问题
I have read plenty of tutorial and posts here on SO regarding the use of WakeLock and WifiLock, but still didn't get to a solution of my issue.
I'm writing an app that has, when you start it, the only effect of creating and starting a (foreground) service. This service run two threads that are an UDP broadcast listener (using java.io) and a TCP server (using java.nio). In the onCreate of the service I acquire a wakelock and a wifilock, and I release them in the onDestroy.
Everything works fine as far as the phone is awake, but when the display goes off the UDP broadcast receiver stops receiving broadcast messages, and will not receive any until I switch on again the display. Practically, the locks are not working at all and there is no difference in put them...where am I wrong? I'm sure I'm doing something stupid somewhere, but can't find it by myself.
Here is some code:
This is what Activity does:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
onlyStartService = true;
}@Override
protected void onStart() {
super.onStart();
Intent bIntent = new Intent(this, FatLinkService.class);
getApplicationContext().startService(bIntent);
getApplicationContext().bindService(bIntent, flConnection, BIND_AUTO_CREATE);
}
// service connection to bind idle service
private ServiceConnection flConnection = new ServiceConnection() {
public void onServiceConnected(ComponentName className, IBinder binder) {
linkService.MyLinkBinder flBinder = (LinkService.MylinkBinder) binder;
flServiceInstance = flBinder.getService();
if (onlyStartService) {
condLog("Service bound and finishing activity...");
finish();
}
}
public void onServiceDisconnected(ComponentName className) {
flServiceInstance = null;
}
};
@Override
protected void onStop() {
super.onStop();
if (fatFinish) {
Intent bIntent = new Intent(this, FatLinkService.class);
flServiceInstance.stopServices();
flServiceInstance.stopForeground(true);
flServiceInstance.stopService(bIntent);
condLog("Service stop and unbound");
flServiceInstance = null;
}
getApplicationContext().unbindService(flConnection);
}
This is how service is:
public class LinkService extends Service {
InetAddress iaIpAddr, iaNetMask, iaBroadcast;
private final IBinder mBinder = new MyLinkBinder();
private linklistenBroadcast flBroadServer = null;
private linkTCPServer flTCPServer = null;
private linkUDPClient flBroadClient = null;
List<String> tokens = new ArrayList<String>();
private PowerManager.WakeLock wakeLock;
private WifiManager.WifiLock wifiLock;
public class MylLinkBinder extends Binder {
lLinkService getService() { return LinkService.this; }
}
@Override
public IBinder onBind(Intent intent) {
return mBinder;
}
@Override
public void onCreate() {
super.onCreate();
getLocks();
}
@Override
public int onStartCommand(Intent intent, int flags, int startId)
{
instantiateServices();
// notifies presence to other fat devices
condLog("Service notifying fat presence...");
flBroadClient = new LinkUDPClient();
flBroadClient.startSending(LinkProtocolConstants.BRCMD_PRESENCE + String.valueOf(LinkProtocolConstants.tcpPort), iaBroadcast, LinkProtocolConstants.brPort);
return START_STICKY;
}
public void getLocks() {
// acquire a WakeLock to keep the CPU running
condLog("Acquiring power lock");
WifiManager wm = (WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE);
wifiLock = wm.createWifiLock(WifiManager.WIFI_MODE_FULL , "MyWifiLock");
wifiLock.acquire();
PowerManager pm = (PowerManager) getApplicationContext().getSystemService(Context.POWER_SERVICE);
wakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "MyWakeLock");
wakeLock.acquire();
}
public void stopServices() {
if (flTCPServer != null)
flTCPServer.stopServer();
if (flBroadServer != null)
flBroadServer.stopSelf();
}
private void instantiateServices() {
populateAddresses(); // just obtain iaIpAddr
if (flTCPServer == null) {
condLog("Instantiating TCP server");
flTCPServer = new LinkTCPServer(iaIpAddr, FatLinkProtocolConstants.tcpPort);
flTCPServer.execute();
}
if (flBroadServer == null) {
condLog("Instantiating UDP broadcast server");
Intent notifyIntent = new Intent(this, LinkMain.class); // this is the main Activity class
notifyIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
notifyIntent.setAction("FROM_NOTIFICATION");
PendingIntent notifyPIntent = PendingIntent.getActivity(this, 0, notifyIntent, 0);
Notification fixNotification = new Notification.Builder(getApplicationContext())
.setContentTitle("Link")
.setSmallIcon(R.mipmap.imgLink)
.setContentIntent(notifyPIntent)
.build();
startForeground(1234, fixNotification);
flBroadServer = new LinklistenBroadcast();
flBroadServer.start();
}
}
private final class LinklistenBroadcast extends Thread {
private boolean bStopSelf = false;
DatagramSocket socket;
public void stopSelf() {
bStopSelf = true;
socket.close();
}
@Override
public void run() {
condLog( "Listening broadcast thread started");
bStopSelf = false;
try {
//Keep a socket open to listen to all the UDP trafic that is destinated for this port
socket = new DatagramSocket(null);
socket.setReuseAddress(true);
socket.setSoTimeout(LinkGeneric.BR_SOTIMEOUT_MILS);
socket.setBroadcast(true);
socket.bind(new InetSocketAddress(InetAddress.getByName("0.0.0.0"), FatLinkProtocolConstants.brPort));
while (true) {
condLog("Ready to receive broadcast packets...");
//Receive a packet
byte[] recvBuf = new byte[1500];
DatagramPacket packet = new DatagramPacket(recvBuf, recvBuf.length);
try {
socket.receive(packet);
} catch (InterruptedIOException sException) {
