Android listview 删除行不起作用

Question

我试图在用户单击删除按钮时删除一行。我面临的问题是，如果我删除任何行，它会删除 UI 上的最后一行。我有一个带有 Arraylist 的适配器。单击我从 arraylist 中删除该项目并调用 notifydatasetchanged 。在调试时，我看到正确的项目已被删除 UI 我看到最后一行没有看到（删除的行仍然可以看到）

public class MenuDetailsAdapter extends BaseAdapter {
    private Activity activity;
    private LayoutInflater inflater;
    private List<MenuItem> menuItems;
    private View userView,itemView ;
    public MenuDetailsAdapter(Activity activity, List<MenuItem> menuItems) {
        this.activity=activity;
        this.menuItems = menuItems;
    }

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

    @Override
    public Object getItem(int pos) {
        return menuItems.get(pos);
    }

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

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

        if (inflater == null) {
            inflater = (LayoutInflater) activity
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        }
        if(convertView==null)
        {
            convertView= inflater.inflate(R.layout.menu_card_row, null);
            ImageView im= (ImageView) convertView.findViewById(R.id.btnRemoveItemRow);
            im.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    menuItems.remove(position);
                    notifyDataSetChanged();
                }
            });
            TextView tvItemName=(TextView) convertView.findViewById(R.id.tvItem_name);
            tvItemName.setText(((MenuItem) getItem(position)).getName());

            TextView tvItemPrice=(TextView) convertView.findViewById(R.id.tvItemPrice);
            tvItemPrice.setText(tvItemPrice.getText().toString()+ ((MenuItem) getItem(position)).getCost());

            TextView tvItemQty=(TextView) convertView.findViewById(R.id.tvItem_qty);
            tvItemQty.setText(tvItemQty.getText().toString()+ ((MenuItem) getItem(position)).getQuanity());
        }
        return convertView;
    }
}

Answer 1

private void deleteRow(int position)
{
menuItems.remove(position);

notifyDataSetChanged();
}

Answer 2

如下更改您的 getView 方法 -

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

    if(convertView == null){
         convertView= inflater.inflate(R.layout.menu_card_row, null);
    }

    ImageView im= (ImageView) convertView.findViewById(R.id.btnRemoveItemRow);
    im.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            menuItems.remove(position);
            notifyDataSetChanged();
        }
    });
    TextView tvItemName=(TextView) convertView.findViewById(R.id.tvItem_name);
    tvItemName.setText(((MenuItem) getItem(position)).getName());

    TextView tvItemPrice=(TextView) convertView.findViewById(R.id.tvItemPrice);
    tvItemPrice.setText(tvItemPrice.getText().toString()+ ((MenuItem) getItem(position)).getCost());

    TextView tvItemQty=(TextView) convertView.findViewById(R.id.tvItem_qty);
    tvItemQty.setText(tvItemQty.getText().toString()+ ((MenuItem) getItem(position)).getQuanity());

return convertView;

}

Answer 3

用这些代码替换代码....这可能对您有所帮助

  public class MenuDetailsAdapter extends BaseAdapter {
    private Activity activity;
    private LayoutInflater inflater;
    private List<MenuItem> menuItems;
    private View userView,itemView ;
    public MenuDetailsAdapter(Activity activity, List<MenuItem> menuItems) {
        this.activity=activity;
        this.menuItems = menuItems;
    }

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

    @Override
    public Object getItem(int pos) {
        return menuItems.get(pos);
    }

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

   public class ViewHolder {

    ImageView im;
    TextView tvItemName;
    TextView tvItemPrice;
    TextView tvItemQty;

    }


    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
    final ViewHolder _viewHolder;
     if (convertView == null) {


            _viewHolder = new ViewHolder();

            LayoutInflater _layInflater = (LayoutInflater) _context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

            convertView = _layInflater.inflate(R.layout.menu_card_row, null);


            _viewHolder.tvItemName=(TextView) convertView.findViewById(R.id.tvItem_name);

            _viewHolder.tvItemPrice=(TextView) convertView.findViewById(R.id.tvItemPrice);
            _viewHolder.tvItemQty=(TextView) convertView.findViewById(R.id.tvItem_qty)



            convertView.setTag(_viewHolder);


