在应用程序中一次性登录 - FirebaseAuth [英] One time login in app - FirebaseAuth

问题描述

我正在开发一款使用 Firebase 身份验证通过电话号码登录用户的应用.我想添加一个功能，以便用户只有一次登录，即即使用户杀死应用程序并再次启动它，他也应该登录.另外，我不想添加注销功能.可以为此做些什么?

I'm working on an app that uses Firebase authentication to sign in users through phone number. I want to add a functionality such that there is only one-time login for the user, i.e. even if the user kills the app and starts it again, he should be logged in. Also, I don't want to add a logout feature. What can be done for this?

推荐答案

实现此目的的最简单方法是使用侦听器.假设您有两个活动，LoginActivity 和 MainActivity.可以在 LoginActivity 中创建的侦听器应如下所示:

The simplest way to achieve this is to use a listener. Let's assume you have two activities, the LoginActivity and the MainActivity. The listener that can be created in the LoginActivity should look like this:

FirebaseAuth.AuthStateListener authStateListener = new FirebaseAuth.AuthStateListener() {
    @Override
    public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
        FirebaseUser firebaseUser = firebaseAuth.getCurrentUser();
        if (firebaseUser != null) {
            Intent intent = new Intent(LoginActivity.this, MainActivity.class);
            startActivity(intent);
            finish();
        }
    }
};

这基本上意味着如果用户已登录，则跳过LoginActivity 并转到MainActivity.

This basically means that if the user is logged in, skip the LoginActivity and go to the MainActivity.

实例化 FirebaseAuth 对象:

FirebaseAuth firebaseAuth = FirebaseAuth.getInstance();

然后开始监听 onStart() 方法的变化，如下所示:

And start listening for changes in your onStart() method like this:

@Override
protected void onStart() {
    super.onStart();
    firebaseAuth.addAuthStateListener(authStateListener);
}

在MainActivity中，你应该做同样的事情:

In the MainActivity, you should do the same thing:

FirebaseAuth.AuthStateListener authStateListener = new FirebaseAuth.AuthStateListener() {
    @Override
    public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
        FirebaseUser firebaseUser = firebaseAuth.getCurrentUser();
        if (firebaseUser == null) {
            Intent intent = new Intent(MainActivity.this, LoginActivity.class);
            startActivity(intent);
        }
    }
};

这基本上意味着如果用户没有登录，跳过MainActivity并转到LoginActivity.在此活动中，您应该执行与 LoginActivity 中相同的操作，您应该开始侦听 onStart() 中的更改.

Which basically means that if the user is not logged in, skip the MainActivity and go to the LoginActivity. In this activity you should do the same thing as in the LoginActivity, you should start listening for changes in the onStart().

在这两个活动中，不要忘记在不再需要的那一刻删除侦听器.因此，在您的 onStop() 方法中添加以下代码行:

In both activities, don't forget to remove the listener in the moment in which is not needed anymore. So add the following line of code in your onStop() method:

@Override
protected void onStop() {
    super.onStop();
    firebaseAuth.removeAuthStateListener(authStateListener);
}

这篇关于在应用程序中一次性登录 - FirebaseAuth的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！