ExpandableListView的简单使用

1,xml中引入布局ExpandableListView

<?xml version="1.0" encoding="utf-8"?><LinearLayout 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">    <ExpandableListView        android:layout_width="match_parent"        android:layout_height="match_parent"        android:id="@+id/elv_main"></ExpandableListView></LinearLayout>

2,Adapter的编写,继承BaseExpandableListAdapter并实现抽象方法,并对应各个方法填充对应参数。注意一般前面一个id为parentId，后面一个为childId

public class MyExpandableListViewAdapter extends BaseExpandableListAdapter{    private Map<String,List<String>>data=new HashMap<>();    private String[] parentList=new String[]{};    private Context context;    public MyExpandableListViewAdapter(Context context, Map<String, List<String>> data, String[] parentList) {        this.context=context;        this.data=data;        this.parentList=parentList;    }    //  获得父项的数量    @Override    public int getGroupCount() {        return data.size();    }    //  获得某个父项的子项数目    @Override    public int getChildrenCount(int parentPos) {        return data.get(parentList[parentPos]).size();    }    //  获得某个父项    @Override    public Object getGroup(int parentPos) {        return data.get(parentList[parentPos]);    }    //  获得某个父项的某个子项    @Override    public Object getChild(int parentPos, int childPos) {        return data.get(parentList[parentPos]).get(childPos);    }    //  获得某个父项的id    @Override    public long getGroupId(int parentPos) {        return parentPos;    }    //  获得某个父项的某个子项的id    @Override    public long getChildId(int parentPos, int childPos) {        return childPos;    }    //  按函数的名字来理解应该是是否具有稳定的id，这个函数目前一直都是返回false，没有去改动过    @Override    public boolean hasStableIds() {        return false;    }    //  获得父项显示的view    @Override    public View getGroupView(int parentPos, boolean b, View view, ViewGroup viewGroup) {        if (view==null){            LayoutInflater inflater= (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);            view=inflater.inflate(R.layout.parent_item,null);        }        view.setTag(R.layout.parent_item,parentPos);        view.setTag(R.layout.child_item,-1);        TextView text = (TextView) view.findViewById(R.id.parent_title);        text.setText(parentList[parentPos]);        return view;    }    @Override    public View getChildView(int parentPos, int childPos, boolean b, View view, ViewGroup viewGroup) {        if (view == null) {            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);            view = inflater.inflate(R.layout.child_item, null);        }        view.setTag(R.layout.parent_item, parentPos);        view.setTag(R.layout.child_item, childPos);        TextView text = (TextView) view.findViewById(R.id.child_title);        text.setText(data.get(parentList[parentPos]).get(childPos));        text.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                Toast.makeText(context, "点到了内置的textview", Toast.LENGTH_SHORT).show();            }        });        return view;    }    //  子项是否可选中，如果需要设置子项的点击事件，需要返回true    @Override    public boolean isChildSelectable(int i, int i1) {        return true;    }}

3,Activity中引用

public class MainActivity extends AppCompatActivity {    private ExpandableListView elv_main;    private MyExpandableListViewAdapter adapter;    private Map<String,List<String>> data=new HashMap<>();    private String[] parentList=new String[]{"first","second","third"};    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        elv_main=findViewById(R.id.elv_main);        initData();        adapter=new MyExpandableListViewAdapter(this,data,parentList);        elv_main.setAdapter(adapter);    }    private void initData() {        for (int i=0;i<parentList.length;i++){            List<String> list=new ArrayList<>();            for (int j=0;j<8;j++){                list.add("item"+j);            }            data.put(parentList[i],list);        }    }}

到这里就没了，很简单