android 实现QQ好友列表（扩展listview:ExpandableListView）-白红宇

android 实现QQ好友列表（扩展listview:ExpandableListView）

阅读量：5920 次

发布时间：2019-06-19

本文共 10549 字，大约阅读时间需要 35 分钟。

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：

[java]

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

/*很重要：实现ChildView点击事件，必须返回true*/

return true;

}

private class GroupViewHolder {

TextView mGroupName;

TextView mGroupCount;

}

private class ChildViewHolder {

ImageView mIcon;

TextView mChildName;

TextView mDetail;

}

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

布局group_item_layout.xml如下:

[java]

<?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>

另外一个就是ChildView，本例仿QQ好友列表，如图：

哈哈，熟悉吧。布局child_item_layout.xml如下：

[java]

<?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"

android:descendantFocusability="blocksDescendants"

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>

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：

主Activity如下：

onChildClick

[java]

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);

}

/*

* 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

@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);

}

}

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：

[java]

android:descendantFocusability="blocksDescendants"

上面已标示红色的啦。

细心的同学会发现 Item 是啥？也贴出来吧

[java]

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 + "]";

}

转载于:https://my.oschina.net/zhangjie830621/blog/108060

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