Android ViewPager更新片段
从片段收藏夹更新Android ViewPager更新片段,android,android-fragments,android-viewpager,Android,Android Fragments,Android Viewpager,从片段收藏夹更新 viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() { @Override public void onPageSelected(int position) { getActionBar().setSelectedNavigationItem(position); if(position == 1)
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) {
}
});
当我打开FragmentFavorites时,应用程序崩溃(mTextView nullpointer),尽管我在onCreateView()中找到了它
更新
mTextView = (TextView) rootView.findViewById(R.id.textview_fact);
新建FragmentFavorites实例时,尚未调用onCreateView()。您应该从ViewPager中找到FragmentFavorites实例,而不是创建一个实例 你能展示一下你是如何膨胀的
rootView
吗?你确定rootView
实际上是保存textview\u fact
的正确视图吗?如果我不调用update,一切正常
mTextView = (TextView) rootView.findViewById(R.id.textview_fact);
@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;
}