Loading icon (progress) while logging into FTP in Android application

Question

How can I get a loading icon (like a small circle running rund) while I am logging into a FTP server in an Android application? I know that there is a progress bar in the AsyncTask , but want to grey out the MainView (MainActivity) and display a loading icon as long as the login takes place.

How to do that?

Answer 1

If you want the Progress "icon" to be shown as a Dialog (a smaller screen over your Activity) you can use ProgressDialog : http://developer.android.com/reference/android/app/ProgressDialog.html

To use it:

ProgressDialog pd = new ProgressDialog(this); 
pd.setTitle(title);
pd.setMessage(message);
pd.show();

...

pd.dismiss(); //Use it when the task is over

This is how it looks like:

If you just want your layout to be seen like it's deactivated you can use the alpha property (opacity). For example, in an application where I want a layout to be seen darker than usual I use:

AlphaAnimation alphaDeselected = new AlphaAnimation(1F, 0.25F);
alphaDeselected.setDuration(0);
view.startAnimation(alphaDeselected);

Of course, the view will be seen darker if the background is dark.

EDIT: How to apply it.

I usually show the ProgressDialog right before starting the AsyncTask.

pd = new ProgressDialog(this); // I declared pd as a global variable to access it from AsyncTask
pd.setTitle(title);
pd.setMessage(message);
pd.show();
mAuthTask = new UserLoginTask();
mAuthTask.execute((Void) null);

Then I dismiss the ProgressDialog when the AsyncTask finishes or is canceled:

public class UserLoginTask extends AsyncTask<Void, Void, Boolean> {
    @Override
    protected Boolean doInBackground(Void... params) {
        ...
    }

    @Override
    protected void onPostExecute(final Boolean success) {
        pd.dismiss();

        ...
    }

    @Override
    protected void onCancelled() {
        pd.dismiss();

        ...
    }
}