
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Press here to change layout.
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</Text>
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</Text>
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<View ref="view" onLayout={this.onViewLayout} style={viewStyle}>
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<Image
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ref="img"
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onLayout={this.onImageLayout}
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style={styles.image}
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source={{
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uri:
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'https://fbcdn-dragon-a.akamaihd.net/hphotos-ak-prn1/t39.1997/p128x128/851561_767334496626293_1958532586_n.png',
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}}
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/>
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<Text>
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ViewLayout:{' '}
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{JSON.stringify(this.state.viewLayout, null, ' ') + '\n\n'}
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</Text>
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<Text ref="txt" onLayout={this.onTextLayout} style={styles.text}>
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A simple piece of text.{this.state.extraText}
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</Text>
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<Text>
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{'\n'}
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Text w/h: {textLayout.width}/{textLayout.height + '\n'}
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Image x/y: {imageLayout.x}/{imageLayout.y}
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</Text>
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</View>
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</View>
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);
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}
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}
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var styles = StyleSheet.create({
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view: {
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padding: 12,
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borderColor: 'black',
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borderWidth: 0.5,
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backgroundColor: 'transparent',
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},
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text: {
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alignSelf: 'flex-start',
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borderColor: 'rgba(0, 0, 255, 0.2)',
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borderWidth: 0.5,
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},
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image: {
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width: 50,
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height: 50,
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marginBottom: 10,
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alignSelf: 'center',
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},
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pressText: {
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fontWeight: 'bold',
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},
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italicText: {
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fontStyle: 'italic',
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},
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});
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exports.title = 'Layout Events';
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exports.description =
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'Examples that show how Layout events can be used to ' +
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'measure view size and position.';
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exports.examples = [
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{
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title: 'LayoutEventExample',
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render: function(): React.Element<any> {
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return <LayoutEventExample />;
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},
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},
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];
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