我需要从服务器显示图像。我下载图像表单服务器。图像在列表视图行中从服务器显示。
问题是 -
1）图像仅显示在列表视图的第一行，第一行的图像连续变化。但是一段时间后其他行也有图像，但方式错误（第一行不包含图像网址，但在列表视图中显示图像）。
1。来自服务器的GetCategory详细信息
private class GetCategoryFromServer extends AsyncTask<Void, Void, String> {
@Override
protected String doInBackground(Void... params) {
// TODO Auto-generated method stub
return JsonParser.Webserice_Call_URL(ConstantsUrl.Get_All_category,
null, null);
}
@Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
// System.out.println("result from response " + result);
try {
parseResponse(result);
} catch (Exception e) {
e.printStackTrace();
}
categoryAdapter.notifyDataSetChanged();
}
}
2。解析结果＆amp;存储在ArrayList
private void parseResponse(String result) throws Exception {
categoryList.clear();
JSONArray jsonArrayMain = new JSONArray(result);
for (int i = 0; i < jsonArrayMain.length(); i++) {
JSONObject categoryJson = jsonArrayMain.getJSONObject(i);
CategoryMetadata metadataObj = new CategoryMetadata();
metadataObj.setName(JsonParser
.getkeyValue_Str(categoryJson, "name"));
metadataObj.setId(JsonParser.getkeyValue_Str(categoryJson, "id"));
metadataObj.setUrlKey(JsonParser.getkeyValue_Str(categoryJson,
"urlkey"));
metadataObj.setDesc(JsonParser
.getkeyValue_Str(categoryJson, "desc"));
metadataObj.setImage(JsonParser.getkeyValue_Str(categoryJson,
"image"));
metadataObj.setParentId(JsonParser.getkeyValue_Str(categoryJson,
"parent_id"));
categoryList.add(metadataObj);
}
// System.out.println("size of arrayList" + categoryList.size());
}
** 3。适配器类**
private class CategoryAdapter extends BaseAdapter {
private LayoutInflater mInflater;
public CategoryAdapter() {
mInflater = LayoutInflater.from(getActivity());
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return categoryList.size();
}
@Override
public CategoryMetadata getItem(int arg0) {
// TODO Auto-generated method stub
return categoryList.get(arg0);
}
@Override
public long getItemId(int arg0) {
// TODO Auto-generated method stub
return arg0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
ViewHolder holderObj = null;
if (convertView == null) {
holderObj = new ViewHolder();
convertView = mInflater.inflate(R.layout.row_category, null);
holderObj.categoryTitle = (TextView) convertView
.findViewById(R.id.title);
holderObj.background = (LinearLayout) convertView
.findViewById(R.id.background);
convertView.setTag(holderObj);
} else {
holderObj = (ViewHolder) convertView.getTag();
}
CategoryMetadata value = getItem(position);
holderObj.categoryTitle.setText(value.getName());
try {
String _url = value.getImage().toString();
if (_url != null && !_url.equals("")) {
new ImageDownloaderTask(holderObj.background).execute(value
.getImage());
}
} catch (Exception e) {
e.printStackTrace();
}
return convertView;
}
}
private class ViewHolder {
private LinearLayout background;
private TextView categoryTitle;
}
4.下载图片
private class ImageDownloaderTask extends AsyncTask<String, Void, Bitmap> {
private final LinearLayout imageViewReference;
public ImageDownloaderTask(LinearLayout imageView) {
// TODO Auto-generated constructor stub
imageViewReference = imageView;
}
@Override
protected Bitmap doInBackground(String... params) {
// TODO Auto-generated method stub
return AppUtiles.download(params[0], getActivity());
}
@SuppressLint("NewApi") @Override
protected void onPostExecute(Bitmap bitmap) {
// TODO Auto-generated method stub
super.onPostExecute(bitmap);
if (isCancelled()) {
bitmap = null;
}
if (imageViewReference != null && isAdded()) {
// LinearLayout imageView = (LinearLayout) imageViewReference
// .get();
// if (imageView != null&&isAdded()) {
/*
* if (bitmap != null) { imageView.setImageBitmap(bitmap); }
* else { imageView.setImageDrawable(imageView.getContext().
* getResources() .getDrawable(R.drawable.list_placeholder)); }
*/
Drawable d = new BitmapDrawable(getResources(), bitmap);
if (bitmap != null) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
imageViewReference.setBackground(d);
;
} else {
imageViewReference.setBackgroundDrawable(d);
}
}
categoryAdapter.notifyDataSetChanged();
// }
}
}
}