show and dismiss progress dialog while running a thread in android

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. 开发者_开发百科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();
}

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()));

Please try Below Code .

private Handler responseHandler=null;
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
                responseHandler.sendEmptyMessage(0);
         });
         thread.start();
    }

    responseHandler = new Handler() 
        {                               
            public void handleMessage(Message msg)  
            {
                super.handleMessage(msg);
                try 
                {
                    dismissProgressDialog() 
                } 
                catch (Exception e) 
                {
                    e.printStackTrace();
                }                       
            }
        };
}

Here in this code when ever your dowload will completed it called response handler and your progress dialog will dismiss.

In downloadFiles() you show the dialog, then start a number of threads and after they've been started the dialog got dismissed. I don't think this is what you want as the dialog gets closed right after the last thread is started and not after the last thread has finished.

The dismissProgressDialog() method must be called after the last thread has finished its work. So at the end of the code run in the thread you have to check whether other threads are still running or whether you can dismiss the dialog as no other threads are running.

Try the following code and let me know how it goes:

private Handler mHandler = new Handler(){
    public void handleMessage(Message msg)  
    {
        dismissProgressDialog() 
    }
};

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();
    }
    mHandler.sendEmptyMessage(0);
    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();
}