Develop Reference

Displaying error message in an activity from a seperate public asyncTask class

I am creating the user registration part of my app. I am using the AsyncTask class to handle this work on a separate thread. I have my AsyncTask class in a seperate class file. This
public class CreateAccountTask extends AsyncTask<String, Void, String>{
private ProgressDialog mpDialog;
private CreateAccountTask task;
private Context context;
private Activity activity;
private CreateAccount createAccount;
private AsyncTaskListener asyncTaskListener;
public CreateAccountTask(Activity activity, AsyncTaskListener asyncTaskListener){
this.activity = activity;
this.asyncTaskListener = asyncTaskListener;
}
#Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
mpDialog = new ProgressDialog(activity);
//mpDialog.setTitle("Creating Account");
mpDialog.setMessage("Please wait.");
mpDialog.setCancelable(false);
mpDialog.setIndeterminate(false);
mpDialog.setButton(DialogInterface.BUTTON_NEGATIVE, "CANCEL", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface arg0, int arg1) {
// TODO Auto-generated method stub
//task.cancel(true);
mpDialog.dismiss();
}
});
mpDialog.show();
}
#Override
protected String doInBackground(String... arg0) {
// TODO Auto-generated method stub
String fphoneNo = arg0[1];
String fpassword = arg0[0];
// create instance of the parseUser Class
ParseUser newUser = new ParseUser();
newUser.setUsername(fphoneNo);
newUser.setPassword(fpassword);
// here Check if progress dialog has been cancelled
if (!isCancelled()){
// if dialog has not been cancelled create the new user here
newUser.signUpInBackground(new SignUpCallback() {
#Override
public void done(ParseException e) {
// Something went wrong Sorry!
if(e != null ){
if(!isCancelled()){
mpDialog.dismiss();
String errorMessage = e.getMessage().toString();
ErrorHappened(errorMessage);
}
else{
String errorMessage = "Registration Cancelled!";
ErrorHappened(errorMessage);
}
}
// No Problems
else {
if (!isCancelled()) {
// Wait for five seconds before starting the activity
//verifyingUser();
}
else {
String errorMessage = "Registration Cancelled2!";
ErrorHappened(errorMessage);
//Delete user in background
ParseUser currentUser = ParseUser.getCurrentUser();
if (currentUser != null) {
currentUser.deleteInBackground();
}
}
}
}
});
}
return null;
}
#Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
asyncTaskListener.onTaskComplete(result);
}
private void ErrorHappened(String errorMessage) {
Crouton CreateMagic = Crouton.makeText(createAccount, errorMessage, CroutonClass.ALERT);
CreateMagic.setConfiguration(CroutonClass.configure);
CreateMagic.show();
}
}
In my onPreExecute method, i start a progressDialog that shows while the background task is being executed. While in my doInBackground method i have i get the username and password supplied by the user in the main Activity and sign up the user. This is where my problem begins, If an error occurs during the user registration, i want to notify the user of this error using a Crouton (A cooler version of a toast). But the app crashes when it gets to the point of displaying the error with the crouton.
My question is:
How do i display the error message in my activity?
2.
here is my Activity:
public class CreateAccount extends ActionBarActivity implements AsyncTaskListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_create_account);
mPassWord = (EditText) findViewById(R.id.password);
mcreateAccount = (Button) findViewById(R.id.createAcct);
mPhoneNumber = (EditText) findViewById(R.id.Phone_Number);
// create account Method
createAccount();
}//end of on create.
public void createAccount() {
mcreateAccount.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
CreateAccountTask newTask = new CreateAccountTask(CreateAccount.this, new CreateAccount());
newTask.execute(passwordString, fpartphoneNo);
});
}
private void verifyingUser() {
}
private void shitHappened(String errorMessage) {
// TODO Auto-generated method stub
Crouton CreateMagic = Crouton.makeText(this, errorMessage, CroutonClass.ALERT);
CreateMagic.setConfiguration(CroutonClass.configure);
CreateMagic.show();
}
#Override
public void onBackPressed() {
// TODO Auto-generated method stub
Crouton.cancelAllCroutons();
super.onBackPressed();
}
#Override
public void onTaskComplete(String result) {
// TODO Auto-generated method stub
}
}

