本文实例讲述了Android实现Activity、Service与Broadcaster三大组件之间互相调用的方法。分享给大家供大家参考，具体如下：

我们研究两个问题，

1、Service如何通过Broadcaster更改activity的一个TextView。

(研究这个问题，考虑到Service从服务器端获得消息之后，将msg返回给activity)

2、Activity如何通过Binder调用Service的一个方法。

(研究这个问题，考虑到与服务器端交互的动作，打包至Service，Activity只呈现界面，调用Service的方法)

结构图见如下：

效果图如下：

点击“start service”按钮，启动Service，然后更改Activity的UI。

点击“send msg to server”按钮调用Service的方法，显示NotificationBar

代码：

1、新建一个MyService类，继承Service

package com.ljq.activity; import android.app.Notification; import android.app.NotificationManager; import android.app.PendingIntent; import android.app.Service; import android.content.Context; import android.content.Intent; import android.graphics.Color; import android.os.Binder; import android.os.IBinder; public class MyService extends Service { private NotificationManager notificationManager = null; private final IBinder binder = new LocalBinder(); @Override public void onCreate() { sendMsgtoActivty("Service is oncreating.n"); } @Override public IBinder onBind(Intent intent) { String msg = "Activity is sendding message to service,n Service send msg to server!n"; sendMsgtoActivty(msg); return binder; } /** * 把信息传递给activity * * @param msg */ private void sendMsgtoActivty(String msg) { Intent intent = new Intent("com.android.Yao.msg"); intent.putExtra("msg", msg); this.sendBroadcast(intent); } @Override public void onDestroy() { super.onDestroy(); if(notificationManager!=null){ notificationManager.cancel(0); notificationManager=null; } } /** * 在状态栏显示通知 * * @param msg */ private void showNotification(String msg) { notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE); // 定义Notification的各种属性 Notification notification =new Notification(R.drawable.icon, "A Message Coming!", System.currentTimeMillis()); //FLAG_AUTO_CANCEL 该通知能被状态栏的清除按钮给清除掉 //FLAG_NO_CLEAR 该通知不能被状态栏的清除按钮给清除掉 //FLAG_ONGOING_EVENT 通知放置在正在运行 //FLAG_INSISTENT 是否一直进行，比如音乐一直播放，知道用户响应 notification.flags |= Notification.FLAG_ONGOING_EVENT; // 将此通知放到通知栏的"Ongoing"即"正在运行"组中 notification.flags |= Notification.FLAG_NO_CLEAR; // 表明在点击了通知栏中的"清除通知"后，此通知不清除，经常与FLAG_ONGOING_EVENT一起使用 notification.flags |= Notification.FLAG_SHOW_LIGHTS; //DEFAULT_ALL 使用所有默认值，比如声音，震动，闪屏等等 //DEFAULT_LIGHTS 使用默认闪光提示 //DEFAULT_SOUNDS 使用默认提示声音 //DEFAULT_VIBRATE 使用默认手机震动，需加上<uses-permission android:name="android.permission.VIBRATE" />权限 notification.defaults = Notification.DEFAULT_LIGHTS; //叠加效果常量 //notification.defaults=Notification.DEFAULT_LIGHTS|Notification.DEFAULT_SOUND; notification.ledARGB = Color.BLUE; notification.ledOnMS =5000; //闪光时间，毫秒 // 设置通知的事件消息 //Intent notificationIntent =new Intent(MainActivity.this, MainActivity.class); // 点击该通知后要跳转的Activity Intent notificationIntent = new Intent(getApplicationContext(), MainActivity.class); // 加载类，如果直接通过类名，会在点击时重新加载页面，无法恢复最后页面状态。 notificationIntent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP); PendingIntent contentItent = PendingIntent.getActivity(this, 0, notificationIntent, 0); notification.setLatestEventInfo(this, "Message", "Message:" + msg, contentItent); // 把Notification传递给NotificationManager notificationManager.notify(0, notification); } /** * 从activity获取信息 * * @param msg */ public void receiverMsgtoActivity(String msg){ sendMsgtoActivty("n receiverMsgtoActivity:"+msg); } public void sendMsgtoServer(String msg) { showNotification(msg); } public class LocalBinder extends Binder { public MyService getService() { return MyService.this; } } }

2、新建MyBroadcastreceiver类，继承BroadcastReceiver，用来发送Intent启动服务

package com.ljq.activity; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; /** * 发送Intent启动服务 * * @author jiqinlin * */ public class MyBroadcastreceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { Intent service = new Intent(context, MyService.class); context.startService(service); } }

