Question

我有一个带有6个屏幕的ViewPager（mViewPagerMain）。在屏幕4，我在另一个内部有另一个ViewPager（mViewPagerSub）。我在CustumViewPager上禁用mViewPagerMain的滚动，当使用mViewPagerSub时 - 效果很好。现在的问题是：当我滚动主页时一切正常，所有东西都加载。当我从屏幕4（包含子屏幕）向后滚动到屏幕2并返回到4时，子视图中的前2个屏幕未加载。如果我向前滚动并返回子，则一切都正确加载。

的onCreate：

protected void onCreate(Bundle savedInstanceState) {
   mSectionsPagerAdapterMain = new SectionsPagerAdapterMain(getSupportFragmentManager());
   mSectionsPagerAdapterSub = new SectionsPagerAdapterSub(getSupportFragmentManager());
   mViewPagerMain = (CustomViewPager) findViewById(R.id.pagerMain);
   mViewPagerMain.setAdapter(mSectionsPagerAdapter);
}

SectionPagerAdapters :(就像在google示例中一样，对于sub来说相同）

public class SectionsPagerAdapter extends FragmentPagerAdapter {
    public SectionsPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int position) {
        Fragment fragment = null;
        switch (position) {
        case 0:
            fragment = new SettingsFragment(0);
            break;
        case 1:
            fragment = new SettingsFragment(1);
            break;
        case 2:
            fragment = new SettingsFragment(2);
            break;
        // and so on...
        default:
            fragment = new SettingsFragment(0);
        }
        return fragment;
    }

    @Override
    public int getCount() {
        return 6;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        switch (position) {
        case 0:
            return getString(R.string.title_section1).toUpperCase();
        case 1:
            return getString(R.string.title_section2).toUpperCase();
        // and so on ...
        }
        return null;
    }
}

设置片段:(就像在谷歌示例中一样）

public static class SettingsFragment extends Fragment {

    int position = 0;

    public SettingsFragment(int position) {
        this.position = position;

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View rootView;
        if (position == 0) {
            rootView = inflater.inflate(R.layout.main0, container, false);
            main0(rootView);
            return rootView;

        } else if (position == 1) {
            rootView = inflater.inflate(R.layout.main1, container, false);
            main1(rootView);
            return rootView;
        } else if (position == 2) {
            rootView = inflater.inflate(R.layout.main2, container, false);
            main2(rootView);
            return rootView;
        } 
                    //...and so on...
    }

}

相关页面：main4（）：

public static void main4(View rootView) {
    subView = rootView;
    new setAdapterTask().execute();
}

和加载寻呼机的异步任务：

private static class setAdapterTask extends AsyncTask<Void, Void, Void> {
    protected Void doInBackground(Void... params) {
        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        mViewPagerSub = (CustomViewPager)subView.findViewById(R.id.pagerSub);
        mViewPagerSub.setAdapter(mSectionsPagerAdapterSub);
        mViewPagerSub.refresh();
    }
}

CustomViewPager.refresh（）：

public void refresh() {
       getAdapter().notifyDataSetChanged();
}

我尝试使用像这样的PageListener来模拟滚动，但它没有效果：

private static class PageListener extends SimpleOnPageChangeListener {
        public void onPageSelected(int position) {
            currentPage = position;
            if (mViewPagerSub != null && currentPage == 3) {
                mViewPagerSub.setCurrentItem(5);
            } else if (mViewPagerSub != null && currentPage == 4) {
                mViewPagerSub.setCurrentItem(0);
            }
            if (mViewPagerSub != null)
                mViewPagerSub.refresh();
        }
}

Answer 1

回答我自己的问题：这就是诀窍：

private static class PageListener extends SimpleOnPageChangeListener {
   public void onPageSelected(int position) {
      currentPage = position;
      if(currentPage==4 && mViewPagerSub!=null){
         new setAdapterTask().execute();
      }
   }
}

ViewPager中的Android ViewPager无法正确更新

1 个答案: