Activity与Fragment一起的生命周期

最新推荐文章于 2022-06-08 09:50:02 发布

原创最新推荐文章于 2022-06-08 09:50:02 发布 · 388 阅读

2 ·

CC 4.0 BY-SA版权

android基础专栏收录该内容

4 篇文章

订阅专栏

本文探讨了在Android中，当Activity与Fragment一起使用时的生命周期，详细解析了通过布局文件定义和使用FragmentManager添加Fragment时，两者生命周期的交互与变化。通过实例展示了在不同情况下Fragment与Activity的生命周期回调顺序，帮助开发者理解并掌握这一关键知识点。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

1 背景

之前学习Fragment以及Activity的生命周期都是分开学习的,而两个一起的生命周期自己只知道Fragment的生命周期是依赖Activity的.最近接触到了一些东西,需要对这部分的内容了解一下,也就想写个blog把这些内容给记录下来,毕竟android的东西还是很多很细的.好记性不如烂笔头啊!

2 实现方式

Activity中两种调用Fragment的方式:

第一种: 在布局文件中进行定义

第二种: 使用FragmentManager来定义

以上两种方式,Fragment与Activity的生命周期不一致,

下面是具体的例子以及生命周期.

例子主要实现的功能是:在Activity中调用Fragment,在Fragment里面点击按钮弹出新的Activity,并将父Activity finish掉.

3 Activity与Fragment一起时的生命周期(分调用方式)

3.1 第一种: 在布局文件中进行定义

3.1.1 Activity的代码

public class FragmentLifeCycleActivity extends AppCompatActivity {
    private static final String TAG = "Activity";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fragment_life_cycle);
        Log.i(TAG, "onCreate: ");

    }

    @Override
    protected void onStart() {
        super.onStart();
        Log.i(TAG, "onStart: ");
    }

    @Override
    protected void onResume() {
        super.onResume();
        Log.i(TAG, "onResume: ");
    }

    @Override
    protected void onPause() {
        super.onPause();
        Log.i(TAG, "onPause: ");
    }

    @Override
    protected void onStop() {
        super.onStop();
        Log.i(TAG, "onStop: ");
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.i(TAG, "onDestroy: ");
    }
}

3.1.2 Activity的布局文件

<merge xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <fragment
        android:id="@+id/fragment_test"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:name="base.example.com.interviewTest.FragmentLifeCycleTestFragment"/>

</merge>

3.1.3 Fragment的代码

public class FragmentLifeCycleTestFragment extends Fragment implements View.OnClickListener {

    private static final String TAG = "Fragment";

    public FragmentLifeCycleTestFragment() {
        // Required empty public constructor
    }
    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        Log.i(TAG, "onAttach: ");
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.i(TAG, "onCreate: ");
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        Log.i(TAG, "onCreateView: ");
        View view = inflater.inflate(R.layout.fragment_fragment_life_cycle_test, container, false);
        Button btn = view.findViewById(R.id.btn_finish);
        btn.setOnClickListener(this);
        return view;
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.btn_finish:
                FragmentLifeCycleTestFragment.this.getActivity().finish();
//                android.os.Process.killProcess(android.os.Process.myPid());
                startActivity(new Intent(FragmentLifeCycleTestFragment.this.getActivity(),MainActivity.class));
                FragmentLifeCycleTestFragment.this.getActivity().finish();
                break;
        }
    }

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        Log.i(TAG, "onViewCreated: ");
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        Log.i(TAG, "onActivityCreated: ");
    }

    @Override
    public void onStart() {
        super.onStart();
        Log.i(TAG, "onStart: ");
    }

    @Override
    public void onResume() {
        super.onResume();
        Log.i(TAG, "onResume: ");
    }

    @Override
    public void onPause() {
        super.onPause();
        Log.i(TAG, "onPause: ");
    }

    @Override
    public void onStop() {
        super.onStop();
        Log.i(TAG, "onStop: ");
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        Log.i(TAG, "onDestroyView: ");
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.i(TAG, "onDestroy: ");
    }

    @Override
    public void onDetach() {
        super.onDetach();
        Log.i(TAG, "onDetach: ");
    }

