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...

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();
    }
   android 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:www.cppcns.comtext="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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