Android Progressdialog Progress Bar Doing Things In The Right Order

I just about got this, but I have a small problem in the order of things going off. Specifically, in my thread() I am setting up an array that is used by a Spinner. Problem is the

Solution 1:

Don't know if you've ever solved this, but this works for me:

public class Start extends Activity {
private static final String TAG = "PriceList";

ArrayAdapter<ProductCategory> category_adapter;
ArrayAdapter<ProductGroup> group_adapter;

ArrayList<ProductCategory> categories;
ArrayList<ProductGroup> groups;

ArrayList<Price> prices;

Spinner group_spinner;
Spinner category_spinner;
ProgressDialog progressDialog;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    group_spinner = (Spinner) findViewById(R.id.group_spinner);
    category_spinner = (Spinner) findViewById(R.id.category_spinner);

    // product category spinner
    categories = new ArrayList<ProductCategory>();

    category_adapter = new CustomArrayAdapter<ProductCategory>(categories);
    category_adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

    // load category spinner from database
    loadCategory();     // adapter MUST be setup before this is called

    category_spinner.setAdapter(category_adapter);
    category_spinner.setOnItemSelectedListener(new OnItemSelectedListener () {


    ..... other stuff ...... 


private final Handler handler = new Handler() {
    @Override
    public void handleMessage(final Message msg) {
        Log.v(TAG, "worker thread done, setup adapter");

        switch (msg.what) {
        case Constants.CATEGORIES:
            category_adapter.notifyDataSetChanged();
            break;
        case Constants.GROUPS:
            group_adapter.notifyDataSetChanged();
            break;
        case Constants.PRICES:
            startActivity(new Intent(Start.this, ShowPrices.class));
            break;
        default:
        }
        // dismiss dialog
        progressDialog.dismiss();
    }
};

    // loadCategory() essentially the same....

private void loadGroup(final String cat) {
    Log.v(TAG, "loadGroup");

    progressDialog = new ProgressDialog(this);
    progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
    progressDialog.setMessage("Retrieving Product Groups...");
    progressDialog.setMax(100);
    progressDialog.setProgress(0);
    progressDialog.show();

    new Thread() {

        @Override
        public void run() {

            int count = 100;
            int i = 0;

            SQLiteDatabase db = DbUtils.getStaticDb();

            Cursor c = db.rawQuery("select count(*) from productgroup where category = \'"
                            + cat + "\';", null);
            c.moveToFirst();
            if (!c.isAfterLast()) {
                count = c.getInt(0);
            }
            c.close();

            progressDialog.setMax(count);

            groups.clear();
            groups.add(new ProductGroup("-1", "--- Select ---"));

            StringBuilder sb = new StringBuilder("select _id,description from productgroup");
            sb.append(" where category = \'");
            sb.append(cat);
            sb.append("\' order by description;");
            Log.v(TAG, sb.toString());

            c = db.rawQuery(sb.toString(), null);
            c.moveToFirst();
            while (!c.isAfterLast()) {
                Log.v(TAG, c.getString(0));
                groups.add(new ProductGroup(c.getString(0), c.getString(1)));
                i++;
                if (i % 5 == 0) {
                    progressDialog.setProgress(i);
                }
                c.moveToNext();
            }
            c.close();

            // tell UI thread OK
            handler.sendEmptyMessage(Constants.GROUPS);
        }
    }.start();
}

    // custom ArrayAdapter allows us to have our own ArrayList<T>

class CustomArrayAdapter<T> extends ArrayAdapter<T> {

    CustomArrayAdapter(ArrayList<T> list) {
        super(Start.this, android.R.layout.simple_spinner_item, list);
    }

}

Solution 2:

All the work after loadData() in onCreate() needs to be done after the work in run() in the thread triggered in loadData() has been completed. Try inlining loadData(), and adding this post-setup work to a runOnUiThread() after pd.dismiss().

Solution 3:

I would also suggest you to use https://github.com/commonsguy/cwac-task it has very nice AsyncTaskEx impl, which you can use to do heavy work without locking the ui.

Example class;

protected class DoHeavyWorkAsync extends AsyncTaskEx<Void, Integer, String> {
        private static final String TAG = "DoHeavyWorkAsync";

        @Override
        protected String doInBackground(Void... arg0) {

            // do heavy work here. e.g. loadDataFromSomewhere();
            YourActivity.this.runOnUiThread(new Runnable() {
                public void run() {
                    // you can do ui work on the main activity from here
                }
            });

            return null;
        }

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

            Log.d(TAG, "onPreExecute()");
                    //e.g. display "loading..." 
        }
        @Override
        protected void onPostExecute(String result) {
            super.onPostExecute(result);
            Log.d(TAG, "onPostExecute()");
        }
    }

from your main activity you can call like this;

(new DoHeavyWorkAsync()).execute();