android - 在 saveOnIstanceState() 之后 viewPager.setCurrentItem() 似乎不起作用

Question

我有一个实现 ViewPager 的片段，在这个片段中，我使用该onSaveInstanceState()方法保存 ViewPager 状态。我可以使用 viewPager.getCurrentItem() 将它保存在包中，但是当我去恢复 ViewPager 的状态时，viewPager.setCurrentItem()它似乎不起作用。如何正确保存片段状态？

这是我的片段代码

public class HomeFragment extends Fragment {
private ViewPager viewPager;
private ViewPagerAdapter adapter;
Integer[] colors=null;
List<Model> models;
private String[] mDescriptions;
private String[] mTitle;
private String mPlayerName;


@Override
public void onSaveInstanceState(@NonNull Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putInt("currentItem", viewPager.getCurrentItem());
}




@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

    models = new ArrayList<>();
    Resources res = getResources();
    mDescriptions = res.getStringArray(R.array.newGameDescription);
    mTitle = res.getStringArray(R.array.newGame);
    models.add(new Model(R.drawable.ic_launcher_background,mTitle[0], mDescriptions[0]));
    models.add(new Model(R.drawable.ic_launcher_background,mTitle[1], mDescriptions[1]));
    models.add(new Model(R.drawable.ic_launcher_background,mTitle[2], mDescriptions[2]));
    models.add(new Model(R.drawable.ic_launcher_background,mTitle[3], mDescriptions[3]));

    adapter = new ViewPagerAdapter(getContext(), models, mPlayerName);
    int orientation = getResources().getConfiguration().orientation;
    adapter.setOrientation(orientation);

    View view = inflater.inflate(R.layout.fragment_home, container, false);

    viewPager = (ViewPager) view.findViewById(R.id.gameModeViewPager);
    viewPager.setAdapter(adapter);
    viewPager.setPadding(130,0,130,0);

    return view;
}


@Override
public void onActivityCreated(final Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
    if (savedInstanceState != null) {
        // Restore last state for checked position.
        viewPager.postDelayed(new Runnable() {

            @Override
            public void run() {
                int item = savedInstanceState.getInt("currentItem");
                viewPager.setCurrentItem(item);
            }
        }, 100);
    }
}

}

欢迎任何建议和评论，在此先感谢

标签： androidandroid-fragmentsandroid-viewpageronsaveinstancestate

Answer 1

onCreateView不返回捆绑值，onSaveInstanceState您必须从中获取它onActivityCreated

     @public void onActivityCreated(Bundle savedInstanceState) {
                  super.onActivityCreated(savedInstanceState);
                      if (savedInstanceState != null) {
                // Restore last state for checked position.
    viewPager.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener()
            {
                @Override
                public void onGlobalLayout()
                {
                   int item = savedInstanceState.getInt("currentItem");
                   viewPager.setCurrentItem(item);    
        }
     }); 
   }