分组列表视图(ExpandableListView)
和ListView不同的是它是一个两级的滚动列表视图,每一个组可以展开,显示一些子项,类似于
QQ列表,这些项目来至于ExpandableListAdapter的子类,也就是说,要实现向里面添加项目,必
须写一个子类实现ExpandableListAdapter的接口或者使用系统为我们实现在子类
常用属性
1. android:childDivider 指定各组内子类表项之间的分隔条,
2. android:childIndicator 显示在子列表旁边的Drawable对象
3. android:childIndicatorLeft 子列表项指示符的左边约束位置
4. android:childIndicatorRight 子列表项指示符的右边约束位置
5. android:groupIndicator 显示在组列表旁边的Drawable对象
6. android:indicatorLeft 组列表项指示器的左边约束位置
7. android:indicatorRight 组列表项指示器的右边约束位置
一般适用于ExpandableListView的Adapter都要继承BaseExpandableListAdapter这个类，
并且必须重载getGroupView和getChildView这两个最为重要的方法。
当扩展BaseExpandableListAdapter时，要实现全部方法，关键是实现其中的四个方法。
1、首相activity_main.xml布局搭建
1 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 2 android:layout_width="match_parent" 3 android:layout_height="match_parent"> 4 5 <ExpandableListView 6 android:layout_width="wrap_content" 7 android:layout_height="wrap_content" 8 android:id="@+id/elv"/> 9 10 </RelativeLayout>
activity_main.xml
2、然后是搭建QQ分组的布局
1 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 2 android:layout_width="match_parent" 3 android:layout_height="match_parent" 4 android:orientation="vertical" > 5 6 <TextView 7 android:id="@+id/groupName" 8 android:layout_width="wrap_content" 9 android:layout_height="wrap_content" 10 android:textSize="20sp" 11 android:text="分组名称" /> 12 13 <TextView 14 android:id="@+id/groupOnline" 15 android:layout_alignParentRight="true" 16 android:layout_width="wrap_content" 17 android:layout_height="wrap_content" 18 android:text="0/8" /> 19 20 </RelativeLayout>
item_group.xml
3、再搭建分组中各选项的布局（QQ联系人，包括头像，昵称，签名）
这里由于引用了外部的自定义的控件，所以这里包名加类名
1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 2 android:layout_width="match_parent" 3 android:layout_height="match_parent" 4 android:layout_gravity="center_vertical" 5 android:orientation="horizontal" > 6 7 <com.test.lesson7_expandablelistview.CircleImageView 8 android:id="@+id/img" 9 android:layout_width="80dp" 10 android:layout_height="80dp" 11 android:src="@drawable/ic_launcher" /> 12 13 <LinearLayout 14 android:layout_width="match_parent" 15 android:layout_height="wrap_content" 16 android:layout_marginLeft="10dp" 17 android:orientation="vertical" > 18 19 <TextView 20 android:id="@+id/nickName" 21 android:layout_width="match_parent" 22 android:layout_height="wrap_content" 23 android:text="昵称" 24 android:textSize="18sp" /> 25 26 <LinearLayout 27 android:layout_width="match_parent" 28 android:layout_height="wrap_content" 29 android:layout_marginTop="10dp" 30 android:orientation="horizontal" > 31 32 <TextView 33 android:id="@+id/online" 34 android:layout_width="wrap_content" 35 android:layout_height="wrap_content" 36 android:text="[在线]" /> 37 38 <TextView 39 android:id="@+id/sign" 40 android:layout_width="wrap_content" 41 android:layout_height="wrap_content" 42 android:layout_marginLeft="10dp" 43 android:text="我要飞的更高~" /> 44 </LinearLayout> 45 </LinearLayout> 46 47 </LinearLayout>
item_child.xml
4、圆角图片形状
在res/values中建circle_attr.xml
1 <resources> 2 3 <declare-styleable name="CircularImage"> 4 <attr name="border_width" format="dimension" /> 5 <attr name="border_color" format="color" /> 6 </declare-styleable> 7 8 </resources>
5、然后新建一个CircleImageView继承ImageView
此处自定义控件是在GitHub上下载
1 public class CircleImageView extends ImageView {
2 private static final Xfermode MASK_XFERMODE;
3 private Bitmap mask;
4 private Paint paint;
5 private int mBorderWidth = 10;
6 private int mBorderColor = Color.parseColor("#f2f2f2");
7 private boolean useDefaultStyle = false;
8
9 static {
10 PorterDuff.Mode localMode = PorterDuff.Mode.DST_IN;
11 MASK_XFERMODE = new PorterDuffXfermode(localMode);
12 }
13
14 public CircleImageView(Context context) {
15 super(context);
16 }
17
18 public CircleImageView(Context context, AttributeSet attrs) {
19 this(context, attrs, 0);
20 }
21
22 public CircleImageView(Context context, AttributeSet attrs, int defStyle) {
23 super(context, attrs, defStyle);
24 TypedArray a = context.obtainStyledAttributes(attrs,
25 R.styleable.CircularImage);
26 mBorderColor = a.getColor(R.styleable.CircularImage_border_color,
27 mBorderColor);
