java.lang.IllegalStateException: Cannot add header view to list -- setAdapter has already been called.

分析：android 4.2.X及以下的版本，addHeaderView必须在setAdapter之前，否则会抛出IllegalStateException。

android 4.2.X（API 17） ListView源码如下：

public void addHeaderView(View v, Object data, boolean isSelectable) {  
   
        if (mAdapter != null && ! (mAdapter instanceof HeaderViewListAdapter)) {  
            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);  
   
        // in the case of re-adding a header view, or adding one later on,  
        // we need to notify the observer  
        if (mAdapter != null && mDataSetObserver != null) {  
            mDataSetObserver.onChanged();  
        }  
}  

　　

android 4.3.X（API 18）ListView源码如下：

    public void addHeaderView(View v, Object data, boolean isSelectable) {
        ......

        // Wrap the adapter if it wasn't already wrapped.
        if (mAdapter != null) {
            if (!(mAdapter instanceof HeaderViewListAdapter)) {
                mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, mAdapter);
            }

            // In the case of re-adding a header view, or adding one later on,
            // we need to notify the observer.
            if (mDataSetObserver != null) {
                mDataSetObserver.onChanged();
            }
        }
    }

所以为了兼容android4.2.x及以下的版本，最好先addHeaderView,后setAdapter.