在社交媒体Android应用中实现启动屏幕和身份验证

这是“在Android Studio上构建社交媒体应用程序”教程的第1部分，我们将在本文中介绍以下功能：

• 创建启动画面
• 认证部分：
  • 注册，以及
  • 登录

分步实施

步骤1：创建一个新项目

要在Android Studio中创建新项目，请参阅如何在Android Studio中创建/启动新项目。请注意，选择Java作为编程语言。

第2步：将您的应用连接到Firebase

转到“工具”>“ Firebase”>“身份验证”，然后将您的应用程序连接到Firebase，然后将Firebase身份验证SDK添加到您的应用程序中，如下图所示。

然后转到Firebase控制台>身份验证>登录方法，然后启用电子邮件/密码。

步骤3：建立4个新的空白活动

转到程序包名称>右键单击>新建>活动>空活动，并将活动命名为SpalshScreen ， RegistrationActivity ， LoginActivity和DashboardActivity 。您也可以参考本文“如何在android studio中创建新的空活动”。

步骤4：使用SpalshScreen活动

导航至应用程序> res>布局> activity_spalsh_screen.xml，然后将以下代码添加到该文件中。以下是activity_spalsh_screen.xml文件的代码。

使用SpalshScreen。 Java文件。在这里，我们正在检查用户是否为null，然后转到LoginActivity 。否则，请移至DashboardActivity。

new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                FirebaseUser user=mAuth.getCurrentUser();
                if(user==null){
                    Intent intent = new Intent(SpalshScreen.this, LoginActivity.class);
                    startActivity(intent);
                    finish();
                }
                else {
                    Intent mainIntent= new Intent(SpalshScreen.this, DashboardActivity.class);
                    mainIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
                    startActivity(mainIntent);
                    finish();
                }
            }
      },1000);

下面是SpalshScreen的代码。 Java文件。

Java

package com.example.socialmediaapp;
  
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
  
import androidx.appcompat.app.AppCompatActivity;
  
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
  
public class SpalshScreen extends AppCompatActivity {
  
    FirebaseUser currentUser;
    private FirebaseAuth mAuth;
  
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_spalsh_screen);
        mAuth = FirebaseAuth.getInstance();
        if (mAuth != null) {
            currentUser = mAuth.getCurrentUser();
        }
        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                FirebaseUser user = mAuth.getCurrentUser();
                if (user == null) {
                    Intent intent = new Intent(SpalshScreen.this, LoginActivity.class);
                    startActivity(intent);
                    finish();
                } else {
                    Intent mainIntent = new Intent(SpalshScreen.this, DashboardActivity.class);
                    mainIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
                    startActivity(mainIntent);
                    finish();
                }
            }
        }, 1000);
    }
}

步骤5：使用RegistrationActivity活动

导航到应用程序> res>布局> activity_registration.xml，然后将以下代码添加到该文件中。以下是activity_registration.xml文件的代码。在这里，我们为名称，电子邮件和密码创建了三个EditText，并为注册用户创建了一个Button 。

使用RegistrationActivity。 Java文件。使用用户编写的电子邮件和密码创建用户。如果失败，那么我们将显示错误。

mAuth.createUserWithEmailAndPassword(emaill, pass).addOnCompleteListener(new OnCompleteListener() {
            @Override
            public void onComplete(@NonNull Task task) {
                if (task.isSuccessful()){
                    progressDialog.dismiss();
                }
                else {
                    progressDialog.dismiss();
                    Toast.makeText(RegistrationActivity.this,"Error",Toast.LENGTH_LONG).show();
                }
            }
        }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                progressDialog.dismiss();
                Toast.makeText(RegistrationActivity.this,"Error Occured",Toast.LENGTH_LONG).show();
            }
     });

下面是RegistrationActivity的代码。 Java文件。

Java

package com.example.socialmediaapp;
  
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.Bundle;
import android.util.Patterns;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
  
import androidx.annotation.NonNull;
import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AppCompatActivity;
  
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.OnFailureListener;
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.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
  
import java.util.HashMap;
  
public class RegistrationActivity extends AppCompatActivity {
  
    private EditText email, password, name;
    private Button mRegister;
    private TextView existaccount;
    private ProgressDialog progressDialog;
    private FirebaseAuth mAuth;
  
