PanResponder 内的 ScrollView

我正在自己实现一个选项卡导航器，并在 React-Native 中滑动。它工作正常，但是当我的一个选项卡中有一个 ScrollView 时，它似乎会损坏。左右滑动来更改选项卡效果很好，并且在滚动视图中向下和向上滚动也可以。当我单击拖动滚动视图，然后向侧面移动而不释放滑动时，它会中断。然后选项卡系统将重置为第一个选项卡。

我做了一个黑客，当滚动视图滚动时，我禁止从选项卡内部滑动。这可行，但感觉像是一个糟糕的解决方案，因为选项卡内容必须知道它位于选项卡内。

import React, { Component, PropTypes } from 'react';
import { connect } from 'react-redux';
import { View, Animated, Dimensions, PanResponder } from 'react-native';
import Immutable from 'immutable';
import Tab1 from './Tab1';
import Tab2 from './Tab2';
import ScrollViewTab from './ScrollViewTab';


@connect(
    state => ({
        tabs: state.tabs
    })
)

export default class Tabs extends Component {
    static propTypes = {
        tabs: PropTypes.instanceOf(Immutable.Map).isRequired,
        dispatch: PropTypes.func.isRequired
    };
    constructor(props) {
        super(props);
        this.justLoaded = true;
        this.state = {
            left: new Animated.Value(0),
            tabs: [{ // Tabs must be in order, despite index.
                name: 'tab1',
                component: <Tab1 setTab={this.setTab} />,
                index: 0
            }, {
                name: 'tab2',
                component: <Tab2 setTab={this.setTab} />,
                index: 1
            }, {
                name: 'scrollViewTab',
                component: <ScrollViewTab setTab={this.setTab} />,
                index: 2
            }]
        };
        this.getIndex = this.getIndex.bind(this);
    }
    componentWillMount() {
        this.panResponder = PanResponder.create({
            onMoveShouldSetResponderCapture: () => true,
            onMoveShouldSetPanResponderCapture: (evt, gestureState) => {
                if (Math.abs(gestureState.dx) > 10) {
                    return true;
                }
                return false;
            },
            onPanResponderGrant: () => {
                this.state.left.setOffset(this.state.left._value);
                this.state.left.setValue(0);
            },
            onPanResponderMove: (e, gestureState) => {
                if (this.isSwipingOverLeftBorder(gestureState) ||
                    this.isSwipingOverRightBorder(gestureState)) return;
                Animated.event([null, {
                    dx: this.state.left
                }])(e, gestureState);
            },
            onPanResponderRelease: (e, gestureState) => {
                this.state.left.flattenOffset();

                if (this.isSwipingOverLeftBorder(gestureState) ||
                    this.isSwipingOverRightBorder(gestureState)) {
                    return;
                }

                Animated.timing(
                    this.state.left,
                    { toValue: this.calcX(gestureState) }
                ).start();
            }
        });
    }
    componentDidMount() {
        this.justLoaded = false;
    }
    getStyle() {
        const oldLeft = this.state.left;
        let left = 0;
        const screenWidth = Dimensions.get('window').width;
        // Set tab carouselle coordinate to match the selected tab.
        this.state.tabs.forEach((tab) => {
            if (tab.name === this.props.tabs.get('tab')) {
                left = -tab.index * screenWidth;
            }
        });


        if (this.justLoaded) {
            Animated.timing(
                this.state.left,
                { toValue: left,
                    duration: 0
                }
            ).start();

            return { transform: [{ translateX: oldLeft }], flexDirection: 'row', height: '100%' };
        }
        Animated.timing(
                this.state.left,
            { toValue: left
            }
            ).start();
        return { transform: [{ translateX: oldLeft }], flexDirection: 'row', height: '100%' };
    }
    getIndex(tabN) {
        let index = 0;

        this.state.tabs.forEach((tab) => {
            if (tab.name === tabN) {
                index = tab.index;
            }
            return tab;
        });

        return index;
    }
    setTab(tab, props) {
        this.navProps = props;
        this.props.dispatch({ type: 'SET_TAB', tab });
    }
    isSwipingOverLeftBorder(gestureState) {
        return (this.props.tabs.get('tab') === this.state.tabs[0].name &&
                gestureState.dx > 0);
    }
    isSwipingOverRightBorder(gestureState) {
        return (this.props.tabs.get('tab') === this.state.tabs[this.state.tabs.length - 1].name &&
                gestureState.dx < 0);
    }
    calcX(gestureState) {
        const screenWidth = Dimensions.get('window').width;
        const activeTab = this.getIndex(this.props.tabs.get('tab'));
        let coord = 0;

        if (gestureState.dx > screenWidth * 0.2) {
            coord = (activeTab * screenWidth) - screenWidth;
        } else if (gestureState.dx < -(screenWidth * 0.2)) {
            coord = (activeTab * screenWidth) + screenWidth;
        } else {
            coord = activeTab * screenWidth;
        }

        this.updateTab(-coord, screenWidth);

        return -coord;
    }
    updateTab(coord, screenWidth) {
        // Update current tab according to location and screenwidth
        this.state.tabs.forEach((tab) => {
            if (coord === -tab.index * screenWidth) {
                this.props.dispatch({ type: 'SET_TAB', tab: tab.name });
            }
        });
    }
    render() {
        return (
          <View
            style={{ flex: 1 }}
          >
            <Animated.View
              style={this.getStyle()}
              {...this.panResponder.panHandlers}
            >
              {this.state.tabs.map(tab => tab.component)}
            </Animated.View>
          </View>
        );
    }
}

尝试使用 onMoveShouldSetResponder 的函数，这样它只会在gestureState.dx远大于gestureState.dy时水平滑动，如下所示：

onMoveShouldSetResponder: (evt, gestureState) => {
    return Math.abs(gestureState.dx) > Math.abs(gestureState.dy * 3);
},

您还可以在 onPanResponderMove 中使用一个函数来跟踪滑动手势的方向，然后在 onPanResponderRelease 中重置，这样当垂直滑动变为水平滑动时就不会出现问题，如下所示：

checkSwipeDirection(gestureState) {
    if( 
        (Math.abs(gestureState.dx) > Math.abs(gestureState.dy * 3) ) &&
        (Math.abs(gestureState.vx) > Math.abs(gestureState.vy * 3) )
    ) {
        this._swipeDirection = "horizontal";
    } else {
        this._swipeDirection = "vertical";
    }
}
canMove() {
    if(this._swipeDirection === "horizontal") {
        return true;
    } else {
        return false;
    }
}

然后像这样使用它：

onMoveShouldSetPanResponder: this.canMove,
onPanResponderMove: (evt, gestureState) => {
    if(!this._swipeDirection) this.checkSwipeDirection(gestureState);

// Your other code here
},
onPanResponderRelease: (evt, gestureState) => {
    this._swipeDirection = null;
}

我在 Medium 上发现了 Satyajit Sahoo 写的一篇很棒的文章我如何构建 React Native 选项卡视图 https://medium.com/@satya164/how-i-built-react-native-tab-view-7adfb2570af6它更深入地展示了如何实现您自己的选项卡视图。我建议您查看该博客文章，因为它对我非常有帮助。

更新：查看此处的文档手势响应器生命周期 https://facebook.github.io/react-native/docs/gesture-responder-system.html#responder-lifecycle如果您希望父组件阻止子组件成为手势响应程序，反之亦然。