PullToRefresh嵌套GridView实现悬浮以及上拉刷新

使用PullToRefreshlistView嵌套GridView并且实现悬浮功能，总的来说是由以下几个要点需要去注意：

• 导入PullToRefresh开源库
• 为listview设置Adapter
• 为listview设置刷新方法
• 为gridview设置Adapter

---

导入PullToRefresh开源库

一、导入Library
下载源码后（https://github.com/chrisbanes/Android-PullToRefresh），里面有个Library工程，添加工程到Eclipse中；
如果是Android Studio用户也大同小异，添加module到AS中；

为listview设置Adapter

为listview设置刷新方法

为gridview设置Adapter

新建工程，并且引用刚才导入的library。定义activity_main.xml如下：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity" >
   <FrameLayout
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/frame">
        <com.handmark.pulltorefresh.library.PullToRefreshListView
                    xmlns:ptr="http://schemas.android.com/apk/res-auto"
                    android:id="@+id/list"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"
                    android:divider="@color/gray"
                    android:dividerHeight="2dp"
                    android:fadingEdge="horizontal"
                    android:fastScrollEnabled="false"
                    android:footerDividersEnabled="true"
                    android:headerDividersEnabled="true"
                    android:smoothScrollbar="true"
                    android:background="@color/white"
                    ptr:ptrMode="pullUpFromBottom"
                    />
        <TextView 
            android:layout_width="fill_parent"
                android:layout_height="45dp"
                android:id="@+id/header"
                android:text="悬浮部分"
                android:textSize="16sp"
                android:gravity="center"
                android:background="@color/pink"
                android:visibility="gone"/>
    FrameLayout>
LinearLayout>

list是上拉刷新控件，header是悬浮部分
接下来在Activity中拿到组件和悬浮部分并且为listview设置监听器：

package com.zlm.pulltorefreshdemo;

import java.util.ArrayList;

import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.Window;
import android.widget.AbsListView;
import android.widget.ListView;

import com.zlm.pulltorefreshdemo.R;
import com.handmark.pulltorefresh.library.PullToRefreshBase;
import com.handmark.pulltorefresh.library.PullToRefreshListView;

public class MainActivity extends Activity {
    private PullToRefreshListView mListView;
    private View header;
    private ArrayList strs;
    private DemoAdapter adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);//隐藏标题
        setContentView(R.layout.activity_main);
        initView();
        setAdapter();
    }

    private void initView() {
        mListView = (PullToRefreshListView)findViewById(R.id.list);
        header = findViewById(R.id.header);
        //设置滚动监听，当第二个item开始离开屏幕是显示header
        mListView.setOnScrollListener(new AbsListView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {
            }
            @Override
            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
                if (firstVisibleItem >= 2) {
                    header.setVisibility(View.VISIBLE);
                } else {
                    header.setVisibility(View.GONE);
                }
            }
        });
        //设置刷新监听，当又刷新动作发生，调用函数
        mListView.setOnRefreshListener(new PullToRefreshBase.OnRefreshListener() {
            @Override
            public void onRefresh(PullToRefreshBase refreshView) {
                new RefreshTask().execute();
            }
        });
    }

    private void setAdapter() {
        strs = new ArrayList();
        String str = "a";
        for(int i = 0;i < 20;i++) {
            strs.add(str);
        }
        adapter = new DemoAdapter(this,strs);
        mListView.setAdapter(adapter);
    }

    private class RefreshTask extends AsyncTask<Void, Void, ArrayList<String>> {
        @Override
        protected ArrayList doInBackground(Void... params) {
            ArrayList data2 = new ArrayList();
            String url = "b";
            for(int i = 0;i < 5;i++) {
                data2.add(url);
            }
            strs.addAll(data2);
            return strs;
        }
        @Override
        protected void onPostExecute(ArrayList result){
            adapter.setStrs(result);//将更新的数据源传入adapter中
            adapter.notifyDataSetChanged();//更新界面
            mListView.onRefreshComplete();//刷新完毕
            super.onPostExecute(result);
        }
    }
}

相对应的Adapter的写法如下：

package com.zlm.pulltorefreshdemo;

import java.lang.reflect.Field;
import java.util.ArrayList;

import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.ListAdapter;
import android.widget.TextView;

public class DemoAdapter extends BaseAdapter{
    private Context mContext;
    private ArrayList strs;
    public DemoAdapter(Context mContext,ArrayList strs) {
        this.mContext = mContext;
        this.strs = strs;
    }

    public void setStrs(ArrayList strs) {
        this.strs = strs;
    }


    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return 3;
    }

    @Override
    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return strs.get(position);
    }

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return position;
    }

    @Override
    public int getItemViewType(int position) {
        int p = position;
        if (p == 0 || p == 1)
            return p;
        else
            return 2;
    }

