由于监控在最顶端的App需要持续进行，所以首先需要单独开一个后台进程，运行一个单例Manager。

初始化Manager

private TopAppManager() {
    // workHandler
    workerThread = new HandlerThread(getClass().getName());
    workerThread.start();
    workerThreadHandler = new Handler(workerThread.getLooper()) {

        @Override
        public void handleMessage(Message msg) {
            monitorInWorkThread();
        }
    };
    isAccessibilityAvailable = HSAccessibilityManager.getInstance().isAvailable();
    isUsageAccessGranted = HSUsageAccessMgr.getInstance().checkPermission(new HSUsageAccessMgr.PermissionListener() {
        @Override
        public void onPermissionChanged(boolean isGranted) {
            isUsageAccessGranted = isGranted;
            if (isUsageAccessGranted && !isAccessibilityAvailable) {
                resumeMonitor();
            }
        }
    });

    HSAccessibilityManager.getInstance().registerEvent(new HSAccessibilityManager.AccEventListener() {
        @Override
        public void onAvailable() {
            isAccessibilityAvailable = true;
            L.l("isAccessibilityAvailable:" + isAccessibilityAvailable);
            pauseMonitor();
        }

        @Override
        public void onEvent(AccessibilityEvent event) {
            if (event.getEventType() == AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED) {
                if (TextUtils.isEmpty(event.getPackageName()) || TextUtils.isEmpty(event.getClassName())) {
                    return;
                }
                ComponentName componentName = new ComponentName(event.getPackageName().toString(), event.getClassName().toString());
                if (TopAppUtil.tryGetActivityInfo(componentName) == null) {
                    return;
                }
                tryToNotifyTopApp(event.getPackageName().toString());
            }
        }

        @Override
        public void onUnavailable(@HSTopAppManager.FailCode int code, String failMsg) {
            L.l("onUnavailable code:" + code + " msg:" + failMsg);
            isAccessibilityAvailable = false;
            resumeMonitor();
            L.l("resumeMonitor");
        }
    });
    //sendBroadcast HSTopAppManager.BROADCAST_TOP_APP_MONITOR_INITIATED
    Intent intent = new Intent(HSTopAppManager.BROADCAST_TOP_APP_MONITOR_INITIATED);
    intent.putExtra(HSTopAppManager.EXTRA_DATA_TOP_APP, getTopApp());
    intent.setPackage(HSApplication.getContext().getPackageName());
    HSApplication.getContext().sendBroadcast(intent);
}

创建一个唯一的HandlerThread对象；使用HandlerThread对象在创建一个Handler，并且重写handleMessage方法

如果已经获得Accessibility的权限，那么实现监听很容易，这里需要提前判定是否已经有了这个权限，这个方法的实现，以后再写。

如果已经获得UsageAccess权限，对于实现监听也非常重要，这里也在提前判断是否已经获得UsageAccess权限。关于这个权限的判断，以后会写。

然后动态注册广播，去监听亮屏、灭屏和用户操作等广播

    private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            switch (intent.getAction()) {
                case Intent.ACTION_SCREEN_ON:
                case Intent.ACTION_USER_PRESENT:
                    resumeMonitor();
                    break;
                case Intent.ACTION_SCREEN_OFF:
                    pauseMonitor();
                    break;
            }
        }
    };

未完待续……