React-native: undefined is not an object (evalating '_this.props.navigation.navigate') onpress答案

【问题标题】：React-native: undefined is not an object (evaluating '_this.props.navigation.navigate') onpressReact-native: undefined is not an object (evalating '_this.props.navigation.navigate') onpress
【发布时间】：2019-06-02 12:10:00
【问题描述】：

const AppStackLog = createDrawerNavigator(
  {

    Login: {
      screen: LogintStack,
      navigationOptions: (navOpt) => ({
        drawerLabel: ({focused}) =>(
        <TouchableOpacity style={[styles.button]} onPress={() => this.navigation.navigate('App')}>
         <Text><Icon

            size={17}
            name="log-in"
            family="Galio"
            color={focused ? 'white' : materialTheme.COLORS.MUTED} />
       <Text size={18}>        Logout</Text></Text>       
      </TouchableOpacity>
        ),
      }),
    },



  },
  Menu
);

export default createSwitchNavigator(
  {
    App: AppStack,
    Home: HomeStack,
    Auth:AppStackLog,
  },
  {
    initialRouteName: 'App',
  }
);

【问题讨论】：

标签： javascript react-native navigation

【解决方案1】：

this 不会指向某个特定组件，它会指向定义此代码时this 等于的任何内容。相反，navOpt 参数具有您需要的内容：

<TouchableOpacity style={[styles.button]} onPress={() => navOpt.navigation.navigate('App')}>

【讨论】：

你是说它没有用吗？请告诉我失败的原因。