如何在UIView中将CALayer居中？我有以下代码，但似乎无法让CALayer在View中居中。该层的图像似乎总是以其右下角位于屏幕中央结束。UIView代码:-(void)awakeFromNib{testLayer=[CALayerlayer];testLayer=[[UIScreenmainScreen]scale];testLayer=kCAGravityCenter;testLayer.contents=(id)self.testImage.CGImage;[testLayersetPosition:self.center];[self.layeraddSublayer: