【原创】StickHeaderListView的简单实现，解决footerView问题

1、前言：

前几天用了GitHub上se.emilsjolander.stickylistheaders这个组件，然后发现这个组件的listview不能添加footerView，加了footer后，滑倒footer的时候head会消失，与我项目中的需求不符。

于是就自己写了一个StickHeaderListView，实现比较简单，做法和stickylistheaders基本相同只是没有封装那么多功能，可以添加footer但不能添加header，有需要的同学可以拿去改良后用。

另外由于是临时写的一个组件，代码没做什么优化，如果有想法可以提点意见，谢谢！

2、示例效果：

3、组件源码：

 /**
  * 带头部固定的列表
  * Created by shengdong.huang on 2016/6/24.
  */
 public class StickHeaderListView extends FrameLayout {

     /** 页面引用 */
     protected Context context;
     /** 列表视图 */
     protected ListView listView;
     /** 适配器 */
     protected StickHeaderAdapter adapter;
     /** 头部布局 */
     protected FrameLayout headLayout;
     /** 滚动监听器 */
     protected OnScrollListener listener;
     /** 提供Adapter响应的观察者 */
     protected DataSetObserver mDataSetObserver = new DataSetObserver() {
         @Override
         public void onChanged() {
             if (listView != null && headLayout != null && adapter != null) {
                 refreshHead(listView.getFirstVisiblePosition(), true);
             }
         }

         @Override
         public void onInvalidated() {
         }
     };

     /**
      * 滚动监听器
      */
     protected AbsListView.OnScrollListener scrollListener = new AbsListView.OnScrollListener() {

         @Override
         public void onScrollStateChanged(AbsListView view, int scrollState) {
             if (listener != null) {
                 listener.onScrollStateChanged(view, scrollState);
             }
         }

         @Override
         public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
             if (listener != null) {
                 listener.onScroll(view, firstVisibleItem, visibleItemCount, totalItemCount);
             }
             // 刷新
             refreshHead(firstVisibleItem, false);
         }
     };

     protected void refreshHead(int firstVisibleItem, boolean forceRefresh) {
         // 防空
         if (headLayout == null || adapter == null || adapter.getHeadPos() == null
                 || listView.getChildAt(0) == null) {
             return;
         }

         // 获取头部位置记录
         ArrayList<Integer> headPos = adapter.getHeadPos();
         // 是否有找到head
         boolean find = false;

         // 获取head中的位置
         int prevHeadPos = -1;
         if (headLayout.getChildCount() > 0 && headLayout.getChildAt(0) != null &&
                 headLayout.getChildAt(0).getTag() != null) {
             prevHeadPos = (int) headLayout.getChildAt(0).getTag();
         }

         // 反向遍历头部位置记录
         for (int i = (headPos.size() - 1); i>=0; i--) {
             // 如果当前位置大于等于某个头部记录，表示应该使用该头部
             if (firstVisibleItem >= headPos.get(i)) {
                 // 获取headLayout中视图的pos标签

                 // 构造或者从headLayout中获取视图
                 View v;
                 if (prevHeadPos == -1 || prevHeadPos != headPos.get(i) || forceRefresh) {
                     // 无Pos标签或POS标签不配对
                     headLayout.removeAllViews();
                     v = listView.getAdapter().getView(headPos.get(i), null, null);
                     v.setTag(headPos.get(i));
                     LayoutParams params = new FrameLayout.LayoutParams(-1, -2);
                     v.setLayoutParams(params);
                     headLayout.addView(v);
                 } else if (i+1 < headPos.size() && firstVisibleItem == headPos.get(i+1) - 1) {
                     // 当前第一个item的top值
                     int top = listView.getChildAt(0).getTop();
                     // Pos标签配对但，有下一个head，且下一个head的pos为下一个item时
                     v = headLayout.getChildAt(0);
                     // 设置head的Top
                     LayoutParams params = (LayoutParams) v.getLayoutParams();
                     params.setMargins(0, top, 0, -top);
                     v.setLayoutParams(params);
                 } else {
                     // 修正head top没有回到0的问题
                     v = headLayout.getChildAt(0);
                     LayoutParams params = (LayoutParams) v.getLayoutParams();
                     if (params.topMargin != 0) {
                         params.setMargins(0, 0, 0, 0);
                         v.setLayoutParams(params);
                     }
                 }
                 find = true;
                 break;
             }
         }
         // 未找到head的情况,清空Head
         if (!find && headLayout != null) {
             headLayout.removeAllViews();
         }
     }

     public StickHeaderListView(Context context) {
         super(context);
         this.context = context;
     }

     public StickHeaderListView(Context context, AttributeSet attrs) {
         super(context, attrs);
         this.context = context;
     }

     public void setBackgroundColor(int color) {
         if (listView != null) {
             listView.setBackgroundColor(color);
         }
     }

     public void addFooterView(View v) {
         if (listView != null) {
             listView.addFooterView(v);
         }
     }

