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Android广播机制

2015-10-29 15:03 525 查看

动态注册系统广播

系统广播不用sendBroadcast()系统自动会发送

定义全局变量 ConnectionChangeReceiver myReceiver;

中注册广播

在oncreate(){
.....
IntentFilter filter=new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);
myReceiver=new ConnectionChangeReceiver();
this.registerReceiver(myReceiver, filter);

}
class ConnectionChangeReceiver extends BroadcastReceiver {

@Override
public void onReceive(Context arg0, Intent arg1) {

ConnectivityManager conManager = (ConnectivityManager) getApplicationContext()
.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = conManager.getActiveNetworkInfo();
if (networkInfo != null) { // 注意，这个判断一定要，要不然会出错
netStatus = networkInfo.isAvailable();
networkErr.setVisibility(View.GONE);

}else{
netStatus=false;
networkErr.setVisibility(View.VISIBLE);

}
}

}
//中取消注册
onDestroy(){
.......	this.unregisterReceiver(myReceiver); //取消监听网络的广播注册
}

//静态注册系统广播

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
 package="com.bignerdranch.android.photogallery"
 android:versionCode="1"
 android:versionName="1.0" >

 <uses-sdk
   android:minSdkVersion="8"
   android:targetSdkVersion="17" />

 <uses-permission android:name="android.permission.INTERNET" />
 <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
 <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

 <application
   ... >
   <activity
     ... >
     ...
   </activity>
   <service android:name=".PollService" />
   <receiver android:name=".StartupReceiver">
       <intent-filter>
           <action android:name="android.intent.action.BOOT_COMPLETED" />
       </intent-filter>
   </receiver>
 </application>

</manifest>
public class StartupReceiver{

@Override
public void onReceive(Context context, Intent intent) {
   Log.i(TAG, "Received broadcast intent: " + intent.getAction());

   //静态注册的广播 文中广播是监听程序启动完成状态，监听到就会走onReceive（）方法 可以在这里加代码开启操作
}
}

发送普通广播

首先定义一个广播 intentfilter 名字 public static final String ACTION_SHOW_NOTIFICATION =
       "com.bignerdranch.android.photogallery.SHOW_NOTIFICATION";

发送广播sendBroadcast(new Intent(ACTION_SHOW_NOTIFICATION));

//广播接收端 动态自定义注册
public abstract class VisibleFragment extends Fragment {
   public static final String TAG = "VisibleFragment";

   private BroadcastReceiver mOnShowNotification = new BroadcastReceiver() {
       @Override
       public void onReceive(Context context, Intent intent) {
           Toast.makeText(getActivity(),
                   "Got a broadcast:" + intent.getAction(),
                   Toast.LENGTH_LONG)
               .show();
       }
   };

   @Override
   public void onResume() {
       super.onResume();
       IntentFilter filter = new IntentFilter(PollService.ACTION_SHOW_NOTIFICATION);
       getActivity().registerReceiver(mOnShowNotification, filter);
   }

   @Override
   public void onPause() {
       super.onPause();
       getActivity().unregisterReceiver(mOnShowNotification);
   }
}

动态发送有序化广播

首先定义一个intentFilter name

public static final String ACTION_SHOW_NOTIFICATION = "com.bignerdranch.android.photogallery.SHOW_NOTIFICATION";
public static final String PERM_PRIVATE = "com.bignerdranch.android.photogallery.PRIVATE";

PERM_PRIVATE是一个自定义设置广播权限的值

在AndroidManifest中加上自定义权限

<span style="font-size:14px;"><permission android:name="com.bignerdranch.android.photogallery.PRIVATE"
android:protectionLevel="signature" />  //signature代表只能是当前app响应
<uses-permission android:name="com.bignerdranch.android.photogallery.PRIVATE" /></span>

发送有序化的广播

广播发送端

<span style="font-size:12px;">Intent i = new Intent(ACTION_SHOW_NOTIFICATION);
i.putExtra("REQUEST_CODE", requestCode);
i.putExtra("NOTIFICATION", notification);
//Context.sendOrderedBroadcast(Intent,String,BroadcastReceiver,Handler,int,String,Bundle)
sendOrderedBroadcast(i, PERM_PRIVATE, null, null, Activity.RESULT_OK, null, null);   </span>

广播接收

注册了两个广播接收者由于广播接收者2的priority很低那么先是广播接收者1收到广播并响应，1可以设置广播是否让广播继续往下传 setResultCode（Activity.RESULT_CANCELED）
广播2判断这个结果确定是否响应if (getResultCode() != Activity.RESULT_OK)

广播接收器1//动态接收者

private BroadcastReceiver mOnShowNotification = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
// if we receive this, we're visible, so cancel
// the notification
Log.i(TAG, "canceling notification");
setResultCode(Activity.RESULT_CANCELED);
}
};

@Override
public void onResume() {
super.onResume();
IntentFilter filter = new IntentFilter(PollService.ACTION_SHOW_NOTIFICATION);
getActivity().registerReceiver(mOnShowNotification, filter, PollService.PERM_PRIVATE, null);
}

@Override
public void onPause() {
super.onPause();
getActivity().unregisterReceiver(mOnShowNotification);
}
}

广播接收器2静态注册接收

android:priority="-999"级别最低 他将最后收到广播                                                                                                          在AndroidManifest中
<receiver android:name=".NotificationReceiver"
android:exported="false">
<intent-filter
android:priority="-999">
<action android:name="com.bignerdranch.android.photogallery.SHOW_NOTIFICATION" />
public class NotificationReceiver extends BroadcastReceiver {
private static final String TAG = "NotificationReceiver";

@Override
public void onReceive(Context c, Intent i) {
Log.i(TAG, "received result: " + getResultCode());
if (getResultCode() != Activity.RESULT_OK)
// a foreground activity cancelled the broadcast
return;

int requestCode = i.getIntExtra("REQUEST_CODE", 0);
Notification notification = (Notification)i.getParcelableExtra("NOTIFICATION");

NotificationManager notificationManager = (NotificationManager)
c.getSystemService(Context.NOTIFICATION_SERVICE);
notificationManager.notify(requestCode, notification);
}
}

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标签： 广播

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