OC-NSString为什么用copy修饰而不是用strong

<div align=center><img src="Example/Example/Images/JXCategoryView.png" width="405" height="63" /></div> [](#) [](#) [](https://cocoapods.org/pods/JXCategoryView) [](#) A powerful and easy to use category view (segmentedcontrol, segmentview, pagingview, pagerview, pagecontrol) (腾讯新闻、今日头条、QQ音乐、网易云音乐、京东、爱奇艺、腾讯视频、淘宝、天猫、简书、微博等所有主流APP分类切换滚动视图) 与其他的同类三方库对比的优点： - 使用协议封装指示器逻辑，可以为所欲为的自定义指示器效果； - 提供更加全面丰富、高度自定义的效果； - 使用子类化管理cell样式，逻辑更清晰，扩展更简单； - 高度封装列表容器，使用便捷，完美支持列表的生命周期调用； ## Swift版本 如果你在找Swift版本，请点击查看[JXSegmentedView](https://github.com/pujiaxin33/JXSegmentedView) ## 效果预览 ### 指示器效果预览 说明 | Gif | ----|------| LineView | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/LineView.gif" width="343" height="80"> | LineView延长 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/JDLineStyle.gif" width="343" height="80"> | LineView延长+偏移 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/IQIYILineStyle.gif" width="343" height="80"> | LineView🌈彩虹风格 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/RainbowLineView.gif" width="343" height="80"> | DotLineView点线效果 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/IndicatorCustomizeGuide.gif" width="334" height="88"> | BallView QQ黏性红点 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/QQBall.gif" width="343" height="84"> | TriangleView 三角形底部 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/TriangleBottom.gif" width="343" height="80"> | TriangleView 三角形顶部 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/TriangleTop.gif" width="343" height="80"> | BackgroundView椭圆形 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/BackgroundEllipseLayer.gif" width="343" height="80"> | BackgroundView椭圆形+阴影 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/BackgroundViewShadow.gif" width="343" height="80"> | BackgroundView长方形 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/Rectangle.gif" width="343" height="80"> | BackgroundView遮罩有背景 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/TitleMask.gif" width="343" height="80"> | BackgroundView遮罩无背景 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/TitleMaskNoBackgroundView.gif" width="343" height="80"> | BackgroundView渐变色 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/GradientBGIndicatorView.gif" width="350" height="80"> | ImageView底部(小船) | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/IndicatorImageView.gif" width="343" height="137"> | ImageView背景(最佳男歌手) | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/BackgroundImageView.gif" width="343" height="80"> | ImageView滚动效果(足球) | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/Football.gif" width="343" height="135"> | 混合使用 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/Mixed.gif" width="343" height="80"> | 以下均支持上下位置切换： `JXCategoryIndicatorLineView`、`JXCategoryIndicatorImageView`、`JXCategoryIndicatorBallView`、`JXCategoryIndicatorTriangleView` ### Cell样式效果预览 说明 | Gif | ----|------| 颜色渐变 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/TitleColorGradient.gif" width="343" height="80"> | 大小缩放 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/TitleZoom.gif" width="350" height="80"> | 大小缩放+底部锚点 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/TitleLabelAnchorBottom.gif" width="350" height="80"> | 大小缩放+顶部锚点 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/TitleLabelAnchorTop.gif" width="350" height="80"> | 大小缩放+字体粗细 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/TitleZoomStrokeWidth.gif" width="350" height="80"> | 大小缩放+点击动画 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/TitleZoomSelectedAnimation.gif" width="350" height="80"> | 大小缩放+cell宽度缩放 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/TitleZoomCellWidth.gif" width="350" height="80"> | TitleImage_Top | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/TitleImageTop.gif" width="343" height="80"> | TitleImage_Left | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/TitleImageLeft.gif" width="343" height="80"> | TitleImage_Bottom | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/TitleImageBottom.gif" width="343" height="80"> | TitleImage_Right | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/TitleImageRight.gif" width="343" height="80"> | cell图文混用 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/CellMixed.gif" width="343" height="90"> | Image | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/CellImage.gif" width="343" height="80"> | 数字 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/Number.gif" width="343" height="80"> | 红点 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/CellRedDot.gif" width="343" height="80"> | 多行文本 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/MultiLineText.gif" width="350" height="80"> | 多行富文本 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/AttributeView.gif" width="343" height="80"> | Cell背景色渐变 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/CellBackgroundColorGradient.gif" width="343" height="80"> | 分割线 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/SeparatorLine.gif" width="343" height="80"> | ### 特殊效果预览 说明 | Gif | ----|------| 数据源过少<br/> averageCellSpacingEnabled默认为YES | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/averageCellSpacingEnabledYES.gif" width="343" height="80"> | 数据源过少<br/> averageCellSpacingEnabled为NO | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/master/JXCategoryView/averageCellSpacingEnabledNO.gif" width="343" height="80"> | SegmentedControl<br/>参考[`SegmentedControlViewController`](https://github.com/pujiaxin33/JXCategoryView/tree/master/Example/Example/Examples/SegmentedControl/SegmentedControlViewController.m)类 | <img src="https://github.com/pujiaxin33/JXExampleImages/blob/mast