condLog(sockExcept.toString());
break;
} catch (SocketException sockExcept) {
condLog(sockExcept.toString());
}
if (bStopSelf) {
condLog("Broadcast server stopped...");
break;
}
int len = packet.getLength();
String datarecvd = new String(packet.getData()).trim();
//datarecvd = datarecvd.substring(0, len);
//Packet received
String message = new String(packet.getData()).trim();
condLog("<<< broadcast packet received from: " + packet.getAddress().getHostAddress() + " on port: " + packet.getPort() + ", message: " + message);
if (packet.getAddress().equals(iaIpAddr)) {
condLog("Ooops, it's me! discarding packet...");
continue;
}
else
condLog("<<< Packet received; data size: " + len + " bytes, data: " + datarecvd);
//See if the packet holds the right command (message)
// protocol decode
// here do some tuff
} catch (IOException ex) {
condLog(ex.toString());
}
if (socket.isBound()) {
condLog( "Closing socket");
socket.close();
}
condLog( "UDP server thread end.");
flTCPServer = null;
flBroadServer = null;
}
public boolean isThreadRunning() {
return !bStopSelf;
};
}
// Utility functions
public boolean checkBroadcastConnection (DatagramSocket socket, int timeOutcycles) {
int tries = 0;
while (!socket.isConnected()) {
tries++;
if (tries >= timeOutcycles)
return false;
}
return true;
}
@Override
public void onDestroy() {
super.onDestroy();
if (wakeLock != null) {
if (wakeLock.isHeld()) {
wakeLock.release();
}
}
if (wifiLock != null) {
if (wifiLock.isHeld()) {
wifiLock.release();
}
}
}
}
And, finally, here is the manifest:
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="xxxxxx.ink" >
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.WRITE_SETTINGS" />
<application
android:allowBackup="true"
android:icon="@mipmap/imgLinkmascotte"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".LinkMain"
android:label="@string/app_name"
android:theme="@android:style/Theme.Translucent.NoTitleBar.Fullscreen">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service android:name=".LinkService" />
</application>
</manifest>
I have read this, and I have the doubt the problem is the same but it is actually happening to me on all the phone I have tried (galaxy Tab 7.1, galaxy tag 10, Galaxy SIII, Galaxy Note 3 Neo, Galaxy SIII mini) with android releases from 4.0 to 4.4.
I have already tried the solution posted here, but anything changed (again...it is a bit frustrating).
I have even tried to set the "Keep wifi option in standby" to "Always" in all the phones I've tried, but still nothing.
I have studied the WakeFulIntentService class, that is supposed to work as everybody is saying that it is, but I can't see any significant different in my code.
I really hope someone can help me, I'm really stuck on this since last week.
EDIT: following the waqaslam answer, I have checked on a device that has "Wifi optimisation" option in Wifi-Advaced settings, and it actually works as soon as I uncked the option. So, now, the problem become: can I disable Wifi optimisation in devices that haven't that option shown in the advanced menu? as I wrote below in my comment, this seems not to be related to android release, as I have two devices (both Samsung) with 4.4.2 and they are not showing the option.
New EDIT: from the edited waqaslam answer, I have tried to add multicastlock to my service, but again anything changed. This is getting annoying, there's hardly something easy and clear to do with android.
thank you very much C.
回答1:
I think the problem is not with the WakeLocks but the Wi-Fi settings.
In newer versions of android, there's an additional setting in Settings -> Wi-Fi -> Advanced called Wi-Fi optimization, which (if turned-on) disables all the low priority communications (like listening to UDP broadcasts) when the display is off.
Disabling the option should allow your device to listen UDP broadcasts even when the display is switched-off.
You may also use WifiManager.MulticastLock in order to acquire WiFi lock that should listen to these special broadcasts when screen is switched-off.
WifiManager wifi = (WifiManager) this.getSystemService(Context.WIFI_SERVICE);
MulticastLock lock = wifi.createMulticastLock("lockWiFiMulticast");
lock.setReferenceCounted(false);
lock.acquire();
and when done with the lock, then call:
lock.release();
Also, don't forget to add the following permission to your manifest:
<uses-permission android:name="android.permission.CHANGE_WIFI_MULTICAST_STATE"/>
For more info, you may read this.
回答2:
Writing that just to mark the post as answered. I finally realilzed that there is no solution, or at least there is no solution working well on "all" the phones with "all" the android distribution (or at least from JB).
I have solved my personal issue just revisiting the concept of my app, considering that: - Sending UDP broadcast is always working even in idle mode - TCP servers are not affected by WiFi optimisation.
thank you all for the help and suggestion C.
回答3:
May be the reason is this .
Starting from Android 6.0 (API level 23), Android introduces two power-saving features that extend battery life for users by managing how apps behave when a device is not connected to a power source. Doze reduces battery consumption by deferring background CPU and network activity for apps when the device is unused for long periods of time. App Standby defers background network activity for apps with which the user has not recently interacted
来源：https://stackoverflow.com/questions/28627928/wakelock-and-wifilock-not-working