奇怪的片段生命週期行爲：onCreate調用兩次

Question

我創建了簡單的片段。

片段CLASS

public class MyFragment extends Fragment { 
static int count = 0; 
static TextView tv; 

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

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
    View view = inflater.inflate(R.layout.frag, container, false); 
    tv = (TextView) view.findViewById(R.id.tv); 
    return view; 
} 

public static TextView setMyText(String text) { 
    tv.setText(text); 
    return tv; 
} 
} 

但事情是的onCreate片段稱爲兩次（在活動首次推出）。任何人有一個想法爲什麼？事實上，每個生命週期方法都會被調用兩次（onAttach，onResume ..）。我是而不是旋轉屏幕或任何東西，如果有人可能會問。這是常見的情況還是我在這裏做錯了什麼？

活動類

public class MainActivity extends FragmentActivity { 

private static int COUNT = 0; 
private static int COUNT2 = 5; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.view_pager); 

    ViewPager vp = (ViewPager) findViewById(R.id.vp); 
    vp.setAdapter(new MyAdapter(getSupportFragmentManager())); 
    vp.setOnPageChangeListener(new CustomPageListener());  
} 


private static class MyAdapter extends FragmentStatePagerAdapter { 

    public MyAdapter(FragmentManager fm) { 
     super(fm); 
    } 

    @Override 
    public Fragment getItem(int position) { 

    MyFragment mf = new MyFragment(); 
    return mf;  
    } 

    @Override 
    public int getCount() { 
     return 5; 
    } 

} 

private class CustomPageListener extends ViewPager.SimpleOnPageChangeListener { 



    @Override 
    public void onPageSelected(int position) { 

     MyFragment.setMyText("This is page "+position); 

    } 

} 

} 

Answer 1

默認FragmentStatePagerAdapter將實例化ViewPager兩頁。 onCreate被稱爲兩次，每個片段一次返回public Fragment getItem(int position)