}

3.1.4 Fragment的布局文件

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".interviewTest.FragmentLifeCycleTestFragment">
    
    <Button
        android:id="@+id/btn_finish"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_blank_fragment"
        android:layout_gravity="center"/>

</FrameLayout>

3.1.5 对应的生命周期log

 I/Fragment: onAttach: 
 I/Fragment: onCreate: 
 I/Fragment: onCreateView: 
 I/Fragment: onViewCreated: 
 I/Activity: onCreate: 
 I/Fragment: onActivityCreated: 
 I/Fragment: onStart: 
 I/Activity: onStart: 
 I/Activity: onResume: 
 I/Fragment: onResume: 
 I/Fragment: onPause: 
 I/Activity: onPause: 
 I/Fragment: onStop: 
 I/Activity: onStop: 
 I/Fragment: onDestroyView: 
 I/Fragment: onDestroy: 
 I/Fragment: onDetach: 
 I/Activity: onDestroy:

总结: Fragment.onAttach()->Fragment.onCreate()->Fragment.onCreateView()->Fragment.onViewCreated
->Activity.onCreate()->Fragment.onActivityCreated->Fragment.onStart()->Activity.onStart()
->Activity.onResume()->Fragment.onResume()
->Fragment.onPause()->Activity.onPause()->Fragment.onStop()->Activity.onStop()
->Fragment.onDestroyView()->Fragment.onDestroy()->Fragment.onDetach()->Activity.onDestroy()

3.2 第二种: 使用FragmentManager来定义

3.2.1 Activity的代码

public class FragmentLifeCycleActivity extends AppCompatActivity {
    private static final String TAG = "Activity";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fragment_life_cycle);
        Log.i(TAG, "onCreate: ");
        FragmentLifeCycleTestFragment fragmentLifeCycleTestFragment = new FragmentLifeCycleTestFragment();
        FragmentManager fragmentManager = this.getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.replace(R.id.root,fragmentLifeCycleTestFragment);
        fragmentTransaction.addToBackStack(null);
        fragmentTransaction.commit();

    }

    @Override
    protected void onStart() {
        super.onStart();
        Log.i(TAG, "onStart: ");
    }

    @Override
    protected void onResume() {
        super.onResume();
        Log.i(TAG, "onResume: ");
    }

    @Override
    protected void onPause() {
        super.onPause();
        Log.i(TAG, "onPause: ");
    }

    @Override
    protected void onStop() {
        super.onStop();
        Log.i(TAG, "onStop: ");
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.i(TAG, "onDestroy: ");
    }
}

3.2.2 Activity的布局文件

<merge xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <LinearLayout
        android:id="@+id/root"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"></LinearLayout>

</merge>

3.2.3 Fragment的代码

同3.1.3 Fragment的代码

3.2.4 Fragment的布局文件

同3.1.4 Fragment的布局文件

3.2.5 对应的生命周期log

I/Activity: onCreate: 
I/Fragment: onAttach: 
I/Fragment: onCreate: 
I/Fragment: onCreateView: 
I/Fragment: onViewCreated: 
I/Fragment: onActivityCreated: 
I/Fragment: onStart: 
I/Activity: onStart: 
I/Activity: onResume: 
I/Fragment: onResume: 
I/Fragment: onPause: 
I/Activity: onPause:  
I/Fragment: onStop: 
I/Activity: onStop: 
I/Fragment: onDestroyView: 
I/Fragment: onDestroy: 
I/Fragment: onDetach: 
I/Activity: onDestroy:

总结: Activity.onCreate()->Fragment.onAttach()->Fragment.onCreate()->Fragment.onCreateView()->Fragment.onViewCreated
->Fragment.onActivityCreated->Fragment.onStart()->Activity.onStart()
->Activity.onResume()->Fragment.onResume()
->Fragment.onPause()->Activity.onPause()->Fragment.onStop()->Activity.onStop()
->Fragment.onDestroyView()->Fragment.onDestroy()->Fragment.onDetach()->Activity.onDestroy()

鸡汤一枚:人生需要的是智慧,不是聪明.小聪明只能用来做小事,真正成大事的人靠的是智慧.