Ios 是否将UIButton添加到AVCaptureVideoPreviewLayer？

我想向AVCaptureVideoPreviewLayer添加UIButton或其他类型的按钮

以下是我尝试过的：

[self.view.layer addSublayer:_videoPreviewLayer];
UIButton * sButton = [[UIButton alloc] initWithFrame:CGRectMake(10, 0, 300, 100)];
[sButton setBackgroundColor:[UIColor yellowColor]];
[sButton setTitle:@"Stop" forState:UIControlStateNormal];
[sButton setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
[_videoPreviewLayer addSublayer:sLabel.layer];
[_captureSession startRunning];

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我还尝试了与添加的UIView类似的东西，即使AVCapture没有启动。但是，我无法向该视图添加子视图

派对有点晚了，但我一直在做类似的事情，所以我想与大家分享一下：

UIButton * btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
btn.frame = CGRectMake(200, 200, 100, 50);
[btn setTitle:@"Hello, world!" forState:UIControlStateNormal];
[btn setBackgroundColor:[UIColor blueColor]];
[btn becomeFirstResponder];
UIAccessibilityPostNotification(UIAccessibilityScreenChangedNotification,  btn);
[self.view addSubview:btn];

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为什么不在videoPreviewLayer的containerView.layer上添加按钮呢？那可能会起作用。我该怎么做？videoPreviewLayer.containerview.layer不存在。