        } else {
            _viewHolder = (ViewHolder) convertView.getTag();
        }


            _viewHolder.tvItemName.setText(((MenuItem) getItem(position)).getName());
           _viewHolder.tvItemPrice.setText(tvItemPrice.getText().toString()+ ((MenuItem) getItem(position)).getCost());
          _viewHolder.tvItemQty.setText(tvItemQty.getText().toString()+ ((MenuItem) getItem(position)).getQuanity());

        _viewHolder.im.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    menuItems.remove(position);
                    notifyDataSetChanged();
                }
            })


        return convertView;
    }

Answer 4

您不能直接从此处删除视图，除非您的适配器在 Activity Class 内。通过使用您的代码，您无法为超级 class 构造函数提供更新。

因此您可以在 Activity -

中尝试此代码

listview.setOnItemClickListner(.... use listner


    menuItems.remove(position);
    MenuDetailsAdapter adapter = MenuDetailsAdapter(Activity activity, List<MenuItem> menuItems);
    adapter.notifyDataSetChanged();


);

Answer 5

用这些代码替换代码....这可能对您有所帮助。您只能更改 imageview 点击侦听器。

    convertView= inflater.inflate(R.layout.menu_card_row, null);
    ImageView im= (ImageView) convertView.findViewById(R.id.btnRemoveItemRow);
    im.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            menuItems.remove(position);
            notifyDataSetChanged();
        }
    });
    TextView tvItemName=(TextView) convertView.findViewById(R.id.tvItem_name);
    tvItemName.setText(((MenuItem) getItem(position)).getName());

    TextView tvItemPrice=(TextView) convertView.findViewById(R.id.tvItemPrice);
    tvItemPrice.setText(tvItemPrice.getText().toString()+ ((MenuItem) getItem(position)).getCost());

    TextView tvItemQty=(TextView) convertView.findViewById(R.id.tvItem_qty);
    tvItemQty.setText(tvItemQty.getText().toString()+ ((MenuItem) getItem(position)).getQuanity());

Answer 6

public class MenuDetailsAdapter extends BaseAdapter {
private Activity activity;
private LayoutInflater inflater;
private List<MenuItem> menuItems;
private View userView,itemView ;
public MenuDetailsAdapter(Activity activity, List<MenuItem> menuItems) {
    this.activity=activity;
    this.menuItems = menuItems;
}

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

@Override
public Object getItem(int pos) {
    return menuItems.get(pos);
}

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

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

    if (inflater == null) {
        inflater = (LayoutInflater) activity
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }
    if(convertView==null)
    {
        convertView= inflater.inflate(R.layout.menu_card_row, null);
        ImageView im= (ImageView) convertView.findViewById(R.id.btnRemoveItemRow);
        im.setOnClickListener(new Listener(position));
        TextView tvItemName=(TextView) convertView.findViewById(R.id.tvItem_name);
        tvItemName.setText(((MenuItem) getItem(position)).getName());

        TextView tvItemPrice=(TextView) convertView.findViewById(R.id.tvItemPrice);
        tvItemPrice.setText(tvItemPrice.getText().toString()+ ((MenuItem) getItem(position)).getCost());

        TextView tvItemQty=(TextView) convertView.findViewById(R.id.tvItem_qty);
        tvItemQty.setText(tvItemQty.getText().toString()+ ((MenuItem) getItem(position)).getQuanity());




    }


    return convertView;
}

 class Listener implements View.OnClickListener {


        private  int position;

        Listener(int  position) {
            this.data = position;

        }

        @Override
        public void onClick(View v) {
                 menuItems.remove(position);
                notifyDataSetChanged();
        }
    }

    }

Answer 7

您的 ListView 工作正常，但是，您似乎误解了 Android 中的 ListView 的工作原理。在 Android 中为了节省内存 ListViews 使用 recycling mechanism.

您在 getView 中的逻辑不正确，您每隔 convertView 就返回一次 null。实际上，每个非空 convertViews 都是那些已经离开屏幕或已从模型中删除的剪贴视图。

在您的情况下，每当您删除一行时，其对应的视图将被标记为废料并将从 ListView 中删除，因此，您的 ListView 将丢失其中一行现在确实需要另一行来覆盖它的所有区域。因此，它从 getView 方法请求另一行，在那里，您将返回相同的 removed/scrap 视图，而您不应该这样做。

Answer 8

使用这个：

public void deleteRow(int position)
{ 
    menuItems.remove(position);

    adapter.notifyDataSetChanged(); 
}

Android listview 删除行不起作用

Android listview Delete row not working

android

android-listview