Android 二级菜单---------ExpandableListView

1、分析二级菜单内容

从上面图可见 ，

一级菜单是一个String

二级菜单是imagerView 、String 

我们从第二级写数据开始，String类型   int 类型

public class Chile {
    private String name;
    private int img;

    public String getName() {
        return name;
    }

    public int getImg() {
        return img;
    }

    public Chile(String name, int img) {
        this.name = name;
        this.img = img;
    }   
}

然后在写第一级  String类型  还有 集合（这个就是存放着多个子条目）

public class Group {

    private  String  group_str;
    private ArrayList<Chile> data;

    public Group(String group_str, ArrayList<Chile> data) {
        this.group_str = group_str;
        this.data = data;
    }

    public String getGroup_str() {
        return group_str;
    }

    public ArrayList<Chile> getData() {
        return data;
    }
    public Group() {
        super();
    }
}

2、适配所有

public class Expand_Adapter extends BaseExpandableListAdapter {

    private Context context;
   
    private ArrayList<Group> data;

    public Expand_Adapter(Context context, ArrayList<Group> data) {
        super();
        this.context = context;
        this.data = data;
    }


    /**
     * @param groupPosition 父标题
     * @param childPosition 子标题
     * @return
     */
    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return data.get(groupPosition).getData().get(childPosition);
    }

    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return childPosition;
    }


    /**
     * 获取子布局的视图
     *
     * @param groupPosition
     * @param childPosition
     * @param isLastChild
     * @param convertView
     * @param parent
     * @return
     */
    @Override
    public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {

        Chile chile = data.get(groupPosition).getData().get(childPosition);
        View view = View.inflate(context, R.layout.layout_chile, null);
        TextView textView = view.findViewById(R.id.child);
        ImageView imageView = view.findViewById(R.id.child_img);
        textView.setText(chile.getName());
        imageView.setBackgroundResource(chile.getImg());

        return view;
    }


    @Override
    public int getChildrenCount(int groupPosition) {
        return data.get(groupPosition).getData().size();
    }


    @Override
    public Object getGroup(int groupPosition) {
        return data.get(groupPosition);
    }

    @Override
    public long getGroupId(int groupPosition) {

        return groupPosition;
    }

    @Override
    public int getGroupCount() {
        return data.size();
    }

//一级标题布局的加载以及图标切换

    @Override

public View getGroupView( int groupPosition , boolean isExpanded , View convertView , ViewGroup parent) { Group group = data.get(groupPosition) ; View view = View. inflate( context , R.layout. layout_group , null) ; TextView textView = view.findViewById(R.id. group) ; textView.setText(group.getGroup_str()) ; ImageView imageView = view.findViewById(R.id. group_image) ; if (isExpanded) { imageView.setBackgroundResource(R.drawable. down) ; } else { imageView.setBackgroundResource(R.drawable. up) ; } return view ; } @Override public boolean isChildSelectable( int groupPosition , int childPosition) { return true; } @Override public boolean hasStableIds() { return false; }}

3、创建、设置

private ExpandableListView expandableListView;
private ArrayList<Group> data = new ArrayList<Group>();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main5);
    expandableListView = (ExpandableListView) findViewById(R.id.expand);
    // 数据准备
    initData();
    expandableListView.setGroupIndicator(null);
    Log.e("ArrayList<Group> data",""+data.size());
    // 设置设配器
    Expand_Adapter adapter = new Expand_Adapter(getApplicationContext(),
            data);
    expandableListView.setAdapter(adapter);
}

4、看看布局怎样的吧

1）、主布局

setContentView(R.layout.activity_main5);

<ExpandableListView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:groupIndicator="@null"
    android:id="@+id/expand"
    >

</ExpandableListView>

2）、

layout_chile.xml

<ImageView
    android:layout_width="20dp"
    android:layout_height="20dp"
    android:id="@+id/child_img"/>

<TextView
    android:id="@+id/child"
    android:textColor="#101010"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="tttttttt"/>

3)、layout_group.xml

<RelativeLayout

 xmlns:android="http://schemas.android.com/apk/res/android" 

  android:layout_width="match_parent"

android :layout_height= "90dp" > <TextView android :id= "@+id/group" android :layout_width= "wrap_content" android :layout_height= "30dp" android :layout_centerVertical= "true" android :layout_marginLeft= "20dp" android :text= " 标题栏 " android :textColor= "#99d70505" /> <ImageView android :id= "@+id/group_image" android :layout_width= "20dp" android :layout_height= "20dp" android :layout_alignParentEnd= "true" android :layout_centerVertical= "true" android :layout_gravity= "end" android :layout_marginRight= "20dp" android :background= "@drawable/up" /> </RelativeLayout>

当你复制完我的代码之后你会发现这个东西怎么高度不会变？？？

什么鬼？？？

慢慢研究，需要的留言。