我使用 onPress "handler" 渲染了下面这种列表:
我发现 onPress 处理程序是无用的,因为我无法获取被选中的比赛的参考。我得到了“ref未定义”的错误。
var races = Engine.possibleRaces;
function racePressed(ref) {
console.log("REF: " + ref); // is never called
}
var races = Engine.possibleRaces;
var rowViews = [];
for (var i = 0; i < races.length; i++) {
rowViews.push(
<Text
ref={i}
onPress={() => racePressed(ref)} // ref is not defined
style={styles.raceText}>{races[i].text}
</Text>
);
}
<View style={{width: Screen.width, flexDirection:'row', flexWrap: 'wrap', alignItems: "center"}}>
{rowViews}
</View>
我尝试将i作为参数传递,但不起作用,因为它在迭代结束后才有值。基本上,它具有races.length的值。
onPress={() => racePressed(i)} // Same as races.length
编辑:
我已经将问题隔离到以下程序中。
'use strict';
import React, {
AppRegistry,
Component,
StyleSheet,
Text,
View
} from 'react-native';
let texts = [{text: "Click wrapper text1"}, {text: "Click wrapper text2"}];
class sandbox extends Component {
rowPressed(ref, i) {
console.log("rowPressed: " + ref + " " + i)
}
render() {
var rows = [];
for (var i = 0; i < texts.length; i++) {
rows.push(
<Text
ref={i}
onPress={() => this.rowPressed.bind(this, i)}
style={styles.raceText}>{texts[i].text}
</Text>
);
}
return (
<View style={styles.container}>
<View>
{rows}
</View>
</View>
);
}
}
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
alignItems: 'center'
}
});
AppRegistry.registerComponent('sandbox', () => sandbox);
除以下警告外,回调没有被调用也没有抛出任何错误。
[tid:com.facebook.React.JavaScript] Warning: Each child in an array or iterator should have a unique "key" prop. Check the render method of `sandbox`. See https://fb.me/react-warning-keys for more information.
render: function() { function rowPressed(id) { // Cannot read property 'state' of undefined this.state.races[id].chosen != this.state.races[id].chosen; } this.rowPressed = this.rowPressed.bind(this); ... onPress={() => rowPressed(i)}
- Markku