【Android】监听蓝牙状态变化

【关键词】

广播

LocalBroadcastManager

监听蓝牙状态

【问题】

广播的用法；
使用LocalBroadcastManager注册蓝牙广播，接收不到消息；

【解决方案】

在自定义广播的时候才使用LocalBroadcastManager，并且需求是：广播只在本APP中有效；
不要尝试通过LocalBroadcastManager操作（注册，取消注册，发送）系统的广播；

【权限】

<uses-permissionandroid:name="android.permission.BLUETOOTH"/>

<uses-permissionandroid:name="android.permission.BLUETOOTH_ADMIN"/>

【注册】

mContext.registerReceiver(mReceiver,makeFilter());

【注销】

mContext.unregisterReceiver(mReceiver);

【代码】

privateIntentFiltermakeFilter(){

IntentFilterfilter=newIntentFilter();

filter.addAction(BluetoothAdapter.ACTION_STATE_CHANGED);

returnfilter;

}

privateBroadcastReceivermReceiver=newBroadcastReceiver(){

@Override

publicvoidonReceive(Contextcontext,Intentintent){

LogUtil.e(TAG,"onReceive---------");

switch(intent.getAction()){

caseBluetoothAdapter.ACTION_STATE_CHANGED:

intblueState=intent.getIntExtra(BluetoothAdapter.EXTRA_STATE,0);

switch(blueState){

caseBluetoothAdapter.STATE_TURNING_ON:

LogUtil.e("onReceive---------STATE_TURNING_ON");

break;

caseBluetoothAdapter.STATE_ON:

LogUtil.e("onReceive---------STATE_ON");

break;

caseBluetoothAdapter.STATE_TURNING_OFF:

LogUtil.e("onReceive---------STATE_TURNING_OFF");

BleUtil.toReset(mContext);

break;

caseBluetoothAdapter.STATE_OFF:

LogUtil.e("onReceive---------STATE_OFF");

BleUtil.toReset(mContext);

break;

}

break;

}

}

};

【参考资料】

LocalBroadcastManagervsContext.registerReceiver(),
Context.sendBroadcast(Intent),andContext.unregisterReceiver()aretheysame?

LocalBroadcastManagerisasitsnamesays,animplementationofthebroadcastmethodsthatareonlyavailabletoyourapp.Thishassomebenefits,withthebiggestbeingsafety,onelessholeto
watchoutfor.Intermsofimplementation,thereareafewthingstokeepinmind:

ThisclassisfromtheAndroidSupportLibrary
Themethodcallshavetobeprefacedwith

LocalBroadcastManager.getInstance([CONTEXT])

where

[CONTEXT]

is
asubclassoftheContextclass,suchasActivity.
Whenyouusethisclass,itispurelyforyourapp.Usingittoregisterreceiversandmakebroadcaststhataresystemwidewillfail.

SothisclassisnotthesameasContext,itissimplyaveryspecific,app-onlyimplementationofContext'sreceiver/broadcastmethods.Youshoulduseitwhenthereisabsolutelynopointforyourlistenertolisten
onglobal(system-wide)broadcastsandwhenyourbroadcastdoesnotneedtotargetanythingoutsideyourapp.