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);
    }

}

如何保留用户登录我的应用程序的权限？我已经使用firebase进行身份验证了吗？如何尝试保持登录状态？我尝试了很多尝试，但它们的工作方式与仅登录一次然后又没有一样除非您注销或删除应用程序，否则无需再次登录。我还可以举一些例子，例如facebook snapchat instagram AnyHelp会非常有帮助。我将开始提供任何帮助

Answer 1

您可以使用shared preference并将所需的数据保存到其中，并保持登录状态，以便在重新打开应用程序时可以检查此状态并使用户直接登录

Answer 2

您可以做的是，当用户启动应用程序时，可以检查使用用户是否已登录。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);
        }
    }
}

请参见创建一个名为您想要创建的名称的类。我创建名为“ .Home”的类，然后复制上面的代码并将其粘贴到此处之后，进入清单文件并将其粘贴：在最顶部，您可以在任何问题的情况下随意发表评论并与他人联系，谢谢将此粘贴到清单文件中： android：name =“。Home”

如何让用户保持登录状态？

3 个答案: