如何在安卓系统中使用FileObserver监控"/sys/class/“

Question

我正在尝试使用FileObserver监控"/sys/class/udc“文件夹。我的应用程序是系统权限应用程序，所以应该不会有权限问题。我无法检测到更改事件。

String path = "/sys/class/udc";
static final int mask = (
    FileObserver.CREATE |
    FileObserver.DELETE |
    FileObserver.DELETE_SELF |
    FileObserver.MODIFY |
    FileObserver.MOVED_FROM |
    FileObserver.MOVED_TO |
    FileObserver.MOVE_SELF
);

public UsbCableDisconncetEvent(String path) {
    super(path, mask);
    Log.d(TAG, "DisconnectEventHandler modified");
}

public void onEvent(int event, String path) {
    Log.d(TAG, "recieved moified event " + event);
}

FileObserver是否支持监控"/sys/class“文件？

Answer 1

在阅读了Android框架代码之后，我能够找到我问题的答案。使用FileObesever监控内核事件(uevent)的用户可以参考以下代码：

private static final String STATE_PATH = "/sys/class/android_usb/android0/state";
public final UEventObserver mUEventObserver = new UEventObserver() {
       @Override
        public void onUEvent(UEventObserver.UEvent event) {
            Log.d(TAG, "USB UEVENT: " + event.toString());
        }
    };
mUEventObserver.startObserving(USB_STATE_MATCH);

You will start receiving events and should be able to see the same in the logs.