Notifications and any other UI manipulation is only allowed from the UIThread. If you look at the documentation of AsyncTask, doInBackground() runs on its own Thread, while onPreExecute(), onPostExecute() and onCancelled() run on the UIThread.
In your case, you should use protected void onCancelled(String result) for the Notification. This runs on the UIThread and helps you to distinguish between a successful and unsuccessful operations. To use this, call cancel() and check in doInBackground() if the operation was cancelled.
onCancelled() will then be executed instead of onPostExecute()
In your special case it could be a problem of the context, because you are storing your CreateAccount.this in the constructor in activity of your CreateAccountTask, but you are using createAccount. Try changing it to the following:
Crouton.makeText(activity, errorMessage, CroutonClass.ALERT);

Use runOnUiThread as below...
#Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
runOnUiThread(new Runnable() {
#Override
public void run() {
mpDialog = new ProgressDialog(activity);
//mpDialog.setTitle("Creating Account");
mpDialog.setMessage("Please wait.");
mpDialog.setCancelable(false);
mpDialog.setIndeterminate(false);
mpDialog.setButton(DialogInterface.BUTTON_NEGATIVE, "CANCEL", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface arg0, int arg1) {
// TODO Auto-generated method stub
//task.cancel(true);
mpDialog.dismiss();
}
});
mpDialog.show();
}
}

WindowManager$BadTokenException near dialog.show in AsyncTask android

How to show a dialog box in AsyncTask. Getting BadToketException in dialog.show();
I tried many ways but I could not solve it.
Also tried to pass context to the dialog box in different ways, but it is giving me the same result.
public class RetriveStock extends AsyncTask<Void, Void, Void> {
#Override
protected Void doInBackground(Void... params) {
message = client.clientReceive(1); // I get data here.
return null;
}
#Override
protected void onCancelled() {
super.onCancelled();
}
#Override
protected void onPostExecute(Void result) {
if (message.contains("AlertExecuted:")) {
final Dialog dialog = new Dialog(CreateAlert.this);
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.setContentView(R.layout.display_dialog);// Dialog layout
TextView dialogText = (TextView) dialog.findViewById(R.id.digMsg);
dialogText.setText("Alert Executed!");
Button ok = (Button) dialog.findViewById(R.id.ok);
ok.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
dialog.dismiss();
}
});
try {
dialog.show(); //WindowManager$BadTokenException
} catch (Exception e) {
e.printStackTrace();
}
}
super.onPostExecute(result);
}
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
}
Please help.

protected void onPreExecute() {
// TODO Auto-generated method stub
// progressDialog = ProgressDialog.show(this, "", "loading news content");
progressDialog = new ProgressDialog(context , AlertDialog.THEME_HOLO_LIGHT);
progressDialog.setMessage(""+getString(R.string.laodnews));
progressDialog.setIndeterminateDrawable(getResources().getDrawable(R.drawable.animate));
progressDialog.setCancelable(false);
progressDialog.show();
}
start dailoge in pre execute and stop in onpostexecute..

is CreateAlert registered activity in manifest..if not then you have to pass registered activity context

Async task not working well

I have used Async task to send a mail when user presses the button "b" but its showing an error and the error is "Error while executing doInBackground" and "First Activity has leaked a Window"
public class FirstActivity extends Activity implements OnClickListener
{
Button b;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
b=(Button)findViewById(R.id.button);
b.setOnClickListener(this);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
#Override
public void onClick(View v) {
ProgressDialog progress = new ProgressDialog(this);
progress.setMessage("Loading...");
new MyTask(progress).execute();
Intent i=new Intent(this,newclass.class);
startActivity(i);
}
// TODO Auto-generated method stub
public class MyTask extends AsyncTask<Void, Void, Void> {
private ProgressDialog progress;
public MyTask(ProgressDialog progress)
{
this.progress = progress;
}
public void onPreExecute()
{
super.onPreExecute();
progress.show();
}
public Void doInBackground(Void... unused)
{
String detail="sending mmail";
new MainActivity(detail);
return null;
}
public void onPostExecute(Void unused)
{
progress.dismiss();
}
}
}

try to use this method in doInBackground...
public Void doInBackground(Void... unused)
{
runOnUiThread(new Runnable()
{
public void run()
{
// TODO Auto-generated method stub
String detail="sending mmail";
new MainActivity(detail);
return null;
}
});
}

You are trying to navigate to a new Activity, MainActivity, while the ProgressDialog is still on. That is causing the memory leak.

