ultrasonic-app-subsonic-android/ultrasonic/src/main/java/org/moire/ultrasonic/util/ModalBackgroundTask.java

/*
 This file is part of Subsonic.

 Subsonic is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 Subsonic is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with Subsonic.  If not, see <http://www.gnu.org/licenses/>.

 Copyright 2009 (C) Sindre Mehus
 */
package org.moire.ultrasonic.util;

import android.app.Activity;
import android.app.AlertDialog;

import org.moire.ultrasonic.R;

import timber.log.Timber;

/**
 * @author Sindre Mehus
 */
public abstract class ModalBackgroundTask<T> extends BackgroundTask<T>
{
	private final AlertDialog progressDialog;
	private Thread thread;
	private final boolean finishActivityOnCancel;
	private boolean cancelled;

	public ModalBackgroundTask(Activity activity, boolean finishActivityOnCancel)
	{
		super(activity);
		this.finishActivityOnCancel = finishActivityOnCancel;
		progressDialog = createProgressDialog();
	}

	public ModalBackgroundTask(Activity activity)
	{
		this(activity, true);
	}

	private AlertDialog createProgressDialog()
	{
		AlertDialog.Builder builder = new InfoDialog.Builder(getActivity());
		builder.setTitle(R.string.background_task_wait);
		builder.setMessage(R.string.background_task_loading);
		builder.setOnCancelListener(dialogInterface -> cancel());
		builder.setPositiveButton(R.string.common_cancel, (dialogInterface, i) -> cancel());

		return builder.create();
	}

	@Override
	public void execute()
	{
		cancelled = false;
		progressDialog.show();

		thread = new Thread()
		{
			@Override
			public void run()
			{
				try
				{
					final T result = doInBackground();
					if (cancelled)
					{
						progressDialog.dismiss();
						return;
					}

					getHandler().post(new Runnable()
					{
						@Override
						public void run()
						{
							try
							{
								progressDialog.dismiss();
							}
							catch (Exception e)
							{
								// nothing
							}

							done(result);
						}
					});

				}
				catch (final Throwable t)
				{
					if (cancelled)
					{
						return;
					}
					getHandler().post(new Runnable()
					{
						@Override
						public void run()
						{
							try
							{
								progressDialog.dismiss();
							}
							catch (Exception e)
							{
								// nothing
							}

							error(t);
						}
					});
				}
			}
		};
		thread.start();
	}

	protected void cancel()
	{
		cancelled = true;
		if (thread != null)
		{
			thread.interrupt();
		}

		if (finishActivityOnCancel)
		{
			getActivity().finish();
		}
	}

	protected boolean isCancelled()
	{
		return cancelled;
	}

	@Override
	protected void error(Throwable error)
	{
		Timber.w(error);
		new ErrorDialog(getActivity(), getErrorMessage(error), getActivity(), finishActivityOnCancel);
	}

	@Override
	public void updateProgress(final String message)
	{
		getHandler().post(() -> progressDialog.setMessage(message));
	}
}