# 七、系统框架

- [47、熟悉系统框架](/objective-c2-0/qi-xi-tong-kuang-jia/47-shou-xi-xi-tong-kuang-jia.md)
- [48、多用块枚举，少用for循环](/objective-c2-0/qi-xi-tong-kuang-jia/48-duo-yong-kuai-mei-ju-shao-yong-for-xun-huan.md)
- [49、对自定义其内存管理语义的collection使用无缝桥接](/objective-c2-0/qi-xi-tong-kuang-jia/49-dui-zi-ding-yi-qi-nei-cun-guan-li-yu-yi-de-collection-shi-yong-wu-feng-qiao-jie.md)
- [50、构建缓存时选用NSCache而非NSDictionary](/objective-c2-0/qi-xi-tong-kuang-jia/50-gou-jian-huan-cun-shi-xuan-yong-nscache-er-fei-nsdictionary.md)
- [51、精简load与initialize的实现代码](/objective-c2-0/qi-xi-tong-kuang-jia/51-jing-jian-load-yu-initialize-de-shi-xian-dai-ma.md)
- [52、别忘了NSTimer会保留其目标对象](/objective-c2-0/qi-xi-tong-kuang-jia/52-bie-wang-le-nstimer-hui-bao-liu-qi-mu-biao-dui-xiang.md)