android 實現QQ好友列表（擴展listview:ExpandableListView）

時間 2019-12-14

標籤 android 實現好友列表擴展 listview expandablelistview 欄目 Android 简体版

原文原文鏈接

某些android開發羣裏，看到有些新手問怎麼實現QQ好友列表，其實網上一搜挺多的。接觸Android，也才一年的時間，大部分時間花在工做上（解bug。。。），界面上開發不多參與。本身維護的系統應用裏，有個ExpandableListView的界面（其實android例子APIDemo也有相似的例子）就在這裏寫個Demo供新手參考。 html

ExpandableListView的用法：難點就是重寫BaseExpandableListAdapter及提供的數據源。 java

下面看看繼承BaseExpandableListAdapter的適配器： android

[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：實現ChildView點擊事件，必須返回true*/
 return true;
 }

 private class GroupViewHolder {
 TextView mGroupName;
 TextView mGroupCount;
 }

 private class ChildViewHolder {
 ImageView mIcon;
 TextView mChildName;
 TextView mDetail;
 }

}

 裏面用到的有兩個佈局，GroupView（子list沒展開的view）如圖：
佈局group_item_layout.xml以下: app

另一個就是ChildView，本例仿QQ好友列表，如圖：佈局

哈哈，熟悉吧。佈局child_item_layout.xml以下： ui

[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>
 適配器弄好了，ExpandableListView就用系統的，如今只剩下顯示的問題啦
 先來幾張效果圖： this

主Activity以下： spa

onChildClick xml

[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 設置佈局極可能onChildClick進不來，要在 ChildView layout 里加上
 * android:descendantFocusability="blocksDescendants",
 * 還有isChildSelectable裏返回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);
 }

}
 這這個demo的時候，想實現ChildView的點擊事件，實現接口onChildClick，發現不進來，很尷尬。。。最後仍是在網上找到答案了，第一，在適配器裏isChildSelectable 必須返回true，第二，ChildView佈局child_item_layout.xml最外層的layout設置個屬性：

[java]
android:descendantFocusability="blocksDescendants"
上面已標示紅色的啦。
細心的同窗會發現 Item 是啥？也貼出來吧

[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 + "]"; } }

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