ProgressDialog doesn't appear immediately

问题:

I have a fragment with some buttons in it, when a button is clicked it should show a ProgressDialog, load an array of bitmaps and show it in the fragment in a gallery, dismiss ProgressDialog.

But the ProgressDialog doesn't show immediately, it take something like 1 or 2 seconds and it just blink at the moment when my gallery is show.

Im doing this after click:

try{
    progress = ProgressDialog.show(activity, "", "Loading images", true);

    //load images
    //show gallery

}catch(){
    //...
}finally{
    handler.sendEmptyMessage(0);
}

My Handler at onCreate:

handler = new Handler() {
    public void handleMessage(Message msg) {
         progress.dismiss();
    }
};

Im using Android 3.1

Logcat shows anything :(

03-09 13:17:32.310: D/DEBUG(5695): before show()
03-09 13:17:32.350: D/DEBUG(5695): after show()

回答1:

You are loading the images on the main UI thread - you should do this in a background process as it may cause your UI to become unresponsive (and cause your ProgressDialog to show up at the wrong time).

You should look into using an AsyncTask to carry out loading of the images in the background.

Display the ProgressDialog in AsyncTask.onPreExecute, load images in AsyncTask.doInBackground and dismiss the dialog in AsyncTask.onPostExecute.

回答2:

Documentation does not tell much about setIndeterminate(boolean), so I'm not sure. But I use this in my app, and it works:

ProgressDialog fDialog = new ProgressDialog(your-context);
fDialog.setMessage(your-message);
fDialog.setIndeterminate(true);
// fDialog.setCancelable(cancelable);
fDialog.show();

Could you try it?