iOS8 模糊视图(毛玻璃效果) UIVisualEffectView

在需要模糊的UIView上，添加一个UIVisualEffectView对象即可,若直接在storyboad里面直接加UIVisualEffectView，你的项目必须是iOS8以上才能用

- (void)viewDidLoad {

    [super viewDidLoad];

//    UIImageView *imageview = [[UIImageView alloc] init];

//    

//    imageview.frame = CGRectMake(10, 200, 300, 300);

//    

//    imageview.image = [UIImage imageNamed:@"2"];

//    

//    imageview.contentMode = UIViewContentModeScaleAspectFit;

//    

//    imageview.userInteractionEnabled = YES;

//    

//    [self.view addSubview:imageview];

    UIBlurEffect *blur = [UIBlurEffect effectWithStyle:UIBlurEffectStyleLight];

    UIVisualEffectView *effectview = [[UIVisualEffectView alloc] initWithEffect:blur];

   // effectview.frame = CGRectMake(0, 0, imageview.frame.size.width/2, 300);

    effectview.frame = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height);

    //[imageview addSubview:effectview];

    [self.view addSubview:effectview];

    UIButton *btn = [UIButton buttonWithType:UIButtonTypeSystem];

    btn.frame = CGRectMake(10, 50, 100, 40);

    [btn setTitle:@"btn" forState:UIControlStateNormal];

    [effectview.contentView addSubview:btn];

}