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  • android 实现QQ好友列表

    在某些Android开发群里，看到有些新手问怎么实现QQ好友列表，其实网上一搜挺多的。接触Android，也才一年的时间，大部分时间花在工作上（解bug。。。），界面上开发很少参与。自己维护的系统应用里，有个ExpandableListView的界面（其实android例子APIDemo也有类似的例子）就在这里写个Demo供新手参考。        ExpandableListView的用法：难点就是重写BaseExpandableListAdapter及提供的数据源。

            下面看看继承BaseExpandableListAdapter的适配器：

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    <SPAN xmlns="http://www.w3.org/1999/xhtml">package com.xyz.expande;
      
    import java.util.List;
      
    import android.app.AlertDialog;
    import android.content.Context;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.BaseExpandableListAdapter;
    import android.widget.ImageView;
    import android.widget.TextView;
      
    public class ExpandAdapter extends BaseExpandableListAdapter {
      
        private Context mContext;
        private LayoutInflater mInflater = null;
        private String[]   mGroupStrings = null;
        private List<List<Item>>   mData = null;
      
        public ExpandAdapter(Context ctx, List<List<Item>> list) {
            mContext = ctx;
            mInflater = (LayoutInflater) mContext
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            mGroupStrings = mContext.getResources().getStringArray(R.array.groups);
            mData = list;
        }
      
        public void setData(List<List<Item>> list) {
            mData = list;
        }
      
        @Override
        public int getGroupCount() {
            // TODO Auto-generated method stub
            return mData.size();
        }
      
        @Override
        public int getChildrenCount(int groupPosition) {
            // TODO Auto-generated method stub
            return mData.get(groupPosition).size();
        }
      
        @Override
        public List<Item> getGroup(int groupPosition) {
            // TODO Auto-generated method stub
            return mData.get(groupPosition);
        }
      
        @Override
        public Item getChild(int groupPosition, int childPosition) {
            // TODO Auto-generated method stub
            return mData.get(groupPosition).get(childPosition);
        }
      
        @Override
        public long getGroupId(int groupPosition) {
            // TODO Auto-generated method stub
            return groupPosition;
        }
      
        @Override
        public long getChildId(int groupPosition, int childPosition) {
            // TODO Auto-generated method stub
            return childPosition;
        }
      
        @Override
        public boolean hasStableIds() {
            // TODO Auto-generated method stub
            return false;
        }
      
        @Override
        public View getGroupView(int groupPosition, boolean isExpanded,
                View convertView, ViewGroup parent) {
            // TODO Auto-generated method stub
            if (convertView == null) {
                convertView = mInflater.inflate(R.layout.group_item_layout, null);
            }
            GroupViewHolder holder = new GroupViewHolder();
            holder.mGroupName = (TextView) convertView
                    .findViewById(R.id.group_name);
            holder.mGroupName.setText(mGroupStrings[groupPosition]);
            holder.mGroupCount = (TextView) convertView
                    .findViewById(R.id.group_count);
            holder.mGroupCount.setText("[" + mData.get(groupPosition).size() + "]");
            return convertView;
        }
      
        @Override
        public View getChildView(int groupPosition, int childPosition,
                boolean isLastChild, View convertView, ViewGroup parent) {
            // TODO Auto-generated method stub
            if (convertView == null) {
                convertView = mInflater.inflate(R.layout.child_item_layout, null);
            }
            ChildViewHolder holder = new ChildViewHolder();
            holder.mIcon = (ImageView) convertView.findViewById(R.id.img);
            holder.mIcon.setBackgroundResource(getChild(groupPosition,
                    childPosition).getImageId());
            holder.mChildName = (TextView) convertView.findViewById(R.id.item_name);
            holder.mChildName.setText(getChild(groupPosition, childPosition)
                    .getName());
            holder.mDetail = (TextView) convertView.findViewById(R.id.item_detail);
            holder.mDetail.setText(getChild(groupPosition, childPosition)
                    .getDetail());
            return convertView;
        }
      
