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
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(...);
}
其他回答
摘自Android文档:
比如sendBroadcast(Intent),但是如果有任何接收器 这个函数将阻塞并立即分发它们 返回之前。
你可以把这次入侵看成是"ping "服务。因为我们可以同步广播,所以我们可以在UI线程上同步广播并获得结果。
服务
@Override
public void onCreate() {
LocalBroadcastManager
.getInstance(this)
.registerReceiver(new ServiceEchoReceiver(), new IntentFilter("ping"));
//do not forget to deregister the receiver when the service is destroyed to avoid
//any potential memory leaks
}
private class ServiceEchoReceiver extends BroadcastReceiver {
public void onReceive (Context context, Intent intent) {
LocalBroadcastManager
.getInstance(this)
.sendBroadcastSync(new Intent("pong"));
}
}
活动
bool serviceRunning = false;
protected void onCreate (Bundle savedInstanceState){
LocalBroadcastManager.getInstance(this).registerReceiver(pong, new IntentFilter("pong"));
LocalBroadcastManager.getInstance(this).sendBroadcastSync(new Intent("ping"));
if(!serviceRunning){
//run the service
}
}
private BroadcastReceiver pong = new BroadcastReceiver(){
public void onReceive (Context context, Intent intent) {
serviceRunning = true;
}
}
当然,在许多应用程序中,赢家是服务上的静态布尔字段,在service . oncreate()中设置为true,在service . ondestroy()中设置为false,因为它要简单得多。
对于kotlin,可以使用下面的代码。
fun isMyServiceRunning(calssObj: Class<SERVICE_CALL_NAME>): Boolean {
val manager = requireActivity().getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager
for (service in manager.getRunningServices(Integer.MAX_VALUE)) {
if (calssObj.getName().equals(service.service.getClassName())) {
return true
}
}
return false
}
得到它!
你必须调用startService()为你的服务正确注册和传递BIND_AUTO_CREATE是不够的。
Intent bindIntent = new Intent(this,ServiceTask.class);
startService(bindIntent);
bindService(bindIntent,mConnection,0);
现在是ServiceTools类:
public class ServiceTools {
private static String LOG_TAG = ServiceTools.class.getName();
public static boolean isServiceRunning(String serviceClassName){
final ActivityManager activityManager = (ActivityManager)Application.getContext().getSystemService(Context.ACTIVITY_SERVICE);
final List<RunningServiceInfo> services = activityManager.getRunningServices(Integer.MAX_VALUE);
for (RunningServiceInfo runningServiceInfo : services) {
if (runningServiceInfo.service.getClassName().equals(serviceClassName)){
return true;
}
}
return false;
}
}
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(...);
}
可以有多个具有相同类名的服务。
我刚刚创建了两个应用程序。第一个应用程序的包名是com.example.mock。我在应用程序中创建了一个名为lorem的子包和一个名为Mock2Service的服务。因此它的完全限定名是com.example.mock.lorem.Mock2Service。
然后我创建了第二个应用程序和一个名为Mock2Service的服务。第二个应用程序的包名是com.example.mock.lorem。服务的完全限定名是com.example.mock.lorem。Mock2Service。
这是我的logcat输出。
03-27 12:02:19.985: D/TAG(32155): Mock-01: com.example.mock.lorem.Mock2Service
03-27 12:02:33.755: D/TAG(32277): Mock-02: com.example.mock.lorem.Mock2Service
更好的方法是比较ComponentName实例,因为ComponentName的equals()比较包名和类名。一个设备上不能安装两个包名相同的应用程序。
ComponentName的equals()方法。
@Override
public boolean equals(Object obj) {
try {
if (obj != null) {
ComponentName other = (ComponentName)obj;
// Note: no null checks, because mPackage and mClass can
// never be null.
return mPackage.equals(other.mPackage)
&& mClass.equals(other.mClass);
}
} catch (ClassCastException e) {
}
return false;
}
ComponentName