ProgressDialog not shown in AsyncTask

Question

I have a huge database (40MB) on an SDCard. I need fetch data, with LIKE in query, which is very slow.

DB request takes about 5 seconds. Therefore, I need to do it asynchronously and with ProgressDialog.

I tried it with AsyncTask, but problem is with ProgressDialog.
It was implemented this way:

private class GetDataFromLangDB extends AsyncTask<String, String, String> {

    private final ProgressDialog dialog = new ProgressDialog(TranslAndActivity.this);

    @Override
    protected void onPreExecute() {
        super.onPreExecute();

         urDBCursor.close();
         curDBCursor = null;
         scaAdapter = null;

         this.dialog.setMessage("Loading data...");
         this.dialog.show();

    } 

    @Override
    protected String doInBackground(String... whatSearch) {
        String result = "";

        if (myDatabaseAdapter != null) {
            curDBCursor = myDatabaseAdapter.fetchAll(whatSearch[0]);
        }
        return result;
    }

    @Override
        protected void onPostExecute(String result) {
            super.onPostExecute(result);

            if (this.dialog.isShowing()) {
                this.dialog.dismiss();
            }

            prepareListView();
    }
}

The problem is that ProgressDialog is not shown during the DB request. After finished database query, it flash on screen for a short time. When user tries to tap on screen during database request, UI is freezed, and after DB request message about 'not responding' is shown.

I tried it with a thread this way:

public void startProgress(View view, final String aWhatSearch) {

        final ProgressDialog dialog = new ProgressDialog(MyActivity.this);
        if (curDBCursor != null){
            curDBCursor.close();
            curDBCursor = null;
        }

        dialog.setMessage("Loading data...");
        dialog.show();
        Runnable runnable = new Runnable() {
            public void run() {
                curDBCursor = myDatabaseAdapter.fetchAll(aWhatSearch);
                // dirty trick
                try {
                    Thread.sleep(250); // it must be here to show progress
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

                handler.post(new Runnable() {
                    public void run() {
                        if (dialog.isShowing()) {
                            dialog.dismiss();
                        }
                        prepareListView();
                    }
                });

            }
        };
        new Thread(runnable).start();
    }

The result was the same, but when I used the trick with Thread.sleep(250); ProgressDialog was shown during the database request. But it is not spinning, it looks freezed during the DB request.

DB stuff is called this way (after tap on search button):

btnSearchAll.setOnClickListener(new OnClickListener() {
    public void onClick(View v) {
        // AsyncTask
        new GetDataFromLangDB().execute(edtTextToSearch.getText().toString());

        // or Thread 
        //startProgress(null, edtTextToSearch.getText().toString());
    }
});

I found a lot of problems like this in SO, but nothing was useful for me. Could it be that DB is on SD Card?

DB is on SDcard is not the reason for this . Can you paste the part of code from where you are calling the AsyncTask . — Sunny Kumar Aditya, Aug 17 '12 at 08:09

score 1 · Answer 1 · answered Aug 17 '12 at 08:14

1

I put the definition of the dialog into the AsyncTask Class and it works fine for me. Take a look at this exampel (You have to change NAMEOFCLASS in the name of your CLASS:

private class doInBackground extends AsyncTask<Integer, Integer, Void> {

   final ProgressDialog dialog = new ProgressDialog(NAMEOFCLASS.this) {

    @Override
    protected void onPreExecute() {
        dialog.setCancelable(false);
        dialog.setTitle(getString(R.string.daten_wait_titel));
        dialog.setIcon(R.drawable.icon);
        dialog.setMessage(getString(R.string.dse_dialog_speichern));
        dialog.show();
    }

    @Override
    protected void onCancelled() {
        dialog.cancel();
    }

....

    @Override
    protected void onProgressUpdate(Integer... values) {
                   // DO YOUR UPDATE HERE
    }

    @Override
    protected void onPostExecute(Void result) {
        dialog.dismiss();
                }

}

answered Aug 17 '12 at 08:14

JackTools.Net

734
6
13

I think that his definition of the dialog is in AsyncTask. He reference it by using this.dialog – sinisha Aug 17 '12 at 08:30
Yes definition of the dialog is in the AsyncTask. Therefore I'm confused what's wrong there. Maybe during the heavy DB load -> device is not responding due to the busy SQLite driver.... **Maybe I need service for this (?) ** – Peter Aug 17 '12 at 08:38
Ok. that's right. Then the only diference is the line Super.OnPreExcecute(); Perhaps it will help to delete this line. – JackTools.Net Aug 17 '12 at 08:44
@Peter And could you give us the logcat? – sinisha Aug 17 '12 at 08:45
@JackTools.Net If he deletes super.OnPreExecute it will definitely crash the application – sinisha Aug 17 '12 at 08:48
Well I use the exampe I posted several times and it works fine for ne without this line of code. – JackTools.Net Aug 17 '12 at 09:01

score 0 · Answer 2 · edited May 23 '17 at 10:24

0

Maybe this SO answer could help you. It looks like similar problem. Try to use AsyncQueryHandler for querying your database

edited May 23 '17 at 10:24

Community

1
1

answered Aug 17 '12 at 09:27

sinisha

1,013
13
30

score 0 · Answer 3 · answered Aug 17 '12 at 10:35

declare you Dialog box on Class (Activity) level like this

private ProgressDialog dialog = null;

show the progress dialog and call the AsyncTask class when you want to start you Busy work..like onButton click or any

dialog = ProgressDialog.show(this,"Sending Email to your account please! wait...", true);
SendingEmailTask task = new SendingEmailTask();
String s = "";
task.execute(s);

create your inner class like

private class SendingEmailTask extends AsyncTask<String, Void, String> {

    protected String doInBackground(String... urls) {
         //do your work here..
         // like fetching the Data from DB or any
         return null;
       }

       @Override
       protected void onPostExecute(String str) {
           //hide progress dialog here
           dialog.dismiss();
       }
}

let me know if this help!!

thanks for an answer, but it did not help. It still the same. I will try sinisha answer with AsyncQueryHandler, or I try to wrap it into a **Service** — Peter, Aug 17 '12 at 11:36
okay i didn't check with DB loading so not sure about that but i do this for sending email etc and it works fine with me..well good luck with AsyncQueryHandler — swiftBoy, Aug 17 '12 at 12:29

ProgressDialog not shown in AsyncTask

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