show and dismiss progress dialog while running a thread in android

Question

I have a method in my activity to download a set of files. This downloading is taking place when I start a new activity. I have used threads, because it downloads completely whereas AsyncTask may sometimes fail to download all files, it may get stuck in between.

Now, a black screen is shown when the downloading takes place. I want to show it within a ProgressDialog so that user may feel that something is getting downloaded.

I have added a ProgressDialog, but its not showing. Can anyone tell where did I go wrong?

Below is my code:

Inside onCreate() I have written:

downloadFiles();

private boolean downloadFiles() {
    showProgressDialog();
    for(int i = 0; i < filesList.size();i++) {
        Thread thread = new Thread(new Runnable() {    
            @Override
            public void run() {
                //downloading code
         });
         thread.start();
         thread.run();
    }
    dismissProgressDialog();
    return true;
}

//ProgressDialog progressDialog; I have declared earlier.
private void showProgressDialog() { 
    progressDialog = new ProgressDialog(N12ReadScreenActivity.this);
    progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
    progressDialog.setMessage("Downloading files...");
    progressDialog.show();
}

private void dismissProgressDialog() {
    if(progressDialog != null)
        progressDialog.dismiss();
}

Solution

Try this .. it's simple

ProgressDialog progress = new ProgressDialog(this);
progress.Indeterminate = true;
progress.SetProgressStyle(ProgressDialogStyle.Spinner);
progress.SetMessage("Downloading Files...");
progress.SetCancelable(false);

RunOnUiThread(() =>
{
    progress.Show();
});
Task.Run(()=>
//downloading code here...
).ContinueWith(Result=>RunOnUiThread(()=>progress.Hide()));