The error is because you are starting a new activity immediately after starting your progress dialog (the dialog loses its context).
You need to move it to onPostExecute().
public void onPostExecute(Void unused){
progress.dismiss();
Intent i = new Intent(this,newclass.class);
startActivity(i);
}

Json Element returns null in AsyncTask

When I call only wpCategories = JsonToElement.getllAllCategory(); in the buttons onClick methood it works fine. (wpCategories get filled with data). But when I put this in a asynctask, wpCategories returns null. (is the doInBackground not being called?)
Here is my buttons on click methood:
public void onImageGridClick(View view) {
new GetJsonElementTask().execute();
Intent intent = new Intent(this, CategoryGridActivity.class);
intent.putParcelableArrayListExtra(Extra.IMAGES, wpCategories);
startActivity(intent);
}
And the asyncTask:
private class GetJsonElementTask extends AsyncTask<Void, Integer, String> {
#Override
protected void onPreExecute() {
progressDialog = ProgressDialog.show(HomeActivity.this, "",
"Loading...");
}
#Override
protected String doInBackground(Void... arg0) {
wpCategories = JsonToElement.getllAllCategory();
return null;
}
#Override
protected void onPostExecute(String value) {
progressDialog.dismiss();
}
#Override
protected void onProgressUpdate(Integer... progress) {
Log.v("DEBUG_LOG", "In onProgressUpdate");
}
}

Start your Activity inside onPostExecute because this method execute after doInBackground execution complete :
#Override
protected String doInBackground(Void... arg0) {
wpCategories = JsonToElement.getllAllCategory();
return wpCategories; //<<< return value from here
}
#Override
protected void onPostExecute(String value) {
progressDialog.dismiss();
Intent intent = new Intent(this, CategoryGridActivity.class);
intent.putParcelableArrayListExtra(Extra.IMAGES, value);
startActivity(intent);
}

Try following
public void onImageGridClick(View view) {
new GetJsonElementTask().execute();
}
public void startCategoryGridActivity(){
Intent intent = new Intent(this, CategoryGridActivity.class);
intent.putParcelableArrayListExtra(Extra.IMAGES, wpCategories);
startActivity(intent);
}
And the asyncTask:
private class GetJsonElementTask extends AsyncTask<Void, Integer, String> {
#Override
protected void onPreExecute() {
progressDialog = ProgressDialog.show(HomeActivity.this, "",
"Loading...");
}
#Override
protected String doInBackground(Void... arg0) {
wpCategories = JsonToElement.getllAllCategory();
return null;
}
#Override
protected void onPostExecute(String value) {
progressDialog.dismiss();
startCategoryGridActivity();
}
#Override
protected void onProgressUpdate(Integer... progress) {
Log.v("DEBUG_LOG", "In onProgressUpdate");
}
}

My Dialog.show() not work

I am making a loading effect when calling MainActivity. I have no idea why my Dialog.show is not working in the AsyncTask. All i just see the just the instant when it dismiss, but the dialog never appear before that.
Thank you.
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
new LoadViewTask().execute();
setContentView(R.layout.activity_main);
....}
private class LoadViewTask extends AsyncTask<Void, Integer, Void>
{
#Override
protected void onPreExecute() {
progressDialog = ProgressDialog.show(MainActivity.this,"Loading...","Loading application View, please wait...", false, false);
}
#Override
protected Void doInBackground(Void... params)
{
try
{
synchronized (this)
{
int counter = 0;
while(counter <= 4)
{
this.wait(1000);
counter++;
publishProgress(counter*25);
}
}
}
catch (InterruptedException e)
{
e.printStackTrace();
}
return null;
}
#Override
protected void onProgressUpdate(Integer... values)
{
progressDialog.setProgress(values[0]);
}
#Override
protected void onPostExecute(Void result)
{
progressDialog.dismiss();
}
}

You should use FragmentDialogs for using dialogs in Android.
Here it is well explained:
http://developer.android.com/intl/es/reference/android/app/DialogFragment.html

Try to set the content view before starting your async task:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Set the content view first
setContentView(R.layout.activity_main);
new LoadViewTask().execute();
....}