Question

I use the function to show picture:

Bitmap imageBitmap = loadBitmap(URL);

loadBitmap() as below:

private Bitmap loadBitmap(String url) {
try {
Bitmap bm = BitmapFactory.decodeStream((InputStream)this.fetch(url));
return bm;
}
catch(Exception e) {
e.printStackTrace();
return null;
}
} 

And fetch() below:

public Object fetch(String address) {
try {
URL url = new URL(address);
Object content = url.getContent();
return content;
}
catch(Exception e) {
e.printStackTrace();
}
return this;
}

I want to show the loading progress or a load.png while it loading.
And end with the picture loading finish and show it.
How can I do?
I try to make like ProgressDialog.
But I don’t know how to use?

Answer 1

You can use AsyncTask to show a Progress Dialog on the PreExecute() method and hide/dismiss it in the PostExecute() method.

ProgressDialog prog = new ProgressDialog(this); // Create Progress Dialog


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

    @Override
    protected void onPreExecute() {
        // TODO Auto-generated method stub
        super.onPreExecute();
        //Display progressDialog before download starts
        prog.show();

    }

    @Override
    protected void onPostExecute(Void result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);
        prog.hide(); //Hide Progress Dialog else use dismiss() to dismiss the dialog
    }

    @Override
    protected Void doInBackground(Void... params) {
        // TODO Auto-generated method stub
        /*
         * Perform download and Bitmap conversion here
         * 
         */
        return null;
    }

}

And finally call the AsyncTask through,

DownloadBitmap dd = new DownloadBitmap();
dd.execute();