React Native移动应用程序的后退按钮只应在第一个屏幕时退出应用程序。

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英文:

React native mobile back button should exit app only for first screen

问题

我试图处理移动设备的返回按钮,仅当用户在第一个屏幕上时退出应用程序,如果在其他屏幕上则应返回到上一个屏幕。

我尝试过在React Native中仅在第一个屏幕上使用backHandler,但它会应用于所有屏幕。我希望如果是第一个屏幕则退出应用程序。

英文:

I was trying to handle mobile back button should exit the app only when user is on first screen, and should be go back to prev screen if its on other screen.

I tried react native backHandler only on first screen but its getting applied for all the screen. I want to exit the app if its the first screen

答案1

得分: 1

I got the solution

import the hooks

import { useFocusEffect, useRoute } from '@react-navigation/native';

we can use the useRoute hook by @react-navigation/native to get the route name

const route = useRoute();

useFocusEffect(
React.useCallback(() => {
const onBackPress = () => {
if (route.name === 'HomeScreen') {
Alert.alert('Hold on!', 'Are you sure you want to go back?', [
{
text: 'Cancel',
onPress: () => null,
style: 'cancel',
},
{text: 'YES', onPress: () => BackHandler.exitApp()},
]);
return true;
} else {
return false;
}
};

const subscription = BackHandler.addEventListener('hardwareBackPress', onBackPress);

return () => subscription.remove();

}, [])
);

英文:

I got the solution

import the hooks

import { useFocusEffect, useRoute } from '@react-navigation/native';

we can use the useRoute hook by @react-navigation/native to get the route name

  const route = useRoute();

  useFocusEffect(
    React.useCallback(() => {
      const onBackPress = () => {
        if (route.name === 'HomeScreen') {
          Alert.alert('Hold on!', 'Are you sure you want to go back?', [
          {
            text: 'Cancel',
            onPress: () => null,
            style: 'cancel',
          },
          {text: 'YES', onPress: () => BackHandler.exitApp()},
        ]);
          return true;
        } else {
          return false;
        }
      };

      const subscription = BackHandler.addEventListener('hardwareBackPress', onBackPress);

      return () => subscription.remove();
    }, [])
  );

答案2

得分: 0

你可以通过在你的第一个屏幕组件中使用 useEffect 钩子来设置一个监听器,用于监听返回按钮的按下事件,使用 React Native 的 BackHandler API。然后,在事件处理函数中,你可以检查当前屏幕是否是第一个屏幕,并调用 BackHandler API 中的 exitApp 方法来退出应用程序。

以下是一些实现这一功能的示例代码:

import React, { useEffect } from 'react';
import { BackHandler } from 'react-native';

const FirstScreen = () => {
  useEffect(() => {
    const backAction = () => {
      if (isFirstScreen()) {
        BackHandler.exitApp();
        return true;
      } else {
        return false;
      }
    };

    const backHandler = BackHandler.addEventListener(
      'hardwareBackPress',
      backAction,
    );

    return () => backHandler.remove();
  }, []);

  const isFirstScreen = () => {
    // 逻辑来确定当前屏幕是否是第一个屏幕
    // 如果是,返回 true;否则返回 false
  };

  return (
    // 你的第一个屏幕组件代码
  );
};

export default FirstScreen;

在 useEffect 钩子中,我们使用 BackHandler.addEventListener 方法设置了一个监听器,用于监听 hardwareBackPress 事件。事件处理函数 backAction 检查当前屏幕是否是第一个屏幕,使用 isFirstScreen 函数进行判断。如果是第一个屏幕,则调用 BackHandler.exitApp 方法退出应用程序,否则返回 false 以允许默认的返回按钮行为发生。最后,在从 useEffect 钩子返回的清理函数中,我们使用 backHandler.remove 方法来移除监听器,以避免任何内存泄漏。

英文:

You can achieve this by using the useEffect hook in your first screen component to set up a listener for the back button press event using the BackHandler API from React Native. Then, in the event handler, you can check if the current screen is the first screen and call the exitApp method from the BackHandler API to exit the app.

Here's some example code to achieve this:

import React, { useEffect } from 'react';
import { BackHandler } from 'react-native';

const FirstScreen = () => {
  useEffect(() => {
    const backAction = () => {
      if (isFirstScreen()) {
        BackHandler.exitApp();
        return true;
      } else {
        return false;
      }
    };

    const backHandler = BackHandler.addEventListener(
      'hardwareBackPress',
      backAction,
    );

    return () => backHandler.remove();
  }, []);

  const isFirstScreen = () => {
    // Logic to determine if current screen is the first screen
    // Return true if it is, false otherwise
  };

  return (
    // Your first screen component code
  );
};

export default FirstScreen;

In the useEffect hook, we set up a listener for the hardwareBackPress event using the BackHandler.addEventListener method. The event handler, backAction, checks if the current screen is the first screen using the isFirstScreen function. If it is, it calls the BackHandler.exitApp method to exit the app, otherwise it returns false to allow the default back button behavior to occur. Finally, in the cleanup function returned from the useEffect hook, we remove the listener using the backHandler.remove method to avoid any memory leaks.

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  • 本文由 发表于 2023年4月19日 16:57:23
  • 转载请务必保留本文链接:https://go.coder-hub.com/76052583.html
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