I'm trying to measure a view using a ref
, but the width
returned is 0 despite the fact that I see the view displayed on the screen (and it's far from being equal to 0).
I tried to follow this : https://github.com/facebook/react-native/issues/953 but it just doesn't work ... I just want to get the actual width of the View.
Here is my code :
var Time = React.createClass({
getInitialState: function() {
return({ progressMaxSize: 0 });
},
componentDidMount: function() {
this.measureProgressBar();
},
measureProgressBar: function() {
this.refs.progressBar.measure(this.setWidthProgressMaxSize);
},
setWidthProgressMaxSize: function(ox, oy, width, height, px, py) {
this.setState({ progressMaxSize: width });
},
render: function() {
return(
<View style={listViewStyle.time} ref="progressBar">
<View style={listViewStyle.progressBar} >
<View style={[listViewStyle.progressMax, { width: this.state.progressMaxSize }]}/>
</View>
</View>
);
}
});
The styles associated :
time: {
position: 'absolute',
bottom: 5,
left: 5,
right: 5,
backgroundColor: '#325436',
flexDirection: 'row',
},
progressBar: {
flex: 1,
backgroundColor: '#0000AA',
},
progressMax: {
position: 'absolute',
top: 0,
left: 0,
backgroundColor: '#000',
height: 30,
},
To measure view size, no need to use ref at all. You can get it from nativeEvent passed by onLayout.
measureView(event: Object) {
console.log(`*** event: ${JSON.stringify(event.nativeEvent)}`);
// you'll get something like this here:
// {"target":1105,"layout":{"y":0,"width":256,"x":32,"height":54.5}}
}
render() {
return (
<View onLayout={(event) => {this.measureView(event)}} />
);
}