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_registration);
        ActionBar actionBar = getSupportActionBar();
        actionBar.setTitle("Create Account");
        actionBar.setDisplayShowHomeEnabled(true);
        actionBar.setDisplayHomeAsUpEnabled(true);
        email = findViewById(R.id.register_email);
        name = findViewById(R.id.register_name);
        password = findViewById(R.id.register_password);
        mRegister = findViewById(R.id.register_button);
        existaccount = findViewById(R.id.homepage);
        mAuth = FirebaseAuth.getInstance();
        progressDialog = new ProgressDialog(this);
        progressDialog.setMessage("Register");
          
        mRegister.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String emaill = email.getText().toString().trim();
                String uname = name.getText().toString().trim();
                String pass = password.getText().toString().trim();
                if (!Patterns.EMAIL_ADDRESS.matcher(emaill).matches()) {
                    email.setError("Invalid Email");
                    email.setFocusable(true);
                } else if (pass.length() < 6) {
                    password.setError("Length Must be greater than 6 character");
                    password.setFocusable(true);
                } else {
                    registerUser(emaill, pass, uname);
                }
            }
        });
        existaccount.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startActivity(new Intent(RegistrationActivity.this, LoginActivity.class));
            }
        });
    }
  
    private void registerUser(String emaill, final String pass, final String uname) {
        progressDialog.show();
        mAuth.createUserWithEmailAndPassword(emaill, pass).addOnCompleteListener(new OnCompleteListener() {
            @Override
            public void onComplete(@NonNull Task task) {
                if (task.isSuccessful()) {
                    progressDialog.dismiss();
                    FirebaseUser user = mAuth.getCurrentUser();
                    String email = user.getEmail();
                    String uid = user.getUid();
                    HashMap hashMap = new HashMap<>();
                    hashMap.put("email", email);
                    hashMap.put("uid", uid);
                    hashMap.put("name", uname);
                    hashMap.put("onlineStatus", "online");
                    hashMap.put("typingTo", "noOne");
                    hashMap.put("image", "");
                    FirebaseDatabase database = FirebaseDatabase.getInstance();
                    DatabaseReference reference = database.getReference("Users");
                    reference.child(uid).setValue(hashMap);
                    Toast.makeText(RegistrationActivity.this, "Registered User " + user.getEmail(), Toast.LENGTH_LONG).show();
                    Intent mainIntent = new Intent(RegistrationActivity.this, DashboardActivity.class);
                    mainIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
                    startActivity(mainIntent);
                    finish();
                } else {
                    progressDialog.dismiss();
                    Toast.makeText(RegistrationActivity.this, "Error", Toast.LENGTH_LONG).show();
                }
            }
        }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                progressDialog.dismiss();
                Toast.makeText(RegistrationActivity.this, "Error Occured", Toast.LENGTH_LONG).show();
            }
        });
    }
  
    @Override
    public boolean onSupportNavigateUp() {
        onBackPressed();
        return super.onSupportNavigateUp();
    }
}

步骤6：使用LoginActivity活动

导航至应用程序> res>布局> activity_login.xml，然后将以下代码添加到该文件中。以下是activity_login.xml文件的代码。在这里，我们为电子邮件和密码创建了两个EditText，并为登录创建了一个按钮。

使用LoginActivity。 Java文件。使用用户编写的电子邮件和密码登录用户。如果失败，那么我们将显示错误。

mAuth.signInWithEmailAndPassword(emaill, pass).addOnCompleteListener(new OnCompleteListener() {
            @Override
            public void onComplete(@NonNull Task task) {

                if (task.isSuccessful()) {
                    loadingBar.dismiss();

                }
                else {
                    loadingBar.dismiss();
                    Toast.makeText(LoginActivity.this,"Login Failed",Toast.LENGTH_LONG).show();
                }
            }
        }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                loadingBar.dismiss();
                Toast.makeText(LoginActivity.this,"Error Occured",Toast.LENGTH_LONG).show();
            }
    });

下面是LoginActivity的代码。 Java文件。

Java

package com.example.socialmediaapp;
  
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.text.InputType;
import android.util.Patterns;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;
  
import androidx.annotation.NonNull;
import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AppCompatActivity;
  
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.OnFailureListener;
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.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
  
import java.util.HashMap;
  
public class LoginActivity extends AppCompatActivity {
  
    private EditText email, password, name;
    private Button mlogin;
    private TextView newdnewaccount, reocverpass;
    FirebaseUser currentUser;
    private ProgressDialog loadingBar;
    private FirebaseAuth mAuth;
  
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        ActionBar actionBar = getSupportActionBar();
        actionBar.setTitle("Create Account");
        actionBar.setDisplayShowHomeEnabled(true);
        actionBar.setDisplayHomeAsUpEnabled(true);
          
        // initialising the layout items
        email = findViewById(R.id.login_email);
        password = findViewById(R.id.login_password);
        newdnewaccount = findViewById(R.id.needs_new_account);
        reocverpass = findViewById(R.id.forgetp);
        mAuth = FirebaseAuth.getInstance();
        mlogin = findViewById(R.id.login_button);
        loadingBar = new ProgressDialog(this);
        mAuth = FirebaseAuth.getInstance();
          
        // checking if user is null or not
        if (mAuth != null) {
            currentUser = mAuth.getCurrentUser();
        }
  
        mlogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String emaill = email.getText().toString().trim();
                String pass = password.getText().toString().trim();
                  
                // if format of email doesn't matches return null
                if (!Patterns.EMAIL_ADDRESS.matcher(emaill).matches()) {
                    email.setError("Invalid Email");
                    email.setFocusable(true);
  
                } else {
                    loginUser(emaill, pass);
                }
            }
        });
          
