如何知道单击按钮的列表项的索引

Question

所以我正在处理一个列表视图，我想实现一个删除按钮。但是由于某种原因，每当我按下任何列表项上的删除按钮时，列表中的最后一项都会自动删除。我几乎尝试了所有内容，但我无法理解如何知道单击按钮的项目的索引，因此我可以轻松删除该特定项目。

这是代码：

// full subtask adapter code

package com.example.taskmasterv3;

import android.content.Context;
import android.content.Intent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import java.util.ArrayList;

public class SubtaskAdapter extends ArrayAdapter<subtask> {


    private final Context context;
    private ArrayList<subtask> values;


    public SubtaskAdapter(Context context, ArrayList<subtask> list) {

        //since your are using custom view,pass zero and inflate the custom view by overriding getview

        super(context, 0 , list);
        this.context = context;
        this.values = list;
    }



    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {

        //check if its null, if so inflate it, else simply reuse it
        if (convertView == null) {
            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = inflater.inflate(R.layout.subtask_item, parent, false);
        }



        //use convertView to refer the childviews to populate it with data
        TextView tvSubtaskName = convertView.findViewById(R.id.tvSubtaskName);
        ImageView ivPri = convertView.findViewById(R.id.ivPri);
        ImageView ivTime = convertView.findViewById(R.id.ivTime);
        ImageView ivDelete = convertView.findViewById(R.id.ivDelete);

        tvSubtaskName.setText(values.get(position).getSubtaskName());

        if (values.get(position).isPriHigh()) {
            ivPri.setImageResource(R.drawable.priority_high);
        } else if (values.get(position).isPriMed()) {
            ivPri.setImageResource(R.drawable.priority_med);
        } else if (values.get(position).isPriLow()) {
            ivPri.setImageResource(R.drawable.priority_low);
        }

        if (values.get(position).isTimeMore()) {
            ivTime.setImageResource(R.drawable.time_symbol_more);
        } else if (values.get(position).isTimeMed()) {
            ivTime.setImageResource(R.drawable.time_symbol_med);
        } else if (values.get(position).isTimeLess()) {
            ivTime.setImageResource(R.drawable.time_symbol_less);
        }




        // Delete button for subtasks (NOT WORKING)

        ivDelete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                
             SubtaskAdapter.this.remove(SubtaskAdapter.this.getItem(position));
             notifyDataSetChanged();



            }
        });

        //return the view you inflated
        return convertView;
    }




    //to keep adding the new subtasks try the following
    public void addANewSubTask(subtask newSubTask){
        ArrayList<subtask> newvalues = new ArrayList<>(this.values);
        newvalues.add(newSubTask);
        this.values = newvalues;
        notifyDataSetChanged();

    }


}

Answer 1

ivDelete.setOnClickListener(new View.OnClickListener() {

将其更改为：

ivDelete.setOnClickListener(new View.OnClickListener() {
ivDelete.setTag(position);

public void onClick(View v) {

改为：

public void onClick(View v) {
// int position = v.getTag();
int position = (Integer)v.getTag();

Answer 2

尝试使用以下代码：

        ivDelete.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            values .remove(position);
            notifyDataSetChanged();

         //SubtaskAdapter.this.remove(SubtaskAdapter.this.getItem(position));
         //notifyDataSetChanged();

        }
    });