运行 后台服务时的意外行为
Unexpected behaviour when running Service in background
在我的应用程序中，我有一项服务。它在主 activity 启动时启动并执行以下操作：
timer.scheduleAtFixedRate (
new TimerTask() {
public void run() {
appendToFile("diff: "+(System.currentTimeMillis()-lastTime));
lastTime = System.currentTimeMillis();
}
}, 0, 1);
基本上，它会创建一个 Timer，每毫秒更新一次。在每次更新时，计时器都会查看上次调用它的时间，并将计时器调用之间的时间保存到一个文件中。由于系统中总是存在开销，我希望每行输出超过 1 毫秒，可能在 10 毫秒左右。
这是应用程序休眠时的快照。
diff: 6
diff: 8
diff: 5
diff: 81
diff: 12
diff: 12
diff: 54
diff: 60
diff: 5734
diff: 77
diff: 9
diff: 20
diff: 6
diff: 21
diff: 10
diff: 13
diff: 16895
diff: 13
diff: 82
diff: 269
diff: 35
diff: 25
diff: 24
diff: 20
diff: 30
diff: 26
diff: 11
diff: 14
diff: 49
diff: 57
diff: 9
我的问题是关于我有时会得到的有些奇怪的结果。中间的 16895 表示该服务由于某种原因在系统空闲时等待了将近 17 秒 运行 它的任务。但是，紧接着它会在 10 到 30 毫秒之间显示更正常的结果。我知道这是在系统休眠期间，因为日志中有更多条目。该服务从未被破坏，因为我也记录了对 onDestroy() 的所有调用。
是否有解释为什么服务会突然暂停？有什么方法可以确保它一直 运行 吗？
就像你说的，系统正在休眠。当服务被取出内存时，服务是"destroyed"。休眠系统只是暂时的暂停，因为它会在 CPU 醒来后立即恢复。
您可以使用AlarmManager which will schedule an even to happen at a specific time. It'll wake the system up. You can also use a wake lock yourself or use a WakefulBroadcastReceiver唤醒系统以保持CPU运行。
请注意，保留 CPU 运行 会消耗大量电池电量，因此请谨慎使用，仅在绝对需要时使用。
在我的应用程序中，我有一项服务。它在主 activity 启动时启动并执行以下操作：
timer.scheduleAtFixedRate (
new TimerTask() {
public void run() {
appendToFile("diff: "+(System.currentTimeMillis()-lastTime));
lastTime = System.currentTimeMillis();
}
}, 0, 1);
基本上，它会创建一个 Timer，每毫秒更新一次。在每次更新时，计时器都会查看上次调用它的时间，并将计时器调用之间的时间保存到一个文件中。由于系统中总是存在开销，我希望每行输出超过 1 毫秒，可能在 10 毫秒左右。
这是应用程序休眠时的快照。
diff: 6
diff: 8
diff: 5
diff: 81
diff: 12
diff: 12
diff: 54
diff: 60
diff: 5734
diff: 77
diff: 9
diff: 20
diff: 6
diff: 21
diff: 10
diff: 13
diff: 16895
diff: 13
diff: 82
diff: 269
diff: 35
diff: 25
diff: 24
diff: 20
diff: 30
diff: 26
diff: 11
diff: 14
diff: 49
diff: 57
diff: 9
我的问题是关于我有时会得到的有些奇怪的结果。中间的 16895 表示该服务由于某种原因在系统空闲时等待了将近 17 秒 运行 它的任务。但是，紧接着它会在 10 到 30 毫秒之间显示更正常的结果。我知道这是在系统休眠期间，因为日志中有更多条目。该服务从未被破坏，因为我也记录了对 onDestroy() 的所有调用。
是否有解释为什么服务会突然暂停？有什么方法可以确保它一直 运行 吗？
就像你说的，系统正在休眠。当服务被取出内存时，服务是"destroyed"。休眠系统只是暂时的暂停，因为它会在 CPU 醒来后立即恢复。
您可以使用AlarmManager which will schedule an even to happen at a specific time. It'll wake the system up. You can also use a wake lock yourself or use a WakefulBroadcastReceiver唤醒系统以保持CPU运行。
请注意，保留 CPU 运行 会消耗大量电池电量，因此请谨慎使用，仅在绝对需要时使用。