Question

您好我正在尝试为我的应用构建一个登录系统。我试图确保在我进入下一个活动之前登录，但是如果我进入while循环，firebase似乎停止尝试登录。喜欢认真的wtf？我正在android studio btw中构建它。

以下是一些代码：

void handleLogin() {
//Check our form
    if (!validateForm()) {
       Toast.makeText(getApplication(), "All Fields Required",
            Toast.LENGTH_SHORT).show();
       return;
    }
    //Sign in the user
    mAuth.createUserWithEmailAndPassword(email, password)
           .addOnCompleteListener(this, new     OnCompleteListener<AuthResult>  () {
            @Override
            public void onComplete(@NonNull Task<AuthResult> task) {
                Log.d(TAG, "signInWithEmail:onComplete:" + task.isSuccessful());
                if (!task.isSuccessful()) {
                    Log.w(TAG, "signInWithEmail", task.getException());
                    Toast.makeText(getApplication(), "Authentication failed.",
                            Toast.LENGTH_SHORT).show();
                }
            }
        });
 }

/*************************************************
 * ON CREATE - The Activity runs from here!
 *************************************************/
@Override
protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   mAuth = FirebaseAuth.getInstance();
   setContentView(R.layout.activity_create_profile);

   //Checking authState from Firebase
   mAuthListener = new FirebaseAuth.AuthStateListener() {
       @Override
       public void onAuthStateChanged(@NonNull FirebaseAuth mAuth) {
            FirebaseUser user = mAuth.getCurrentUser();
            if (user != null) {
               Log.d(TAG, "onAuthStateChanged:signed_in:" + user.getUid());
               isLogged = true;
               System.out.println("Logged in: " + isLogged);
            } else {
               Log.d(TAG, "onAuthStateChanged:signed_out");
       }
    }
};

//Pop up for when adminID is activated
adminIDField = (EditText) findViewById(R.id.editText13);
adminIDField.setOnFocusChangeListener(new View.OnFocusChangeListener() {
    @Override
    public void onFocusChange(View v, boolean hasFocus) {
        if (hasFocus)
            showPopUp();
        else
            System.out.println("Admin ID entered...");
    }
});

// Create Profile Button
createProfile = (Button) findViewById(R.id.button13);
createProfile.setOnClickListener(new View.OnClickListener() {
    public void onClick(View view) {
        Calendar currentTime = Calendar.getInstance();
        Calendar timeOut = (Calendar)currentTime.clone();
        timeOut.add(Calendar.SECOND, 10);
        emailString = (EditText) findViewById(R.id.editText7);
        passwordString = (EditText) findViewById(R.id.editText8);
        firstNameField = (EditText) findViewById(R.id.editText10);
        lastNameField = (EditText) findViewById(R.id.editText11);
        apartmentField = (EditText) findViewById(R.id.editText12);
        Intent intent = new Intent("android.intent.action.MENU");

        handleLogin();

        while(!isLogged){ //THIS IS WHERE MY PROBLEM OCCURS
            System.out.println("Authenticating...");
            try{
                Thread.sleep(250);
            }catch (InterruptedException e){
                e.printStackTrace();
            }
        }
        //handleDataStorage();
        //startActivity(intent);
    }
});
}

出于某些原因，当我没有while循环时，它会让我很好地登录，但是当我在循环中包含登录时，它会永远停留在那里。那是为什么？

Answer 1

使用Thread.sleep()的自旋循环等待某事发生是一个非常糟糕的主意。 Android（以及大多数现代环境）实现事件驱动模型，无需执行此操作。

如果您查看代码，可以归结为：

 doThingA();
 waitForThingA();
 doSomethingThatDependsOnThingA();

在事件驱动模型中，您可以将其写为：

doThingAandThen(doSomethingThatDependsOnThingA);

如果查看已有的代码，可以找到已经遵循此模式的示例。例如，此代码响应用户的身份验证状态更改：

mAuthListener = new FirebaseAuth.AuthStateListener() {
   @Override
   public void onAuthStateChanged(@NonNull FirebaseAuth mAuth) {
        FirebaseUser user = mAuth.getCurrentUser();
        if (user != null) {
           Log.d(TAG, "onAuthStateChanged:signed_in:" + user.getUid());
           isLogged = true;
           System.out.println("Logged in: " + isLogged);
        } else {
           Log.d(TAG, "onAuthStateChanged:signed_out");
   }
}

您希望在用户登录时处理数据存储并转换到其他活动。通过将该代码放入此所谓的身份验证状态侦听器，您可以在没有等待循环的情况下完成相同操作：

//Checking authState from Firebase
mAuthListener = new FirebaseAuth.AuthStateListener() {
   @Override
   public void onAuthStateChanged(@NonNull FirebaseAuth mAuth) {
        FirebaseUser user = mAuth.getCurrentUser();
        if (user != null) {
           Log.d(TAG, "onAuthStateChanged:signed_in:" + user.getUid());
           isLogged = true;
           handleDataStorage();
           //startActivity(intent);
        } else {
           Log.d(TAG, "onAuthStateChanged:signed_out");
   }
}

进入while循环时，CreateUserWithEmailandPassword会停止吗？

1 个答案: