ListView addHeaderView causes position to increase by one?

问题:

Below is a code snippet with a ListView. I added an emptyView and a headerView. Adding the headerView causes the position in the onItemClick to be increased by one.

So without the headerView the first list element would have position 0, with the headerView the position of the first list element would be 1!

This causes errors in my adapter, e.g. when calling getItem() and using some other methods, see below. Strange thing: In the getView() method of the adapter the first list element is requested with position 0 even if the headerView is added!!

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {     ListView list = (ListView) viewSwitcher.findViewById(R.id.list);     View emptyView = viewSwitcher.findViewById(R.id.empty);     list.setEmptyView(emptyView);      View sectionHeading = inflater.inflate(R.layout.heading, list, false);     TextView sectionHeadingTextView = (TextView) sectionHeading.findViewById(R.id.headingText);     sectionHeadingTextView.setText(headerText);     list.addHeaderView(sectionHeading);      list.setAdapter(listAdapter);      list.setOnItemClickListener(new OnItemClickListener() {          @Override         public void onItemClick(AdapterView<?> parent, View view, int position, long id) {             listAdapter.getItem(position);             //Do something with it         }     }); } 

Some adapter methods:

@Override public int getViewTypeCount() {     return TYPE_COUNT; }  @Override public int getItemViewType(int position) {     return (position < items.size()) ? ITEM_NORMAL : ITEM_ADVANCED; }      @Override public Product getItem(int position) {     return items.get(position); } @Override public boolean areAllItemsEnabled() {     return false; }  @Override public boolean isEnabled(int position) {     return (position < items.size()); } 

Is this the normal behaviour when adding a headerView?? And how to overcome the issues in my adapter?

回答1:

I just came across this problem and the best way seems to use the ListView.getItemAtPosition(position) instead of ListAdapter.getItem(position) as the ListView version accounts for the headers, ie:-

Do this instead:

myListView.getItemAtPosition(position) 

回答2:

If you don't care about the click to the header, subtract the number of header views from the position to get the position for your adapter:

        listView.addHeaderView(inflater.inflate(                 R.layout.my_hdr_layout, null), null, false);         listView.setAdapter(m_adapter);         listView.setOnItemClickListener(new OnItemClickListener() {          @Override         public void onItemClick(AdapterView<?> parent, View view,                 int position, long id) {             position -= listView.getHeaderViewsCount();             final MyObject object = m_adapter.getItem(position);          }     }); 

回答3:

If you add a header to a ListView that becomes the first item in the list. You could compensate for this by overriding the getCount() to return one item less, but ensure you handle the getItem(), getItemId() and so on as the header would be the item in position 0.

回答4:

When implementing AdapterView.OnItemClickListener we just subtract the headers from the position.

@Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) {     position -= mListView.getHeaderViewsCount();     // what ever else follows... } 

回答5:

No need to change any code. Simply use below code.

 list.setOnItemClickListener(new OnItemClickListener() {      @Override      public void onItemClick(AdapterView<?> parent, View view, int position, long id) {       parent.getAdapter().getItem(position);          //Do something with it      } }); 

回答6:

Do not use your adapter, use 'decorated' adapter from getAdapter.

回答7:

One solution to this is to map the id to index. Basically make id return the index in the list and the the click listener would do:

public void onItemClick(AdapterView<?> parent, View view, int position, long id) {             listAdapter.getItem((int) id); } 

回答8:

Hi we can resolve this in this way first you create your header view, after inject in your list and the last step unable the setOnClickListener. its works for me. any feedback welcome

ViewGroup headerView = (ViewGroup) getLayoutInflater().inflate(R.layout.your_header, list,false); list.addHeaderView(headerView); headerView.setEnabled(false); headerView.setOnClickListener(null); 

回答9:

Not to add much new that @Ramesh didn't add but some extra context:

personList.setOnItemClickListener(new OnItemClickListener() {     @SuppressWarnings("unchecked")     public void onItemClick( AdapterView<?> parent, View view, int position, long duration) {         Map<String, Object> person = (Map<String, Object>) parent.getAdapter().getItem(position);         if (person != null){              // If the header was clicked on a null  is returned              OnPersonUiChangeListener listener = (OnPersonUiChangeListener) getActivity();             listener.onSelectedPersonChanged(person);         }     } }); 

回答10:

Use getSelectedItemPosition() Return the position of the currently selected item within the adapter's data set. This method don't need to worry about the size of headers or footers.

回答11:

This might help somebody, improving on Farid_z and Philipp's answer, we can correctly apply the setItemChecked and setTitle with something like this

        FragmentManager fragmentManager = getSupportFragmentManager();         fragmentManager.beginTransaction().replace(R.id.content_frame, fragment).commit();         position += 1;         mDrawerList.setItemChecked(position, true);         mDrawerList.setSelection(position);         position -= 1;         setTitle(mNavigationDrawerItemTitles[position]);         mDrawerLayout.closeDrawer(mDrawerList); 

文章来源: ListView addHeaderView causes position to increase by one?