Question

登录成功后，这将返回Main2Activity，我可以一次又一次登录。但是，关闭并从最近的列表中删除后，应重新启动应用程序，并从MainActivity中启动。如果条件为真，如何直接将Main2Activity导航到MainActivity。

Main2Activity代码

public class Main2Activity extends AppCompatActivity {

    private static final String TAG = "Main2Activity";
    int AUTHUI_REQUEST_CODE = 1001;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

        if (FirebaseAuth.getInstance().getCurrentUser() != null) {
            startActivity(new Intent(this, MainActivity.class));
            this.finish();
        }
    }

    public void loginRegister(View view) {

        List<AuthUI.IdpConfig> providers = Arrays.asList(
                new AuthUI.IdpConfig.EmailBuilder().build(),
                new AuthUI.IdpConfig.GoogleBuilder().build(),
                new AuthUI.IdpConfig.PhoneBuilder().build()
        );

        Intent intent = AuthUI.getInstance()
                .createSignInIntentBuilder()
                .setAvailableProviders(providers)
                .setTosAndPrivacyPolicyUrls("https://example.com","https://example.com")
                .setLogo(R.drawable.i789)
                .build();

        startActivityForResult(intent, AUTHUI_REQUEST_CODE);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == AUTHUI_REQUEST_CODE){
            if (requestCode == RESULT_OK){
                FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
                Log.d(TAG, "onActivityResult: "+ user.getEmail());
                if (user.getMetadata().getCreationTimestamp() == user.getMetadata().getLastSignInTimestamp()){
                    Toast.makeText(this, "Welcome", Toast.LENGTH_SHORT).show();
                }else{
                    Toast.makeText(this, "Welcome back again", Toast.LENGTH_SHORT).show();
                }
            Intent t = new Intent(this,MainActivity.class);
             startActivity(t);
             this.finish();

        }else{
                IdpResponse response =IdpResponse.fromResultIntent(data);
                if (response == null){
                    Log.d(TAG, "onActivityResult: the user has cancelled the sign in request");
                }else {
                    Log.e(TAG, "onActivityResult: ",response.getError() );
                }

            }
        }
    }
}

代码-主要活动

public class MainActivity extends AppCompatActivity implements FirebaseAuth.AuthStateListener {
    private static final String TAG = "MainActivity";

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

        private void startLogin(){
                Intent intent = new Intent(this,Main2Activity.class);
                startActivity(intent);
                finish();
        }

    public void signout(View view){
     AuthUI.getInstance().signOut(this);

    }

    @Override
    protected void onStart() {
        super.onStart();
        FirebaseAuth.getInstance().addAuthStateListener(this);
    }

    @Override
    protected void onStop() {
        super.onStop();
        FirebaseAuth.getInstance().removeAuthStateListener(this);
    }

    @Override
    public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
        if (firebaseAuth.getCurrentUser() == null){
            startLogin();
            return;
        }
        firebaseAuth.getCurrentUser().getIdToken(true)
                .addOnSuccessListener(new OnSuccessListener<GetTokenResult>() {
                    @Override
                    public void onSuccess(GetTokenResult getTokenResult) {
                        Log.d(TAG, "onSuccess: "+getTokenResult.getToken());
                    }
                });
    }
}

Answer 1

我建议您创建一个启动屏幕（启动屏幕），该屏幕最初会在启动时首先检查身份验证，无论用户是否从服务器登录。所有这些将在后台线程中处理，并且ui线程将进行启动屏幕动画（如果您愿意的话）。因此，如果用户已登录，则导航到mainActivity，或者导航到loginActivity。希望对您有帮助。

登录成功后如何返回MainActivity？

1 个答案: