android - BackHandler 'hardwareBackPress 只工作一次 | react native

Question

我需要在 Android 设备上处理 Back Press，但我的 BackHandler 只工作一次。

这是我的代码 fragment -

 componentWillUnmount() {
        BackHandler.removeEventListener('hardwareBackPress', this.handleBackPress);
    }
    componentDidMount() {
        BackHandler.addEventListener('hardwareBackPress', this.handleBackPress);
    }

        handleBackPress = () => {

            console.log("handleBackPress Called on RootMenuView : current View ? : " + this.state.mainView);

            if (this.state.mainView === "Main"){
                return false;
            } else{
                this.state.mainView = "Main";
                this.forceUpdate();
                return true;
            }

        }

我需要在菜单 View 上处理这个，因为我需要在其他组件的后退时显示默认组件。

Answer 1

 componentWillUnmount() {
    BackHandler.removeEventListener('hardwareBackPress', this.handleBackPress);
   }
   componentDidMount() {
    BackHandler.addEventListener('hardwareBackPress', this.handleBackPress);
 }

    handleBackPress = () => {

        console.log("handleBackPress Called on RootMenuView : current View ? : " + this.state.mainView);

        if (this.state.mainView === "Main"){
            return false;
        } else{
             //not this
            //this.state.mainView = "Main";
            // use this
           this.setState({mainView: "Main"})
            this.forceUpdate();
            return true;
        }

    }