使用電子郵件和密碼進行 Firebase 身份驗證

Question

我對 Android Studio 和 Firebase 也比較陌生。 我已完成設置並連接到 Firebase，但此錯誤不斷彈出，導致應用程序崩潰：

 --------- beginning of crash
2019-01-17 14:38:11.420 10795-10795/com.example.asus.cab E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.asus.cab, PID: 10795
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.asus.cab/com.example.asus.cab.DriverLoginRegisterActivity}: java.lang.IllegalStateException: Default FirebaseApp is not initialized in this process com.example.asus.cab. Make sure to call FirebaseApp.initializeApp(Context) first.
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2902)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3037)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1797)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6642)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
     Caused by: java.lang.IllegalStateException: Default FirebaseApp is not initialized in this process com.example.asus.cab. Make sure to call FirebaseApp.initializeApp(Context) first.
        at com.google.firebase.FirebaseApp.getInstance(com.google.firebase:firebase-common@@16.0.4:240)
        at com.google.firebase.auth.FirebaseAuth.getInstance(Unknown Source:1)
        at com.example.asus.cab.DriverLoginRegisterActivity.onCreate(DriverLoginRegisterActivity.java:45)
        at android.app.Activity.performCreate(Activity.java:7131)
        at android.app.Activity.performCreate(Activity.java:7122)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2882)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3037) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1797) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:193) 
        at android.app.ActivityThread.main(ActivityThread.java:6642) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 

我也像這樣初始化 Firebase Auth，mAuth = FirebaseAuth.getInstance(); 但我仍然遇到同樣的錯誤

我也確實包含了依賴classpath 'com.google.gms:google- services:4.1.0'

和插件apply plugin: 'com.google.gms.google-services'在大多數解決方案中都提到過，但似乎沒有任何效果

這是以下代碼，根據 logcat，第 48 行中的錯誤指向 mAuth = FirebaseAuth.getInstance();

public class DriverLoginRegisterActivity extends AppCompatActivity {

    private Button DriverLoginButton;
    private Button DriverRegisterButton;
    private TextView DriverRegisterLink;
    private TextView DriverStatus;
    private EditText EmailDriver;
    private EditText PasswordDriver;
    private ProgressDialog loadingBar;
    private FirebaseAuth mAuth;

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

        DriverLoginButton = (Button) findViewById(R.id.driver_login_btn);
        DriverRegisterButton = (Button) findViewById(R.id.driver_register_btn);
        DriverRegisterLink = (TextView) findViewById(R.id.register_driver_link);
        DriverStatus = (TextView) findViewById(R.id.driver_status);
        EmailDriver = (EditText) findViewById(R.id.email_driver);
        PasswordDriver = (EditText) findViewById(R.id.password_driver);
        loadingBar = new ProgressDialog(this);

        // Initialize Firebase Auth
        mAuth = FirebaseAuth.getInstance();

        DriverRegisterButton.setVisibility(View.INVISIBLE);
        DriverRegisterButton.setEnabled(false);

        DriverRegisterLink.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                DriverLoginButton.setVisibility(View.INVISIBLE);
                DriverRegisterLink.setVisibility(View.INVISIBLE);
                DriverStatus.setText("Register Driver");   
                DriverRegisterButton.setVisibility(View.VISIBLE);
                DriverLoginButton.setEnabled(true);
            }
        });

        DriverRegisterButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view)
            {
                String email = EmailDriver.getText().toString();
                String password = PasswordDriver.getText().toString();

                RegisterDriver(email, password);
            }
        });


    }

    private void RegisterDriver(String email, String password) {
        if (TextUtils.isEmpty(email)) {
            Toast.makeText(DriverLoginRegisterActivity.this, "Please Enter Email..", Toast.LENGTH_SHORT).show();

        }

        if (TextUtils.isEmpty(password)) {
            Toast.makeText(DriverLoginRegisterActivity.this, "Please Enter Password..", Toast.LENGTH_SHORT).show();

        } else {
            loadingBar.setTitle("Driver Registration");
            loadingBar.setMessage("Please wait...");
            loadingBar.show();


            mAuth.createUserWithEmailAndPassword(email, password)
                    .addOnCompleteListener(new OnCompleteListener<AuthResult>() {
                        @Override
                        public void onComplete(@NonNull Task<AuthResult> task) {
                            if (task.isSuccessful()) {
                                Toast.makeText(DriverLoginRegisterActivity.this, "Driver Register Succesful..", Toast.LENGTH_SHORT).show();
                                loadingBar.dismiss();
                            } else {
                                Toast.makeText(DriverLoginRegisterActivity.this, "Registration Unsuccessful, Please Try Again..", Toast.LENGTH_SHORT).show();
                                loadingBar.dismiss();
                            }
                        }
                    });
        }
    }
}

Answer 1

確保您遵循 firebase 文檔的每一步：
有關身份驗證的 Firebase 文檔
您需要將 google services 添加到您的項目級 gradle 文件中：

classpath 'com.google.gms:google-services:4.2.0'

並且您需要將 firebase 核心依賴項添加到您的應用程序級 gradle 文件中：

implementation 'com.google.firebase:firebase-core:16.0.6'

確保您在登錄方法下的控制台中啟用了身份驗證選項

Answer 2

您的 logcat 本身為您的問題提供了解決方案：

您需要在應用程序類中調用FirebaseApp.initializeApp(Context) 。

Answer 3

您收到此錯誤是因為在您的代碼中，您尚未初始化 Firebase。

只需將此添加到您的活動的創建方法中

FirebaseApp.initializeApp(this);
mAuth = FirebaseAuth.getInstance();

Answer 4

正如之前有人指出的那樣，該錯誤表明您要么錯過了調用 FirebaseApp.initializeApp(Context) 方法，要么順序不正確。

最近使用 Firebase Auth SDK 進行了更新，新方法非常簡單且代碼最少。 請參閱此處了解更多詳情https://firebase.google.com/docs/auth/android/firebaseui

這是設置身份驗證提供程序和啟動身份驗證意圖的方法。 您需要為回調處理和 UI 自定義（如果適用）添加單獨的邏輯，這些邏輯也可在上述文檔鏈接中找到。

// Choose authentication providers
List<AuthUI.IdpConfig> providers = Arrays.asList(
        new AuthUI.IdpConfig.EmailBuilder().build(),
        new AuthUI.IdpConfig.PhoneBuilder().build(),
        new AuthUI.IdpConfig.GoogleBuilder().build(),
        new AuthUI.IdpConfig.FacebookBuilder().build(),
        new AuthUI.IdpConfig.TwitterBuilder().build());

// Create and launch sign-in intent
startActivityForResult(
        AuthUI.getInstance()
                .createSignInIntentBuilder()
                .setAvailableProviders(providers)
                .build(),
        RC_SIGN_IN);