ExpandListView实现下拉列表案例

ExpandListView实现下拉列表案例,供大家参考,具体内容如下

使用方式与ListView类似,是ListView的一个延申,Group为TextView,子元素为ListView。

效果图:

代码:

实体类:

Group.java

public class Group {     private String gName;     public Group() {     }     public Group(String gName) {         this.gName = gName;     }     public String getName() {         return gName;     }     public void setName(String gName) {         this.gName = gName;     } }

Item.java

public class Item {     private int iId;     private String iName;     public Item() {     }     public Item(int iId, String iName) {         this.iId = iId;         this.iName = iName;     }     public int getId() {         return iId;     }     public String getName() {         return iName;     }     public void setId(int iId) {         this.iId = iId;     }     public void setName(String iName) {         this.iName = iName;     } }

自定义适配器:ExpandableListViewAdapter.java

public class ExpandableListViewAdapter extends BaseExpandableListAdapter {     private Context mContext;     private ArrayList<Group> groupList;     private ArrayList<ArrayList<Item>> itemList;     public ExpandableListViewAdapter(Context context, ArrayList<Group> gData, ArrayList<ArrayList<Item>> iData) {         this.mContext = context;         this.groupList = gData;         this.itemList = iData;     }     //返回Group的个数     @Override     public int getGroupCount() {         return groupList.size();     }     //返回某个Group对应的Item的个数     @Override     public int getChildrenCount(int groupPosition) {         return itemList.get(groupPosition).size();     }     //返回某个Group对象     @Override     public Object getGroup(int groupPosition) {         return groupList.get(groupPosition);     }     //返回某个Item对象     @Override     public Object getChild(int groupPosition, int childPosition) {         return itemList.get(groupPosition).get(childPosition);     }     //返回Group的id     @Override     public long getGroupId(int groupPosition) {         return groupPosition;     }     //返回Item的id     @Override     public long getChildId(int groupPosition, int childPosition) {         return childPosition;     }     @Override     public boolean hasStableIds() {         return false;     }     //获取指定组处的组数据     @Override     public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {         ViewHolderGroup holderGroup = null;         if (convertView == null) {             convertView = LayoutInflater.from(mContext).inflate(R.layout.item_exlist_group,parent,false);             holderGroup = new ViewHolderGroup();             holderGroup.tv_name_group = convertView.findViewById(R.id.tv_group_name);             convertView.setTag(holderGroup);         }else {             holderGroup = (ViewHolderGroup) convertView.getTag();         }         holderGroup.tv_name_group.setText(groupList.get(groupPosition).getName());         return convertView;     }     //获取指定组的数据、指定子列表项处的子列表项数据     @Override     public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {         ViewHolderItem holderItem = null;         if (convertView == null) {             convertView = LayoutInflater.from(mContext).inflate(R.layout.item_exlist_item,parent,false);             holderItem = new ViewHolderItem();             holderItem.iv_img_icon = convertView.findViewById(R.id.img_icon);             holderItem.tv_name_item = convertView.findViewById(R.id.tv_item_name);             convertView.setTag(holderItem);         }else {             holderItem = (ViewHolderItem) convertView.getTag();         }         holderItem.iv_img_icon.setImageResource(itemList.get(groupPosition).get(childPosition).getId());         holderItem.tv_name_item.setText(itemList.get(groupPosition).get(childPosition).getName());         return convertView;     }     //设置子列表是否可选中     @Override     public boolean isChildSelectable(int groupPosition, int childPosition) {         return true;     }     class ViewHolderGroup {         TextView tv_name_group;     }     class ViewHolderItem {         ImageView iv_img_icon;         TextView tv_name_item;     } }

主布局:ExpandableListViewActivity.java

public class ExpandableListViewActivity extends AppCompatActivity {     @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_expandable_list_view);         //View         ExpandableListView exListView = findViewById(R.id.expand_list_person);         //Model         ArrayList<Group> groupList = new ArrayList<>();         ArrayList<ArrayList<Item>> itemList = new ArrayList<>();         groupList.add(new Group("朋友"));         groupList.add(new Group("同事"));         groupList.add(new Group("陌生人"));         //用来存放单个item,下面用三个不同的item集合存放对应分类的item         ArrayList<Item> items = new ArrayList<>();         //朋友         items.add(new Item(R.mipmap.img2, "小莉"));         items.add(new Item(R.mipmap.img7, "小红"));         items.add(new Item(R.mipmap.img8, "小美"));         itemList.add(items);         //同事         items = new ArrayList<>();         items.add(new Item(R.mipmap.img17, "小倩"));         items.add(new Item(R.mipmap.img12, "小雯"));         items.add(new Item(R.mipmap.img13, "小芳"));         itemList.add(items);         //陌生人         items = new ArrayList<>();         items.add(new Item(R.mipmap.img14, "小涵"));         items.add(new Item(R.mipmap.img15, "小蕾"));         items.add(new Item(R.mipmap.img16, "小雪"));         itemList.add(items);         ExpandableListViewAdapter adapter = new ExpandableListViewAdapter(this, groupList, itemList);         exListView.setAdapter(adapter);         //为下拉列表中子元素绑定点击事件         exListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() {             @Override             public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {                 Toast.makeText(getApplicationContext(), "你点击了" + itemList.get(groupPosition).get(childPosition).getName(), Toast.LENGTH_SHORT).show();                 return true;             }         });     } }

activity_expandable_list_view.xml

<?xml version="1.0" encoding="utf-8"?> <RelativeLayout 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:padding="5dp"     tools:context=".MainActivity">     <ExpandableListView         android:id="@+id/expand_list_person"         android:layout_width="match_parent"         android:layout_height="match_parent" /> </RelativeLayout>

item_exlist_group.xml

<?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="match_parent"     android:orientation="horizontal"     android:padding="5dp">     <TextView         android:id="@+id/tv_group_name"         android:layout_width="match_parent"         android:layout_height="56dp"         android:gravity="center_vertical"         android:paddingLeft="30dp"         android:text="AP"         android:textStyle="bold"         android:textSize="20sp" /> </LinearLayout>

item_exlist_item.xml

<?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="match_parent"     android:orientation="horizontal"     android:padding="5dp">     <ImageView         android:id="@+id/img_icon"         android:layout_width="48dp"         android:layout_height="48dp"         android:focusable="false"         android:src="@mipmap/img2" />     <TextView         android:id="@+id/tv_item_name"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_marginLeft="15dp"         android:layout_marginTop="15dp"         android:focusable="false"         android:text="小莉"         android:textSize="18sp" /> </LinearLayout>

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