我想在开始新意图时破坏活动

Question

我有两个活动 MainActivity 和 signUp。 MainActivity 在应用程序启动时创建，它获取 firebase 身份验证实例，如果未找到用户，则转到注册。

public class MainActivity extends AppCompatActivity {

Intent intent;

FirebaseAuth.AuthStateListener authStateListener;
FirebaseAuth firebaseAuth;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Log.d("MainActivity","Created..");

    new Handler().postDelayed(() -> {

        firebaseAuth = FirebaseAuth.getInstance();

        authStateListener = firebaseAuth -> {
            FirebaseUser user = firebaseAuth.getCurrentUser();
            if(user!=null) {
                intent = new Intent(MainActivity.this, HomeScreen.class);
                Log.d("Authentication", "User already signed in..");
                intent.putExtra("state", "alreadySignIned");
                startActivity(intent);
                MainActivity.this.finish();
            }
        };

        intent = new Intent(this,signUp.class);
        startActivity(intent);
        MainActivity.this.finish();

        firebaseAuth.addAuthStateListener(authStateListener);
    },5000);
}

}

现在，当新用户在 signUp 中注册时，它会转到主屏幕 activity 但我面临的问题是，当新用户注册并从 MainActivity 开始意图时，authStateListener 正在获取用户。

public class signUp extends AppCompatActivity {

Intent intent;

FirebaseAuth firebaseAuth;
boolean buttonPress = false;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.signup);

    EditText emailUp,passUp,userName;
    Button signUp;
    TextView toSignIn;

    emailUp = findViewById(R.id.signUpEmail);
    passUp = findViewById(R.id.signUpPass);
    signUp = findViewById(R.id.signUpButton);
    userName = findViewById(R.id.signUpUserName);
    toSignIn = findViewById(R.id.toSignIn);

    firebaseAuth = FirebaseAuth.getInstance();

    signUp.setOnClickListener(v -> {
        buttonPress = true;
        String email = emailUp.getText().toString();
        String pass = passUp.getText().toString();
        String name = userName.getText().toString();

        if(email.isEmpty()){
            emailUp.setError("Please enter email id..");
            emailUp.requestFocus();
        } else if(pass.isEmpty()){
            passUp.setError("Please enter password..");
            passUp.requestFocus();
        } else {
            firebaseAuth.createUserWithEmailAndPassword(email,pass).addOnCompleteListener(task -> {
                if(!task.isSuccessful()){
                    Toast.makeText(signUp.this,"Sign up Unsuccessful, please try again.",Toast.LENGTH_SHORT).show();
                } else {
                    Log.d("Authentication","User signing up..");
                    intent = new Intent(this,HomeScreen.class);
                    intent.putExtra("state","signedUp");
                    intent.putExtra("name",name);
                    startActivity(intent);
                    signUp.this.finish();
                }
            });
        }
    });

}

}

这是来自主屏幕的日志 activity

2020-05-18 14:04:33.355 29696-29696/com.example.movietracker I/BiChannelGoogleApi: [FirebaseAuth: ] getGoogleApiForMethod() returned Gms: com.google.firebase.auth.api.internal.zzaq@8f143e5
2020-05-18 14:05:04.668 29696-29711/com.example.movietracker D/FirebaseAuth: Notifying id token listeners about user ( 82Q12yEqqjUP0AWGuGoxok4pvae2 ).
2020-05-18 14:05:04.669 29696-29711/com.example.movietracker D/FirebaseAuth: Notifying auth state listeners about user ( 82Q12yEqqjUP0AWGuGoxok4pvae2 ).
2020-05-18 14:05:04.669 29696-29696/com.example.movietracker D/Authentication: User already signed in..
2020-05-18 14:05:04.734 29696-29696/com.example.movietracker D/Homescreen Activity: Created..
2020-05-18 14:05:04.734 29696-29696/com.example.movietracker D/Intent: State alreadySignIned
2020-05-18 14:05:04.771 29696-29696/com.example.movietracker D/Cursor: Count on create 0
2020-05-18 14:05:04.773 29696-29696/com.example.movietracker D/Homescreen Activity: Started..
2020-05-18 14:05:04.773 29696-29696/com.example.movietracker D/Username: Username null
2020-05-18 14:05:04.819 29696-29696/com.example.movietracker D/NetworkSecurityConfig: No Network Security Config specified, using platform default
2020-05-18 14:05:04.826 29696-29696/com.example.movietracker D/WatchList DB: Size 0
2020-05-18 14:05:04.826 29696-29696/com.example.movietracker D/WatchListID: Size 0
2020-05-18 14:05:04.838 29696-29696/com.example.movietracker D/Authentication: User signing up..

这里它在注册时通知 authStateListener，在一些代码之后它从注册中获取意图 class。我希望它销毁 MainActivity 并直接从 signUp 获取意图而不通知 authStateListener。

请帮忙。

Answer 1

你可以像这样摧毁一个activity：

第 1 步：在 MainActivity

中声明一个 Activity 变量

public static Activity MainActivityContext;

第 2 步：在 OnCreate 方法 MainActivity

中初始化 MainActivityContext 变量

MaMainActivityContext = this;

第 3 步：现在转到要销毁 MainActivity 的 java 语句并写入

MainActivity.MainActivityContext.finish();

Answer 2

MainActivity 始终启动 signup Activity。在用户已经存在的情况下，HomeScreen Activity 也会启动。这可能不是你想要的。

此外，authListener 回调调用 MainActivity.this.finish() 但此时 MainActivity 已经完成，所以这也是错误的。

如果您不希望 authListener 在用户注册时触发，您应该在创建用户之前删除侦听器。

总的来说，您的代码可以改进。您应该查看更多教程，以更好地了解如何执行此操作。

我想在开始新意图时破坏活动

I want to destroy activities on starting a new intent

authentication

android

android-intent

activity-lifecycle

firebase