28 final int def = (int) (2 * context.getResources().getDisplayMetrics().density + 0.5f);
29 mBorderWidth = a.getDimensionPixelOffset(
30 R.styleable.CircularImage_border_width, def);
31 a.recycle();
32 }
33
34 private void useDefaultStyle(boolean useDefaultStyle) {
35 this.useDefaultStyle = useDefaultStyle;
36 }
37
38 @Override
39 protected void onDraw(Canvas canvas) {
40 if (useDefaultStyle) {
41 super.onDraw(canvas);
42 return;
43 }
44 final Drawable localDraw = getDrawable();
45 if (localDraw == null) {
46 return;
47 }
48 if (localDraw instanceof NinePatchDrawable) {
49 return;
50 }
51 if (this.paint == null) {
52 final Paint localPaint = new Paint();
53 localPaint.setFilterBitmap(false);
54 localPaint.setAntiAlias(true);
55 localPaint.setXfermode(MASK_XFERMODE);
56 this.paint = localPaint;
57 }
58 final int width = getWidth();
59 final int height = getHeight();
60 int layer = canvas.saveLayer(0.0F, 0.0F, width, height, null, 31);
61 localDraw.setBounds(0, 0, width, height);
62 localDraw.draw(canvas);
63 if ((this.mask == null) || (this.mask.isRecycled())) {
64 this.mask = createOvalBitmap(width, height);
65 }
66 canvas.drawBitmap(this.mask, 0.0F, 0.0F, this.paint);
67 canvas.restoreToCount(layer);
68 drawBorder(canvas, width, height);
69 }
70
71 private void drawBorder(Canvas canvas, final int width, final int height) {
72 if (mBorderWidth == 0) {
73 return;
74 }
75 final Paint mBorderPaint = new Paint();
76 mBorderPaint.setStyle(Paint.Style.STROKE);
77 mBorderPaint.setAntiAlias(true);
78 mBorderPaint.setColor(mBorderColor);
79 mBorderPaint.setStrokeWidth(mBorderWidth);
80 canvas.drawCircle(width / 2, height / 2, (width - mBorderWidth) / 2,
81 mBorderPaint);
82 canvas = null;
83 }
84
85 public Bitmap createOvalBitmap(final int width, final int height) {
86 Bitmap.Config localConfig = Bitmap.Config.ARGB_8888;
87 Bitmap localBitmap = Bitmap.createBitmap(width, height, localConfig);
88 Canvas localCanvas = new Canvas(localBitmap);
89 Paint localPaint = new Paint();
90 final int padding = (mBorderWidth - 3) > 0 ? mBorderWidth - 3 : 1;
91
92 RectF localRectF = new RectF(padding, padding, width - padding, height
93 - padding);
94 localCanvas.drawOval(localRectF, localPaint);
95
96 return localBitmap;
97 }
98
99 }
CircleImageView
6、创建Group类
1 public class Group {
2 //分组名
3 public String groupName;
4 //有很多User
5 public List<User> list;
6
7 public Group(String groupName){
8 this.groupName = groupName;
9 list = new ArrayList<User>();
10 }
11 //添加User
12 public void addUser(User user){
13 list.add(user);
14 }
15
16 //获取某个分组中User的数量
17 public int getChildCount() {
18 return list.size();
19 }
20 //获取某个分组中User在线的数量
21 public int getOnlineCount(){
22 int sum = 0;
23 for (User user : list) {
24 if(user.isOnline()){
25 sum++;
26 }
27 }
28 return sum;
29 }
30 //获取分组中某个孩子
31 public User getChild(int childPosition) {
32 return list.get(childPosition);
33 }
34
35
36 }
Group.java
7、创建User类
1 public class User {
2 private int imgId;
3 private String nickName;
4 private boolean isOnline;
5 private String sign;
6
7
8 public User() {
9 super();
10 }
11 public User(int imgId, String nickName, boolean isOnline, String sign) {
12 super();
13 this.imgId = imgId;
14 this.nickName = nickName;
15 this.isOnline = isOnline;
16 this.sign = sign;
17 }
18
19 public int getImgId() {
20 return imgId;
21 }
22 public void setImgId(int imgId) {
23 this.imgId = imgId;
24 }
25 public String getNickName() {
26 return nickName;
27 }
28 public void setNickName(String nickName) {
29 this.nickName = nickName;
30 }
31 public boolean isOnline() {
32 return isOnline;
33 }
34 public void setOnline(boolean isOnline) {
35 this.isOnline = isOnline;
36 }
37 public String getSign() {
38 return sign;
39 }
40 public void setSign(String sign) {
41 this.sign = sign;
42 }
43
44
45
46
47 }
User
8、设置适配器
1 public class GroupAdapter extends BaseExpandableListAdapter{
2
3 Context context;
4 List<Group> list;
5
6 public GroupAdapter(Context context, List<Group> list) {
7 this.context = context;
8 this.list = list;
9 }
10
11 @Override
12 public View getGroupView(int groupPosition, boolean isExpanded,
