android fragment activity 生命周期,【Android】Activity与Fragment的生命周期的关系

一、问题描述：

假设有两个Activity(1和2),每个Activity拥有一个Fragment，并分别有一个Button，点击Button1可以start Activity2，然后点击Button2可以finish掉自己(即Activity2),然后返回到Activity1。根据这个简单模型描述一下Activity和Fragment的生命周期之间的依赖关系？

二、生命周期知识

Activity和Fragment的生命周期图谱可以参考我的另外一篇博客：【Android】Fragment的生命周期详解，他们的关系大致如下图：

三、代码验证

MainActivity和SecondActivity的布局是这样的，里面各添加了一个Fragment：

/**

* MainActivity布局xml文件

*/

android:orientation="vertical" android:layout_width="fill_parent"

android:layout_height="fill_parent">

android:text="开启第二个Activity"

android:layout_gravity="center"

android:layout_width="wrap_content"

android:layout_height="wrap_content">Button>

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical"

android:background="#339999">

LinearLayout>

LinearLayout>

/**

* MainActivity.java代码，SecondActivity的代码与之类似，这里就不贴那么多了

*/

public class MainActivity extends Activity {

private static final String LOG_TAG = "MainActivity";

private Button mButton;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

Log.w(LOG_TAG, "==============onCreate()");

FragmentManager fragmentManager = getFragmentManager();

FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

FirstFragment firstFragment = new FirstFragment();

fragmentTransaction.add(R.id.linearlayout, firstFragment);

fragmentTransaction.commit();

mButton = (Button) findViewById(R.id.button);

mButton.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

Log.w(LOG_TAG, "------------------mButton onClick-------------------");

startActivity(new Intent(MainActivity.this, SecondActivity.class));

}

});

}

@Override

protected void onStart() {

super.onStart();

Log.w(LOG_TAG, "==============onStart()");

}

@Override

protected void onRestart() {

super.onRestart();

Log.w(LOG_TAG, "==============onRestart()");

}

@Override

protected void onResume() {

super.onResume();

Log.w(LOG_TAG, "==============onResume()");

}

@Override

protected void onPause() {

super.onPause();

Log.w(LOG_TAG, "==============onPause()");

}

@Override

protected void onStop() {

super.onStop();

Log.w(LOG_TAG, "==============onStop()");

}

@Override

protected void onDestroy() {

super.onDestroy();

Log.w(LOG_TAG, "==============onDestroy()");

}

}

/**

* FirstFragment.java代码， SecondFragment和它差不多一样

*/

public class FirstFragment extends Fragment {

private static final String LOG_TAG = "FirstFragment";

private static final String ARG_PARAM1 = "param1";

private static final String ARG_PARAM2 = "param2";

private String mParam1;

private String mParam2;

public FirstFragment() {

}

@Override

public void onAttach(Activity activity) {

super.onAttach(activity);

Log.w(LOG_TAG, "onAttach...");

}

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

Log.w(LOG_TAG, "onCreate...");

if (getArguments() != null) {

mParam1 = getArguments().getString(ARG_PARAM1);

mParam2 = getArguments().getString(ARG_PARAM2);

}

}

@Override

public View onCreateView(LayoutInflater inflater, ViewGroup container,

Bundle savedInstanceState) {

Log.w(LOG_TAG, "onCreateView...");

return inflater.inflate(R.layout.fragment_first, container, false);

}

@Override

public void onActivityCreated(Bundle savedInstanceState) {

super.onActivityCreated(savedInstanceState);

Log.w(LOG_TAG, "onActivityCreated...");

}

@Override

public void onStart() {

super.onStart();

Log.w(LOG_TAG, "onStart...");

}

@Override

public void onResume() {

super.onResume();

Log.w(LOG_TAG, "onResume...");

}

@Override

public void onPause() {

super.onPause();

Log.w(LOG_TAG, "onPause...");

}

@Override

public void onStop() {

super.onStop();

Log.w(LOG_TAG, "onStop...");

}

@Override

public void onDestroyView() {

super.onDestroyView();

Log.w(LOG_TAG, "onDestroyView...");

}

@Override

public void onDestroy() {

super.onDestroy();

Log.w(LOG_TAG, "onDestroy...");

}

@Override

public void onDetach() {

super.onDetach();

Log.w(LOG_TAG, "onDetach...");

}

}

四、运行结果

1、第一次打开以后：

com.example.kuguan.anlearning W/MainActivity﹕ ==============onCreate()

com.example.kuguan.anlearning W/FirstFragment﹕ onAttach...

com.example.kuguan.anlearning W/FirstFragment﹕ onCreate...

com.example.kuguan.anlearning W/FirstFragment﹕ onCreateView...

com.example.kuguan.anlearning W/FirstFragment﹕ onActivityCreated...

com.example.kuguan.anlearning W/MainActivity﹕ ==============onStart()

com.example.kuguan.anlearning W/FirstFragment﹕ onStart...

com.example.kuguan.anlearning W/MainActivity﹕ ==============onResume()

com.example.kuguan.anlearning W/FirstFragment﹕ onResume...

