tableView滑动很卡的原因

最近发现项目中自己写的列表在滑动时有些卡,而同事的列表很顺畅,两个列表显示的内容基本相同,都是几个imageView和几个label还有1个按钮,功能上主要是异步加载图片.

经过分析查找,最终发现问题的根源在于图标的圆角处理方式:

我的列表的cell在处理圆角时直接使用 :
iconImageView = [[UIImageView alloc]init];

iconImageView.layer.cornerRadius = 12;

而同事处理圆角时使用CAShapeLayer处理:

@interface CollectionViewCellImageView : UIImageView

@property (nonatomic, strong) CAShapeLayer * maskLayer;
@property (nonatomic, assign) CGFloat   maskCornerRadius;
@property (nonatomic, strong) NSURL * url;

@end

@implementation CollectionViewCellImageView

- (instancetype)init
{
    self = [super init];
    if (self) {
        _maskLayer = [CAShapeLayer new];
        _maskLayer.fillColor = [UIColor whiteColor].CGColor;
        _maskLayer.fillRule = kCAFillRuleEvenOdd;
        [self.layer addSublayer:_maskLayer];
    }
    return self;
}

- (void)setMaskCornerRadius:(CGFloat)maskCornerRadius{
    _maskCornerRadius = maskCornerRadius;
    _maskLayer.borderWidth = 0.5;
    _maskLayer.borderColor = hllColor(120, 120, 120, 0.3).CGColor;
    _maskLayer.cornerRadius = maskCornerRadius;
}

- (void)layoutSubviews{
    [super layoutSubviews];
    _maskLayer.frame = self.layer.bounds;
    UIBezierPath* path = [UIBezierPath bezierPathWithRect:self.layer.bounds];
    [path appendPath:[UIBezierPath bezierPathWithRoundedRect:self.layer.bounds cornerRadius:self.maskCornerRadius]];
    _maskLayer.path = path.CGPath;
    
}

@end

创建UIImageView的子类,使用时

iconImageView = [[CollectionViewCellImageView alloc]init];

        iconImageView.maskCornerRadius = 12.0f;

修改后,列表滑动非常流畅.