native react 二级菜单_react native 侧滑菜单

React Native中实现侧滑菜单可以使用第三方组件库，如react-native-drawer、react-native-side-menu等，也可以自己手写实现。以下是手写实现的简单示例：

1. 安装react-native-gesture-handler库

npm install react-native-gesture-handler

2. 在App.js中引入GestureHandlerRootView，并在render方法中添加侧滑菜单和主页布局

import { GestureHandlerRootView } from 'react-native-gesture-handler';

class App extends Component {
  constructor(props) {
    super(props);
    this.state = {
      isMenuOpen: false,
    };
  }

  render() {
    return (
      <GestureHandlerRootView style={{ flex: 1 }}>
        <View style={{ flex: 1 }}>
          {this.state.isMenuOpen ?
            <View style={{ flex: 1, backgroundColor: 'white' }}>
              <Text>侧滑菜单</Text>
            </View> :
            <View style={{ flex: 1, backgroundColor: 'white' }}>
              <Text>主页布局</Text>
            </View>
          }
        </View>
      </GestureHandlerRootView>
    );
  }
}

3. 添加手势识别和动画

import { PanGestureHandler, State } from 'react-native-gesture-handler';

class App extends Component {
  constructor(props) {
    super(props);
    this.state = {
      isMenuOpen: false,
      gestureState: State.UNDETERMINED,
      translateX: new Animated.Value(0),
    };
    this.onGestureEvent = Animated.event(
      [{ nativeEvent: { translationX: this.state.translateX } }],
      { useNativeDriver: true }
    );
  }

  onHandlerStateChange = event => {
    if (event.nativeEvent.oldState === State.ACTIVE) {
      const { translationX } = event.nativeEvent;
      if (translationX < -50) {
        this.setState({ isMenuOpen: true });
        Animated.spring(this.state.translateX, {
          toValue: -200,
          useNativeDriver: true,
        }).start();
      } else {
        Animated.spring(this.state.translateX, {
          toValue: 0,
          useNativeDriver: true,
        }).start();
      }
    }
  };

  render() {
    return (
      <GestureHandlerRootView style={{ flex: 1 }}>
        <View style={{ flex: 1 }}>
          <PanGestureHandler
            onGestureEvent={this.onGestureEvent}
            onHandlerStateChange={this.onHandlerStateChange}
          >
            <Animated.View
              style={{
                flex: 1,
                transform: [{ translateX: this.state.translateX }],
              }}
            >
              {this.state.isMenuOpen ?
                <View style={{ flex: 1, backgroundColor: 'white' }}>
                  <Text>侧滑菜单</Text>
                </View> :
                <View style={{ flex: 1, backgroundColor: 'white' }}>
                  <Text>主页布局</Text>
                </View>
              }
            </Animated.View>
          </PanGestureHandler>
        </View>
      </GestureHandlerRootView>
    );
  }
}

这样就可以实现一个简单的侧滑菜单了。需要注意的是，手写实现的侧滑菜单可能会存在一些问题，如滑动冲突、性能问题等，使用第三方组件库可以避免这些问题。