现在，看起来我确实需要一个服务，但不完全是IntentService: IntentServicecalls stopSelf()，而我的服务应该挂起。
有趣的Service.onDestroy()是，当用户从“运行服务”中选择“停止”时调用，而不是当用户从“应用程序”中选择“强制停止”时调用。“停止调试”也不会导致Service.onDestroy()调用。
编辑：
我目前的解决方案是使用从自定义子类派生的Service类；IntentService该代码是从“网络”某处的来源借来的。在派生的子类中，我重写onDestroy()并相信这是可用的最佳应用程序终止通知。
package com.xyz.customandroid;
import android.app.Service;
import android.content.Intent;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.IBinder;
import android.os.Looper;
import android.os.Message;
public abstract class HangAroundIntentService extends Service {
/** An extra with this name and the value of boolean true marks an intent as a cancel intent. See {@link #markedAsCancelIntent(Intent)}. */
private static final String CANCEL_MARK = "com.xyz~.customandroid.HangAroundIntentService.cancelQueue()";
private static final int WHAT_MAGIC = 0; // the "what" field for messages
private volatile Looper mServiceLooper;
private volatile ServiceHandler mServiceHandler;
private String mName;
private boolean mRedelivery;
private boolean mHangAround = true;
private final class ServiceHandler extends Handler {
public ServiceHandler(Looper looper) {
super(looper);
}
@Override
public void handleMessage(Message msg) {
onHandleIntent((Intent)msg.obj);
if (!mHangAround) {
stopSelf(msg.arg1);
}
}
}
/**
* Creates an IntentService. Invoked by your subclass's constructor.
*
* @param name Used to name the worker thread, important only for debugging.
*/
public HangAroundIntentService(String name) {
super();
mName = name;
}
/**
* Remove all pending messages from the handler queue.
* Processing of the message already fetched from the queue
* is not terminated by this function.
*
* Although this function is public, it is recommended
* to use the cancel intents instead.
* see {@link #markedAsCancelIntent(Intent)} and {@link #isCancelIntent(Intent)}.
*/
public void cancelQueue() {
mServiceHandler.removeMessages(WHAT_MAGIC);
}
/**
* Sets intent redelivery preferences. Usually called from the constructor
* with your preferred semantics.
*
* <p>If enabled is true,
* {@link #onStartCommand(Intent, int, int)} will return
* {@link Service#START_REDELIVER_INTENT}, so if this process dies before
* {@link #onHandleIntent(Intent)} returns, the process will be restarted
* and the intent redelivered. If multiple Intents have been sent, only
* the most recent one is guaranteed to be redelivered.
*
* <p>If enabled is false (the default),
* {@link #onStartCommand(Intent, int, int)} will return
* {@link Service#START_NOT_STICKY}, and if the process dies, the Intent
* dies along with it.
*/
public void setIntentRedelivery(boolean enabled) {
mRedelivery = enabled;
}
/**
* If enabled is true (default), the service does not stop after processing an intent.
*/
public void setServiceHangAround(boolean enabled) {
mHangAround = enabled;
}
@Override
public void onCreate() {
// TODO: It would be nice to have an option to hold a partial wakelock
// during processing, and to have a static startService(Context, Intent)
// method that would launch the service & hand off a wakelock.
super.onCreate();
HandlerThread thread = new HandlerThread("IntentService[" + mName + "]");
thread.start();
mServiceLooper = thread.getLooper();
mServiceHandler = new ServiceHandler(mServiceLooper);
}
/**
* If intent is a cancel intent, {@link #cancelQueue()} is invoked immediately;
* no other action is done for a cancel intent, whatever information it might contain.
*
* Intents that are not cancel intents are queued
* to be seen from {@link #onHandleIntent(Intent)}.
*/
@Override
public void onStart(Intent intent, int startId) {
if (isCancelIntent(intent)) {
cancelQueue();
} else {
Message msg = mServiceHandler.obtainMessage(WHAT_MAGIC);
msg.arg1 = startId;
msg.obj = intent;
mServiceHandler.sendMessage(msg);
}
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
onStart(intent, startId);
return mRedelivery ? START_REDELIVER_INTENT : START_NOT_STICKY;
}
@Override
public void onDestroy() {
mServiceLooper.quit();
}
@Override
public IBinder onBind(Intent intent) {
return null;
}
/**
* This method is invoked on the worker thread with a request to process.
* Only one Intent is processed at a time, but the processing happens on a
* worker thread that runs independently from other application logic.
* So, if this code takes a long time, it will hold up other requests to
* the same IntentService, but it will not hold up anything else.
*
* @param intent The value passed to {@link
* android.content.Context#startService(Intent)}.
*/
protected abstract void onHandleIntent(Intent intent);
/**
* Mark an Intent as cancel intent. The Intent will not be placed in the queue;
* instead, it will cause immediate cleaning of the queue
* (unless you redefine {@link #onStart(Intent, int)} in a derived class).
* @param intent to be modified
* @return the original intent after modification
*/
public static Intent markedAsCancelIntent(Intent intent) {
intent.putExtra(CANCEL_MARK, true);
return intent;
}
/**
* Check if the intent has been marked as a cancel intent.
* @param intent to be checked
* @return true if it is a cancel intent
*/
public static boolean isCancelIntent(Intent intent) {
return intent.getBooleanExtra(CANCEL_MARK, false);
}
}
我的服务类定义为：
public class MyService extends HangAroundIntentService {
public MyService() {
super("MyService");
}
public void onDestroy() {
MyData.getMyData().shutdown();
super.onDestroy();
}
// service-specific static methods not shown
}
未完待续...