ViewPager更新片段

Question

viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

        @Override
        public void onPageSelected(int position) {
            getActionBar().setSelectedNavigationItem(position);
            if(position == 1)
            {
                new FragmentFavorites().update(getApplicationContext());
            }
        }

        @Override
        public void onPageScrolled(int arg0, float arg1, int arg2) {
        }

        @Override
        public void onPageScrollStateChanged(int arg0) {
        }
    });

来自 FragmentFavorites

的

更新

public void update(Context context) {
    savedFacts = com.invizorys.sexpro.util.Util.readFactsList(context);

    if (savedFacts.size() > 0)
        mTextView.setText(savedFacts.get(currentFactIndex));
    else
        mTextView.setText("you still have not saved any fact");
}

当我打开FragmentFavorites应用程序崩溃（mTextView nullpointer）时，尽管我在onCreateView（）中找到它

mTextView = (TextView) rootView.findViewById(R.id.textview_fact);

更新

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    ViewGroup rootView = (ViewGroup) inflater.inflate(R.layout.fragment_favorites, container, false);
    ...
    mTextView = (TextView) rootView.findViewById(R.id.textview_fact);
    ...
    return rootView;
}

Answer 1

当您新建FragmentFavorites实例时，尚未调用onCreateView（）。您应该从ViewPager中找到FragmentFavorites实例，而不是创建一个。