你真的会用AsyncTask吗?(二)

超时处理

import java.util.Timer;
import java.util.TimerTask;

import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.widget.Toast;

public class TimeoutTestActivity extends Activity {
	private final static int TIME_OUT = 3 * 1000;
	private final static int SLEEP_TIME = 2 * 1000;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		//new TimeOutTask().execute();
		new CancelSelfWhenTimeOutTask().execute();
	}

	private class CancelSelfWhenTimeOutTask extends AsyncTask<Void, Void, Void> {
		private boolean done = false;

		@Override
		protected Void doInBackground(Void... params) {
			cancelSelfWhenTimeOut();
			sleep();
			return null;
		}

		@Override
		protected void onPostExecute(Void result) {
			super.onPostExecute(result);
			Toast.makeText(TimeoutTestActivity.this, "任务完成", Toast.LENGTH_SHORT)
					.show();
		}

		private void cancelSelfWhenTimeOut() {
			new Timer().schedule(new TimerTask() {

				@Override
				public void run() {
					if (!done) {
						CancelSelfWhenTimeOutTask.this.cancel(true);
					}
				}
			}, TIME_OUT);
		}

		private void sleep() {
			try {
				Thread.sleep(SLEEP_TIME);
				done = true;
			} catch (InterruptedException e) {
			}
		}
	}

	private class TimeOutTask extends AsyncTask<Void, Void, Void> {
		private boolean done = false;
		private boolean isTimeOut = false;

		@Override
		protected Void doInBackground(Void... params) {
			try {
				throwTimeOutException();
			} catch (Exception e) {
				isTimeOut = true;
			}
			sleep();
			return null;
		}

		@Override
		protected void onPostExecute(Void result) {
			super.onPostExecute(result);
			if (isTimeOut) {
				Toast.makeText(TimeoutTestActivity.this, "任务超时",
						Toast.LENGTH_SHORT).show();
			} else {
				Toast.makeText(TimeoutTestActivity.this, "任务完成",
						Toast.LENGTH_SHORT).show();
			}
		}

		private void throwTimeOutException() {
			new Timer().schedule(new TimerTask() {

				@Override
				public void run() {
					if (!done) {
						isTimeOut = true;
					}
				}
			}, TIME_OUT);
		}

		private void sleep() {
			try {
				Thread.sleep(SLEEP_TIME);
				done = true;
			} catch (InterruptedException e) {
			}
		}
	}

}