PanResponder React本機參數

Question

我的panResponder有問題我的代碼：

componentWillMount() {
    this._panResponder = PanResponder.create({
      onStartShouldSetPanResponder: (evt, gestureState) => false,
      onStartShouldSetPanResponderCapture: (evt, gestureState) => true,
      onMoveShouldSetPanResponder: (evt, gestureState) => Math.abs(gestureState.dy) > 5,
      onMoveShouldSetPanResponderCapture: (evt, gestureState) => true,
      onPanResponderMove: this._handlePanResponderMove,
    });
  }

_handlePanResponderMove(event, gestureState) {
    if (gestureState.dy > current) {
      console.log("Down");
    } else {
      console.log("Up");
    }
    current = gestureState.dy;
  }

componentTag() {
   return tabTag.map((item, id) => {
      return(
        <View key={id} >
            <View {...this._panResponder.panHandlers}>
                <Icon name="ios-reorder" ></Icon>
            </View>
        </View>
      );
    });
}

render() {
   return (
     {this.componentTag}
   );
}

我想知道什么時候我在函數_handlePanResponderMove我的數組的ID的值，但我不能給函數參數

Answer 1

handlePanResponderMove中的event參數為您提供觸摸目標的節點ID。 即Event.nativeEvent.target可以幫助您。

Answer 2

里面你componentTag你使用this關鍵字，要做到這一點，你需要綁定this給你的方法。

您需要一個類似以下的構造函數：

constructor() {
   this.componentTag = this.componentTag.bind(this);

   //since you're using this keyword on componentDidMount as well,
   this.componentWillMount = this.componentWillMount.bind(this);
}