Android无法清空列表视图项

Question

I am trying to prevent my listview items to append when i press the button twice. I tried to use .Clear() but I dont know where to put it or how to put it, sometimes it stops items from even populating or doesn't clear the items at all.

global stuffs:

ArrayAdapter<CharSequence> adapter;
ArrayList<MessageDetails> details;

My button:

        @Override
        public void onClick(View arg0) {
            // TODO Auto-generated method stub
            try
            {
                //Tried clearing adapter first before code runs but items do not even get displayed
                adapter.clear();
                adapter.notifyDataSetChanged();
                //sendPostData calls refreshListView method
                new sendPostData().execute(nric.getText().toString());
            }
            catch (Exception e)
            {

            }
        }

my refreshListView() method:

private void refreshListView()
{       
    adapter = new ArrayAdapter<CharSequence>(getActivity().getApplicationContext(), android.R.layout.simple_list_item_1, items);
    myInfoList.setAdapter(adapter);

    details = new ArrayList<MessageDetails>();
    MessageDetails Detail;

    Detail = new MessageDetails();

    for (int i =0; i < itemName.size(); i++)
    {
        float totalprice = itemPrice.get(i) * Quantity.get(i);
        Detail = new MessageDetails();
        Detail.setitemName(itemName.get(i));
        Detail.setItemDescription(description.get(i));
        Detail.setitemPrice(String.valueOf(totalprice));
        Detail.setQuantity(Quantity.get(i).toString() + " sets");
        Detail.setDate(purchaseDate.get(i).toString());
        details.add(Detail);
    }   

    myInfoList.setAdapter(new CustomAdapter(details , getActivity()));
}

EDIT removed first adapter.

Global item:

CustomAdapter mCustomAdapter;

refreshListView:

private void refreshListView()
{           
    details = new ArrayList<MessageDetails>();
    MessageDetails Detail;

    Detail = new MessageDetails();

    for (int i =0; i < itemName.size(); i++)
    {
        float totalprice = itemPrice.get(i) * Quantity.get(i);
        Detail = new MessageDetails();
        Detail.setitemName(itemName.get(i));
        Detail.setItemDescription(description.get(i));
        Detail.setitemPrice(String.valueOf(totalprice));
        Detail.setQuantity(Quantity.get(i).toString() + " sets");
        Detail.setDate(purchaseDate.get(i).toString());
        details.add(Detail);
    }   

    mCustomAdapter = new CustomAdapter(details , getActivity());
    myInfoList.setAdapter(mCustomAdapter);
}

Answer 1

you submit two differnts Adapter instance to your ListView , and the latter override the former instance. So you should keep a reference to CustomAdapter and write a method do clear the dataset.

CustomAdapter mCustomAdpater = new CustomAdapter(details , getActivity()); 
myInfoList.setAdapter(mCustomAdpater); 

inside CustomAdapter, write your own clear() method and, inside onClick() you will call

mCustomAdpater.clear();

Answer 2

This worked for me:

        listview.removeAllViewsInLayout();
        listview.removeAllViewsFromAdapter();
        listview.setAdapter(null);
        listview.refreshDrawableState();
        listview.removeViews(0, listview.getChildCount());