How to fix the issue where the progress dialog is not displaying on Android.

If the ProgressDialog does not show up on Android, you can try the following solutions:

1. Check if the ProgressDialog is correctly created and displayed. Make sure to call the ProgressDialog constructor correctly and use the show() method to display the dialog.
2. Check if updating the ProgressDialog is being done on the UI thread. The ProgressDialog can only be updated on the UI thread. Updating the ProgressDialog on a non-UI thread may result in display issues.
3. Check the style and theme of the ProgressDialog. Make sure that the style and theme of the ProgressDialog are correctly set, such as using ProgressDialog.STYLE_SPINNER to set the style.
4. Check if the ProgressDialog is being obscured by other controls. Sometimes the ProgressDialog might be hidden by other controls, you can try using the bringToFront() method to bring the ProgressDialog to the front.
5. Check if ProgressDialog is shown and hidden multiple times within a short period. Showing and hiding ProgressDialog too frequently in a short time may result in issues such as it not displaying or showing for a very short duration.
6. Verify if it was cancelled before the ProgressDialog was displayed. If the dismiss() method was called to cancel the dialog before the ProgressDialog was displayed, it will not be shown.
7. Check if the Activity is being closed immediately after the ProgressDialog is displayed. If the Activity is closed immediately after the ProgressDialog is displayed, the ProgressDialog will not be shown.

If none of the above methods work, you can try using alternative solutions, such as using a ProgressBar or a custom dialog instead of a ProgressDialog.