Android AsyncTask的简单Demo

      package com.samir;

import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.DialogInterface;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.Window;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;

public class MainActivity extends Activity {

	Button btnStart;
	MyTask objMyTask;

	private static final int SLEEP_TIME=((60*1000)/100);
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		btnStart = (Button) findViewById(R.id.btnstart);
		btnStart.setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View v) {
				objMyTask = new MyTask();
				objMyTask.execute();
			}
		});
	}

	class MyTask extends AsyncTask<Void, Integer, Void> {

		Dialog dialog;
		ProgressBar progressBar;
		TextView tvLoading,tvPer;
		Button btnCancel;

		@Override
		protected void onPreExecute() {
			super.onPreExecute();
			dialog = new Dialog(MainActivity.this);
			dialog.setCancelable(false);
			dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
			dialog.setContentView(R.layout.progressdialog);

			progressBar = (ProgressBar) dialog.findViewById(R.id.progressBar1);
			tvLoading = (TextView) dialog.findViewById(R.id.tv1);
			tvPer = (TextView) dialog.findViewById(R.id.tvper);
			btnCancel = (Button) dialog.findViewById(R.id.btncancel);

			btnCancel.setOnClickListener(new OnClickListener() {

				@Override
				public void onClick(View v) {
					objMyTask.cancel(true);
					dialog.dismiss();
				}
			});

			dialog.show();
		}

		@Override
		protected Void doInBackground(Void... params) {

			for (int i = 1; i <100; i++) {
				if (isCancelled()) {
					break;
				} else {
					System.out.println(i);
					publishProgress(i);
					try {
						Thread.sleep(SLEEP_TIME);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
			}

			return null;
		}

		@Override
		protected void onProgressUpdate(Integer... values) {
			super.onProgressUpdate(values);
			progressBar.setProgress(values[0]);
			tvLoading.setText("Loading...  " + values[0] + " %");
			tvPer.setText(values[0]+" %");
		}

		@Override
		protected void onPostExecute(Void result) {
			super.onPostExecute(result);

			dialog.dismiss();

			AlertDialog alert = new AlertDialog.Builder(MainActivity.this)
					.create();

			alert.setTitle("Completed!!!");
			alert.setMessage("Your Task is Completed SuccessFully!!!");
			alert.setButton("Dismiss", new DialogInterface.OnClickListener() {

				@Override
				public void onClick(DialogInterface dialog, int which) {
					dialog.dismiss();

				}
			});
			alert.show();
		}
	}

}