Android - show progress dialog while doing work on UI thread

Question

I need to do some work on the UI thread, specifically setting up some views, etc. - this can't be done in a background thread. The process is invoked on a button click and takes about a second or so to complete - without a progress dialog it looks as if the app is frozen. I use progress dialog with AsynTask s in several places and it works fine - however here I'm struggling.

I started with simple:

showDialog(DIALOG_PLEASE_WAIT);
viewInfo.setFromGuide(true);          //this method just sets a variable
viewInfo.setVenue(venue);             //this method does a lot of UI manipulation and takes a second or so
showScreen(VIEW_INFO);                //this method shows the corresponding view in ViewFlipper
dismissDialog(DIALOG_PLEASE_WAIT);

However the dialog would not show (sort of expected, as this is all on UI thread.

Then I changed the code to this:

Handler hnd = new Handler() {
    @Override
    handleMessage(Message m) {
        viewInfo.setFromGuide(true);
        viewInfo.setVenue(venue);
        showScreen(VIEW_INFO);
        dismissDialog(DIALOG_PLEASE_WAIT);
    }
}
showDialog(DIALOG_PLEASE_WAIT);
new Thread() {
    public void run() {
       hnd.sendEmptyMessage(0);
    }
}.start();

This still doesn't show the dialog - naturally, the UI work in handleMessage is still done on the UI thread. So, what can I do to show the progress dialog?

Answer 1

如果真的需要a second or so to complete ，那么您可以只使用简单的Toast通知，并显示“请稍候”之类的消息

Answer 2

当您使用AsyncTask您可以覆盖onProgressUpdate ， publishProgress()从doInBackGround内部调用publishProgress()时都会调用publishProgress() ，因此您可以在后台工作时顺利地发布结果，因为onProgressUpdate在UI线程上有效。