当ListView有Header时，onItemClick里的position不正确

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@Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);       setContentView(R.layout.home);       mAdapter = new MyAdapter(this);       mListView = (ListView) findViewById(R.id.list);     mListView.addHeaderView(getLayoutInflater().inflate(R.layout.list_header));     mListView.setAdapter(mAdapter);     mListView.setOnClickListener(this); }   @Override public void onItemClick(AdapterView<?> parent, View v, int position, long id) {     doSomething(mAdapter.getItem(position)); }

 Google了下，发现有个老外issue过一个bug，和我遇到的问题一样，不过这个bug被RomainGuy reject掉了，理由是，你用错了，请用getAdapter。这回答的太简洁了，完全没法理解，所以只好又去仔细研究ListView的代码，终于领会他的意思了。把其中addHeaderView和setAdapter方法贴下来

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/**  * Add a fixed view to appear at the top of the list. If addHeaderView is  * called more than once, the views will appear in the order they were  * added. Views added using this call can take focus if they want.  * <p>  * NOTE: Call this before calling setAdapter. This is so ListView can wrap  * the supplied cursor with one that that will also account for header  * views.  *  * @param v The view to add.  * @param data Data to associate with this view  * @param isSelectable whether the item is selectable  */ public void addHeaderView(View v, Object data, boolean isSelectable) {     if (mAdapter != null) {         throw new IllegalStateException(                 "Cannot add header view to list -- setAdapter has already been called.");     }       FixedViewInfo info = new FixedViewInfo();     info.view = v;     info.data = data;     info.isSelectable = isSelectable;     mHeaderViewInfos.add(info); }   /**  * Sets the data behind this ListView.  *  * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter},  * depending on the ListView features currently in use. For instance, adding  * headers and/or footers will cause the adapter to be wrapped.  *  * @param adapter The ListAdapter which is responsible for maintaining the  *        data backing this list and for producing a view to represent an  *        item in that data set.  *  * @see #getAdapter()  */ @Override public void setAdapter(ListAdapter adapter) {     if (null != mAdapter) {         mAdapter.unregisterDataSetObserver(mDataSetObserver);     }       resetList();     mRecycler.clear();       if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) {         mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter);     } else {         mAdapter = adapter;     }       //其它的一些代码这里省略之... }

 

 

从代码和注释里都可以很清楚的得知，addHeaderView一定要在setAdapter之前调用，如果不这样做，addHeaderView会抛出一个异常。android为什么要这样？这是因为，在setAdapter的时候，会针对我遇到的这种情况（也就是添加Header后position不正确的这种情况）做些特殊的处理。setAdapter在内部判断了当前ListView是否有Header或者Footer，如果没有，就直接使用参数传进来的adapter；如果有，则用一个decorated的HeaderViewListAdapter来替换参数。这个HeaderViewListAdapter的使命，就是排除Header和Footer，让position（当然也包括getItem, getItemId）等方法的position参数）正确返回。

分析到这里，解决方案就出来了：在onItemClick不要直接使用我们声明的adapter，而是用ListView里的那个decorated adapter。获取它的方法就是调用parent.getAdapter()。当然，如果ListView没有Header和Footer，直接使用声明的adapter也没有问题，不过为了避免出错，还是统一使用decorated adapter比较好。

把onItemClick改成下面这样，就可以了

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@Override public void onItemClick(AdapterView<?> parent, View v, int position, long id) {     doSomething(parent.getAdapter().getItem(position)); }

 本文由Roy最初发表于：http://blog.chengbo.net/2012/03/09/onitemclick-return-wrong-position-when-listview-has-headerview.html，你可以在保持文章完整和保留本声明的情况下转帖、分发和印刷等。