android Fragment 生命周期方法调用顺序-编程知识

文章目录

- Intro
- log 及结论
- 代码

Intro

界面设计：点击左侧按钮，会将右侧青色的RightFragment 替换成黄色的AnotherRightFragment，而这两个 Fragment 的生命周期方法都会打印日志。
所以只要看执行结果中的日志，就可以知道 Fragment 的不同生命周期方法的执行顺序。
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点击按钮后，右侧的Fragment被替换：

log 及结论

2024-03-24 20:40:26.903 FragmentUsageTestActivi  W  Fragment的生命周期：=====》切换Fragment
2024-03-24 20:40:26.916 RightFragment            D  Fragment的生命周期: RightFragment onAttach: 
2024-03-24 20:40:26.916 RightFragment            D  Fragment的生命周期: RightFragment onCreate: 
2024-03-24 20:40:26.917 RightFragment            D  Fragment的生命周期: RightFragment onActivityCreated: 
2024-03-24 20:40:26.919 RightFragment            D  Fragment的生命周期: RightFragment onStart: 
2024-03-24 20:40:26.921 RightFragment            D  Fragment的生命周期: RightFragment onResume: 
2024-03-24 20:40:38.070 FragmentUsageTestActivi  W  Fragment的生命周期：=====》切换Fragment
2024-03-24 20:40:38.081 RightFragment            D  Fragment的生命周期: RightFragment onPause: 
2024-03-24 20:40:38.081 RightFragment            D  Fragment的生命周期: RightFragment onStop: 
2024-03-24 20:40:38.082 AnotherRightFragment     D  Fragment的生命周期: AnotherRightFragment onAttach: 
2024-03-24 20:40:38.082 AnotherRightFragment     D  Fragment的生命周期: AnotherRightFragment onCreate: 
2024-03-24 20:40:38.087 AnotherRightFragment     D  Fragment的生命周期: AnotherRightFragment onActivityCreated: 
2024-03-24 20:40:38.088 AnotherRightFragment     D  Fragment的生命周期: AnotherRightFragment onStart: 
2024-03-24 20:40:38.090 RightFragment            D  Fragment的生命周期: RightFragment onDestroyView: 
2024-03-24 20:40:38.091 AnotherRightFragment     D  Fragment的生命周期: AnotherRightFragment onResume: 
2024-03-24 20:40:42.935 FragmentUsageTestActivi  W  Fragment的生命周期：=====》点击了【返回】按钮 (onBackPressed)
2024-03-24 20:40:42.936 AnotherRightFragment     D  Fragment的生命周期: AnotherRightFragment onPause: 
2024-03-24 20:40:42.937 AnotherRightFragment     D  Fragment的生命周期: AnotherRightFragment onStop: 
2024-03-24 20:40:42.939 RightFragment            D  Fragment的生命周期: RightFragment onActivityCreated: 
2024-03-24 20:40:42.939 RightFragment            D  Fragment的生命周期: RightFragment onStart: 
2024-03-24 20:40:42.940 AnotherRightFragment     D  Fragment的生命周期: AnotherRightFragment onDestroyView: 
2024-03-24 20:40:42.940 AnotherRightFragment     D  Fragment的生命周期: AnotherRightFragment onDestroy: 
2024-03-24 20:40:42.940 AnotherRightFragment     D  Fragment的生命周期: AnotherRightFragment onDetach: 
2024-03-24 20:40:42.940 RightFragment            D  Fragment的生命周期: RightFragment onResume: 
2024-03-24 20:40:44.765 FragmentUsageTestActivi  W  Fragment的生命周期：=====》点击了【返回】按钮 (onBackPressed)
2024-03-24 20:40:44.766 RightFragment            D  Fragment的生命周期: RightFragment onPause: 
2024-03-24 20:40:44.767 RightFragment            D  Fragment的生命周期: RightFragment onStop: 
2024-03-24 20:40:44.768 RightFragment            D  Fragment的生命周期: RightFragment onDestroyView: 
2024-03-24 20:40:44.769 RightFragment            D  Fragment的生命周期: RightFragment onDestroy: 
2024-03-24 20:40:44.769 RightFragment            D  Fragment的生命周期: RightFragment onDetach: 
2024-03-24 20:40:48.307 FragmentUsageTestActivi  W  Fragment的生命周期：=====》点击了【返回】按钮 (onBackPressed)

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结论与《第一行代码》中所述一致：
在这里插入图片描述

代码

可以查看以下三个提交点（改动一样, gitee网速最快，不过三个网站界面有不同，看你习惯看哪个）：
gitee: https://gitee.com/wuyujin1997/android-demo/commit/0d75711e244b7c59ed009326b8174bedcb4caff8
github: https://github.com/wuyujin1997/AndroidDemo/commit/0d75711e244b7c59ed009326b8174bedcb4caff8
bitbucket: https://bitbucket.org/wuyujin1997/androiddemo/commits/0d75711e244b7c59ed009326b8174bedcb4caff8

主要的生命周期方法日志类如下（其他的就不贴了，见上 git commit link）：

import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;public class BaseFragmentForLifecycleLog extends Fragment {private String TAG;public BaseFragmentForLifecycleLog() {TAG = this.getClass().getSimpleName();}@Overridepublic void onAttach(@NonNull Context context) {super.onAttach(context);Log.d(TAG, "Fragment的生命周期: " + TAG + " onAttach: ");}@Overridepublic void onCreate(@Nullable Bundle savedInstanceState) {super.onCreate(savedInstanceState);Log.d(TAG, "Fragment的生命周期: " + TAG + " onCreate: ");}@Nullable@Overridepublic View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {Log.d(TAG, "Fragment的生命周期: " + TAG + " onCreateView: ");return super.onCreateView(inflater, container, savedInstanceState);}@Overridepublic void onActivityCreated(@Nullable Bundle savedInstanceState) {super.onActivityCreated(savedInstanceState);Log.d(TAG, "Fragment的生命周期: " + TAG + " onActivityCreated: ");}@Overridepublic void onStart() {super.onStart();Log.d(TAG, "Fragment的生命周期: " + TAG + " onStart: ");}@Overridepublic void onResume() {super.onResume();Log.d(TAG, "Fragment的生命周期: " + TAG + " onResume: ");}@Overridepublic void onPause() {super.onPause();Log.d(TAG, "Fragment的生命周期: " + TAG + " onPause: ");}@Overridepublic void onStop() {super.onStop();Log.d(TAG, "Fragment的生命周期: " + TAG + " onStop: ");}@Overridepublic void onDestroyView() {super.onDestroyView();Log.d(TAG, "Fragment的生命周期: " + TAG + " onDestroyView: ");}@Overridepublic void onDestroy() {super.onDestroy();Log.d(TAG, "Fragment的生命周期: " + TAG + " onDestroy: ");}@Overridepublic void onDetach() {super.onDetach();Log.d(TAG, "Fragment的生命周期: " + TAG + " onDetach: ");}}