我制作了一个应用程序，其中获取产品列表以及名称，描述和图像，我能够显示图像< / strong>以详细的产品形式，而点击任何ListView项目行但是获得问题以在ListView中显示图像，I不知道为什么我会遇到这个问题..
请让我知道我失踪的地方：
代码：
public class CategoryActivity extends ListActivity {
// Connection detector
ConnectionDetector cd;
// Alert dialog manager
AlertDialogManager alert = new AlertDialogManager();
// Progress Dialog
private ProgressDialog pDialog;
// Creating JSON Parser object
JSONParser jsonParser = new JSONParser();
ArrayList<HashMap<String, String>> albumsList;
// albums JSONArray
JSONArray albums = null;
String imagepath;
// albums JSON url
private static final String URL_ALBUMS = "http://XXX.com/albums.php";
// ALL JSON node names
static final String TAG_ID = "id";
static final String TAG_NAME = "name";
static final String TAG_DESCRIPTION = "description";
static final String TAG_IMAGEPATH = "imagepath";
static final String TAG_SONGS_COUNT = "songs_count";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_category);
cd = new ConnectionDetector(getApplicationContext());
// Check for internet connection
if (!cd.isConnectingToInternet()) {
// Internet Connection is not present
alert.showAlertDialog(CategoryActivity.this, "Internet Connection Error",
"Please connect to working Internet connection", false);
// stop executing code by return
return;
}
// Hashmap for ListView
albumsList = new ArrayList<HashMap<String, String>>();
// Loading Albums JSON in Background Thread
new LoadCategories().execute();
// get listview
ListView lv = getListView();
/**
* Listview item click listener
* TrackListActivity will be lauched by passing album id
* */
lv.setOnItemClickListener(new android.widget.AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View view, int arg2,
long arg3) {
// on selecting a single album
// TrackListActivity will be launched to show tracks inside the album
Intent i = new Intent(getApplicationContext(), ProductListActivity.class);
// send album id to tracklist activity to get list of songs under that album
String album_id = ((TextView) view.findViewById(R.id.album_id)).getText().toString();
i.putExtra("album_id", album_id);
startActivity(i);
}
});
}
/**
* Background Async Task to Load all Albums by making http request
* */
class LoadCategories extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(CategoryActivity.this);
pDialog.setMessage("Loading Please Wait ...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting Albums JSON
* */
protected String doInBackground(String... args) {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
// getting JSON string from URL
String json = jsonParser.makeHttpRequest(URL_ALBUMS, "GET",
params);
// Check your log cat for JSON reponse
Log.d("Albums JSON: ", "> " + json);
try {
albums = new JSONArray(json);
if (albums != null) {
// looping through All albums
for (int i = 0; i < albums.length(); i++) {
JSONObject c = albums.getJSONObject(i);
// Storing each json item values in variable
String id = c.getString(TAG_ID);
String name = c.getString(TAG_NAME);
String description = c.getString(TAG_DESCRIPTION);
String imageurl = c.getString(TAG_IMAGEPATH);
String songs_count = c.getString(TAG_SONGS_COUNT);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_ID, id);
map.put(TAG_NAME, name);
map.put(TAG_DESCRIPTION, description);
map.put(TAG_IMAGEPATH,imageurl);
map.put(TAG_SONGS_COUNT, songs_count);
// adding HashList to ArrayList
albumsList.add(map);
}
}else{
Log.d("Albums: ", "null");
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog after getting all albums
pDialog.dismiss();
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
CategoryActivity.this, albumsList,
R.layout.list_item_categories, new String[]
{
TAG_ID, TAG_NAME, TAG_DESCRIPTION, TAG_IMAGEPATH, TAG_SONGS_COUNT
},
new int[]
{
R.id.album_id, R.id.album_name, R.id.album_description, R.id.list_image, R.id.songs_count
}
);
// updating listview
setListAdapter(adapter);
}
});
}
}
}
答案 0 :(得分：2)
别担心
我想你必须使用下面的代码，它对你有用，几天前我在我的应用程序中使用了：
首先将onPostExecute 替换为：
protected void onPostExecute(String file_url) {
/**
* Updating parsed JSON data into ListView
* */
adapter = new LazyAdapter(
CategoryActivity.this, albumsList);
// updating listview
setListAdapter(adapter);
// updating UI from Background Thread
pDialog.dismiss();
}
现在创建一个LazyAdapter类并放在代码下面，只需要复制和粘贴我已经改变了你的方式：
public class LazyAdapter extends BaseAdapter {
private Activity activity;
private ArrayList<HashMap<String, String>> data;
private static LayoutInflater inflater=null;
public ImageLoader imageLoader;
public LazyAdapter(Activity a, ArrayList<HashMap<String, String>> d) {
activity = a;
data=d;
inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
imageLoader=new ImageLoader(activity.getApplicationContext());
}
public int getCount() {
return data.size();
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
View vi=convertView;
if(convertView==null)
vi = inflater.inflate(R.layout.listrow, null);
TextView title = (TextView)vi.findViewById(R.id.title);
TextView description = (TextView)vi.findViewById(R.id.description);
TextView cost = (TextView)vi.findViewById(R.id.cost);
ImageView thumb_image=(ImageView)vi.findViewById(R.id.list_image);
HashMap<String, String> item = new HashMap<String, String>();
item = data.get(position);
// Setting all values in listview
title.setText(item.get(Catalogue.KEY_TITLE));
description.setText(item.get(Catalogue.KEY_DESCRIPTION));
cost.setText(item.get(Catalogue.KEY_COST));
imageLoader.DisplayImage(item.get(Catalogue.KEY_THUMB_URL), thumb_image);
return vi;
}
}
快乐......快乐的编码快乐的结局