【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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