Question

我有一个asycn任务被调用：

GetListsJSON task = new GetListsJSON(getActivity());
        task.setOnArticleSelectedListener(this);
        task.execute(url);

然后运行此异步任务以检索JSON并填充listview：

public class GetListsJSON extends AsyncTask<String, Void, String> {

    Context c;
    private ProgressDialog Dialog;

    public GetListsJSON (Context context)
    {
        c = context;
        Dialog = new ProgressDialog(c);
    }

    //****************code for on click
    OnArticleSelectedListener listenerBeer;
    public interface OnArticleSelectedListener{
        public void onArticleSelected(String myString, String brewery);

    }
    public void setOnArticleSelectedListener(OnArticleSelectedListener listener){
        this.listenerBeer = listener;


    }
    //******************end code for onClick

    @Override
    protected String doInBackground(String... arg0) {
        // TODO Auto-generated method stub
        return readJSONFeed(arg0[0]);
    }

    protected void onPreExecute() {
        Dialog.setMessage("Getting Lists");

        Dialog.setTitle("Loading");
        Dialog.setCancelable(false);
        Dialog.show();
    }

    protected void onPostExecute(String result){
        //decode json here
        try{

            JSONArray jsonArray = new JSONArray(result);

            final List<BeerData> beerList = new ArrayList<BeerData>();

            //acces listview
            final ListView lv = (ListView) ((Activity) c).findViewById(R.id.allYourBeersList);

            Log.d("list", "inside async");

            //make array list for beer

            //tasteList.add("");
            for(int i = 0; i < jsonArray.length(); i++) {

                String bID = jsonArray.getJSONObject(i).getString("id");
                String listName = jsonArray.getJSONObject(i).getString("name");

                Log.d("list", listName);

                //create beer object
                BeerData thisBeer = new BeerData(listName, bID, "a", "a", "a", "a",
                        "a","a", "a", "a", "a", "breweryID", "breweryName",
                        "a", "a", "a","a", "a", "a");

                //add beer to list
                beerList.add(thisBeer);


            }

            //update listview
            BeerSearchAdapter adapter1 = new BeerSearchAdapter(c ,R.layout.listview_item_row, beerList);
            lv.setAdapter(adapter1);

            //set up clicks
            lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> arg0, View arg1,
                                        int arg2, long arg3) {

                    BeerData beerInfo = beerList.get(arg2);
                    String idToSend = beerInfo.beerId;

                    //************************Launch listener interface
                    listenerBeer.onArticleSelected(idToSend, beerInfo.beerBreweryId);




                }
            });




        }
        catch(Exception e){

        }

        Dialog.dismiss();

    }





    public String readJSONFeed(String URL) {
        StringBuilder stringBuilder = new StringBuilder();
        HttpClient httpClient = new DefaultHttpClient();
        HttpGet httpGet = new HttpGet(URL);
        try {
            HttpResponse response = httpClient.execute(httpGet);
            StatusLine statusLine = response.getStatusLine();
            int statusCode = statusLine.getStatusCode();
            if (statusCode == 200) {
                HttpEntity entity = response.getEntity();
                InputStream inputStream = entity.getContent();
                BufferedReader reader = new BufferedReader(
                        new InputStreamReader(inputStream));
                String line;
                while ((line = reader.readLine()) != null) {
                    stringBuilder.append(line);
                }
                inputStream.close();
            } else {
                Log.d("JSON", "Failed to download file");
            }
        } catch (Exception e) {
            Log.d("readJSONFeed", e.getLocalizedMessage());
        }
        return stringBuilder.toString();
    }

}

我知道JSON解析正在运行，因为我的日志吐了出来：

03-28 16:04:27.175  30167-30167/com.beerportfolio.beerportfoliopro D/list﹕ inside async
03-28 16:04:27.175  30167-30167/com.beerportfolio.beerportfoliopro D/list﹕ My Fridge
03-28 16:04:27.175  30167-30167/com.beerportfolio.beerportfoliopro D/list﹕ Wish List

列表应加载的页面的xml是：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    tools:context=".MainActivity" >

    <LinearLayout
        android:id="@+id/linlaHeaderProgress"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:gravity="center"
        android:orientation="vertical"
        android:visibility="gone" >

        <ProgressBar
            android:id="@+id/pbHeaderProgress"
            style="android@style/Spinner"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >
        </ProgressBar>
    </LinearLayout>

    <ListView
        android:id="@android:id/list"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:dividerHeight="0px"
        android:divider="@null"
        >
    </ListView>

</LinearLayout>

Answer 1

你有这一行：

final ListView lv = (ListView) ((Activity) c).findViewById(R.id.allYourBeersList);

但是在您的xml文件中，您使用以下ID定义ListView： @android：id / list

您应该将其切换到xml文件中的以下内容：

@+id/allYourBeersList

Android ListView未填充

1 个答案: