Question

我在iOS App中使用Vuforia SDK 6.2.9版。所有工作都很好，但是当应用从后台进入时出错。

运行VUFORIA的viewcontroller正在侦听 UIApplicationWillResignActiveNotification 和 UIApplicationDidBecomeActiveNotification 通知。在UIApplicationWillResignActiveNotification暂停AR的情况下，在UIApplicationDidBecomeActiveNotification的情况下恢复AR。

// we use the iOS notification to pause/resume the AR when the application goes (or come back from) background

[[NSNotificationCenter defaultCenter]
 addObserver:self
 selector:@selector(pauseAR)
 name:UIApplicationWillResignActiveNotification
 object:nil];

[[NSNotificationCenter defaultCenter]
 addObserver:self
 selector:@selector(resumeAR)
 name:UIApplicationDidBecomeActiveNotification
 object:nil];

这些是方法

- (void) pauseAR {
   NSError * error = nil;
   if (![vapp pauseAR:&error]) {
      NSLog(@"Error pausing AR:%@", [error description]);
   }
}

- (void) resumeAR {

    NSError * error = nil;
    if(! [vapp resumeAR:&error]) {
        NSLog(@"Error resuming AR:%@", [error description]);
    }

    // on resume, we reset the flash
    Vuforia::CameraDevice::getInstance().setFlashTorchMode(false);

    [self handleRotation:self.interfaceOrientation];
}

当我返回扫描模式时，应用程序从后台进入后，相机被冻结，出现错误 找不到具有CAEAGLLayer或CAMetalLayer图层类的UIView，它响应选择器renderFrameVuforia

2017-07-17 11:13:01.187406+0200 App[8689:2961061] frame: {{0, 0}, {375, 667}}
2017-07-17 11:13:01.243707+0200 App[8689:2961061] DEBUG/AR(8689) Could not find a UIView with CAEAGLLayer or CAMetalLayer layer class that responds to selector renderFrameVuforia
2017-07-17 11:13:01.253958+0200 App[8689:2961061] Vuforia Library version 6.2.9
2017-07-17 11:13:01.731099+0200 App[8689:2961061] AR View: Rotating to Portrait
2017-07-17 11:13:01.731406+0200 App[8689:2961061] frame: {{0, 0}, {375, 667}}
2017-07-17 11:13:01.731562+0200 App[8689:2961061] VideoBackgroundConfig: size: 750,1334
2017-07-17 11:13:01.731589+0200 App[8689:2961061] VideoMode:w=1280 h=720
2017-07-17 11:13:01.731611+0200 App[8689:2961061] width=750.000 height=1334.000
2017-07-17 11:13:01.731638+0200 App[8689:2961061] ViewPort: X,Y: 0,0 Size X,Y:750,1334
2017-07-17 11:13:02.598959+0200 App[8689:2962160] INFO/AR(8689) 2017-07-18 11:13:02: Completed CloudReco transaction with ID '6f5c61ecc07741a7b652242abf909479'
2017-07-17 11:13:02.843834+0200 App[8689:2961061] frame: {{0, 0}, {375, 667}}
2017-07-17 11:13:02.844215+0200 App[8689:2961061] frame: {{0, 0}, {375, 667}}
2017-07-17 11:13:02.860971+0200 App[8689:2961061] DEBUG/AR(8689) UIView has CAEAGLLayer layer class
2017-07-17 11:13:02.861114+0200 App[8689:2961061] DEBUG/AR(8689) UIView does not respond to selector renderFrameVuforia
2017-07-17 11:13:02.861191+0200 App[8689:2961061] DEBUG/AR(8689) UIView has CAEAGLLayer layer class
2017-07-17 11:13:02.861222+0200 App[8689:2961061] DEBUG/AR(8689) UIView does not respond to selector renderFrameVuforia

感谢您的帮助！

Answer 1

您使用哪种方法拨打pauseAR()？

当我回到ViewController（拥有EAGLView）相机被冻结时，我遇到了同样的问题。

我在pauseAR()和viewWillDisappear()中resumeAR()拨打viewWillAppear()，因为问题出现了，我认为EAGLView中的委托方法renderFrameVuforia()永远不会被调用这是导致问题的问题：

找不到具有CAEAGLLayer或CAMetalLayer图层类的UIView，它响应选择器renderFrameVuforia

所以我查看了Vuforia开发者库，发现：

在调用QCAR :: onResume（）之前，应用程序的视图层次结构已完全设置（此时QCAR会尝试找到符合UIGLViewProtocol的应用程序视图）。

我将名为position的resumeAR()方法更改为viewDidAppear()，一切正常。希望这可以帮到你。

从后台

1 个答案: