[英]How to get value of child component TextInput of NavigatorIOS in react-native
[英]How to get size of a component in react-native?
我知道有
Dimensions.get('window');
但是没有暗线的任意视图呢? 任意视图可以有许多子视图。 视图的大小由子视图的样式和布局决定,很难从子视图计算大小。
您可以使用此处和此处提到的 onLayout 函数测量视图。 要设置它,您需要调用一个 onLayout 函数,该函数接受一个事件并返回一个包含 nativeEvent 对象的对象。 该对象包含 x & y 坐标,以及视图的宽度和高度。
我已经成立了一个例子项目执行的代码在这里:
https://rnplay.org/apps/mbPdZw
以下是测量视图的简单设置:
'use strict';
var React = require('react-native');
var {
AppRegistry,
StyleSheet,
Text,
View,
TouchableHighlight
} = React;
var SampleApp = React.createClass({
getInitialState() {
return {
x: '',
y: '',
width: '',
height: '',
viewHeight: 100
}
},
measureView(event) {
console.log('event peroperties: ', event);
this.setState({
x: event.nativeEvent.layout.x,
y: event.nativeEvent.layout.y,
width: event.nativeEvent.layout.width,
height: event.nativeEvent.layout.height
})
},
changeHeight() {
this.setState({
viewHeight: 200
})
},
render: function() {
return (
<View >
<View onLayout={(event) => this.measureView(event)} style={{height:this.state.viewHeight, marginTop:120, backgroundColor: 'orange'}}>
<Text >The outer view of this text is being measured!</Text>
<Text>x: {this.state.x}</Text>
<Text>y: {this.state.y}</Text>
<Text>width: {this.state.width}</Text>
<Text>height: {this.state.height}</Text>
</View>
<TouchableHighlight style={{flexDirection:'row', alignItems: 'center', justifyContent: 'center', padding:15, backgroundColor: '#ddd', marginTop:10}} onPress={() => this.changeHeight() }>
<Text style={{fontSize:18}}>Change height of container</Text>
</TouchableHighlight>
</View>
);
}
});
var styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
alignItems: 'center',
backgroundColor: '#F5FCFF',
},
welcome: {
fontSize: 28,
textAlign: 'center',
margin: 10,
}
});
AppRegistry.registerComponent('SampleApp', () => SampleApp);
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