Java 线程在几次迭代后被终止

Java 线程在几次迭代后被终止,java,android,multithreading,Java,Android,Multithreading,我试图创建一个包含服务的应用程序,该服务在设备启动时启动,然后记录一些事件 manifest.xml中的服务条目 <receiver android:name="com.myservices.BReceiver" > <intent-filter> <action android:name="android.intent.action.BOOT_COMPLETED" /> <category android:na

我试图创建一个包含服务的应用程序,该服务在设备启动时启动,然后记录一些事件

manifest.xml中的服务条目

<receiver android:name="com.myservices.BReceiver" >
    <intent-filter>
        <action android:name="android.intent.action.BOOT_COMPLETED" />

        <category android:name="android.intent.category.HOME" />
    </intent-filter>
</receiver>
<service android:name="com.myservices.MyService" >
</service>
MService.class

public class MyService extends IntentService {

    private static final String TAG = "MyService";
    private static final long TIMER = 2000;

    public MyService() {
        super("MyService");
    }

    @Override
    protected void onHandleIntent(Intent intent) {

        startLogginThread();

    }

    /**
     * For logging
     */
    private void startLogginThread() {
        Thread thread = new Thread() {
            public void run() {
                while (true) {
                    try {

                        // Logging events
                        myLogger();
                        Log.e(TAG, "Awake");
                        // TIMER
                        Thread.sleep(TIMER);
                    } catch (Exception e) {
                        Log.e("MyService", "local Thread error "+ e.toString());
                    }
                }
            }
        };
        thread.start();
    }

    private void myLogger() {

        // Creating new file to store logs.
        // Check if SD card is available else use internal memory.
        File dir = null;
        if (MyServiceUtil.isExternalStorageReadable() && MyServiceUtil.isExternalStorageWritable()) {
            // External Memory
            File sdCard = Environment.getExternalStorageDirectory();
            dir = new File(sdCard.getAbsolutePath() + "/MyLogger");
            dir.mkdirs();
        } else {
            // Internal Memory
            dir = getFilesDir();
        }

        // Rename to txt for reading
        File file = new File(dir, "log.txt");

        if (!file.exists()) {
            try {
                file.createNewFile();
            } catch (IOException e) {
                Log.e(TAG, "Exception :" + e.toString());
            }
        }

        // Printing timestamp in file
        try {

            PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(file, true)));
            String timeStamp = new SimpleDateFormat("dd.MM.yyyy '-' HH:mm:ss").format(Calendar.getInstance().getTime());
            out.println(timeStamp);

            // Log Location

            out.close();
            Log.e("Logggging", timeStamp);
        } catch (IOException e) {
            Log.e(TAG, "Exception :" + e.toString());
        }

    }

    @Override
    public void onDestroy() {
        Log.e(TAG, "onDestroy called");
        super.onDestroy();
    }

}
结果: 只有几次,比如6-7次日志被打印并存储在文件中。 以下是日志:

11-16 17:00:02.438: E/BReceiver(3187): onReceive started
11-16 17:00:02.438: E/BReceiver(3187): onReceive ended
11-16 17:00:02.458: E/MyService(3187): onDestroy called
11-16 17:00:02.458: D/MyServiceUtil(3187): isExternalStorageReadable started
11-16 17:00:02.468: D/MyServiceUtil(3187): isExternalStorageWritable started
11-16 17:00:02.468: E/Logggging(3187): 16.11.2014 - 17:00:02
11-16 17:00:02.468: E/MyService(3187): Awake
11-16 17:00:04.468: D/MyServiceUtil(3187): isExternalStorageReadable started
11-16 17:00:04.468: D/MyServiceUtil(3187): isExternalStorageWritable started
11-16 17:00:04.478: E/Logggging(3187): 16.11.2014 - 17:00:04
11-16 17:00:04.478: E/MyService(3187): Awake
11-16 17:00:06.478: D/MyServiceUtil(3187): isExternalStorageReadable started
11-16 17:00:06.488: D/MyServiceUtil(3187): isExternalStorageWritable started
11-16 17:00:06.488: E/Logggging(3187): 16.11.2014 - 17:00:06
11-16 17:00:06.488: E/MyService(3187): Awake
11-16 17:00:08.488: D/MyServiceUtil(3187): isExternalStorageReadable started
11-16 17:00:08.488: D/MyServiceUtil(3187): isExternalStorageWritable started
11-16 17:00:08.488: E/Logggging(3187): 16.11.2014 - 17:00:08
11-16 17:00:08.488: E/MyService(3187): Awake
另外,我不明白如果线程已经在运行,为什么会调用onDestroy:

11-16 17:00:02.458:E/MyService(3187):onDestroy呼叫


PS-这只发生在Kitkat中。

要在BroadcastReceiver中执行后台任务,您需要调用sdk 11+,并在完成时调用Pendingreult.finish()

这可以由onReceive(上下文、意图)中的应用程序调用,以 允许它在从该位置返回后保持广播活动 功能。这并没有改变相对稳定的预期 响应广播(在10秒内完成),但允许 将与之相关的工作转移到另一个线程的实现 避免由于磁盘IO导致主UI线程出现故障

您可以在接收器中移动代码并使用goAsync,也可以直接在IntentService中运行代码,因为它与服务不同,它有自己的后台线程

更新

final PendingResult pendingResult = goAsync();

new Thread() {
    public void run() {
        while (SOME_CONDITION) {
            try {
                // Logging events
                myLogger();
                Log.e(TAG, "Awake");
                // TIMER
                Thread.sleep(TIMER);
            } catch (Exception e) {
                Log.e("MyService", "local Thread error "+ e.toString());
            }
        }

        // Finish the broadcast.
        pendingResult.finish();
    }
}.start();

你对意向服务不太了解。onHandleIntent的方法是在框架启动的子线程中调用的,当onHandleIntent完成时,该服务将自行终止,因此原因是您将作业放在启动的新线程中。因此,您应该将代码放入OnHandleContent中

while (true) {
  try {

     // Logging events
     myLogger();
     Log.e(TAG, "Awake");
     // TIMER
     Thread.sleep(TIMER);
  } catch (Exception e) {
    Log.e("MyService", "local Thread error "+ e.toString());
  }
}

如果您能尝试捕获Throwable而不是Exception,您可能会遇到错误。如果这样做,只捕获一次错误,否则可能会进入无限循环。在Android JVM中是否有任何承诺,无论内存多么低或其他条件如何,运行线程的活动都不会被杀死?谢谢,但我不明白如何使用goAsync()的挂起意图。我应该在我的Breceiver中调用goAsync()吗?如有可能,请更新您的答案,例如
while (true) {
  try {

     // Logging events
     myLogger();
     Log.e(TAG, "Awake");
     // TIMER
     Thread.sleep(TIMER);
  } catch (Exception e) {
    Log.e("MyService", "local Thread error "+ e.toString());
  }
}