Question

我对android很新，所以任何人都可以非常轻松地解释如何通过单击父级来使childList动态化吗？

我的问题：我在expandablelistview中有一些静态父级。我的意图是，当我选择一个父母看到它的孩子时，孩子将动态地形成数据库并且它们将是可导航的（我想看到更多细节或者去另一个页面。）

我分三步完成了静态孩子。

使用expandablelistview创建XML文件。
在主java调用适配器
使用expandablelistview绑定适配器。创建自定义适配器。

适配器如下：

package com.example.eschool_only_accrdion_straggle;

import android.R.color;
import android.content.Context;
import android.graphics.Color;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;

public class My_custom_adapter extends BaseExpandableListAdapter {

    private Context context;

    String [] parentList={"Summer Fruit", "Winter Fruit", "Hard fruit", "Watery Fruit"};
    // String [][] childList={{"Lychy", "Mango"},{"Banana"},{"Pomy Granade"},{"pani Fruit"}};


    public My_custom_adapter(Context context) {
        this.context = context;
    }

    // In Here 1st Parameter is for PARENT and 2nd one is for CHILD

    @Override
    public Object getChild(int groupPosition, int childPosition) { 
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public long getChildId(int groupPosition, int childPosition) {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public View getChildView(int groupPosition, int childPosition, 
            boolean arg2, View arg3, ViewGroup arg4) {

        TextView TxtV_child=new TextView(context);
        TxtV_child.setText(childList[groupPosition][childPosition]);
        TxtV_child.setPadding(35, 0, 0, 0);
        TxtV_child.setTextColor(Color.CYAN);
        TxtV_child.setTextSize(17);
        return TxtV_child;
    }

    @Override
    public int getChildrenCount(int groupPosition) {

        return childList[groupPosition].length;
    }

    @Override
    public Object getGroup(int groupPosition) {

        return groupPosition;
    }

    @Override
    public int getGroupCount() {
        // TODO Auto-generated method stub
        return parentList.length;
    }

    @Override
    public long getGroupId(int groupPosition) {
        // TODO Auto-generated method stub
        return groupPosition;
    }

    @Override
    public View getGroupView(int groupPosition, boolean childPosition, View arg2, ViewGroup arg3) {
        TextView TxtV_Parent=new TextView(context);
        TxtV_Parent.setText(parentList[groupPosition]);
        TxtV_Parent.setPadding(5, 5, 0, 5);
        TxtV_Parent.setTextColor(Color.MAGENTA);
        TxtV_Parent.setTextSize(25);
        return TxtV_Parent;
    }

    @Override
    public boolean hasStableIds() {
        // TODO Auto-generated method stub
        return false;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        // TODO Auto-generated method stub
        return true;
    }

}

Answer 1

创建一个扩展“ExpandableListActivity”的活动，例如这个tutorial

初始化您的数据

private ArrayList<String> groups = new ArrayList<String>() ;
private ArrayList<ArrayList<String>> children; 
private NewAdapter mNewAdapter = null;

public void onCreate(Bundle savedInstanceState) {

    // ....
    groups.add("Summer Fruit");
    groups.add("Winter Fruit");
    groups.add("Hard fruit");
    groups.add("Watery Fruit");

    children = new ArrayList<ArrayList<String>>();

    ArrayList<String> a = new ArrayList<String>();
    a.add("Lychy");
    a.add("Mango");
    children.add(a);

    a = new ArrayList<String>();
    a.add("Banana");
    children.add(a);

    a = new ArrayList<String>();
    a.add("Pomy Granade");
    children.add(a);


    a = new ArrayList<String>();
    a.add("pani Fruit");
    children.add(a);

    mNewAdapter = new NewAdapter(groups, children);
    mNewAdapter.setInflater((LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE),this);
    getExpandableListView().setAdapter(mNewAdapter);
    int cpt = mNewAdapter.getGroupCount();
    for(int i = 0; i < cpt; i++ ){
        getExpandableListView().expandGroup(i);
    }
}

然后务必将以下方法覆盖到您的活动中

@Override
public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) {
    // Do here what you need to do when a child is selected
    return true;
}

添加最后添加适配器

class NewAdapter extends BaseExpandableListAdapter{

    public LayoutInflater minflater;
    public Activity activity;
    public ArrayList<String> groups;
    public ArrayList<ArrayList<String>> points;

    public NewAdapter(ArrayList<String> groups, ArrayList<ArrayList<String>> points){
        this.groups = groups;
        this.points = points;
    }

    public void setInflater(LayoutInflater mInflater, Activity act) {
        this.minflater = mInflater;
        activity = act;
    }

    @Override
    public void notifyDataSetChanged() {
        super.notifyDataSetChanged();
    }

    @Override
    public Object getChild(int groupPosition, int childPosition) {
        return null;
    }

    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return 0;
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return ((ArrayList<String>) points.get(groupPosition)).size();
    }

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

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

    @Override
    public void onGroupCollapsed(int groupPosition) {
        super.onGroupCollapsed(groupPosition);
    }

    @Override
    public long getGroupId(int groupPosition) {
        return 0;
    }

    @Override
    public View getGroupView(int groupPosition, boolean childPosition, View arg2, ViewGroup arg3) {
        // ...
        return v;
    }

    @Override
    public boolean hasStableIds() {
        return false;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }

    @Override
    public View getChildView(int groupPosition, final int childPosition, boolean isLastChild, View v, ViewGroup parent) {
        // ....
        return v;
    }
}

在适配器中，确保isChildSelectable（int groupPosition，int childPosition）返回“true”。

如何通过单击android中的父节点在expandablelistview中动态获取子元素

1 个答案: