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Reactjs React native animated.event自定义onScroll侦听器_Reactjs_React Native_Ecmascript 6_Destructuring - Fatal编程技术网

Reactjs React native animated.event自定义onScroll侦听器

Reactjs React native animated.event自定义onScroll侦听器,reactjs,react-native,ecmascript-6,destructuring,Reactjs,React Native,Ecmascript 6,Destructuring,在官方的react native文档中有一个关于动画.event方法的部分。例如,他们使用以下代码: onScroll={Animated.event( // scrollX = e.nativeEvent.contentOffset.x [{ nativeEvent: { contentOffset: { x: scrollX } } }] )} 我想将正确的值映射到Animated.event方法,还想将

在官方的react native文档中有一个关于
动画.event
方法的部分。例如,他们使用以下代码:

onScroll={Animated.event(
   // scrollX = e.nativeEvent.contentOffset.x
   [{ nativeEvent: {
        contentOffset: {
          x: scrollX
        }
      }
    }]
 )}
我想将正确的值映射到
Animated.event
方法,还想将onScroll回调参数映射到我自己的回调。基本上我想这样做:

onScroll={(event) => {
  myOwnCallback(event.nativeEvent.contentOffset.x)
  Animated.event(
    // scrollX = e.nativeEvent.contentOffset.x
    [{nativeEvent: {
        contentOffset: {
          x: scrollX
        }
      }
    }]
  )
}}

您能解释一下怎么做吗?

当您查看源代码时:

/**
   * Takes an array of mappings and extracts values from each arg accordingly,
   * then calls `setValue` on the mapped outputs.  e.g.
   *
   *```javascript
   *  onScroll={Animated.event(
   *    [{nativeEvent: {contentOffset: {x: this._scrollX}}}]
   *    {listener},          // Optional async listener
   *  )
   *  ...
   *  onPanResponderMove: Animated.event([
   *    null,                // raw event arg ignored
   *    {dx: this._panX},    // gestureState arg
   *  ]),
   *```
   *
   * Config is an object that may have the following options:
   *
   *   - `listener`: Optional async listener.
   *   - `useNativeDriver`: Uses the native driver when true. Default false.
   */
  event,
我就是这样做的:

onScroll={Animated.event(
            [{ nativeEvent: { contentOffset: { y: this.state.scrollY } } }],
  {
    useNativeDriver: true,
    listener: event => {
      const offsetY = event.nativeEvent.contentOffset.y
      // do something special
    },
  },
)}

编写处理程序函数,如:

handleScroll=(e)=>{
log(e.nativeEvent.contentOffset.y);
}
您可以像这样添加
listener

onScroll={(event) => {
  myOwnCallback(event.nativeEvent.contentOffset.x)
  Animated.event(
    // scrollX = e.nativeEvent.contentOffset.x
    [{nativeEvent: {
        contentOffset: {
          x: scrollX
        }
      }
    }]
  )
}}
Animated.event(
[{nativeEvent:{contentOffset:{y:this.state.scrollY}}],
{listener:(event)=>this.handleScroll(event)}
)

如何在此处添加函数作为侦听器?我试着把它绑在那里,但似乎没有着火。对此有进一步的解释吗?