Android Context 分析继承结构类图：ContextWrapper是上下文的包装类，ContextImpl是上下文的实现类，Activity是ContextThemeWrapper的直接子类。getApplicationContext都做了什么  翻看ContextWrapper源码:public class ContextWrapper&nbs

    The UML diagram is a graphical notation used to construct and visualize object oriented systems. A class diagram in the Unified Modeling Language is a type of static structure

面向对象设计有五大准则，遵循这五大准则，能够使我们的代码更加健硕，易维护，易扩展。它们分别是:单一职责原则，开闭原则，里氏替换原则，接口隔离原则，依赖倒置原则。

## step 1 解锁手机  - [小米官方解锁工具及教程](https://www.miui.com/unlock/download.html)## step 2 刷Android10官方rom（可选）   如果MIUI版本是12.5.1（Android 11），可以选择降低到V12.5.8.0.RJECNXM（Android 10）,我在Android 11上用

 QuickSort is another algorithm form Divide and Conquer category.It operates by breaking down large problems into smaller,more easily solvable problems.快速排序是分治算法分类中的另一种算法，它通过把大问题拆分成更小，更容易解决的问题操作。

Merge Sort belongs to the category of Divide and Conquer algorithms.These algorithms operate by breaking down large problems into smaller,more easily solvable problems.  归并排序属于分治算法分类，这些算法通过把大的问题拆

Insertion Sort is a simple sorting algorithm that works the waywe sort playing cards in our hands.We sort the first two cards and thenplace the third card in the appropriate position within the first

    Selection Sort is a simple sorting algorithm that find the smallestelement in the array and swaps it with the element in the first position,then find the second smallest elemen

    Bubble sort is an algorithm that is used to sort a list of elements,for exampleelements in an array. This algorithm compares two adjacent elements and then swapsthem if they ar

    今天朋友跟我说服务器要续费了，发给我一张截图比去年贵了好几千，但是服务器上部署的网站和内容太多不好迁移。    然后我找了找，阿里云有针对老用户的续费活动，能省下不少钱 。直达链接：阿里云老用户续费活动 这个优惠还是不错的，一年老用户享受6.5折扣，3年6.3折，5年6折详细步骤：点击活动链接&nbs