3、新建MainActivity类，其实是一个activity，用来呈现界面

package com.ljq.activity; import java.util.List; import android.app.Activity; import android.app.ActivityManager; import android.content.BroadcastReceiver; import android.content.ComponentName; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; import android.content.ServiceConnection; import android.os.Bundle; import android.os.IBinder; import android.util.Log; import android.view.View; import android.widget.TextView; public class MainActivity extends Activity implements View.OnClickListener { private String msg = ""; private TextView txtMsg; private UpdateReceiver receiver; private MyService myService; private final static String TAG=MainActivity.class.getSimpleName(); @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); txtMsg = (TextView) this.findViewById(R.id.txtMsg); this.findViewById(R.id.btnStart).setOnClickListener(this); this.findViewById(R.id.btnSend).setOnClickListener(this); //订阅广播Intent receiver = new UpdateReceiver(); IntentFilter filter = new IntentFilter(); filter.addAction("com.android.Yao.msg"); this.registerReceiver(receiver, filter); //初始化时启动服务 //Intent intent = new Intent(MainActivity.this, MyService.class); //this.bindService(intent, conn, BIND_AUTO_CREATE); } @Override protected void onDestroy() { super.onDestroy(); //结束服务 if(conn!=null){ unbindService(conn); myService=null; } } public class UpdateReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { //获取service传过来的信息 msg = intent.getStringExtra("msg"); txtMsg.append(msg); } } private ServiceConnection conn = new ServiceConnection() { @Override public void onServiceConnected(ComponentName name, IBinder service) { myService = ((MyService.LocalBinder) service).getService(); Log.i(TAG, "onServiceConnected myService: "+myService); } @Override public void onServiceDisconnected(ComponentName name) { myService = null; } }; @Override public void onClick(View v) { Intent intent = new Intent(MainActivity.this, MyService.class); switch (v.getId()) { case R.id.btnStart: //判断服务是否启动 if(false==isServiceRunning(this, MyService.class.getName())){ Log.i(TAG, "start "+MyService.class.getSimpleName()+" service"); this.bindService(intent, conn, BIND_AUTO_CREATE); } Log.i(TAG, MyService.class.getName()+" run status: "+isServiceRunning(this, MyService.class.getName())); break; case R.id.btnSend: //判断服务是否启动 if(false==isServiceRunning(this, MyService.class.getName())){ Log.i(TAG, "start "+MyService.class.getSimpleName()+" service"); this.bindService(intent, conn, BIND_AUTO_CREATE); } Log.i(TAG, MyService.class.getName()+" run status: "+isServiceRunning(this, MyService.class.getName())); Log.i(TAG, "onClick myService: "+myService); //第一次启动服务时此处为null(小编认为虽然服务已启动成功，但是还没全部初始化) if(myService!=null){ myService.sendMsgtoServer("i am sending msg to server"); //从activity传递信息给service myService.receiverMsgtoActivity("this is a msg"); } break; } } /** * 判断服务是否正在运行 * * @param context * @param className 判断的服务名字：包名+类名 * @return true在运行 false 不在运行 */ public static boolean isServiceRunning(Context context, String className) { boolean isRunning = false; ActivityManager activityManager = (ActivityManager) context .getSystemService(Context.ACTIVITY_SERVICE); //获取所有的服务 List<ActivityManager.RunningServiceInfo> services= activityManager.getRunningServices(Integer.MAX_VALUE); if(services!=null&&services.size()>0){ for(ActivityManager.RunningServiceInfo service : services){ if(className.equals(service.service.getClassName())){ isRunning=true; break; } } } return isRunning; } }

4、main.xml布局文件

<"1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:id="@+id/txtMsg" /> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="horizontal" android:layout_width="wrap_content" android:layout_height="wrap_content"> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="start service" android:id="@+id/btnStart"/> <Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="send msg to server" android:id="@+id/btnSend"/> </LinearLayout> </LinearLayout>

5、清单文件AndroidManifest.xml，用来配置组件等信息

<"1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.ljq.activity" android:versionCode="1" android:versionName="1.0"> <application android:icon="@drawable/icon" android:label="@string/app_name"> <activity android:name=".MainActivity" android:label="@string/app_name"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <service android:name=".MyService"/> <receiver android:name=".MyBroadcastreceiver" /> </application> <uses-sdk android:minSdkVersion="7" /> </manifest>

希望本文所述对大家Android程序设计有所帮助。