如何在 React Native 中创建拖放操作？

Question

假设我有两个视图，A 和 B。我希望能够在触摸视图 A 时触发 'dragAndDropStart' 事件，然后启用从 A 到 B 的拖放...显示反馈始终向用户显示（即显示视图 A 和用户手指之间出现的一条线）。放下时（释放拖动手势）我想触发另一个 'dragAndDropEnd' 事件，这次是在视图 B 上。

touchStart 和 touchEnd 处理程序过于有限，因为它们似乎不允许将手势从一个视图切换到另一个视图。他们似乎也没有启用中间 'drag' 状态。

关于使用手势处理程序的 React 本机文档有点含糊不清，我还没有看到任何演示其用法的示例。

有什么想法吗？

Answer 1

您必须将当前的视图矩形与其他视图矩形进行对比，如果您的视图矩形之一在某个点彼此相交，它将 return 为真，然后您会收到通知，即 A 视图已拖动到 B 视图这是我的示例代码，可能会对您有所帮助。

-(void)moveViewWithGestureRecognizer:(UIPanGestureRecognizer *)panGestureRecognizer{

// your current View touch location suppose View A
    CGPoint touchLocation = [panGestureRecognizer locationInView:self.contentView];

    CGRect movingAViewRect = CGRectMake(touchLocation.x, touchLocation.y, self.aView.width, self.aView.height);

 //   NSLog(@"Point not Matched first => %@  and second => %@",NSStringFromCGPoint(touchLocation),NSStringFromCGPoint(self.bView.frame.origins));
    self.aView.center = touchLocation;
      

    if(panGestureRecognizer.state == UIGestureRecognizerStateEnded)
    {
        //All fingers are lifted.
      
    

        if(CGRectIntersectsRect(movingAViewRect,self.bView.frame)){
     
            NSLog(@"Point Matched first => %@  and second => %@",NSStringFromCGRect(movingAViewRect),NSStringFromCGRect (self.bView.frame ));

       // and here you can perform some action for this 
            
            
        }else{
        
            NSLog(@"aView is not drag on bView please drag aView to bView ");
            

        }
      
        
     
       
    }
}

Answer 2

export default class Viewport extends Component{
    constructor(props){
        super(props);

        this.state = {
            showDraggable   : true,
            dropZoneValues  : null,
            pan             : new Animated.ValueXY()
        };

        this.panResponder = PanResponder.create({
            onStartShouldSetPanResponder    : () => true,
            onPanResponderMove              : Animated.event([null,{
                dx  : this.state.pan.x,
                dy  : this.state.pan.y
            }]),
            onPanResponderRelease           : (e, gesture) => {
                if(this.isDropZone(gesture)){
                    this.setState({
                        showDraggable : false
                    });
                }else{
                    Animated.spring(
                        this.state.pan,
                        {toValue:{x:0,y:0}}
                    ).start();
                }
            }
        });
    }

    isDropZone(gesture){
        var dz = this.state.dropZoneValues;
        return gesture.moveY > dz.y && gesture.moveY < dz.y + dz.height;
    }

    setDropZoneValues(event){
        this.setState({
            dropZoneValues : event.nativeEvent.layout
        });
    }

    render(){
        return (
            <View style={styles.mainContainer}>
                <View 
                    onLayout={this.setDropZoneValues.bind(this)}
                    style={styles.dropZone}>
                    <Text style={styles.text}>Drop me here!</Text>
                </View>

                {this.renderDraggable()}
            </View>
        );
    }

    renderDraggable(){
        if(this.state.showDraggable){
            return (
                <View style={styles.draggableContainer}>
                    <Animated.View 
                        {...this.panResponder.panHandlers}
                        style={[this.state.pan.getLayout(), styles.circle]}>
                        <Text style={styles.text}>Drag me!</Text>
                    </Animated.View>
                </View>
            );
        }
    }
}

来源http://moduscreate.com/animated_drag_and_drop_with_react_native/

https://github.com/crysfel/DragAndDrop

如何在 React Native 中创建拖放操作？

How can I create a drag and drop action in React native?

drag-and-drop

gesture

ios

react-native