     public boolean removeFooterView(View v) {
         if (listView != null) {
             return listView.removeFooterView(v);
         }
         return false;
     }

     public int getFooterViewsCount() {
         if (listView != null) {
             return listView.getFooterViewsCount();
         }
         return 0;
     }

     public void setDividerHeight(int height) {
         if (listView != null) {
             listView.setDividerHeight(height);
         }
     }

     public void setCacheColorHint(int color) {
         if (listView != null) {
             listView.setCacheColorHint(color);
         }
     }

     public void setSelector(int resID) {
         if (listView != null) {
             listView.setSelector(resID);
         }
     }

     public void setAdapter(StickHeaderAdapter adapter) {
         if (adapter instanceof BaseAdapter && listView != null) {
             this.adapter = adapter;
             if (adapter != null && mDataSetObserver != null) {
                 try {
                     ((BaseAdapter) adapter).unregisterDataSetObserver(mDataSetObserver);
                 } catch (Exception e) {}
             }
             listView.setAdapter((ListAdapter) this.adapter);
             ((BaseAdapter) adapter).registerDataSetObserver(mDataSetObserver);
         }
     }

     public void setOnScrollListener(OnScrollListener listener) {
         this.listener = listener;
     }

     @Override
     protected void onFinishInflate() {
         super.onFinishInflate();
         // 添加列表，属性直接使用父视图
         listView = new ListView(context);
         listView.setLayoutParams(new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
                 ViewGroup.LayoutParams.MATCH_PARENT));
         addView(listView);
         // 添加head
         headLayout = new FrameLayout(context);
         headLayout.setLayoutParams(new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
                 ViewGroup.LayoutParams.WRAP_CONTENT));
         addView(headLayout);
         // 添加滚动监听
         listView.setOnScrollListener(scrollListener);
     }

     public interface OnScrollListener extends AbsListView.OnScrollListener {}

     public interface StickHeaderAdapter {
         public ArrayList<Integer> getHeadPos();
     }
 }

4、示例代码：

 /**
  * 主页面
  * Created by shengdong.huang on 2016/6/20.
  */
 public class MainActivity extends FragmentActivity {

     private StickHeaderListView listView;
     private TestAdapter adapter;

     @Override
     protected void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         listView = (StickHeaderListView) findViewById(R.id.list);

         View footer = LayoutInflater.from(this).inflate(R.layout.item_head_foot, null);
         footer.setBackgroundColor(Color.GREEN);
         listView.addFooterView(footer);

         View footer2 = LayoutInflater.from(this).inflate(R.layout.item_head_foot, null);
         footer2.setBackgroundColor(Color.BLUE);
         listView.addFooterView(footer2);

         View footer3 = LayoutInflater.from(this).inflate(R.layout.item_head_foot, null);
         footer3.setBackgroundColor(Color.RED);
         listView.addFooterView(footer3);

         listView = (StickHeaderListView) findViewById(R.id.list);

         adapter = new TestAdapter();
         listView.setAdapter(adapter);
     }

     public class TestAdapter extends BaseAdapter implements StickHeaderListView.StickHeaderAdapter {

         private ArrayList<Integer> headpos = new ArrayList<>();

         public TestAdapter() {
             headpos.add(0);
             headpos.add(5);
             headpos.add(15);
         }
         @Override
         public int getCount() {
             return 30;
         }
         @Override
         public Object getItem(int position) {
             return position;
         }
         @Override
         public long getItemId(int position) {
             return position;
         }
         @Override
         public View getView(final int position, View convertView, ViewGroup parent) {
             ViewHolder holder;
             if (convertView == null) {
                 convertView = LayoutInflater.from(MainActivity.this).inflate(R.layout.item_list, null);
                 holder = new ViewHolder();
                 holder.text = (TextView) convertView.findViewById(R.id.text);
                 convertView.setTag(holder);
             } else {
                 holder = (ViewHolder) convertView.getTag();
             }
             holder.text.setText("AAAAAAAAAAAAAAAAAAAAA"+position);
             holder.text.setOnClickListener(new View.OnClickListener() {
                 @Override
                 public void onClick(View v) {
                     Toast.makeText(MainActivity.this, "pos:"+position, Toast.LENGTH_SHORT).show();
                 }
             });
             convertView.setBackgroundColor(0x110011 * position % 0xffffff + 0xff000000);
             return convertView;
         }

         @Override
         public ArrayList<Integer> getHeadPos() {
             return headpos;
         }
     }

     private class ViewHolder {
         TextView text;
     }
 }

5、使用方法：

1、布局中加入StickHeaderListView

2、Adapter实现StickHeaderAdapter接口

3、getHeadPos()中返回headitem的位置，标示listview item中各个head的起点（这点与stickylistheaders不同）

4、如果有需要用到一些listview的方法，请自行在StickHeaderListView中添加，但注意，不能addHeaderView，会导致滑动异常

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