Android四大组件之Service

public class BindService extends Service
{
	private int count;
	private boolean quit;
	// 定义onBinder方法所返回的对象
	private MyBinder binder = new MyBinder();
	<span style="background-color: rgb(102, 255, 153);">// 通过继承Binder来实现IBinder类
	<span style="color:#333333;">public class MyBinder extends Binder //①
	{
		public int getCount()
		{
			// 获取Service的运行状态：count
			return count;
		}
	}
	// 必须实现的方法，绑定该Service时回调该方法
	@Override
	public IBinder onBind(Intent intent)
	{
		System.out.println("Service is Binded");
		// 返回IBinder对象
		return binder;
	}</span></span>
	// Service被创建时回调该方法。
	@Override
	public void onCreate()
	{
		super.onCreate();
		System.out.println("Service is Created");
		// 启动一条线程、动态地修改count状态值
		new Thread()
		{
			@Override
			public void run()
			{
				while (!quit)
				{
					try
					{
						Thread.sleep(1000);
					}
					catch (InterruptedException e)
					{
					}
					count++;
				}
			}
		}.start();
	}
	// Service被断开连接时回调该方法
	@Override
	public boolean onUnbind(Intent intent)
	{
		System.out.println("Service is Unbinded");
		return true;
	}
	// Service被关闭之前回调该方法。
	@Override
	public void onDestroy()
	{
		super.onDestroy();
		this.quit = true;
		System.out.println("Service is Destroyed");
	}
}

public class BindServiceTest extends Activity
{
	Button bind, unbind, getServiceStatus;
	// 保持所启动的Service的IBinder对象
	BindService.MyBinder binder;
	<span style="background-color: rgb(102, 255, 153);">// 定义一个ServiceConnection对象
	private ServiceConnection conn = new ServiceConnection()
	{
		// 当该Activity与Service连接成功时回调该方法
		@Override
		public void onServiceConnected(ComponentName name
			, IBinder service)
		{
			System.out.println("--Service Connected--");
			// 获取Service的onBind方法所返回的MyBinder对象
			binder = (BindService.MyBinder) service; //①
		}

		// 当该Activity与Service断开连接时回调该方法
		@Override
		public void onServiceDisconnected(ComponentName name)
		{
			System.out.println("--Service Disconnected--");
		}
	};</span>

	@Override
	public void onCreate(Bundle savedInstanceState)
	{
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		// 获取程序界面中的start、stop、getServiceStatus按钮
		bind = (Button) findViewById(R.id.bind);
		unbind = (Button) findViewById(R.id.unbind);
		getServiceStatus = (Button) findViewById(R.id.getServiceStatus);
		// 创建启动Service的Intent
		final Intent intent = new Intent();
		// 为Intent设置Action属性
		intent.setAction("org.crazyit.service.BIND_SERVICE");
		bind.setOnClickListener(new OnClickListener()
		{
			@Override
			public void onClick(View source)
			{
				// 绑定指定Serivce
				bindService(intent, conn, Service.BIND_AUTO_CREATE);
			}
		});
		unbind.setOnClickListener(new OnClickListener()
		{
			@Override
			public void onClick(View source)
			{
				// 解除绑定Serivce
				unbindService(conn);
			}
		});
		getServiceStatus.setOnClickListener(new OnClickListener()
		{
			@Override
			public void onClick(View source)
			{
				// 获取、并显示Service的count值
				Toast.makeText(BindServiceTest.this,
					"Serivce的count值为：" + binder.getCount(),
					Toast.LENGTH_SHORT).show(); //②
			}
		});
	}
}