我有一个很大的问题。我试图用动态加载的图像创建一个ListView，使用AsyncTask下载图像，然后将其设置为ListView。我的问题是，在向下滚动时，图像会随机变化。我看到了答案，但我无法想象。
我的代码：
（适配器）
public class ActorAdapter extends ArrayAdapter<Actors> {
ArrayList<Actors> actorList;
private static LayoutInflater vi;
int Resource;
ViewHolder holder;
public ActorAdapter(Context context, int resource, ArrayList<Actors> objects) {
super(context, resource, objects);
vi = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
Resource = resource;
actorList = objects;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
if (v == null) {
holder = new ViewHolder();
v = vi.inflate(Resource, null);
holder.imageHaberFoto = (ImageView) v.findViewById(R.id.ivImage);
holder.tvHaberBaslik = (TextView) v.findViewById(R.id.tvHaberBaslik);
holder.tvHaberTarihi = (TextView) v.findViewById(R.id.tvHaberTarihi);
holder.tvKisaTanim = (TextView) v.findViewById(R.id.tvKisaTanim);
holder.tvDetay = (TextView) v.findViewById(R.id.tvDetay);
v.setTag(holder);
} else {
holder = (ViewHolder) v.getTag();
}
new DownloadImageTask(holder.imageHaberFoto).execute(actorList.get(position).getHaberFoto());
holder.tvHaberBaslik.setText(actorList.get(position).getHaberBaslik());
holder.tvKisaTanim.setText(actorList.get(position).getHaberKisatanim());
holder.tvHaberTarihi.setText(actorList.get(position).getHaberTarihi());
holder.tvDetay.setText(actorList.get(position).getDetay());
return v;
}
static class ViewHolder {
public ImageView imageHaberFoto;
public TextView tvHaberBaslik;
public TextView tvHaberTarihi;
public TextView tvKisaTanim;
public TextView tvDetay;
}
private static class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
ImageView bmImage;
public DownloadImageTask(ImageView bmImage) {
this.bmImage = bmImage;
}
protected Bitmap doInBackground(String... urls) {
String urldisplay = urls[0];
Bitmap mIcon11 = null;
try {
InputStream in = new java.net.URL(urldisplay).openStream();
mIcon11 = BitmapFactory.decodeStream(in);
} catch (Exception e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return mIcon11;
}
protected void onPostExecute(Bitmap result) {
bmImage.setImageBitmap(result);
}
}
}
演员班：
public class Actors {
private String HaberBaslik;
private String HaberTarihi;
private String HaberKisatanim;
private String HaberlerLink;
private String HaberFoto;
private String Detay;
public Actors() {
}
//Getters and setters
public String getHaberBaslik() {
return HaberBaslik;
}
public void setHaberBaslik(String HaberBaslik) {
this.HaberBaslik = HaberBaslik;
}
public String getHaberTarihi() {
return HaberTarihi;
}
public void setHaberTarihi(String HaberTarihi) {
this.HaberTarihi = HaberTarihi;
}
public String getHaberKisatanim() {
return HaberKisatanim;
}
public void setHaberKisatanim(String HaberKisatanim) {
this.HaberKisatanim = HaberKisatanim;
}
public String getHaberlerLink() {
return HaberlerLink;
}
public void setHaberlerLink(String HaberlerLink) {
this.HaberlerLink = HaberlerLink;
}
public String getDetay() {
return Detay;
}
public void setDetay(String Detay) {
this.Detay = Detay;
}
public String getHaberFoto() {
return HaberFoto;
}
public void setHaberFoto(String HaberFoto) {
this.HaberFoto = "http://www.developers.net/images/"+HaberFoto;
}
}
的ListView：
ArrayList actorsList; ActorAdapter适配器;
new JSONAsyncTask（）。execute（＆＃34; http://www.developers.net/WebServices/GetJson.aspx?q=Haber＆＃34;）;
ListView listview = (ListView) findViewById(R.id.list);
adapter = new ActorAdapter(getApplicationContext(), R.layout.row, actorsList);
listview.setAdapter(adapter);
// JSONAsyncTask
class JSONAsyncTask extends AsyncTask<String, Void, Boolean> {
ProgressDialog dialog;
@Override
protected void onPreExecute() {
super.onPreExecute();
dialog = new ProgressDialog(haberler.this);
dialog.setMessage("Lütfen bekleyin.");
dialog.setTitle("İçerik Yüklemesi");
dialog.show();
dialog.setCancelable(false);
}
@Override
protected Boolean doInBackground(String... urls) {
try {
//------------------>>
HttpGet httppost = new HttpGet(urls[0]);
HttpClient httpclient = new DefaultHttpClient();
HttpResponse response = httpclient.execute(httppost);
// StatusLine stat = response.getStatusLine();
int status = response.getStatusLine().getStatusCode();
if (status == 200) {
HttpEntity entity = response.getEntity();
String data = EntityUtils.toString(entity);
JSONObject jsono = new JSONObject(data);
JSONArray jarray = jsono.getJSONArray("Haberler");
for (int i = 0; i < jarray.length(); i++) {
JSONObject object = jarray.getJSONObject(i);
Actors actor = new Actors();
actor.setHaberBaslik(object.getString("Baslik"));
actor.setHaberKisatanim(object.getString("Kisa"));
actor.setDetay(object.getString("Detay"));
actor.setHaberTarihi(object.getString("Tarih").replace("00:00:00",""));
actor.setHaberFoto(object.getString("Foto"));
actorsList.add(actor);
}
return true;
}
//------------------>>
} catch (ParseException e1) {
e1.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
return false;
}
protected void onPostExecute(Boolean result) {
dialog.cancel();
adapter.notifyDataSetChanged();
if (result == false)
Toast.makeText(getApplicationContext(), "Veri alınamıyor.Lütfen daha sonra tekrar deneyin.", Toast.LENGTH_LONG).show();
}
}