13 View convertView, ViewGroup parent) {
14 GroupHolder holder;
15 if(convertView == null){
16 convertView = View.inflate(context, R.layout.item_grouplayout, null);
17 holder = new GroupHolder(convertView);
18 convertView.setTag(holder);
19 }else{
20 holder = (GroupHolder) convertView.getTag();
21 }
22 //设置数据
23 Group group = getGroup(groupPosition);
24 holder.groupName.setText(group.groupName);
25 holder.groupOnline.setText(group.getOnlineCount()+"/"+getChildrenCount(groupPosition));
26
27 return convertView;
28 }
29
30 @Override
31 public View getChildView(int groupPosition, int childPosition,
32 boolean isLastChild, View convertView, ViewGroup parent) {
33 ChildHolder holder;
34 if(convertView == null){
35 convertView = View.inflate(context, R.layout.item_childlayout, null);
36 holder = new ChildHolder(convertView);
37 convertView.setTag(holder);
38 }else{
39 holder = (ChildHolder) convertView.getTag();
40 }
41 //设置数据
42 User user = getGroup(groupPosition).getChild(childPosition);
43 holder.img.setImageResource(user.getImgId());
44 holder.nickName.setText(user.getNickName());
45 holder.online.setText(user.isOnline()?"[在线]":"[离线]");
46 holder.sign.setText(user.getSign());
47
48 return convertView;
49
50 }
51
52 class GroupHolder{
53 TextView groupName;
54 TextView groupOnline;
55
56 public GroupHolder(View convertView){
57 groupName = (TextView) convertView.findViewById(R.id.groupName);
58 groupOnline = (TextView) convertView.findViewById(R.id.groupOnline);
59
60 }
61 }
62 class ChildHolder{
63 ImageView img;
64 TextView nickName;
65 TextView online;
66 TextView sign;
67
68 public ChildHolder(View convertView){
69 img = (ImageView) convertView.findViewById(R.id.img);
70 nickName = (TextView) convertView.findViewById(R.id.nickName);
71 online = (TextView) convertView.findViewById(R.id.online);
72 sign = (TextView) convertView.findViewById(R.id.sign);
73
74 }
75
76 }
77
78 @Override
79 public int getGroupCount() {
80 return list.size();
81 }
82
83 @Override
84 public int getChildrenCount(int groupPosition) {
85 return list.get(groupPosition).getChildCount();
86 }
87
88 @Override
89 public Group getGroup(int groupPosition) {
90 return list.get(groupPosition);
91 }
92
93 @Override
94 public User getChild(int groupPosition, int childPosition) {
95 return list.get(groupPosition).getChild(childPosition);
96 }
97
98 @Override
99 public long getGroupId(int groupPosition) {
100 return groupPosition;
101 }
102
103 @Override
104 public long getChildId(int groupPosition, int childPosition) {
105 return childPosition;
106 }
107
108 @Override
109 public boolean hasStableIds() {
110 return true;
111 }
112
113 @Override
114 public boolean isChildSelectable(int groupPosition, int childPosition) {
115 return true;
116 }
117
118 }
GroupAdapter
9、MainActivity.java中将所有组件找到，初始化数据源，并给ListView设置适配器
1 public class MainActivity extends Activity {
2
3 ExpandableListView elv;
4 private List<Group> list = new ArrayList<Group>();
5 int[] img = new int[6];
6
7 @Override
8 protected void onCreate(Bundle savedInstanceState) {
9 super.onCreate(savedInstanceState);
10 setContentView(R.layout.activity_main);
11 initData();
12 elv = (ExpandableListView) findViewById(R.id.elv);
13 GroupAdapter adapter = new GroupAdapter(getBaseContext(), list);
14 elv.setAdapter(adapter);
15
16 }
17
18 private void initData() {
19 for (int i = 0; i < img.length; i++) {
20 try {
21 img[i] = R.drawable.class.getField("img0"+(i+1)).getInt(null);
22 } catch (Exception e) {
23 e.printStackTrace();
24 }
25 }
26
27 Group group1 = new Group("贵圈好乱");
28 group1.addUser(new User(img[0], "张翰", true, "我爱娜扎！"));
29 group1.addUser(new User(img[1], "郑爽", false, "妈蛋，要么瘦，要么死！"));
30 group1.addUser(new User(img[2], "胡彦斌", true, "其实我只是长得抽象了"));
31 group1.addUser(new User(img[5], "撒贝宁", true, "子怡当年没选择我是个美丽的错误"));
32 group1.addUser(new User(img[3], "杨幂", false, "其实我跟恺威已经离婚了，现在跟李易峰在一起，就酱~"));
33
34 Group group2 = new Group("超星星");
35 group2.addUser(new User(img[4], "林志炫", true, "其实我的小肚子都是唱歌导致的，哈哈哈"));
36
37 list.add(group1);
38 list.add(group2);
39
40 }
41
42
43 }
MainActivity.java
运行效果有点渣渣。请忽略：
时间： 2024-10-12 17:11:44