BackHandler 不会返回超过 1 个屏幕

本文介绍了BackHandler 不会返回超过 1 个屏幕的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我的每个屏幕上都有这个代码.按 android 后退按钮返回 1 个屏幕.再次按下 android 后退按钮没有任何作用.预期的结果是只要堆栈中有更多屏幕就可以继续返回.缺少什么?

I have this code on each of my screens. Pressing the android back button goes back 1 screen. Pressing android back button again does not do anything. Expected result would be to keep going back as long as there are more screens in the stack. What's missing?

componentWillMount() {
    BackHandler.addEventListener('hardwareBackPress', () => {
        this.props.navigation.goBack();
        return true;
    });
}

componentWillUnmount() {
  BackHandler.removeEventListener('hardwareBackPress')
}

推荐答案

经过反复试验，此代码按预期工作.我相信我的初始代码实际上并没有删除事件侦听器.

After some trial and error, this code works as expected. I believe my initial code was not actually removing the event listener.

componentWillMount() {
    BackHandler.addEventListener('hardwareBackPress', this.backPressed);
}

componentWillUnmount() {
    BackHandler.removeEventListener('hardwareBackPress', this.backPressed);
}

backPressed = () => {
    this.props.navigation.goBack();
    return true;
}

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