        @Override
        public boolean isChildSelectable(int groupPosition, int childPosition) {
            // TODO Auto-generated method stub
            <SPAN style="COLOR: #cc0000">/*很重要：实现ChildView点击事件，必须返回true*/
    </SPAN>        return true;
        }
      
        private class GroupViewHolder {
            TextView mGroupName;
            TextView mGroupCount;
        }
      
        private class ChildViewHolder {
            ImageView mIcon;
            TextView mChildName;
      
    </LinearLayout></SPAN></SPAN>


            TextView mDetail;
        }

    }
    </SPAN>[/mw_shl_code]

    里面用到的有两个布局，GroupView（子list没展开的view）如图：  
    <IGNORE_JS_OP>




    布局group_item_layout.xml如下:

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    <SPAN xmlns="http://www.w3.org/1999/xhtml"><SPAN xmlns="http://www.w3.org/1999/xhtml"><?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="?android:attr/listPreferredItemHeight"
        android:orientation="horizontal" >
      
        <TextView
            android:id="@+id/group_name"
            android:layout_width="wrap_content"
            android:layout_height="?android:attr/listPreferredItemHeight"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:layout_marginLeft="35dip"
            android:gravity="center_vertical"
            android:singleLine="true" />
      
        <TextView
            android:id="@+id/group_count"
            android:layout_width="wrap_content"
            android:layout_height="?android:attr/listPreferredItemHeight"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:layout_marginLeft="5dip"
            android:gravity="center_vertical"
            android:singleLine="true"/>
      
    </LinearLayout></SPAN></SPAN>



    另外一个就是ChildView，本例仿QQ好友列表，如图：
    <IGNORE_JS_OP>




    布局child_item_layout.xml如下：

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    <SPAN xmlns="http://www.w3.org/1999/xhtml"><SPAN xmlns="http://www.w3.org/1999/xhtml"><?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:minHeight="@dimen/min_Height"
        <SPAN style="COLOR: #ff0000">android:descendantFocusability="blocksDescendants"
    </SPAN>    android:orientation="horizontal" >
      
        <ImageButton
            android:id="@+id/img"
            android:layout_width="@dimen/image_width"
            android:layout_height="@dimen/image_width"
            android:layout_marginLeft="2dip"
            android:layout_marginRight="10dip"
            android:layout_gravity="center_vertical" />
      
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:descendantFocusability="blocksDescendants"
            android:orientation="vertical" >
      
            <TextView
                android:id="@+id/item_name"
                android:layout_width="wrap_content"
                android:layout_height="0.0dip"
                android:gravity="center_vertical"
                android:layout_weight="1" />
      
            <TextView
                android:id="@+id/item_detail"
                android:layout_width="wrap_content"
                android:layout_height="0.0dip"
                android:gravity="center_vertical"
                android:singleLine="true"
                android:ellipsize="end"
                android:layout_weight="1" />
              
        </LinearLayout>
      
    </LinearLayout></SPAN></SPAN>




    适配器弄好了，ExpandableListView就用系统的，现在只剩下显示的问题啦

    先来几张效果图：

    <IGNORE_JS_OP>

        <IGNORE_JS_OP>



    <IGNORE_JS_OP>

       <IGNORE_JS_OP>



    主Activity如下：

    onChildClick

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    <SPAN xmlns="http://www.w3.org/1999/xhtml"><SPAN xmlns="http://www.w3.org/1999/xhtml">package com.xyz.expande;
      
    import java.util.ArrayList;
    import java.util.List;
      
    import android.app.Activity;
    import android.app.AlertDialog;
    import android.content.DialogInterface;
    import android.content.DialogInterface.OnClickListener;
    import android.os.Bundle;
    import android.view.View;
    import android.view.ViewGroup.LayoutParams;
    import android.widget.ExpandableListView;
    import android.widget.ExpandableListView.OnChildClickListener;
      
    public class HomeActivity extends Activity implements OnChildClickListener {
      
        private ExpandableListView mListView = null;
        private ExpandAdapter mAdapter = null;
        private List<List<Item>> mData = new ArrayList<List<Item>>();
      
        private int[] mGroupArrays = new int[] { 
                R.array.tianlongbabu,
                R.array.shediaoyingxiongzhuan, 
                R.array.shendiaoxialv };
      
        private int[] mDetailIds = new int[] { 
                R.array.tianlongbabu_detail,
                R.array.shediaoyingxiongzhuan_detail, 
                R.array.shendiaoxialv_detail };
      
        private int[][] mImageIds = new int[][] {
                { R.drawable.img_00, 
                  R.drawable.img_01, 
                  R.drawable.img_02 },
                { R.drawable.img_10, 
                  R.drawable.img_11, 
                  R.drawable.img_12,
                  R.drawable.img_13, 
                  R.drawable.img_14, 
                  R.drawable.img_15,
                  R.drawable.img_16 },
                { R.drawable.img_20,
                  R.drawable.img_21 } };
      
