毛玻璃效果

// blur effect
        float sysVer = [[[UIDevice currentDevice] systemVersion] floatValue];
#if __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_8_0
        if (sysVer >= 8.0)
        {
            [self blurEffectView];
        }
        else
        {
            [self blurEffectViewBefore8];
        }
        
#else
        [self blurEffiteViewBefore8];
#endif

/**
 iOS 8之前版本
 */
- (void)blurEffectViewBefore8
{
    UIToolbar *toolBar = [[UIToolbar alloc] init];
    toolBar.barStyle = UIBarStyleBlackTranslucent;
    
    [_topImgView addSubview:toolBar];
    
    [toolBar mas_makeConstraints:^(MASConstraintMaker *make) {
        make.edges.equalTo(_topImgView);
    }];
}

/**
 iOS 8之后版本
 */
- (void)blurEffectView
{
    UIBlurEffect *blurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleDark];
    UIVisualEffectView *effectView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];
    
    [_topImgView addSubview:effectView];
    
    [effectView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.edges.equalTo(_topImgView);
    }];
}
           

备注：

__IPHONE_OS_VERSION_MAX_ALLOWED 值取决于SDK版本

__IPHONE_OS_VERSION_MIN_REQUIRED 值取决于工程的Deployment Target