【Android】Service通过广播更新UI

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定义一个activity，在activity中定义一个内部广播接收器，并且动态注册该广播接收器：

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;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.service_update_ui);textView = (TextView) findViewById(R.id.count_txt);// 动态注册广播IntentFilter filter = new IntentFilter();filter.addAction(ACTION_UPDATEUI);broadcastReceiver = new UpdateUIBroadcastReceiver();registerReceiver(broadcastReceiver, filter);// 启动服务Intent intent = new Intent(this, ServiceUpdateUI.class);startService(intent);}/** * 定义广播接收器（内部类） *  * @author lenovo *  */private class UpdateUIBroadcastReceiver extends BroadcastReceiver {@Overridepublic void onReceive(Context context, Intent intent) {textView.setText(String.valueOf(intent.getExtras().getInt("count")));}}@Overrideprotected void onDestroy() {System.out.println("onDestroy");super.onDestroy();// 注销广播unregisterReceiver(broadcastReceiver);}}

activity布局文件：

<?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="当前人数：" />    <TextView        android:id="@+id/count_txt"        android:layout_width="wrap_content"        android:layout_height="wrap_content" /></LinearLayout>

定义一个后台service，该service定时发送广播：

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;@Overridepublic IBinder onBind(Intent intent) {return null;}@Overridepublic void onCreate() {super.onCreate();final Intent intent = new Intent();intent.setAction(MainActivity.ACTION_UPDATEUI);timer = new Timer();task = new TimerTask() {@Overridepublic void run() {intent.putExtra("count", ++count);sendBroadcast(intent);}};timer.schedule(task, 1000, 1000);}@Overridepublic void onDestroy() {super.onDestroy();timer.cancel();}}

界面效果：

即使Activity退出再启动，仍然能通过广播接收器得到当前人数。

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