我应该什么时候释放本机（Android NDK）句柄？

我必须使用本机库（这不是我的决定）。该库已经有了一个JNI包装器，示例AndroidNDK代码可以正常工作。但是库初始化例程返回本机句柄，开发者需要正确关闭它们

现在，有一个有趣的问题：从哪里调用close\u handle例程？

至少在理论上，每一次不正确的终止都可能导致磁盘上某个地方的临时文件或其他某种资源泄漏

库初始化需要0.5到1秒，并消耗大量内存

一个

活动

是一个控制器（在MVC意义上），Android可以因为自己的原因杀死它，包括转动设备，并且唯一保证调用的函数是

onPause（）

。因此，

onPause

/

onResume

对于长时间的资源消耗操作来说是一个不好的地方

（我知道android:configChanges=“keyboardHidden | orientation”，但我更喜欢不需要它的解决方案。）

<代码>应用< /代码>将是一个理想的候选者（我认为库是模型的一部分），但没有“应用终止”事件。

服务

听起来很有希望，本机库是一种服务，但我不知道如何实现所需的行为：当应用程序终止时，必须关闭句柄

---

超时：听起来像是一种折衷，但事实上它保证了内存在需要时不可用，但几秒钟后就会可用。

目前看来，我确实需要一项服务，但不完全是

IntentService

：

IntentService

调用

stopSelf（）

，而我的服务应该能维持下去

有趣的是，当用户从“正在运行的服务”中选择“停止”时，调用了

Service.onDestroy（）

，但当用户从“应用程序”中选择“强制停止”时，调用了

。“停止调试”也不会导致调用
Service.ondestory（）

编辑：

我当前的解决方案是使用从自定义
服务
子类派生的类；该代码是从“网络”中找到的
IntentService
的源代码中借来的在派生的子类中，我覆盖了
onDestroy（），并相信这是最好的应用程序终止通知

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);
    }
}

继续…
在实践中，一些本地库泄漏了资源；我必须重新启动流程（这并没有终止活动，而是重新创建了流程）：


我们只能希望没有库泄漏临时磁盘文件…
您指的确切句柄是什么？细节是保密的（“一点健康的妄想症不会伤害任何人”），但库使用初始化分N步，每一步返回一个句柄。在C中，它们是不透明的手柄；对于Java，它们被转换为整数。N个步骤，因为至少在理论上，您可以使用稍微不同的参数重新初始化。该问题被否决。这很奇怪，除非这意味着支持部门收到了类似的询问：）
public class MyService extends HangAroundIntentService {
    public MyService() {
        super("MyService");
    }
    public void onDestroy() {
        MyData.getMyData().shutdown();
        super.onDestroy();
    }
    // service-specific static methods not shown
}