如何在本机react中发出触摸事件

IT技术 javascript reactjs react-native react-native-android
2021-05-08 01:33:44

我正在尝试启用 panResponder 以拖放模式在屏幕上移动组件。然而,这种拖放必须通过longPress此类元素启动

longPress捕获事件,因此当panResponder启用时onStartShouldSetPanResponder => this.state.panEnabled我们需要再次按下。

我想触发一个本地事件,或者,在不再次按下的情况下激活拖动。是否可以重新发出本地事件?我们可以以任何方式将它传递给 panResponder 吗?

谢谢!

1个回答

我已经在不使用的情况下完成了这项工作longTouch,而只是使用了panResponderlongTouch尽管效果相同),请看:

import React, { Component } from 'react';

import {
    View,
    PanResponder
} from 'react-native';

const LONGPRESS_TIMER = 300;

class DraggableComponent extends Component {
    constructor() {
        super();

        this.timer = null;

        this.state = {
            canMove: false
        }

       this._panResponder = this.setUpPanResponder();

   }
   setUpPanResponder() {

       const self = this;

       return PanResponder.create({
           onStartShouldSetPanResponder: (evt, gestureState) => true,
           onStartShouldSetPanResponderCapture: (evt, gestureState) => true,
           onMoveShouldSetPanResponder: (evt, gestureState) => true,
           onMoveShouldSetPanResponderCapture: (evt, gestureState) => true,
           onPanResponderGrant: (evt, gestureState) => {

               self.timer = setTimeout(() => {
                   self.setState({canMove: true});
               }, LONGPRESS_TIMER);

           },
           onPanResponderMove: (evt, gestureState) => {

               if(this.state.canMove) {
                   console.log('moving', gestureState); 
                   // code to move view here
               }

           },
           onPanResponderTerminationRequest: (evt, gestureState) => true,
           onPanResponderRelease: (evt, gestureState) => {

               clearTimeout(self.timer); 
               self.setState({canMove: false});

           }
       });
   }
   render() {

       return <View 
           style={{
               width: 100, 
               height: 100, 
               backgroundColor: this.state.canMove ? 'green' : 'blue'}} 
               {...this._panResponder.panHandlers} />

   }

}

您可以通过更改LONGPRESS_TIMER常量来调整触发“canMove”状态所需的时间,希望有帮助!