【Firebase SDK（使用电子邮件/密码进行身份验证）】在前面的部分中, 我们了解了如何使用Firebase UI对电子邮件/密码或电子邮件链接/无密码进行身份验证。在本部分中, 我们将学习如何使用Firebase SDK进行身份验证。 Firebase SDK与Firebase UI略有相同。让我们看看使用Firebase SDK实施电子邮件/密码身份验证的步骤。
步骤1：
在第一步中, 我们必须执行以下准备步骤：
- 创建一个Android项目。
- 创建Firebase项目。
- 手动或通过Firebase协助将Firebase添加到Android项目或应用程序。
- 添加所需的库和JSON文件。
- 在Firebase控制台中启用电子邮件/密码登录方法。
完成准备工作后, 我们将创建注册, 登录和注销活动。
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第三步：
在下一步中, 我们将为注册活动进行编码。代码如下：
寄存器
public class MainActivity extends AppCompatActivity {//Initialization sectionEditText email, pass, username;
ProgressBar progressBar;
String userid, Email;
FirebaseAuth auth;
//FirebaseAuth Instance@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
email=(EditText)findViewById(R.id.email);
pass=(EditText)findViewById(R.id.password);
username=(EditText)findViewById(R.id.username);
progressBar=(ProgressBar)findViewById(R.id.progressBar);
auth=FirebaseAuth.getInstance();
//Getting instance of FirebaseAuth}// Checking the current all state@Overridepublic void onStart() {super.onStart();
// if user logged in, go to sign-in screenif (auth.getCurrentUser() != null) {startActivity(new Intent(this, Sign_out.class));
finish();
}}@Overrideprotected void onResume(){super.onResume();
progressBar.setVisibility(View.GONE);
}// Register button click public void onRegisterClicked(View view) {//Fetching dataString emailInput = email.getText().toString().trim();
String password = pass.getText().toString().trim();
final String user = username.getText().toString().trim();
//Validation check if (TextUtils.isEmpty(user)) {Toast.makeText(getApplicationContext(), "Enter username!", Toast.LENGTH_SHORT).show();
return;
}if (TextUtils.isEmpty(emailInput)) {Toast.makeText(getApplicationContext(), "Enter email address!", Toast.LENGTH_SHORT).show();
return;
}if (TextUtils.isEmpty(password)) {Toast.makeText(getApplicationContext(), "Enter password!", Toast.LENGTH_SHORT).show();
return;
}if (password.length() <
6) {Toast.makeText(getApplicationContext(), "Password too short, enter minimum 6 characters!", Toast.LENGTH_SHORT).show();
return;
}progressBar.setVisibility(View.VISIBLE);
//create user with email/password by adding complete listenerauth.createUserWithEmailAndPassword(emailInput, password).addOnCompleteListener(MainActivity.this, new OnCompleteListener<
AuthResult>
() {@Overridepublic void onComplete(@NonNull Task<
AuthResult>
task) {Toast.makeText(MainActivity.this, "createUserWithEmail:onComplete:" + task.isSuccessful(), Toast.LENGTH_SHORT).show();
progressBar.setVisibility(View.GONE);
// If sign-in fails, display a message to the user. If sign-in succeeds// the auth state listener will be notified and logic to handle the// signed in user can be handled in the listener.if (!task.isSuccessful()) {Toast.makeText(MainActivity.this, "Authentication failed." + task.getException(), Toast.LENGTH_LONG).show();
Log.e("MyTag", task.getException().toString());
} else {startActivity(new Intent(MainActivity.this, Sign_out.class));
finish();
}}});
}//Login button click public void onLoginClicked(View view) {startActivity(new Intent(this, login.class));
}}步骤4：
之后, 我们将分别为登录和注销活动进行编码。代码如下
登录
public class login extends AppCompatActivity {//Declaration sectionEditText email, password;
ProgressBar progressBar;
FirebaseAuth auth;
@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
email = (EditText) findViewById(R.id.email);
password = (EditText) findViewById(R.id.password);
progressBar = (ProgressBar) findViewById(R.id.progressBar);
auth = FirebaseAuth.getInstance();
//Getting instances of FirebaseAuth }//Checking current user is logging or not @Overridepublic void onStart() {super.onStart();
// If user logged in, go to sign-in screenif (auth.getCurrentUser() != null) {startActivity(new Intent(this, Sign_out.class));
finish();
}}@Overrideprotected void onResume() {super.onResume();
progressBar.setVisibility(View.GONE);
}//Login button clickpublic void loginButtonClicked(View view) {String Email = email.getText().toString();
final String pass = password.getText().toString();
//Validation sectionif (TextUtils.isEmpty(Email)) {Toast.makeText(getApplicationContext(), "Enter email address!", Toast.LENGTH_SHORT).show();
return;
}if (TextUtils.isEmpty(pass)) {Toast.makeText(getApplicationContext(), "Enter password!", Toast.LENGTH_SHORT).show();
return;
}progressBar.setVisibility(View.VISIBLE);
if (password.length() <
6) {password.setError("Should be greater than 6");
}//authenticate user with email/password by adding complete listener auth.signInWithEmailAndPassword(Email, pass).addOnCompleteListener(login.this, new OnCompleteListener<
AuthResult>
() {@Overridepublic void onComplete(@NonNull Task<
AuthResult>
task) {if (!task.isSuccessful()) {// there was an errorToast.makeText(login.this, "Authentication failed." + task.getException(), Toast.LENGTH_LONG).show();
Log.e("MyTag", task.getException().toString());
} else {Intent intent = new Intent(login.this, Sign_out.class);
startActivity(intent);
finish();
}}});
}}登出
public class Sign_out extends AppCompatActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sign_out);
}public void onLogout(View view){FirebaseAuth.getInstance().signOut();
startActivity(new Intent(this, MainActivity.class));
}}输出：
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