我在我的 iOS 应用程序中使用 Vuforia SDK，版本 6.2.9。 一切正常，但应用程序从后台进入时出现错误。

运行 VUFORIA 的 View Controller 正在监听 UIApplicationWillResignActiveNotification 和 UIApplicationDidBecomeActiveNotification 通知。 在 UIApplicationWillResignActiveNotification 情况下暂停 AR，在 UIApplicationDidBecomeActiveNotification 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，相机卡住，报错 无法找到具有响应选择器 renderFrameVuforia 的 CAEAGLLayer 或 CAMetalLayer 图层类的 UIView

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!

最佳答案

在哪个方法中调用 pauseAR() ？

当弹出回 ViewController(拥有 EAGLView)时，我遇到了同样的问题，相机被卡住了。

我在 viewWillDisappear() 中调用了 pauseAR()，在 viewWillAppear() 中调用了 resumeAR()，因为问题出在 EAGLView 中的委托(delegate)方法 renderFrameVuforia() 永远不会被调用，我认为这是导致问题的原因:

Could not find a UIView with CAEAGLLayer or CAMetalLayer layer class that responds to selector renderFrameVuforia

所以我查找了 Vuforia Developer Library 并发现:

The app's view hierarchy is set up completely before calling QCAR::onResume() (at which point QCAR attempts to locate the app's view conforming to UIGLViewProtocol).

我将名为 position 的 resumeAR() 方法更改为 viewDidAppear()，一切正常。希望对您有所帮助。

关于c++ - 从后台进入后 iOS Vuforia 错误，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/45140805/