如何让用户在我的 android 应用中保持登录状态

Question

package com.casser.casser;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import android.app.ProgressDialog;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.AuthResult;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
import com.google.firebase.database.core.Tag;

import org.w3c.dom.Text;

public class Login extends AppCompatActivity {

    EditText email, password;
    Button login;
    TextView txt_signup;

    FirebaseAuth auth;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        // This is ths screen optimization...
        try {
            this.getSupportActionBar().hide();
        } catch (NullPointerException e) {
        }

        View decorView = getWindow().getDecorView();
        int uiOptions = View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
                | View.SYSTEM_UI_FLAG_FULLSCREEN;
        decorView.setSystemUiVisibility(uiOptions);

        setContentView(R.layout.activity_login);
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
    /*
        FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
        if (user != null) {
            // User is signed in
            Intent i = new Intent(Login.this, MainActivity.class);
            i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
            startActivity(i);
        } else {
            // User is signed out

        }
     */
        // This is ths screen optimization... After this the main login screen is there Work from below don't touch code above!

        email = findViewById(R.id.email);
        password = findViewById(R.id.password);
        login = findViewById(R.id.login);
        txt_signup = findViewById(R.id.txt_signup);


        auth = FirebaseAuth.getInstance();



        final SharedPreferences sp;
        sp = getSharedPreferences("login",MODE_PRIVATE);

        if(sp.getBoolean("logged",false)){
            goToMainActivity();
        }

        login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                goToMainActivity();
                sp.edit().putBoolean("logged",true).apply();
            }
        });

        txt_signup.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startActivity(new Intent(Login.this, SignUp.class));

            }
        });
        login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                final ProgressDialog pd = new ProgressDialog(Login.this);
                pd.setMessage("Please wait...");
                pd.show();

                String str_email = email.getText().toString();
                String str_password = password.getText().toString();

                if (TextUtils.isEmpty(str_email) || (TextUtils.isEmpty(str_password))) {
                    Toast.makeText(Login.this, "All fields are required", Toast.LENGTH_SHORT).show();
                } else {

                    auth.signInWithEmailAndPassword(str_email, str_password)
                            .addOnCompleteListener(Login.this, new OnCompleteListener<AuthResult>() {
                                @Override
                                public void onComplete(@NonNull Task<AuthResult> task) {
                                    if (task.isSuccessful()) {
                                        DatabaseReference reference = FirebaseDatabase.getInstance().getReference().child("Users")
                                                .child(auth.getCurrentUser().getUid());

                                        reference.addValueEventListener(new ValueEventListener() {
                                            @Override
                                            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                                                pd.dismiss();
                                                Intent intent = new Intent(Login.this, MainActivity.class);
                                                intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
                                                startActivity(intent);
                                            }

                                            @Override
                                            public void onCancelled(@NonNull DatabaseError databaseError) {
                                                pd.dismiss();

                                            }
                                        });
                                    } else {
                                        pd.dismiss();
                                        Toast.makeText(Login.this, "SignIn failed", Toast.LENGTH_SHORT).show();
                                    }
                                }
                            });
                }

            }
        });


    }


    public void goToMainActivity() {
        Intent i = new Intent(this, MainActivity.class);
        startActivity(i);
    }

}

我怎样才能让用户保持登录我的应用程序我已经用 firebase 完成了身份验证我怎样才能让他们保持登录状态我已经尝试了很多东西但是他们的工作方式不一样就像你登录然后你除非您注销或删除您的应用程序，否则不需要再次登录我也可以举一些例子，比如 facebook snapchat instagram AnyHelp 将非常有帮助我正在开始任何帮助将不胜感激

Answer 1

您可以使用 shared preference 并将所需数据保存到其中并保留登录状态，这样当您重新打开应用程序时可以检查此状态并让用户直接登录

Answer 2

你可以做的一件事是，当用户启动应用程序时，你可以检查用户是否登录。如果没有，您可以执行所需的代码。代码：

@Override
protected void onStart()
{
super.onStart();
FirebaseUser user = FirebaseAuth.getInstance.getCurrentUser();
if(user == null) { 
    // User is not signed in. Execute your own code.
}
else{ //user is signed in }

Answer 3

package com.casser.casser;

import android.app.Application;
import android.content.Intent;

import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;

public class  Home extends Application {

    @Override
    public void onCreate(){
        super.onCreate();

        FirebaseAuth firebaseAuth = FirebaseAuth.getInstance();
        FirebaseUser firebaseUser = firebaseAuth.getCurrentUser();

        if (firebaseUser !=null){
            Intent i = new Intent(Home.this, MainActivity.class);

            i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            startActivity(i);
        }
    }
}

请参阅创建一个 class 任何你想要的名字我创建了名为“.Home”的创建并复制上面的代码并将其粘贴到那里之后进入您的清单文件并粘贴：在最顶部然后您就可以随时发表评论并在任何问题下联系谢谢将其粘贴到清单文件中： android:name=".主页"

如何让用户在我的 android 应用中保持登录状态

How can I let users remain logged in my android app

java

android

firebase

authentication

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