为什么我的列表视图上的删除按钮不起作用[重复]

Question

我想在我的列表视图上实现这个删除按钮...我试图将按钮的标签设置为列表项的位置，然后我尝试使用 remove 方法将其删除，但它只是不起作用。这里可能有什么问题？请注意，我在这方面还很陌生，所以如果我的代码不好，我很抱歉。

这是我的适配器的代码：

// full subtask adapter code

package com.example.taskmasterv3;

import android.content.Context;
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);

        ivDelete.setTag(position);



        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) {

                values.remove(ivDelete.getTag());
                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

我就是这样做的。也许它可以帮助你。无论如何，尝试使用调试器来检查按下时是否调用它

public class ListNoteAdapter extends BaseAdapter implements ListAdapter {

private ArrayList<Nota> arrayList;
private Context context;

public ListNoteAdapter(ArrayList<Nota> arrayList, Context context) {
    this.arrayList = arrayList;
    this.context = context;
}

@Override
public int getCount() {
    return arrayList.size();
}

@Override
public Object getItem(int position) {
    return arrayList.get(position);
}

@Override
public long getItemId(int position) {
    return 0;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View view = convertView;

    if(view == null){
       view = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_view_with_button, parent, false);
    }

    TextView textView = view.findViewById(R.id.list_item);
    textView.setText(arrayList.get(position).toString());

    //When user click on a text view, text will be saved into clipboard
    textView.setOnClickListener( v -> {
        ClipboardManager clipboardManager = (ClipboardManager)context.getSystemService(Context.CLIPBOARD_SERVICE);
        ClipData clipData = ClipData.newPlainText("Note clipboard", textView.getText().toString());
        clipboardManager.setPrimaryClip(clipData);
        Toast.makeText(context, "Testo copiato negli appunti", Toast.LENGTH_SHORT).show();
    });

    ImageButton deleteButton = view.findViewById(R.id.deleteNote);

    deleteButton.setOnClickListener( v -> {

        LayoutInflater layoutInflater = (LayoutInflater)parent.getContext().getSystemService(parent.getContext().LAYOUT_INFLATER_SERVICE);
        View popupView = layoutInflater.inflate(R.layout.delete_popup_window, parent, false);

        Button decline = popupView.findViewById(R.id.deleteDeclineButton);

        /**
         * In order to allow the user to  delete any note voluntarily,
         * a confirming popup window will appear
         */
        PopupWindow popupWindow = new PopupWindow(popupView, ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT, true);

        Button agreed = popupView.findViewById(R.id.deleteAgreeButton);

        agreed.setOnClickListener(v1 ->{

            File file = new File(context.getFilesDir(),
                    arrayList.get(position).date + "@" + arrayList.get(position).time + ".txt");

            if(file.exists())
                file.delete();

            arrayList.remove(position);
            popupWindow.dismiss();

            //Update the list view to show the new note without needing to restart the application
            this.notifyDataSetChanged();
        });

        decline.setOnClickListener(vDecline -> {
            popupWindow.dismiss();
        });

        popupWindow.showAtLocation(popupView, Gravity.CENTER, 0, 0);
    });

    return view;
}

}

Answer 2

为什么不直接按位置删除

 values.remove(position);