布尔在我的异步任务中不起作用

Question

I got a problem. My async task is doing just fine. But on my OnPostExecute I got this:

if (error = true) {
   loginErrorMsg.setText("Incorrect username/password");
} else {
   loginErrorMsg.setText("");
}

Even if error == false he is still showing: Incorrect username/password ...

class LoginUser extends AsyncTask<String, String, String> {

    /**
     * Before starting background thread Show Progress Dialog
     * */
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(LoginActivity.this);
        pDialog.setMessage("Loading");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(true);
        pDialog.show();
        email = inputEmail.getText().toString();
        password = inputPassword.getText().toString();

    }

    /**
     * Creating product
     * */
    protected String doInBackground(String... args) {

        UserFunctions userFunction = new UserFunctions();
        Log.d("Button", "Login");
        JSONObject json = userFunction.loginUser(email, password);
     // check for login response
        try {
            if (json.getString(KEY_SUCCESS) != null) {
                String res = json.getString(KEY_SUCCESS); 
                if(Integer.parseInt(res) == 1){
                    // user successfully logged in
                    // Store user details in SQLite Database
                    DatabaseHandler db = new DatabaseHandler(getApplicationContext());
                    JSONObject json_user = json.getJSONObject("user");

                    // Clear all previous data in database
                    userFunction.logoutUser(getApplicationContext());
                    db.addUser(json_user.getString(KEY_NAME), json_user.getString(KEY_EMAIL), json.getString(KEY_UID), json_user.getString(KEY_CREATED_AT));                        

                    // Launch Dashboard Screen
                    Intent dashboard = new Intent(getApplicationContext(), Main.class);

                    // Close all views before launching Dashboard
                    dashboard.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                    startActivity(dashboard);

                    // Close Login Screen
                    finish();
                }else{
                    // Error in login
                    error = true;
                }
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }


        return null;
    }

    /**
     * After completing background task Dismiss the progress dialog
     * **/
    protected void onPostExecute(String file_url) {
        // dismiss the dialog once done
        pDialog.dismiss();


        if( error = true){
            loginErrorMsg.setText("Incorrect username/password");
        } else {
            loginErrorMsg.setText("");
        }
    }

}

Answer 1

您应该使用双等号。

if (error == true) {   

Answer 2

Operator used for equality test in Java is == , = is the assignment operator. Now your error will always be true cause you assign true to it everytime. Hope this helps.

Answer 3

为了进行比较，您应该使用error == true而不是error = true ，这是一个分配，并且始终为true。

Answer 4

将if(error = true)更改为if(error == true) 。