AsyncTask.java

package moe.feng.bilinyan.util;

import android.os.Handler;
import android.os.Message;
import android.util.Log;

import static moe.feng.bilinyan.BuildConfig.DEBUG;

public abstract class AsyncTask<Params, Progress, Result>
{
	private static final String TAG = AsyncTask.class.getSimpleName();

	private static class AsyncResult<Data> {
		public AsyncTask task;
		public Data[] data;

		public AsyncResult(AsyncTask task, Data... data) {
			this.task = task;
			this.data = data;
		}
	}

	private static final int MSG_FINISH = 1000;
	private static final int MSG_PROGRESS = 1001;

	private static Handler sInternalHandler = new Handler() {
		@SuppressWarnings({"unchecked", "RawUseOfParameterizedType"})
		@Override
		public void handleMessage(Message msg) {
			AsyncResult result = (AsyncResult) msg.obj;
			switch (msg.what) {
				case MSG_FINISH:
					result.task.onPostExecute(result.data[0]);
					break;
				case MSG_PROGRESS:
					result.task.onProgressUpdate(result.data);
					break;
			}
		}
	};

	private Params[] mParams;

	private Thread mThread = new Thread(new Runnable() {
			@Override
			public void run() {
				// TODO: CrashHandler.register();

				try {
					Result result = doInBackground(mParams);
					sInternalHandler.sendMessage(sInternalHandler.obtainMessage(MSG_FINISH, new AsyncResult<Result>(AsyncTask.this, result)));
				} catch (Exception e) {
					// Don't crash the whole app
					if (DEBUG) {
						Log.d(TAG, e.getClass().getSimpleName() + " caught when running background task. Printing stack trace.");
						Log.d(TAG, Log.getStackTraceString(e));
					}
				}

				Thread.currentThread().interrupt();
			}
		});

	protected void onPostExecute(Result result) {}

	protected abstract Result doInBackground(Params... params);

	protected void onPreExecute() {}

	protected void onProgressUpdate(Progress... progress) {}

	protected void publishProgress(Progress... progress) {
		sInternalHandler.sendMessage(sInternalHandler.obtainMessage(MSG_PROGRESS, new AsyncResult<Progress>(this, progress)));
	}

	public void execute(Params... params) {
		onPreExecute();
		mParams = params;
		mThread.start();
	}
}