模态时显示半屏

平常模态时，都是全屏的,这次项目要求突然要半屏,还真有点儿不习惯… 下面给出主要代码:

从一个 viewController 模态到 PickerViewController:

PickerViewController *pic = [[PickerViewController alloc] init];
pic.modalPresentationStyle = UIModalPresentationCustom;
[self presentViewController:pic animated:YES completion:^{
    pic.view.superview.backgroundColor = [UIColor clearColor];
}];
[pic release];

pic.view.superview.backgroundColor = [UIColor clearColor]; 写过这句后,在模态到 PickerViewController 时就已经是透明的了.

然后,在 PickerViewController 中添加一个 View ，设置其 frame 为主屏幕一半

UIView *preView = [[UIView alloc] initWithFrame:CGRectMake(
	0, 
	[UIScreen mainScreen].bounds.size.height / 2, 
	[UIScreen mainScreen].bounds.size.weight, 
	[UIScreen mainScreen].bounds.size.height / 2
	)];
preView.backgroundColor = [UIColor colorWithRed:0.289 green:0.323 blue:0.358 alpha:1.000];
[self.view addSubview:preView];

效果图：