PanResponder
PanResponder
PanResponder将几次触摸调和成一个手势。它使单点触摸手势具有弹性，可用于识别简单的多点触摸手势。
默认情况下，PanResponder持有InteractionManager阻止长时间运行的JS事件中断活动手势的句柄。
它提供了姿态响应系统提供的响应者处理程序的可预测包装。对于每个处理程序，它会gestureState在本机事件对象旁边提供一个新对象：
onPanResponderMove: (event, gestureState) => {}
本地事件是以下形式的合成触摸事件：
nativeEvent
一个gestureState对象具有以下内容：
stateID- 只要屏幕上至少有一次触摸，gestureState的ID就会保持
基本用法
componentWillMount: function() {
this._panResponder = PanResponder.create{
// Ask to be the responder:
onStartShouldSetPanResponder: (evt, gestureState) => true,
onStartShouldSetPanResponderCapture: (evt, gestureState) => true,
onMoveShouldSetPanResponder: (evt, gestureState) => true,
onMoveShouldSetPanResponderCapture: (evt, gestureState) => true,
onPanResponderGrant: (evt, gestureState) => {
// The gesture has started. Show visual feedback so the user knows
// what is happening!
// gestureState.d{x,y} will be set to zero now
},
onPanResponderMove: (evt, gestureState) => {
// The most recent move distance is gestureState.move{X,Y}
// The accumulated gesture distance since becoming responder is
// gestureState.d{x,y}
},
onPanResponderTerminationRequest: (evt, gestureState) => true,
onPanResponderRelease: (evt, gestureState) => {
// The user has released all touches while this view is the
// responder. This typically means a gesture has succeeded
},
onPanResponderTerminate: (evt, gestureState) => {
// Another component has become the responder, so this gesture
// should be cancelled
},
onShouldBlockNativeResponder: (evt, gestureState) => {
// Returns whether this component should block native components from becoming the JS
// responder. Returns true by default. Is currently only supported on android.
return true;
},
}
},
render: function() {
return (
<View {...this._panResponder.panHandlers} />
},
工作示例
要查看它的实际运行情况，请尝试使用RNTester中的PanResponder示例
方法
静态创建（配置）
@param {object} config所有响应者回调的增强版本，它们不仅提供了典型的ResponderSyntheticEvent，还提供了PanResponder手势状态。只需更换这个词Responder用PanResponder在每一个典型的onResponder*回调。例如，该config对象看起来像：
- onMoveShouldSetPanResponder: (e, gestureState) => {...}
