我有一个带有getview方法的Custom ArrayAdapter，如果我向下和向上滚动，就会调用不同视图的方法，这会使这些视图再次加载（例如下载图像）。 在我的ListActivity类中，我只需要调用adapter = new Adapter ...和list.setAdapter（），然后我下载并解析一个json（使用AQuery库）。
public class AdapterPostagem extends ArrayAdapter<Postagem>{
Context context;
LayoutInflater inflater;
boolean memCache = false;
boolean fileCache = true;
String BASE_URL = "https://graph.facebook.com/";
public AdapterPostagem(Context context, int textViewResourceId,
List<Postagem> objects) {
super(context, textViewResourceId, objects);
// TODO Auto-generated constructor stub
inflater = (LayoutInflater)context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
this.context = context;
}
public class ViewHolder{
TextView postagem;
TextView likes;
ImageView foto;
View view;
TextView like;
TextView share;
ProgressBar pb;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
ViewHolder holder = null;
Postagem p = new Postagem();
p = getItem(position);
AQuery aq;
UrlImageViewHelper uHelper = new UrlImageViewHelper();
uHelper.setUseBitmapScaling(false);
if (convertView == null){
convertView = inflater.inflate(R.layout.postagem, parent, false);
Log.d("conv", "convertView_null");
Postagens posts = new Postagens();
Postagens.EndlessScrollListener end = posts.new EndlessScrollListener();
aq = new AQuery(convertView);
aq.scrolled(end);
holder = new ViewHolder();
holder.foto = (ImageView)convertView.findViewById(R.id.foto);
holder.postagem = (TextView)convertView.findViewById(R.id.postagem);
holder.like = (TextView)convertView.findViewById(R.id.likes);
holder.share = (TextView)convertView.findViewById(R.id.shares);
//holder.pb = (ProgressBar)convertView.findViewById(R.id.progress);
if (!p.getUrl_foto().equals("")){
getUrlPhoto(holder.foto, uHelper,p.getId(), aq, R.id.foto);
}else{
holder.foto.setVisibility(View.GONE);
}
holder.postagem.setText(p.getPostagem());
convertView.setTag(holder);
}else{
Log.d("conv", "convertView");
holder = (ViewHolder)convertView.getTag();
Postagens posts = new Postagens();
Postagens.EndlessScrollListener end = posts.new EndlessScrollListener();
aq = new AQuery(convertView);
aq.scrolled(end);
holder.foto = (ImageView)convertView.findViewById(R.id.foto);
holder.postagem = (TextView)convertView.findViewById(R.id.postagem);
if (!p.getId().equals("")){
getUrlPhoto(holder.foto, uHelper,p.getId(), aq, R.id.foto);
}else{
holder.foto.setVisibility(View.GONE);
}
//uHelper.setUrlDrawable(holder.foto, p.getUrl_foto());
setTextWithURL(holder.postagem, p.getPostagem());
//holder.postagem.setText(p.getPostagem());
//holder.likes.setText(Integer.toString(p.getLikes()));
}
return convertView;
}
public void setTextWithURL(TextView t, String s){
String [] parts = s.split("\\s");
String finals = "";
for( String item : parts ) try {
URL url = new URL(item);
// If possible then replace with anchor...
finals = finals + ("<a href=\"" + url + "\">"+ url + "</a> " );
} catch (MalformedURLException e) {
// If there was an URL that was not it!...
finals = finals + item + " ";
System.out.print( item + " " );
}
t.setClickable(true);
t.setPaintFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
t.setMovementMethod(LinkMovementMethod.getInstance());
t.setText(Html.fromHtml(finals));
}
public void setPhoto(ImageView img, UrlImageViewHelper uHelper, AQuery aq, JSONObject json, int id){
String URL = "";
try {
URL = json.getJSONArray("images").getJSONObject(1).getString("source");
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//uHelper.setUrlDrawable(img, URL);
// File file = aq.getCachedFile(URL);
// Bitmap bp = BitmapFactory.decodeFile(file.getPath());
// if (bp != null){
//
// img.setImageBitmap(bp);
//
// }else{
aq.id(img).image(URL, memCache, fileCache, 0, 0, null, 0, AQuery.RATIO_PRESERVE);
//
// }
}
public void getUrlPhoto(final ImageView img, final UrlImageViewHelper uHelper, String id, final AQuery aq, final int id_photo){
aq.ajax(BASE_URL + id, JSONObject.class, new AjaxCallback<JSONObject>() {
@Override
public void callback(String url, JSONObject json, AjaxStatus status) {
Log.d("url", url);
if(json != null){
setPhoto( img, uHelper, aq, json, id_photo);
}else{
Toast.makeText(aq.getContext(), "Error:" + status.getCode(), Toast.LENGTH_LONG).show();
}
}
});
}
}