Ios iPad3上缺少层阴影（但可在模拟器中工作）

我使用以下代码在UIView后面绘制阴影

    self.view.layer.borderColor = [UIColor whiteColor].CGColor;
    self.view.layer.shadowColor = [UIColor blackColor].CGColor;
    self.view.layer.shadowOpacity = 1.0;
    self.view.layer.shadowRadius = 25.0;
    self.view.layer.shadowOffset = CGSizeMake(0, 3);
    self.view.clipsToBounds = NO;

    CGPathRef shadowPath = [UIBezierPath bezierPathWithRect:self.view.layer.bounds].CGPath;
    [self.view.layer setShadowPath:shadowPath];

这在模拟器和iPhone5上都能正常工作。然而在我的iPad3上：根本没有阴影

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知道怎么回事吗？

我找到了解决办法。这与模拟器无关。这是关于肖像画与风景画方向界限的回归。我必须将阴影路径的设置移动到viewdide和didRotateFromInterfaceOrientation方法中，才能在所有可能的启动方向上正确渲染阴影

-(void)viewDidAppear:(BOOL)animated{
    CGPathRef shadowPath = [UIBezierPath bezierPathWithRect:self.view.layer.bounds].CGPath;
    [self.view.layer setShadowPath:shadowPath];
}

-(void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation {
    CGPathRef shadowPath = [UIBezierPath bezierPathWithRect:self.view.layer.bounds].CGPath;
    [self.view.layer setShadowPath:shadowPath];
}