package com.zzj.ui.serviceUpdateUIDemo;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.widget.TextView;

import com.zzj.ui.R;

public class MainActivity extends Activity {
	private TextView textView;
	public static final String ACTION_UPDATEUI = "action.updateUI";
	UpdateUIBroadcastReceiver broadcastReceiver;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);

		setContentView(R.layout.service_update_ui);
		textView = (TextView) findViewById(R.id.count_txt);

		// 動態註冊廣播
		IntentFilter filter = new IntentFilter();
		filter.addAction(ACTION_UPDATEUI);
		broadcastReceiver = new UpdateUIBroadcastReceiver();
		registerReceiver(broadcastReceiver, filter);

		// 啟動服務
		Intent intent = new Intent(this, ServiceUpdateUI.class);
		startService(intent);
	}

	/**
	 * 定義廣播接收器（內部類）
	 * 
	 * @author lenovo
	 * 
	 */
	private class UpdateUIBroadcastReceiver extends BroadcastReceiver {

		@Override
		public void onReceive(Context context, Intent intent) {
			textView.setText(String.valueOf(intent.getExtras().getInt("count")));
		}

	}

	@Override
	protected void onDestroy() {
		System.out.println("onDestroy");
		super.onDestroy();
		// 登出廣播
		unregisterReceiver(broadcastReceiver);
	}
}
 

activity佈局檔案：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="當前人數：" />

    <TextView
        android:id="@+id/count_txt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>
 

package com.zzj.ui.serviceUpdateUIDemo;

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

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;

public class ServiceUpdateUI extends Service {
	private Timer timer;
	private TimerTask task;
	private int count;

	@Override
	public IBinder onBind(Intent intent) {
		return null;
	}

	@Override
	public void onCreate() {
		super.onCreate();

		final Intent intent = new Intent();
		intent.setAction(MainActivity.ACTION_UPDATEUI);

		timer = new Timer();
		task = new TimerTask() {

			@Override
			public void run() {
				intent.putExtra("count", ++count);
				sendBroadcast(intent);
			}
		};
		timer.schedule(task, 1000, 1000);
	}

	@Override
	public void onDestroy() {
		super.onDestroy();
		timer.cancel();
	}

}
 

介面效果：

即使Activity退出再啟動，仍然能通過廣播接收器得到當前人數。