LocalBroadcastManager

Android 中BroadcastReceiver主要用途有

发送通知，更新UI或者数据，应用程序间相互通信，监听系统状态（比如开机，网络等）

Android中BroadcasetReceiver的注册方式

manifest清单文件中的全局注册
按照生命周期，在Service或者Activity中使用代码注册

manifest的注册方式

使用代码注册

SampleActivity

private  MyReceiver receiver; @Override public void onStart() {      super.onStart();      receiver = new MyReceiver();    IntentFilter filter = new IntentFilter();    filter.addAction("android.intent.action.MY_BROADCAST");    registerReceiver(receiver, filter);}@Overridepublic void onStop(){    super.onStop();    unregisterReceiver(receiver);  }

Android中发送广播的方式

普通广播：无论优先级大小，将发送给所有监听Action="com.test.sample.action"的广播,内容不可被修改，无传递性。

Intent intent = new Intent( "com.test.sample.action");sendBroadcast(intent);

异步（黏性）广播: 当处理完之后的Intent ，依然存在，这时候registerReceiver(BroadcastReceiver, IntentFilter) 还能收到他的值，直到你把它去掉 , 无传递性 , 无法终止(abort())广播。

发这个广播需要权限"android.permission.BROADCAST_STICKY" />

去掉是用这个方法removeStickyBroadcast(intent); 但别忘了在执行这个方法的应用里面 AndroidManifest.xml 同样要加上面的权限；

sendStickyOrderedBroadcast(intent, resultReceiver, scheduler,       initialCode, initialData, initialExtras)

有序广播：

按照接收者的优先级顺序接收广播 , 优先级别在 intent-filter 中的 priority 中声明 ,-1000 到1000 之间，值越大优先级越高。可以终止广播意图的继续传播，接收者可以篡改内容，具有传递性。

sendBroadcast(intent);

Android中的BroadcastReceiver可以用来发送信息到另一个广播，这种方式可实现程序或者进程间的通行。

上面回顾了一下Android的广播用例，总体来说安全性都不太好，因此只适用于安全性较低的数据传递，或者页面更新。

在android-support-v4.jar中引入了LocalBroadcastManager，称为局部通知管理器，这种通知的好处是安全性高，效率也高，适合局部通信，可以用来代替Handler更新UI

public class LocalServiceBroadcasterActivity extends Activity {    static final String ACTION_STARTED = "com.example.android.supportv4.STARTED";    static final String ACTION_UPDATE = "com.example.android.supportv4.UPDATE";    static final String ACTION_STOPPED = "com.example.android.supportv4.STOPPED";     LocalBroadcastManager mLocalBroadcastManager;    BroadcastReceiver mReceiver;     @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);         setContentView(R.layout.main);         final TextView callbackData = (TextView) findViewById(R.id.callback);        callbackData.setText("No broadcast received yet");        mLocalBroadcastManager = LocalBroadcastManager.getInstance(this);         IntentFilter filter = new IntentFilter();        filter.addAction(ACTION_STARTED);        filter.addAction(ACTION_UPDATE);        filter.addAction(ACTION_STOPPED);                 mReceiver = new BroadcastReceiver() {            @Override            public void onReceive(Context context, Intent intent) {                if (intent.getAction().equals(ACTION_STARTED)) {                    callbackData.setText("STARTED");                } else if (intent.getAction().equals(ACTION_UPDATE)) {                    callbackData.setText("Got update: " + intent.getIntExtra("value", 0));                } else if (intent.getAction().equals(ACTION_STOPPED)) {                    callbackData.setText("STOPPED");                }            }        };        mLocalBroadcastManager.registerReceiver(mReceiver, filter);                  Button button = (Button) findViewById(R.id.start);        button.setOnClickListener(mStartListener);        button = (Button) findViewById(R.id.stop);        button.setOnClickListener(mStopListener);    }     @Override    protected void onDestroy() {        super.onDestroy();        mLocalBroadcastManager.unregisterReceiver(mReceiver);    }     private OnClickListener mStartListener = new OnClickListener() {        public void onClick(View v) {            startService(new Intent(LocalServiceBroadcasterActivity.this, LocalService.class));        }    };     private OnClickListener mStopListener = new OnClickListener() {        public void onClick(View v) {            stopService(new Intent(LocalServiceBroadcasterActivity.this, LocalService.class));        }    };     public static class LocalService extends Service {        LocalBroadcastManager mLocalBroadcastManager;        int mCurUpdate;         static final int MSG_UPDATE = 1;         Handler mHandler = new Handler() {            @Override            public void handleMessage(Message msg) {                switch (msg.what) {                case MSG_UPDATE: {                    mCurUpdate++;                    Intent intent = new Intent(ACTION_UPDATE);                    intent.putExtra("value", mCurUpdate);                    mLocalBroadcastManager.sendBroadcast(intent);                    Message nmsg = mHandler.obtainMessage(MSG_UPDATE);                    mHandler.sendMessageDelayed(nmsg, 1000);                }                    break;                default:                    super.handleMessage(msg);                }            }        };         @Override        public void onCreate() {            super.onCreate();            mLocalBroadcastManager = LocalBroadcastManager.getInstance(this);        }         public int onStartCommand(Intent intent, int flags, int startId) {            // Tell any local interested parties about the start.            mLocalBroadcastManager.sendBroadcast(new Intent(ACTION_STARTED));             // Prepare to do update reports.            mHandler.removeMessages(MSG_UPDATE);            Message msg = mHandler.obtainMessage(MSG_UPDATE);            mHandler.sendMessageDelayed(msg, 1000);            return ServiceCompat.START_STICKY;        }         @Override        public void onDestroy() {            super.onDestroy();             // Tell any local interested parties about the stop.            mLocalBroadcastManager.sendBroadcast(new Intent(ACTION_STOPPED));             // Stop doing updates.            mHandler.removeMessages(MSG_UPDATE);        }         @Override        public IBinder onBind(Intent intent) {            return null;        }    }}

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