iOS CGAffineTransform on UIView

Question

// view controller implementation
@property (weak, nonatomic) IBOutlet UIView *v;

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
     // Do any additional setup after loading the view, typically from a nib.
     //self.v.layer.backgroundColor = [UIColor blackColor].CGColor;
     CGAffineTransform transform = CGAffineTransformMakeRotation(M_PI_4);
     self.v.layer.affineTransform = transform;
}

@end

我已经成功地将UIView *v连接到接口生成器中的UIView对象。但是由于某种原因，当self.v.layer.affineTransform = transform;被执行时，当我构建和运行它时，v就会从屏幕上消失。这是怎么回事？我该怎么解决这个问题？另外，我将物体的背景色设置为蓝色，这样它就可以在屏幕上看到。

Answer 1

self.v.transform = CGAffineTransformRotate(CGAffineTransformIdentity, M_PI_4);

尝尝这个。