android -BaseAdapter不会向listView添加新项

概述我不知道为什么我的listView不添加新项目.这是代码：ListAdapterladap;privateclassGetContactsAsyncTask<Void,Void,ArrayList<HashMap<String,String>>>{@OverrideprotectedVoiddoInBackground(Void...arg0){Spots_tab1_jsons

我不知道为什么我的ListVIEw不添加新项目.

这是代码：

   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;    }    }

在朋友的帮助下,我解决了我的最后一个问题,新问题就是这个,适配器没有更新,因此它不会向ListVIEw添加新行.我记录了这个baseAdapter中有30个新项目：

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

但它没有添加到ListVIEw.

你能帮我解决这个问题吗？

谢谢

解决方法:

您已使用contactList ArrayList显示ListVIEw项,并且您将更新数据到doinBackground()中的contactList,它运行不在ui线程中的另一个线程,因此您无法从out ui therad更新ui数据,因此您必须将本地ArrayList用于doInBackground()并将新的或更新的数据传递给onPostExecute(),它将此数据更新为ui线程.

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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