本文實例講述了Android實現(xiàn)Activity、Service與Broadcaster三大組件之間互相調(diào)用的方法。分享給大家供大家參考,具體如下:
我們研究兩個問題,
1、Service如何通過Broadcaster更改activity的一個TextView。
(研究這個問題,考慮到Service從服務(wù)器端獲得消息之后,將msg返回給activity)
2、Activity如何通過Binder調(diào)用Service的一個方法。
(研究這個問題,考慮到與服務(wù)器端交互的動作,打包至Service,Activity只呈現(xiàn)界面,調(diào)用Service的方法)
結(jié)構(gòu)圖見如下:

效果圖如下:

點擊“start service”按鈕,啟動Service,然后更改Activity的UI。

點擊“send msg to server”按鈕調(diào)用Service的方法,顯示NotificationBar
代碼:
1、新建一個MyService類,繼承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; } /** * 把信息傳遞給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; } } /** * 在狀態(tài)欄顯示通知 * * @param msg */ private void showNotification(String msg) { notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE); // 定義Notification的各種屬性 Notification notification =new Notification(R.drawable.icon,     "A Message Coming!", System.currentTimeMillis()); //FLAG_AUTO_CANCEL  該通知能被狀態(tài)欄的清除按鈕給清除掉 //FLAG_NO_CLEAR   該通知不能被狀態(tài)欄的清除按鈕給清除掉 //FLAG_ONGOING_EVENT 通知放置在正在運(yùn)行 //FLAG_INSISTENT   是否一直進(jìn)行,比如音樂一直播放,知道用戶響應(yīng) notification.flags |= Notification.FLAG_ONGOING_EVENT; // 將此通知放到通知欄的"Ongoing"即"正在運(yùn)行"組中 notification.flags |= Notification.FLAG_NO_CLEAR; // 表明在點擊了通知欄中的"清除通知"后,此通知不清除,經(jīng)常與FLAG_ONGOING_EVENT一起使用 notification.flags |= Notification.FLAG_SHOW_LIGHTS; //DEFAULT_ALL   使用所有默認(rèn)值,比如聲音,震動,閃屏等等 //DEFAULT_LIGHTS 使用默認(rèn)閃光提示 //DEFAULT_SOUNDS 使用默認(rèn)提示聲音 //DEFAULT_VIBRATE 使用默認(rèn)手機(jī)震動,需加上<uses-permission android:name="android.permission.VIBRATE" />權(quán)限 notification.defaults = Notification.DEFAULT_LIGHTS; //疊加效果常量 //notification.defaults=Notification.DEFAULT_LIGHTS|Notification.DEFAULT_SOUND; notification.ledARGB = Color.BLUE; notification.ledOnMS =5000; //閃光時間,毫秒 // 設(shè)置通知的事件消息 //Intent notificationIntent =new Intent(MainActivity.this, MainActivity.class); // 點擊該通知后要跳轉(zhuǎn)的Activity Intent notificationIntent = new Intent(getApplicationContext(), MainActivity.class); // 加載類,如果直接通過類名,會在點擊時重新加載頁面,無法恢復(fù)最后頁面狀態(tài)。 notificationIntent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP); PendingIntent contentItent = PendingIntent.getActivity(this, 0, notificationIntent, 0); notification.setLatestEventInfo(this, "Message", "Message:" + msg, contentItent); // 把Notification傳遞給NotificationManager notificationManager.notify(0, notification); } /** * 從activity獲取信息 * * @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類,繼承BroadcastReceiver,用來發(fā)送Intent啟動服務(wù)
package com.ljq.activity;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;/** * 發(fā)送Intent啟動服務(wù) * * @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類,其實是一個activity,用來呈現(xiàn)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); //訂閱廣播Intent receiver = new UpdateReceiver(); IntentFilter filter = new IntentFilter(); filter.addAction("com.android.Yao.msg"); this.registerReceiver(receiver, filter); //初始化時啟動服務(wù) //Intent intent = new Intent(MainActivity.this, MyService.class); //this.bindService(intent, conn, BIND_AUTO_CREATE); } @Override protected void onDestroy() { super.onDestroy(); //結(jié)束服務(wù) if(conn!=null){  unbindService(conn);  myService=null; } } public class UpdateReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) {  //獲取service傳過來的信息  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:  //判斷服務(wù)是否啟動  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:  //判斷服務(wù)是否啟動  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); //第一次啟動服務(wù)時此處為null(小編認(rèn)為雖然服務(wù)已啟動成功,但是還沒全部初始化)  if(myService!=null){    myService.sendMsgtoServer("i am sending msg to server");    //從activity傳遞信息給service    myService.receiverMsgtoActivity("this is a msg");   }  break; } } /** * 判斷服務(wù)是否正在運(yùn)行 * * @param context * @param className 判斷的服務(wù)名字:包名+類名 * @return true在運(yùn)行 false 不在運(yùn)行 */ public static boolean isServiceRunning(Context context, String className) { boolean isRunning = false; ActivityManager activityManager = (ActivityManager) context  .getSystemService(Context.ACTIVITY_SERVICE); //獲取所有的服務(wù) 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
<?xml version="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、清單文件AndroidManifest.xml,用來配置組件等信息
<?xml version="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>
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