Android 如何在片段中onCreateView之后再次访问视图?
实际上,我在FragmentPagerAdapter中使用Fragments,但当我再次尝试在fragment中访问视图时,我遇到了一个空的问题。pageNum也为null。我尝试了很多方法来解决这个问题,但都没有成功 FirstFragment.javaAndroid 如何在片段中onCreateView之后再次访问视图?,android,android-fragments,fragment,fragmentpageradapter,Android,Android Fragments,Fragment,Fragmentpageradapter,实际上,我在FragmentPagerAdapter中使用Fragments,但当我再次尝试在fragment中访问视图时,我遇到了一个空的问题。pageNum也为null。我尝试了很多方法来解决这个问题,但都没有成功 FirstFragment.java public class FirstFragment extends Fragment{ private int pageNum; private TextView titleTxt; private LinearLa
public class FirstFragment extends Fragment{
private int pageNum;
private TextView titleTxt;
private LinearLayout topPan;
public static FirstFragment newInstance(int page) {
FirstFragment fragment = new FirstFragment();
Bundle args = new Bundle();
args.putInt("page", page);
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
pageNum = getArguments().getInt("page", 0);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.workflow_item_layout, container, false);
titleTxt = (TextView) view.findViewById(R.id.title);
topPan = (FrameLayout) view.findViewById(R.id.top_pan);
}
public void setTopPanVisible(boolean isVisible) {
topPan.setVisibility(isVisible);
}
pageChangeListener代码
private ViewPager.OnPageChangeListener pageChangeListener = new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
}
@Override
public void onPageScrollStateChanged(int state) {
final int position = pager.getCurrentItem();
if (state == ViewPager.SCROLL_STATE_IDLE) {
final FirstFragment fragment = (FirstFragment) adapter.getItem(position);
fragment.setTopPanVisible(true);
在pageChangeListener中调用“setTopPanVisible”时,topPan为null。视图如何保持活动状态以获得价值 如果您得到一个空指针异常,那么这意味着两件事之一:
onCreateView()
方法之前,您正在调用setTopPanVisible()
view.findviewbyd(R.id.top\u pan)代码>
为了解决此问题,您应该找出您面临的问题。我想在生成片段后更改topPan的可见性,因此,我需要在调用onCreateView后调用setTopPanVisible。您面临的问题是哪一个#1或2?正是1,我正在寻找并尝试。