尝试将标签TabNavigator添加到堆栈Navigator中。 像这样

const Navigation = createStackNavigator（{     TabNavigator，     仪表板：{screen：dashboard}   }）

导出默认的createAppContainer（Navigation）;

一种更好的方法是创建一个ReactNavigator文档中提到的SwitchNavigator。检出https://reactnavigation.org/docs/en/auth-flow.html

      const TabNavigator = createBottomTabNavigator ({
      Home:{screen:Login},Create:{screen:Register}
      },{
        tabBarOptions:{
          activeTintColor:'white',activeBackgroundColor:'#FF4A83',inactiveTintColor:'black',inactiveBackgroundColor:'#FE739F',labelStyle:{
            fontSize:16,padding:10,}
        }
      });

      const Navigation = createStackNavigator({

        dashboard:{screen:dashboard},})

      export default createAppContainer(
        createSwitchNavigator(
          {
            AuthLoading: AuthLoadingScreen,//screen where you check for a token and navigate to App if token is present else to Auth
            Auth: TabNavigator,App: Navigation,},{
            initialRouteName: 'AuthLoading',}
        )
      );

并且在登录类中

      export default class Login extends Component{
        constructor(props) {
          super(props)
          this.state = {
            username: '',password: '',}
          this._login = this._login.bind(this);
        }
         navigationOptions = {
          tabBarLabel: 'Login',}
        _login(){

          if(this.state.username=='shankar' && this.state.password=='12345'){
          //  alert('Successfully login')
          this.props.navigation.navigate('App')
      }else{
            alert('Login or Password incorrect')
          }
        }
        render(){
          return(

         ....
      )}