Fragment使用笔记（二）

Fragment + ViewPager（appcompat）

Fragment生命周期变化

首次加载

1. HomeFragment: setUserVisibleHint: false
2. QuoteFragment: setUserVisibleHint: false
3. HomeFragment: setUserVisibleHint: true
4. HomeFragment: onAttach
5. HomeFragment: onCreate
6. QuoteFragment: onAttach
7. QuoteFragment: onCreate
8. HomeFragment: onViewCreated
9. HomeFragment: onActivityCreated
10. HomeFragment: onStart
11. HomeFragment: onResume
12. QuoteFragment: onViewCreated
13. QuoteFragment: onActivityCreated
14. QuoteFragment: onStart
15. QuoteFragment: onResume

点击第二个Fragment

1. TradeFragment: setUserVisibleHint: false
2. HomeFragment: setUserVisibleHint: false
3. QuoteFragment: setUserVisibleHint: true
4. TradeFragment: onAttach
5. TradeFragment: onCreate
6. TradeFragment: onViewCreated
7. TradeFragment: onActivityCreated
8. TradeFragment: onStart
9. TradeFragment: onResume
10. Fragment: Main Page Selected: 1

点击第四个Fragment

1. MyFragment: setUserVisibleHint: false
2. FinanceFragment: setUserVisibleHint: false
3. QuoteFragment: setUserVisibleHint: false
4. MyFragment: setUserVisibleHint: true
5. MyFragment: onAttach
6. MyFragment: onCreate
7. FinanceFragment: onAttach
8. FinanceFragment: onCreate
9. MyFragment: onViewCreated
10. MyFragment: onActivityCreated
11. MyFragment: onStart
12. MyFragment: onResume
13. FinanceFragment: onViewCreated
14. FinanceFragment: onActivityCreated
15. FinanceFragment: onStart
16. FinanceFragment: onResume
17. Fragment: Main Page Selected: 4
18. TradeFragment: onPause
19. TradeFragment: onStop
20. QuoteFragment: onPause
21. QuoteFragment: onStop
22. HomeFragment: onPause
23. HomeFragment: onStop

点击第一个Fragment

1. HomeFragment: setUserVisibleHint: false
2. QuoteFragment: setUserVisibleHint: false
3. MyFragment: setUserVisibleHint: false
4. HomeFragment: setUserVisibleHint: true
5. HomeFragment: onViewCreated
6. HomeFragment: onActivityCreated
7. HomeFragment: onStart
8. HomeFragment: onResume
9. QuoteFragment: onViewCreated
10. QuoteFragment: onActivityCreated
11. QuoteFragment: onStart
12. QuoteFragment: onResume
13. Fragment: Main Page Selected: 0
14. FinanceFragment: onPause
15. FinanceFragment: onStop
16. MyFragment: onPause
17. MyFragment: onStop

退出页面

1. HomeFragment: onDestroy
2. HomeFragment: onDetach
3. QuoteFragment: onDestroy
4. QuoteFragment: onDetach
5. TradeFragment: onDestroy
6. TradeFragment: onDetach
7. MyFragment: onDestroy
8. MyFragment: onDetach
9. FinanceFragment: onDestroy
10. FinanceFragment: onDetach

小结：

• 支持预加载布局,可根据业务需要预加载数据
• userVisible = true并且onResume才是可见
• userVisible = false(首次创建触发)才是不可见
• attach之后的Fragment不会被detach，直到页面销毁才会被detach，即Fragment可复用
• Fragment中View默认不能复用
• 最多只有三个Fragment同时处于onResume状态，分析是为了实现左右滑动预览的功能
• 不建议Fragment + ViewPager再次嵌套Fragment + ViewPager，生命周期过于复杂，因为预加载一级中不显示的Fragment时，会预加载二级的第一个Fragment和第二个Fragment，如果嵌套过深，可想而知会预加载多少不可见的Fragment

来源：oschina

链接：https://my.oschina.net/u/219974/blog/4471342