    @Override
    public int getViewTypeCount() {
        return 3;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        int type = getItemViewType(position);
        ViewHolder viewHolder = null;
        ViewHolder2 viewHolder2 = null;
        ViewHolder3 viewHolder3 = null;
        if(convertView == null) {
            switch(type) {
                case 0:
                    viewHolder = new ViewHolder();
                    convertView = LayoutInflater.from(mContext).inflate(R.layout.listitem_top_view,null);
                    viewHolder.text = (TextView)convertView.findViewById(R.id.text);
                    convertView.setTag(viewHolder);
                    break;
                case 1:
                    viewHolder2 = new ViewHolder2();
                    convertView = LayoutInflater.from(mContext).inflate(R.layout.listitem_middle_view,null);
                    viewHolder2.text = (TextView)convertView.findViewById(R.id.header);
                    convertView.setTag(viewHolder2);
                    break;
                case 2:
                    viewHolder3 = new ViewHolder3();
                    convertView = LayoutInflater.from(mContext).inflate(R.layout.listitem_bottom_view,null);
                    viewHolder3.gridView = (MyGridView)convertView.findViewById(R.id.gridview);
                    convertView.setTag(viewHolder3);
                    break;
                default:
                    break;
            }
        }else {
            switch(type) {
                case 0:
                    viewHolder = (ViewHolder)convertView.getTag();
                    break;
                case 1:
                    viewHolder2 = (ViewHolder2)convertView.getTag();
                    break;
                case 2:
                    viewHolder3 = (ViewHolder3)convertView.getTag();
                    break;
                default:
                    break;
            }
        }
        switch(type) {
            case 0:
                break;
            case 1:
                break;
            case 2:
                if(viewHolder3.gridView != null) {
                    viewHolder3.gridView.setAdapter(new PullGridAdapter(mContext,strs));
                    setGridViewHeightBasedOnChildren(viewHolder3.gridView);
                }
                break;
            default:
                break;
        }
        return convertView;
    }

    static class ViewHolder{
        private TextView text;
    }

    static class ViewHolder2{
        private TextView text;  
    }

    static class ViewHolder3{
        private MyGridView gridView;
    }

    public static void setGridViewHeightBasedOnChildren(GridView gridView) {
        // 获取GridView对应的Adapter
        ListAdapter listAdapter = gridView.getAdapter();
        if (listAdapter == null) {
            return;
        }
        int rows;
        int columns=3;
        int horizontalBorderHeight=0;
        Class clazz=gridView.getClass();
        try {
            //利用反射，取得每行显示的个数
            Field column=clazz.getDeclaredField("mRequestedNumColumns");
            column.setAccessible(true);
            columns=(Integer)column.get(gridView);
            //利用反射，取得横向分割线高度
            Field horizontalSpacing=clazz.getDeclaredField("mRequestedHorizontalSpacing");
            horizontalSpacing.setAccessible(true);
            horizontalBorderHeight=(Integer)horizontalSpacing.get(gridView);
        } catch (Exception e) {
            // TODO: handle exception
            e.printStackTrace();
        }
        //判断数据总数除以每行个数是否整除。不能整除代表有多余，需要加一行
        if(listAdapter.getCount()%columns>0){
            rows=listAdapter.getCount()/columns+1;
        }else {
            rows=listAdapter.getCount()/columns;
        }
        int totalHeight = 0;
        for (int i = 0; i < rows; i++) { //只计算每项高度*行数
            View listItem = listAdapter.getView(i, null, gridView);
            listItem.measure(0, 0); // 计算子项View 的宽高
            totalHeight += listItem.getMeasuredHeight(); // 统计所有子项的总高度
        }
        ViewGroup.LayoutParams params = gridView.getLayoutParams();
        params.height = totalHeight+horizontalBorderHeight*(rows-1);//最后加上分割线总高度
        gridView.setLayoutParams(params);
    }

    class PullGridAdapter extends BaseAdapter {
        private Context mContext;
        private ArrayList strs;
        public PullGridAdapter(Context mContext,ArrayList strs) {
            this.mContext = mContext;
            this.strs = strs;
        }
        @Override
        public int getCount() {
            if (strs == null) {
                return 0;
            } else {
                return this.strs.size();
            }
        }
        @Override
        public Object getItem(int position) {
            if (strs == null) {
                return null;
            } else {
                return this.strs.get(position);
            }
        }
        @Override
        public long getItemId(int position) {
            return position;
        }
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            ViewHolder4 holder4 = null;
            System.out.println("找到的"+strs.size());
            if (convertView == null) {
                holder4 = new ViewHolder4();
                convertView = LayoutInflater.from
                        (this.mContext).inflate(R.layout.gridview_item, null, false);
                holder4.image = (ImageView)convertView.findViewById(R.id.grid_view_image);
                convertView.setTag(holder4);

            } else {
                holder4 = (ViewHolder4) convertView.getTag();
            }
            if (this.strs != null) {
                if (holder4.image != null) {
                    if(strs.get(position).equals("a")) {
                        holder4.image.setImageResource(R.drawable.a);
                    }else {
                        holder4.image.setImageResource(R.drawable.b);
                    }

                }
            }

            return convertView;
        }

        private class ViewHolder4 {
            ImageView image;
        }
    }
}

其中setGridViewHeightBasedOnChildren用于重新计算GridView的高度，内部类PullGridAdapter是对应的gridview的适配器，注意listview嵌套GridView时，必须复写GridView：

package com.zlm.pulltorefreshdemo;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.GridView;

public class MyGridView extends GridView{

    public MyGridView(Context context, AttributeSet attrs)
    {
        super(context, attrs);
    }

    public MyGridView(Context context)
    {
        super(context);
    }

    public MyGridView(Context context, AttributeSet attrs, int defStyle)
    {
        super(context, attrs, defStyle);
    }

    @Override
    public void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
    {

        int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2,
                MeasureSpec.AT_MOST);
        super.onMeasure(widthMeasureSpec, expandSpec);
    }

}

需要注意的是悬浮部分应该与Activity_main.xml中隐藏的悬浮部分一致，如下：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical" >
    <TextView 
            android:layout_width="fill_parent"
                android:layout_height="45dp"
                android:id="@+id/header"
                android:text="悬浮部分"
                android:textSize="16sp"
                android:gravity="center"
                android:background="@color/pink"/>
LinearLayout>

最后上图：

打开应用

悬浮条

上拉刷新

刷新完毕

上代码：demo.rar