LocalBroadcastManager 的简单介绍

Android应用开发之（小技巧之LocalBroadcastManager）

Android v4 兼容包提供android.support.v4.content.LocalBroadcastManager工具类，帮助大家在自己的进程内进行局部广播发送与注册，使用它比直接通过sendBroadcast(Intent)发送系统全局广播有以下几点好处。

1    因广播数据在本应用范围内传播，你不用担心隐私数据泄露的问题。

2    不用担心别的应用伪造广播，造成安全隐患。

3    相比在系统内发送全局广播，它更高效。

使用方法 通过getInstance(Contextcontext)获取实例，demo如下：

/**

* Demonstrates the use of a LocalBroadcastManager to easily communicate

* data from a service to any other interested code.

*/

public class LocalServiceBroadcaster 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.local_service_broadcaster);

// This is where we print the data we get back.

final TextView callbackData = (TextView)findViewById(R.id.callback);

// Put in some initial text.

callbackData.setText("No broadcast received yet");

// We use this to send broadcasts within our local process.

mLocalBroadcastManager = LocalBroadcastManager.getInstance(this);

// We are going to watch for interesting local broadcasts.

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);

// Watch for button clicks.

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(LocalServiceBroadcaster.this, LocalService.class));

}

};

private OnClickListener mStopListener = new OnClickListener() {

public void onClick(View v) {

stopService(new Intent(LocalServiceBroadcaster.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;

}

}

}

  转自 Android Club