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我正在使用FragmentStatePagerAdapter實現ViewPager。代碼示例如下。訪問方向變化的片段視圖
private class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter {
public ScreenSlidePagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
Log.d("--GetItem", "---");
switch (position) {
case 0:
return ScreenSlidePageFragment.newInstance(b1);
case 1:
return ScreenSlidePageFragment.newInstance(b2);
case 2:
return ScreenSlidePageFragment.newInstance(b3);
default:
return null;
}
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
Log.d("--InstItem", "--");
return super.instantiateItem(container, position);
}
@Override
public int getCount() {
return NUM_PAGES; //set as 3
}
}
ScreenSlidePageFragment如下。
public class ScreenSlidePageFragment extends Fragment implements View.OnClickListener{
Bundle b;
public ScreenSlidePageFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
Log.d("----onCreateFrgmnt--", "11");
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
Log.d("----onCreateViewFrgmnt-", "11");
ViewGroup rootView = (ViewGroup) inflater.inflate(
R.layout.fragment_screen_slide_page, container, false);
return rootView;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
Log.d("----onViewCreatedFrgmnt", "11");
b = getArguments();
TextView tv_city = (TextView) view.findViewById(R.id.city_field);
TextView tv_update = (TextView) view.findViewById(R.id.updated_field);
TextView tv_day = (TextView) view.findViewById(R.id.day);
tv_day.setText("DAY " + String.valueOf(b.getInt("day")));
tv_city.setText(b.getString("city"));
tv_update.setText("Last update on : " + b.getString("date"));
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
public static ScreenSlidePageFragment newInstance(Bundle myBundle) {
ScreenSlidePageFragment f = new ScreenSlidePageFragment();
f.setArguments(myBundle);
return f;
}
}
在MainActivity，我想處理的方向變化。我使用下面的一段代碼。
if (savedInstanceState != null) {
setContentView(R.layout.activity_main);
myViewPager = (MyCustomViewPager) findViewById(R.id.pager);
b1 = savedInstanceState.getBundle("Fragment1");
b2 = savedInstanceState.getBundle("Fragment2");
b3 = savedInstanceState.getBundle("Fragment3");
myViewPager.setOffscreenPageLimit(NUM_PAGES - 1);
myPagerAdapter = new ScreenSlidePagerAdapter(getSupportFragmentManager());
myViewPager.setAdapter(myPagerAdapter);
}
片段重新創建方向更改。 onCreateView以及onViewCreated正在被調用（檢查LogCat）。當我嘗試更新片段中的視圖時出現問題。對於更新我使用下面的代碼：
FragmentStatePagerAdapter adapter = (FragmentStatePagerAdapter) myViewPager.getAdapter();
ScreenSlidePageFragment fragment1 = (ScreenSlidePageFragment) adapter.instantiateItem(myViewPager, 0);
ScreenSlidePageFragment fragment2 = (ScreenSlidePageFragment) adapter.instantiateItem(myViewPager, 1);
ScreenSlidePageFragment fragment3 = (ScreenSlidePageFragment) adapter.instantiateItem(myViewPager, 2);
但是，當我打電話fragment1.getView（），則返回null。但是，當我不改變方向時，相同的代碼運行良好。
如何獲取定位更改的片段視圖？我檢查了一些發佈的解決方案，他們說要將碎片保存在數組中，但這些解決方案對我來說並不合適。我所放的代碼是否無法完成任務？謝謝。