2、点击MainActivity中的按钮“打开第二个Activity”以后：

com.example.kuguan.anlearning W/MainActivity﹕ ----------------mButton onClick-----------------

com.example.kuguan.anlearning W/FirstFragment﹕ onPause...

com.example.kuguan.anlearning W/MainActivity﹕ ==============onPause()

com.example.kuguan.anlearning W/SecondFragment﹕ onAttach...

com.example.kuguan.anlearning W/SecondFragment﹕ onCreate...

com.example.kuguan.anlearning W/SecondFragment﹕ onCreateView...

com.example.kuguan.anlearning W/SecondFragment﹕ onActivityCreated...

com.example.kuguan.anlearning W/SecondActivity﹕ ==============onStart()

com.example.kuguan.anlearning W/SecondFragment﹕ onStart...

com.example.kuguan.anlearning W/SecondActivity﹕ ==============onResume()

com.example.kuguan.anlearning W/SecondFragment﹕ onResume...

com.example.kuguan.anlearning W/FirstFragment﹕ onStop...

com.example.kuguan.anlearning W/MainActivity﹕ ==============onStop()

3、点击SecondActivity的按钮“finish”之后：

com.example.kuguan.anlearning W/SecondActivity﹕ -----------------mButton onClick------------------

com.example.kuguan.anlearning W/SecondFragment﹕ onPause...

com.example.kuguan.anlearning W/SecondActivity﹕ ==============onPause()

com.example.kuguan.anlearning W/MainActivity﹕ ==============onRestart()

com.example.kuguan.anlearning W/MainActivity﹕ ==============onStart()

com.example.kuguan.anlearning W/FirstFragment﹕ onStart...

com.example.kuguan.anlearning W/MainActivity﹕ ==============onResume()

com.example.kuguan.anlearning W/FirstFragment﹕ onResume...

com.example.kuguan.anlearning W/SecondFragment﹕ onStop...

com.example.kuguan.anlearning W/SecondActivity﹕ ==============onStop()

com.example.kuguan.anlearning W/SecondFragment﹕ onDestroyView...

com.example.kuguan.anlearning W/SecondFragment﹕ onDestroy...

com.example.kuguan.anlearning W/SecondFragment﹕ onDetach...

com.example.kuguan.anlearning W/SecondActivity﹕ ==============onDestroy()

4、点击back键使MainActivity退到后台：

com.example.kuguan.anlearning W/FirstFragment﹕ onPause...

com.example.kuguan.anlearning W/MainActivity﹕ ==============onPause()

com.example.kuguan.anlearning W/FirstFragment﹕ onStop...

com.example.kuguan.anlearning W/MainActivity﹕ ==============onStop()

com.example.kuguan.anlearning W/FirstFragment﹕ onDestroyView...

com.example.kuguan.anlearning W/FirstFragment﹕ onDestroy...

com.example.kuguan.anlearning W/FirstFragment﹕ onDetach...

com.example.kuguan.anlearning W/MainActivity﹕ ==============onDestroy()

5、在MianActivity显示的时候，按HOME键：

com.example.kuguan.anlearning W/FirstFragment﹕ onPause...

com.example.kuguan.anlearning W/MainActivity﹕ ==============onPause()

com.example.kuguan.anlearning W/FirstFragment﹕ onStop...

com.example.kuguan.anlearning W/MainActivity﹕ ==============onStop()

6、然后再点击Icon打开：

com.example.kuguan.anlearning W/MainActivity﹕ ==============onRestart()

com.example.kuguan.anlearning W/MainActivity﹕ ==============onStart()

com.example.kuguan.anlearning W/FirstFragment﹕ onStart...

com.example.kuguan.anlearning W/MainActivity﹕ ==============onResume()

com.example.kuguan.anlearning W/FirstFragment﹕ onResume...

【参考资料】：

1、Fragment和Activity