安卓-BaseAdapter不增加新项目的ListView [英] android -BaseAdapter doesn't add new items to listView

问题描述

我不知道为什么我的ListView不增加​​新的项目。

I don't know why my listView doesn't add new items .

这是在code：

   ListAdapter ladap;

    private class GetContacts AsyncTask<Void, Void,ArrayList<HashMap<String, String>>> {    
    @Override
    protected Void doInBackground(Void... arg0) {
        Spots_tab1_json sh = new Spots_tab1_json();
        String jsonStr = sh.makeServiceCall(url + page, Spots_tab1_json.GET);

        ArrayList<HashMap<String, String>> dataC = new ArrayList<HashMap<String, String>>();

        if (jsonStr != null) {
            try {
                JSONObject jsonObj = new JSONObject(jsonStr);
                contacts = jsonObj.getJSONArray(TAG_CONTACTS);

                    for (int i = 0; i < contacts.length(); i++) {
                    JSONObject c = contacts.getJSONObject(i);
                    String id = new String(c.getString("id").getBytes("ISO-8859-1"), "UTF-8");
                    String dates = new String(c.getString("dates").getBytes("ISO-8859-1"), "UTF-8");
                    String price = new String(c.getString("gheymat").getBytes("ISO-8859-1"), "UTF-8");
                    HashMap<String, String> contact = new HashMap<String, String>();
                    contact.put("id", id);
                    contact.put("dates", dates);
                    contact.put("price", price);
                    dataC.add(contact);
                }
                }
            } catch (JSONException e) {
                goterr = true;
            } catch (UnsupportedEncodingException e) {
                goterr = true;
            }
        } else {
            goterr = true;
        }
        return dataC;
    }

    @Override
    protected void onPostExecute(ArrayList<HashMap<String, String>> result) {
        super.onPostExecute(result);
        if (!isCancelled() && goterr == false) {
            if(ladap==null){
                ladap=new ListAdapter(MainActivity.this,result);
                lv.setAdapter(ladap);
            }else{
                ladap.addAll(result);
                ladap.notifyDataSetChanged();
            }

    }
}


    public class ListAdapter extends BaseAdapter {
    Activity activity;
    public ArrayList<HashMap<String, String>> list;

    public ListAdapter(Activity activity,ArrayList<HashMap<String, String>> list) {
        super();
        this.activity = (Activity) activity;
        this.list = list;
    }

    public void addAll(ArrayList<HashMap<String, String>> result) {
        Log.v("this",result.size()+" resultsize");
        this.list = result;
        notifyDataSetChanged();
    }

    public int getCount() {
        return contactList.size();
    }

    public Object getItem(int position) {
        return contactList.get(position);
    }

    public long getItemId(int arg0) {
        return 0;
    }

    private class ViewHolder {
        TextView title,price;
        ImageView img ; 
        //RelativeLayout rl; 
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        LayoutInflater inflater = activity.getLayoutInflater();
        if (convertView == null) {
            convertView = inflater.inflate(R.layout.item, null);
            holder = new ViewHolder();
            holder.title = (TextView) convertView.findViewById(R.id.title);
            holder.price = (TextView) convertView.findViewById(R.id.price);
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }

            item = contactList.get(position);
            holder.price.setText(item.get("price"));
        return convertView;
    }
    }

在朋友们的帮助下，我解决我的最后一个问题，新的问题是这样的，该适配器不更新，因此不会增加新行的ListView。我登录，我在baseAdapter已经30个新项目在这里：

with help of friends ,I solve my last problem , the new problem is this , The adapter doesn't update so it doesn't add new rows to ListView. I logged and I've 30 new items in the baseAdapter here :

public void addAll(ArrayList<HashMap<String, String>> result) {
            Log.v("this",result.size()+" resultsize");
            this.list = result;
            notifyDataSetChanged();
        }

但它不会增加的ListView。

but it's not adding to listView.

你能不能帮我解决这个问题呢？

could you help me to solve this problem ?

感谢

推荐答案

您已经使用contactList的ArrayList来显示ListView项，您将更新数据contactList在doinBackground（），它在UI线程中运行另一个线程没有，所以你不能更新从出UI therad UI数据，因此你必须要当地的ArrayList的doInBackground（）和新的或更新的数据传递给onPostExecute（），它更新这些数据，用户界面​​线程。

You have used contactList ArrayList to showing ListView item and you will update data to contactList in doinBackground() which run another thread not in ui thread so you can not update ui data from out ui therad hence you have to take local ArrayList for doInBackground() and pass new or updated data to onPostExecute() which update this data to ui thread.

private class GetContacts extends AsyncTask<Void, Void, ArrayList<HashMap<String, String>>> {
    @Override
    protected ArrayList<HashMap<String, String>> doInBackground(Void... arg0) {
        Spots_tab1_json sh = new Spots_tab1_json();
        String jsonStr = sh.makeServiceCall(url + page, Spots_tab1_json.GET);

        ArrayList<HashMap<String, String>> data = new ArrayList<HashMap<String, String>>();
        if (jsonStr != null) {
            try {
                JSONObject jsonObj = new JSONObject(jsonStr);
                contacts = jsonObj.getJSONArray(TAG_CONTACTS);

                for (int i = 0; i < contacts.length(); i++) {
                    JSONObject c = contacts.getJSONObject(i);
                    String id = new String(c.getString("id").getBytes("ISO-8859-1"), "UTF-8");
                    String dates = new String(c.getString("dates").getBytes("ISO-8859-1"), "UTF-8");
                    String price = new String(c.getString("gheymat").getBytes("ISO-8859-1"), "UTF-8");
                    HashMap<String, String> contact = new HashMap<String, String>();
                    contact.put("id", id);
                    contact.put("dates", dates);
                    contact.put("price", price);
                    data.add(contact);
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            }
        }
        return data;
    }

    @Override
    protected void onPostExecute(ArrayList<HashMap<String, String>> result) {
        super.onPostExecute(result);
        if(ladap==null){
            ladap=new ListAdapter(MainActivity.this,result);
            lv.setAdapter(ladap);
        }else{
            ladap.addAll(result);
            ladap.notifyDataSetChanged();
        }
    }
}

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