如何更改 ExpandableListView 子项中按钮的可见性？

Question

My code has an ExpandableListView and each child (schedule) can be deleted via a delete button in the child. I want to use a functionality of "Edit" TextView so that if the user clicks on "Edit" the Delete Buttons will be visible. I tried it on my custom adapter MainAdapter but gives me crashes. Could anyone help me?

MainAdapter.java

package com.example.easyplan;

import android.content.Context;
import android.graphics.Typeface;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.ImageButton;
import android.widget.TextView;

import java.util.HashMap;
import java.util.List;

public class MainAdapter extends BaseExpandableListAdapter {
    private Context _context;
    private List<String> listPlan; // header titles
    // child data in format of header title, child title
    private HashMap<String, List<String>> listScheduleMap;
    ImageButton scheduleDeleteBtn;

    public MainAdapter(Context context, List<String> listDataHeader,
                       HashMap<String, List<String>> listChildData) {
        this._context = context;
        this.listPlan = listDataHeader;
        this.listScheduleMap = listChildData;
    }
    @Override
    public Object getChild(int groupPosition, int childPosititon) {
        return this.listScheduleMap.get(this.listPlan.get(groupPosition))
                .get(childPosititon);
    }

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

    @Override
    public View getChildView(final int groupPosition, final int childPosition,
                             boolean isLastChild, View convertView, ViewGroup parent) {

        final String childText = (String) getChild(groupPosition, childPosition);

        if (convertView == null) {
            LayoutInflater infalInflater = (LayoutInflater) this._context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = infalInflater.inflate(R.layout.schedule_group, null);
        }

        TextView txtListChild = (TextView) convertView
                .findViewById(R.id.scheduleGroup);
        scheduleDeleteBtn = convertView.findViewById(R.id.scheduleDeleteBtn);
        scheduleDeleteBtn.setVisibility(View.INVISIBLE);
        scheduleDeleteBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                List<String> plan = listScheduleMap.get(listPlan.get(groupPosition));
                plan.remove(childPosition);
                notifyDataSetChanged();
            }
        });
        txtListChild.setText(childText);
        return convertView;
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        return this.listScheduleMap.get(this.listPlan.get(groupPosition))
                .size();
    }
    @Override
    public Object getGroup(int groupPosition) {
        return this.listPlan.get(groupPosition);
    }

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

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

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded,
                             View convertView, ViewGroup parent) {
        String headerTitle = (String) getGroup(groupPosition);
        if (convertView == null) {
            LayoutInflater infalInflater = (LayoutInflater) this._context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = infalInflater.inflate(R.layout.plan_group, null);
        }

        TextView lblListHeader = (TextView) convertView
                .findViewById(R.id.planGroup);
        lblListHeader.setTypeface(null, Typeface.BOLD);
        lblListHeader.setText(headerTitle);

        return convertView;
    }

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

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

    public void setDeleteVisibility(boolean visible){
        for(int j = 0; j < getGroupCount(); j ++){
            for(int i = 0; i<getChildrenCount(i); i++ ){
                if(visible){

                    scheduleDeleteBtn.setVisibility(View.VISIBLE);
                }else{
                    scheduleDeleteBtn.setVisibility(View.INVISIBLE);
                }
            }
        }
    }
}

PlansFragment.java

package com.example.easyplan;


import android.content.res.Resources;
import android.graphics.drawable.Drawable;
import android.os.Bundle;

import androidx.fragment.app.Fragment;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.ImageButton;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
/**
 * A simple {@link Fragment} subclass.
 */
public class PlansFragment extends Fragment {
    TextView editText;
    MainAdapter mainAdapter;
    ExpandableListView planExplandable;
    List<String> listPlanName;
    HashMap<String, List<String>> listSchedules;
    TextView textView;
    static int count = 0;
    View view;

    public PlansFragment() {

        // Required empty public constructor
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        view = inflater.inflate(R.layout.fragment_plans_fragment, container, false);
        listPlanName = new ArrayList<String>();
        listSchedules = new HashMap<String, List<String>>();

        // get the listview
        planExplandable = (ExpandableListView) view.findViewById(R.id.plansExpandable);
        textView = view.findViewById(R.id.scheduleGroup);
        editText = view.findViewById(R.id.planEditText);


        // preparing list data
       // prepareListData();
        createAPlan(3);
        createAPlan(1);
        createAPlan(3);
        createAPlan(4);

        mainAdapter = new MainAdapter(getActivity(), listPlanName, listSchedules);

        // setting list adapter
        planExplandable.setAdapter(mainAdapter);
        //mainAdapter.setDeleteVisibility(false);
 /*       editText.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mainAdapter.setDeleteVisibility(true);
            }
        });*/
        return view;
    }

    public HashMap<String, String> getData(){

        return null;
    }

    private void createAPlan(int sch){
        listPlanName.add("Plan#"+(count+1));
        List<String> schedules = new ArrayList<String>();
        if(sch > 0 ){
            for (int i = 1; i <= sch; i++){
                schedules.add("Schedule#" + i);
            }
        }
        listSchedules.put(listPlanName.get(count),schedules);
        count++;

    }
}

The child's xml has

<LinearLayout
    android:layout_width="0dp"
    android:layout_height="match_parent"
    android:layout_weight="1.8">

    <TextView
        android:id="@+id/scheduleGroup"
        android:layout_width="355dp"
        android:layout_height="wrap_content"
        android:paddingLeft="?android:attr/expandableListPreferredItemPaddingLeft"
        android:paddingTop="10dp"
        android:paddingBottom="10dp"
        android:textColor="@android:color/black" />
</LinearLayout>
    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="0.2">

        <ImageButton
            android:id="@+id/scheduleDeleteBtn"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            app:srcCompat="@drawable/delete_icon"
            android:visibility="visible"
            android:clickable="true"
            ></ImageButton>
    </LinearLayout>

Answer 1

Inside your fragment use setOnItemClickListener() method on your listView and in overriden method make use of getFirstVisiblePosition() to subtract from the position where you will find the position of that view. then set the visibility.

@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
listPosition = position - planExplandable.getFirstVisiblePosition();
if (planExplandable.getChildAt(listPosition).findViewById(R.id.yourview).getVisibility() == View.INVISIBLE) {
    //Write your logic here
    planExplandable.getChildAt(listPosition).findViewById(R.id.yourview).setVisibility(View.VISIBLE);

}

}

If this won't help then please paste your crash log.