CODEWITHSUNDEEP
javaandroidjson
BMC
BMC

Reputation: 5

how to use run runOnUithread?

The app I am working on has a login/register which connects to a mysql database, At first I was running everything on the UI Thread I later found out it was not working because of the against running long code on Android's UI Thread. I attempted to edit my code to run the long task on a new Thread that i added. . Now my app registers the I see the result in mysql but my app keeps closing because of this error 

android.view.ViewRootImpl$CalledFromWrongThreadException: 
Only the original thread that created a view hierarchy can touch its views.

the error is understandable but I don't know how to run the View or Views back to the UI Thread.

I've done some research about the runOnuithread but I dont know where to place it in my code, or weather I placed the new Thread I added before in the wrong place to begin with please

can anyone help my fix this

here is a snippet of the code

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.register);

    // Importing all assets like buttons, text fields
    inputFullName = (EditText) findViewById(R.id.registerName);
    inputEmail = (EditText) findViewById(R.id.registerEmail);
    inputPassword = (EditText) findViewById(R.id.registerPassword);
    btnRegister = (Button) findViewById(R.id.btnRegister);
    btnLinkToLogin = (Button) findViewById(R.id.btnLinkToLoginScreen);
    registerErrorMsg = (TextView) findViewById(R.id.register_error);

    // Register Button Click event
    btnRegister.setOnClickListener(new View.OnClickListener() {  

        public void onClick(View view) {
             /** According with the new StrictGuard policy,  running long tasks on the Main UI thread is not possible
            So creating new thread to create and execute http operations */
            new Thread (new Runnable() {
                @Override
                 public void run() {
            //
            String name = inputFullName.getText().toString();
            String email = inputEmail.getText().toString();
            String password = inputPassword.getText().toString();
            UserFunctions userFunction = new UserFunctions();

            JSONObject json = userFunction.registerUser(name, email, password);

            // check for login response
            try {
                //

                //
                if (json.getString(KEY_SUCCESS) != null) {

                    registerErrorMsg.setText("");
                    String res = json.getString(KEY_SUCCESS); 
                    if(Integer.parseInt(res) == 1){
                        // user successfully registred
                        // 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(), MainActivity.class);
                        // Close all views before launching Dashboard
                        dashboard.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                        startActivity(dashboard);
                        // Close Registration Screen
                        finish();
                    }else{
                        // Error in registration
                        registerErrorMsg.setText("Error occured in registration");
                    }
                }//
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }
            }).start();
        }
    });

    // Link to Login Screen
    btnLinkToLogin.setOnClickListener(new View.OnClickListener() {

        public void onClick(View view) {

            Intent i = new Intent(getApplicationContext(),
                    LoginActivity.class);
            startActivity(i);
            // Close Registration View
            finish();
        }
    });
}
}

Upvotes: 0

Views: 633

Answers (1)

codeMagic
codeMagic

Reputation: 44571

Since you seem to have network code mixed in with UI code, I'm not going to try and write it for you. I can tell you how it should be and assume that you can rearrange the code yourself since you know what all of it does.

Ok, inside your run() you put your network code then when you need to update the UI you can have 

runOnUiThread(new Runnable()
{
    @Override
    public void run()
    {
        // code to update UI
    }
});

With that said, I recommend using AsyncTask for your network operations. This makes it much easier as it already has the functions for background stuff and updating the UI. You start the task and doInBackground() runs and that is where you do all of your network operations. Then you can update the UI in any of AsyncTasks other 3 methods.

See this answer for an example of using AsyncTask, along with the link to the docs above.

Upvotes: 1

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