我有一个将webview作为服务运行的应用程序，因此音频可以在屏幕锁定时继续播放。该应用程序适用于播客等音频流。但我也想让它与flash视频一起使用。我能够在webview中加载flash视频流并让它播放流畅而稳定但是一旦屏幕关闭或被锁定，音频就会变得不稳定。 3g和WiFi的行为相同。我尝试使用this帖子建议使用唤醒锁：
PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "Tag");
wl.acquire();
//do what you need to do
wl.release();
然而这没有效果。我不确定我的代码中的确切位置，但是我将它放在服务的oncreate中，这没有任何效果，我将它放在oncreate中，用于我的主要活动，结果相同。
但是在帖子的后面，提问的人说WIFI_MODE_FULL_HIGH_PERF能够解决问题。但正如我所说的那样，我在3g上进行了测试，当屏幕关闭时音频结结巴巴。
我有什么想法可以阻止这种行为吗？
此外，我知道这是一款CPU密集型和电池猪应用程序，但我只是将其开发用于个人用途。
这是我的服务的完整代码：
public class MyService extends Service {
private NotificationManager nm;
private static boolean isRunning = false;
ArrayList<Messenger> mClients = new ArrayList<Messenger>(); // Keeps track of all current registered clients.
int mValue = 0; // Holds last value set by a client.
static final int MSG_REGISTER_CLIENT = 1;
static final int MSG_UNREGISTER_CLIENT = 2;
static final int MSG_SET_INT_VALUE = 3;
static final int MSG_SET_STRING_VALUE = 4;
PowerManager.WakeLock wl;
@Override
public IBinder onBind(Intent intent) {
wl.acquire();
return null;
}
@Override
public void onCreate() {
super.onCreate();
Log.i("MyService", "Service Started.");
showNotification();
isRunning = true;
PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
wl = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "Tag");
}
private void showNotification() {
nm = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
// In this sample, we'll use the same text for the ticker and the expanded notification
CharSequence text = getText(R.string.service_started);
// Set the icon, scrolling text and timestamp
Notification notification = new Notification(R.drawable.ic_launcher, text, System.currentTimeMillis());
notification.flags = Notification.FLAG_ONGOING_EVENT;
// The PendingIntent to launch our activity if the user selects this notification
PendingIntent contentIntent = PendingIntent.getActivity(this, 0, new Intent(this, MainActivity.class), 0);
// Set the info for the views that show in the notification panel.
notification.setLatestEventInfo(this, getText(R.string.service_label), text, contentIntent);
// Send the notification.
// We use a layout id because it is a unique number. We use it later to cancel.
nm.notify(R.string.service_started, notification);
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.i("MyService", "Received start id " + startId + ": " + intent);
return START_STICKY; // run until explicitly stopped.
}
public static boolean isRunning()
{
return isRunning;
}
@Override
public void onDestroy() {
super.onDestroy();
nm.cancelAll();
wl.release();
nm.cancel(R.string.service_started); // Cancel the persistent notification.
Log.i("MyService", "Service Stopped.");
isRunning = false;
}
}
我的主要代码：
public class MainActivity extends Activity {
Button btnStart, btnStop, btnBind, btnUnbind, btnUpby1, btnUpby10;
Messenger mService = null;
boolean mIsBound;
WebView mWebView;
private ServiceConnection mConnection = new ServiceConnection() {
public void onServiceConnected(ComponentName className, IBinder service) {
mService = new Messenger(service);
try {
Message msg = Message.obtain(null, MyService.MSG_REGISTER_CLIENT);
mService.send(msg);
} catch (RemoteException e) {
// In this case the service has crashed before we could even do anything with it
}
}
public void onServiceDisconnected(ComponentName className) {
// This is called when the connection with the service has been unexpectedly disconnected - process crashed.
mService = null;
}
};
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
btnStart = (Button)findViewById(R.id.btnStart);
btnStop = (Button)findViewById(R.id.btnStop);
btnBind = (Button)findViewById(R.id.btnBind);
btnUnbind = (Button)findViewById(R.id.btnUnbind);
btnStart.setOnClickListener(btnStartListener);
btnStop.setOnClickListener(btnStopListener);
btnBind.setOnClickListener(btnBindListener);
CheckIfServiceIsRunning();
//webview
mWebView = (WebView) findViewById(R.id.webview);
mWebView.getSettings().setJavaScriptEnabled(true);
mWebView.getSettings().setPluginsEnabled(true);
mWebView.loadUrl(url);
mWebView.setWebViewClient(new HelloWebViewClient());
}
private void CheckIfServiceIsRunning() {
//If the service is running when the activity starts, we want to automatically bind to it.
if (MyService.isRunning()) {
doBindService();
}
}
private OnClickListener btnStartListener = new OnClickListener() {
public void onClick(View v){
startService(new Intent(MainActivity.this, MyService.class));
}
};
private OnClickListener btnStopListener = new OnClickListener() {
public void onClick(View v){
doUnbindService();
stopService(new Intent(MainActivity.this, MyService.class));
}
};
private OnClickListener btnBindListener = new OnClickListener() {
public void onClick(View v){
doBindService();
}
};
private OnClickListener btnUnbindListener = new OnClickListener() {
public void onClick(View v){
doUnbindService();
}
};
void doBindService() {
bindService(new Intent(this, MyService.class), mConnection, Context.BIND_AUTO_CREATE);
mIsBound = true;
}
void doUnbindService() {
if (mIsBound) {
// If we have received the service, and hence registered with it, then now is the time to unregister.
if (mService != null) {
try {
Message msg = Message.obtain(null, MyService.MSG_UNREGISTER_CLIENT);
mService.send(msg);
} catch (RemoteException e) {
// There is nothing special we need to do if the service has crashed.
}
}
// Detach our existing connection.
unbindService(mConnection);
mIsBound = false;
}
}
private class HelloWebViewClient extends WebViewClient {
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
return true;
}
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if ((keyCode == KeyEvent.KEYCODE_BACK) && mWebView.canGoBack()) {
mWebView.goBack();
return true;
}
return super.onKeyDown(keyCode, event);
}
@Override
protected void onDestroy() {
super.onDestroy();
try {
doUnbindService();
} catch (Throwable t) {
Log.e("MainActivity", "Failed to unbind from the service", t);
}
}
@Override
protected void onResume() {
super.onResume();
}
}
答案 0 :(得分：3)
从你的描述来看，听起来你很快就会发布WakeLock。 如果您只是将该代码块放在onCreate for the Service中，那么当您的流代码运行时，您确实没有获得WakeLock。您必须在后台工作期间获得锁定。
我用于此类服务的模式是：
问题可能与WebView的工作方式有关。这就是说，因为这不是生产代码，你可以尝试通过删除释放来简单地“泄漏”唤醒锁，看看是否有帮助。只需在活动开始时创建并获取锁定，而不必担心服务。
服务并没有给你太多帮助。您的代码目前的结构方式仍然存在问题。即使您有服务，您的活动仍然可以在后台删除，只是让服务不会停止。此外，因为WebView是一个View，它确实需要一个Activity和视图层次结构。