为什么没有重新启用Keyguard？

Question

我有一个后台视频录制服务，在此期间我禁用了Keyguard。当我想要停止录制时，我会停止服务并调用OnDestroy()。

我可以在我的跟踪中看到调用了ReenableKeyguard()。但是，在我“强制停止”启动服务的主机应用程序之前，Keyguard仍然是禁用的。

是什么原因导致键盘守卫在调用ReenableKeyguard()时保持禁用状态？

这是销毁Service并重新启用keyguard的代码。(它是C#/Xamarin，但与Java基本相同)

    public override void OnDestroy()
    {
        Tracer.Trace("BackgroundVideoRecorder::OnDestroy();");
        base.OnDestroy();

        try
        {
            camera.Reconnect();
            mediaRecorder.Stop();
            mediaRecorder.Reset();

            camera.StopPreview();
            mediaRecorder.Release();

            camera.Release();
            camera = null;

            if (Common.KeyGuardLocker != null)
            {
                Tracer.Trace("BackgroundVideoRecorder::OnDestroy() - ReenableKeyguard()");
                Common.KeyGuardLocker.ReenableKeyguard();
            }

            windowManager.RemoveView(surfaceView);
        }
        catch (Exception ex)
        {
            Tracer.Trace(ex);
        }
    }

Answer 1

I have the exact same problem and the reason was that i had only permissions to Disable keyguard and not the ones to re-enable it.

android.permission.DISABLE_KEYGUARD android.permission.ENABLE_KEYGUARD