        // If new account then move to Registration Activity
        newdnewaccount.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startActivity(new Intent(LoginActivity.this, RegistrationActivity.class));
            }
        });
          
        // Recover Your Password using email
        reocverpass.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                showRecoverPasswordDialog();
            }
        });
    }
  
    private void showRecoverPasswordDialog() {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Recover Password");
        LinearLayout linearLayout = new LinearLayout(this);
        final EditText emailet = new EditText(this);//write your registered email
        emailet.setText("Email");
        emailet.setMinEms(16);
        emailet.setInputType(InputType.TYPE_TEXT_VARIATION_EMAIL_ADDRESS);
        linearLayout.addView(emailet);
        linearLayout.setPadding(10, 10, 10, 10);
        builder.setView(linearLayout);
        builder.setPositiveButton("Recover", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                String emaill = emailet.getText().toString().trim();
                beginRecovery(emaill);//send a mail on the mail to recover password
            }
        });
        builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
            }
        });
        builder.create().show();
    }
  
    private void beginRecovery(String emaill) {
        loadingBar.setMessage("Sending Email....");
        loadingBar.setCanceledOnTouchOutside(false);
        loadingBar.show();
         
        // send reset password email
        mAuth.sendPasswordResetEmail(emaill).addOnCompleteListener(new OnCompleteListener() {
            @Override
            public void onComplete(@NonNull Task task) {
                loadingBar.dismiss();
                if (task.isSuccessful()) {
                    Toast.makeText(LoginActivity.this, "Done sent", Toast.LENGTH_LONG).show();
                } else {
                    Toast.makeText(LoginActivity.this, "Error Occured", Toast.LENGTH_LONG).show();
                }
            }
        }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                loadingBar.dismiss();
                Toast.makeText(LoginActivity.this, "Error Failed", Toast.LENGTH_LONG).show();
            }
        });
    }
  
    private void loginUser(String emaill, String pass) {
        loadingBar.setMessage("Logging In....");
        loadingBar.show();
          
        // sign in with email and password after authenticating
        mAuth.signInWithEmailAndPassword(emaill, pass).addOnCompleteListener(new OnCompleteListener() {
            @Override
            public void onComplete(@NonNull Task task) {
  
                if (task.isSuccessful()) {
  
                    loadingBar.dismiss();
                    FirebaseUser user = mAuth.getCurrentUser();
  
                    if (task.getResult().getAdditionalUserInfo().isNewUser()) {
                        String email = user.getEmail();
                        String uid = user.getUid();
                        HashMap hashMap = new HashMap<>();
                        hashMap.put("email", email);
                        hashMap.put("uid", uid);
                        hashMap.put("name", "");
                        hashMap.put("onlineStatus", "online");
                        hashMap.put("typingTo", "noOne");
                        hashMap.put("phone", "");
                        hashMap.put("image", "");
                        hashMap.put("cover", "");
                        FirebaseDatabase database = FirebaseDatabase.getInstance();
                          
                        // store the value in Database in "Users" Node
                        DatabaseReference reference = database.getReference("Users");
  
                        // storing the value in Firebase
                        reference.child(uid).setValue(hashMap);
                    }
                    Toast.makeText(LoginActivity.this, "Registered User " + user.getEmail(), Toast.LENGTH_LONG).show();
                    Intent mainIntent = new Intent(LoginActivity.this, DashboardActivity.class);
                    mainIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
                    startActivity(mainIntent);
                    finish();
                } else {
                    loadingBar.dismiss();
                    Toast.makeText(LoginActivity.this, "Login Failed", Toast.LENGTH_LONG).show();
                }
            }
        }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                loadingBar.dismiss();
                Toast.makeText(LoginActivity.this, "Error Occured", Toast.LENGTH_LONG).show();
            }
        });
    }
  
    @Override
    public boolean onSupportNavigateUp() {
        onBackPressed();
        return super.onSupportNavigateUp();
    }
}

步骤7：使用AndroidManifest.xml文件

导航到AndroidManifest.xml文件，并添加以下权限以在应用程序中获得Internet权限。

另外，使SpalshScreen Acticty作为欢迎屏幕。参考以下代码

以下是AndroidManifest.xml文件的完整代码。

步骤8：使用colors.xml文件

转到应用程序> res>值> colors.xml文件，然后使用以下颜色

XML格式

    #CC2E76BE
    #CC073D74
    #0A527E
    #000000
    #fff
    #F5F1F1
    #959595
    #f5f0f0
    #17581A
    #F4511E
    #E61313
    #2CA7E0
    #0a1b97
    #2B2C2E

输出：

登记：

登录：

成功通过身份验证后，管理员可以在Firebase控制台中看到用户，如下所示

有关本文中使用的所有可绘制文件，请参考以下链接： https : //drive.google.com/drive/folders/1M_knOH_ugCuwSP5nkYzeD4dRp-Honzbe?usp=sharing

下面是执行这些操作后的文件结构：

Note: In this part, there is nothing to do with the DashboardActivity.