如何查看后台服务是否正在运行?
我想要一个切换服务状态的Android活动——它让我打开它,如果它是关闭的,如果它是关闭的。
如何查看后台服务是否正在运行?
我想要一个切换服务状态的Android活动——它让我打开它,如果它是关闭的,如果它是关闭的。
当前回答
检查服务是否正在运行的正确方法是简单地询问它。在您的服务中实现一个BroadcastReceiver来响应来自活动的ping。在服务启动时注册BroadcastReceiver,在服务被销毁时注销它。从您的活动(或任何组件)发送一个本地广播意图到服务,如果它响应,您就知道它正在运行。注意下面代码中ACTION_PING和ACTION_PONG之间的细微差别。
public class PingableService extends Service {
public static final String ACTION_PING = PingableService.class.getName() + ".PING";
public static final String ACTION_PONG = PingableService.class.getName() + ".PONG";
public int onStartCommand (Intent intent, int flags, int startId) {
LocalBroadcastManager.getInstance(this).registerReceiver(mReceiver, new IntentFilter(ACTION_PING));
return super.onStartCommand(intent, flags, startId);
}
@Override
public void onDestroy () {
LocalBroadcastManager.getInstance(this).unregisterReceiver(mReceiver);
super.onDestroy();
}
private BroadcastReceiver mReceiver = new BroadcastReceiver() {
@Override
public void onReceive (Context context, Intent intent) {
if (intent.getAction().equals(ACTION_PING)) {
LocalBroadcastManager manager = LocalBroadcastManager.getInstance(getApplicationContext());
manager.sendBroadcast(new Intent(ACTION_PONG));
}
}
};
}
public class MyActivity extends Activity {
private boolean isSvcRunning = false;
@Override
protected void onStart() {
LocalBroadcastManager manager = LocalBroadcastManager.getInstance(getApplicationContext());
manager.registerReceiver(mReceiver, new IntentFilter(PingableService.ACTION_PONG));
// the service will respond to this broadcast only if it's running
manager.sendBroadcast(new Intent(PingableService.ACTION_PING));
super.onStart();
}
@Override
protected void onStop() {
LocalBroadcastManager.getInstance(this).unregisterReceiver(mReceiver);
super.onStop();
}
protected BroadcastReceiver mReceiver = new BroadcastReceiver() {
@Override
public void onReceive (Context context, Intent intent) {
// here you receive the response from the service
if (intent.getAction().equals(PingableService.ACTION_PONG)) {
isSvcRunning = true;
}
}
};
}
其他回答
/**
* Check if the service is Running
* @param serviceClass the class of the Service
*
* @return true if the service is running otherwise false
*/
public boolean checkServiceRunning(Class<?> serviceClass){
ActivityManager manager = (ActivityManager) getSystemService(ACTIVITY_SERVICE);
for (RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE))
{
if (serviceClass.getName().equals(service.service.getClassName()))
{
return true;
}
}
return false;
}
在serviceclass内部定义:
public static Boolean serviceRunning = false;
然后在onStartCommand(…)
public int onStartCommand(Intent intent, int flags, int startId) {
serviceRunning = true;
...
}
@Override
public void onDestroy()
{
serviceRunning = false;
}
然后,调用if(serviceclass。serviceRunning == true)。
同样,如果使用pending intent(例如使用AlarmManager),人们可能会发现另一种替代方法更干净:
public static boolean isRunning(Class<? extends Service> serviceClass) {
final Intent intent = new Intent(context, serviceClass);
return (PendingIntent.getService(context, CODE, intent, PendingIntent.FLAG_NO_CREATE) != null);
}
CODE是一个常量,您在类中私有地定义它,以标识与您的服务相关联的挂起意图。
下面是一个优雅的技巧,涵盖了所有的假设。这只适用于本地服务。
public final class AService extends Service {
private static AService mInstance = null;
public static boolean isServiceCreated() {
try {
// If instance was not cleared but the service was destroyed an Exception will be thrown
return mInstance != null && mInstance.ping();
} catch (NullPointerException e) {
// destroyed/not-started
return false;
}
}
/**
* Simply returns true. If the service is still active, this method will be accessible.
* @return
*/
private boolean ping() {
return true;
}
@Override
public void onCreate() {
mInstance = this;
}
@Override
public void onDestroy() {
mInstance = null;
}
}
然后是:
if(AService.isServiceCreated()){
...
}else{
startService(...);
}
我稍微修改了上面给出的一个解决方案,但是传递的是类而不是泛型字符串名称,以便确保比较来自同一个方法class. getname()的字符串
public class ServiceTools {
private static String LOG_TAG = ServiceTools.class.getName();
public static boolean isServiceRunning(Context context,Class<?> serviceClass){
final ActivityManager activityManager = (ActivityManager)context.getSystemService(Context.ACTIVITY_SERVICE);
final List<RunningServiceInfo> services = activityManager.getRunningServices(Integer.MAX_VALUE);
for (RunningServiceInfo runningServiceInfo : services) {
Log.d(Constants.TAG, String.format("Service:%s", runningServiceInfo.service.getClassName()));
if (runningServiceInfo.service.getClassName().equals(serviceClass.getName())){
return true;
}
}
return false;
}
}
然后
Boolean isServiceRunning = ServiceTools.isServiceRunning(
MainActivity.this.getApplicationContext(),
BackgroundIntentService.class);