        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            initData();
            mListView = new ExpandableListView(this);
            mListView.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,
                    LayoutParams.FILL_PARENT));
            setContentView(mListView);
              
            mListView.setGroupIndicator(getResources().getDrawable(
                    R.drawable.expander_floder));
            mAdapter = new ExpandAdapter(this, mData);
            mListView.setAdapter(mAdapter);
            mListView
                    .setDescendantFocusability(ExpandableListView.FOCUS_AFTER_DESCENDANTS);
            mListView.setOnChildClickListener(this);
        }
      
        <SPAN style="COLOR: #ff0000">/*
         * ChildView 设置 布局很可能onChildClick进不来，要在 ChildView layout 里加上
         * android:descendantFocusability="blocksDescendants",
         * 还有isChildSelectable里返回true
         */
    </SPAN>    @Override
        public boolean onChildClick(ExpandableListView parent, View v,
                int groupPosition, int childPosition, long id) {
            // TODO Auto-generated method stub
            Item item = mAdapter.getChild(groupPosition, childPosition);
            new AlertDialog.Builder(this)
                    .setTitle(item.getName())
                    .setMessage(item.getDetail())
                    .setIcon(android.R.drawable.ic_menu_more)
                    .setNegativeButton(android.R.string.cancel,
                            new OnClickListener() {
                                @Override
                                public void onClick(DialogInterface dialog,
                                        int which) {
                                    // TODO Auto-generated method stub
      
                                }
                            }).create().show();
            return true;
        }
      
        private void initData() {
            for (int i = 0; i < mGroupArrays.length; i++) {
                List<Item> list = new ArrayList<Item>();
                String[] childs = getStringArray(mGroupArrays<I>);
                String[] details = getStringArray(mDetailIds<I>);
                for (int j = 0; j < childs.length; j++) {
                    Item item = new Item(mImageIds<I>[j], childs[j], details[j]);
                    list.add(item);
                }
                mData.add(list);
            }
        }
      
        private String[] getStringArray(int resId) {
            return getResources().getStringArray(resId);
        }
      
    }</SPAN></SPAN>




    这这个demo的时候，想实现ChildView的点击事件，实现接口onChildClick，发现不进来，很尴尬。。。最后还是在网上找到答案了，第一，在适配器里isChildSelectable 必须返回true，第二，ChildView布局child_item_layout.xml最外层的layout设置个属性

    细心的同学会发现 Item 是啥？也贴出来吧

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    package com.xyz.expande;
      
    public class Item {
          
        private int resId;
        private String name;
        private String detail;
          
        public Item(int resId, String name, String detail) {
            this.resId  = resId;
            this.name   = name;
            this.detail = detail;
        }
          
        public void setImageId(int resId) {
            this.resId  = resId;
        }
          
        public int getImageId() {
            return resId;
        }
          
        public void setName(String name) {
            this.name   = name;
        }
          
        public String getName() {
            return name;
        }
          
        public void setDetail(String detail) {
            this.detail = detail;
        }
          
        public String getDetail() {
            return detail;
        }
          
        public String toString() {
            return "Item[" + resId + ", " + name + ", " + detail + "]";
        }
      
    }



    源码下载： <IGNORE_JS_OP> ExpandeList.zip (670.11 KB, 下载次数: 988)

    http://www.eoeandroid.com/forum.php?mod=misc&action=attachcredit&aid=81469&formhash=2f2ef89c

    原文：http://blog.csdn.net/zhouyuanjing/article/details/8254421
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  • 原文地址：https://www.cnblogs.com/lixiaolun/p/3474536.html
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