【发布时间】：2014-01-17 03:44:06
【问题描述】：
我的 ImageView 每 6 个项目在 ListView 上重复 这是我的 CustomAdapter 代码
public class NewsAdapter extends ArrayAdapter<NewsContainer> {
private Context context;
private NewsContainer[] newsContainer;
public NewsAdapter(Context context, int textViewResourceID, NewsContainer[] newsContainers) {
super(context, textViewResourceID, newsContainers);
this.newsContainer = newsContainers;
this.context = context;
}
@Override
public long getItemId(int position){
return position;
}
public View getView(int position, View view, ViewGroup parent){
viewHolder holder = null;
if(view == null){
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = inflater.inflate(R.layout.news_listview, null);
holder = new viewHolder();
holder.image = (ImageView) view.findViewById(R.id.thumbnail);
holder.title = (TextView) view.findViewById(R.id.title);
holder.created_date = (TextView) view.findViewById(R.id.created_date);
holder.category = (TextView) view.findViewById(R.id.category);
holder.post_count = (TextView) view.findViewById(R.id.post_count);
view.setTag(holder);
} else {
holder = (viewHolder) view.getTag();
}
NewsContainer news = newsContainer[position];
SimpleDateFormat format = new SimpleDateFormat("DD/MM/yyyy", Locale.US);
if(news != null){
String date = format.format(news.getCreatedDate());
holder.title.setText(news.getTitle());
holder.post_count.setText(String.valueOf(news.getPostCount()));
holder.created_date.setText(date);
holder.category.setText(Html.fromHtml(news.getCategory()));
if(!news.getThumbnail().equals("empty")){
new ImageDownloaderTask(holder.image).execute(news.getThumbnail());
}
}
return view;
}
static class viewHolder {
ImageView image;
TextView title;
TextView created_date;
TextView category;
TextView post_count;
}
ImageDownloader 类
public class ImageDownloaderTask extends AsyncTask<String, Void, Bitmap> {
private final WeakReference<ImageView> imageViewWeakReference;
public ImageDownloaderTask(ImageView imageView) {
this.imageViewWeakReference = new WeakReference<ImageView>(imageView);
}
@Override
protected Bitmap doInBackground(String... params) {
return downloadBitmap(params[0]);
}
@Override
protected void onPostExecute(Bitmap bitmap){
if(isCancelled()){
bitmap = null;
}
if(imageViewWeakReference != null){
ImageView imageView = imageViewWeakReference.get();
if(imageView != null){
if(bitmap != null){
imageView.setImageBitmap(bitmap);
} else {
imageView.setImageDrawable(imageView.getContext().getResources().getDrawable(R.drawable.ic_loading_image));
}
}
}
}
@TargetApi(Build.VERSION_CODES.FROYO)
static Bitmap downloadBitmap(String url) {
final AndroidHttpClient client = AndroidHttpClient.newInstance("Android");
final HttpGet getRequest = new HttpGet(url);
try {
HttpResponse response = client.execute(getRequest);
final int statusCode = response.getStatusLine().getStatusCode();
if (statusCode != HttpStatus.SC_OK) {
Log.w("ImageDownloader", "Error " + statusCode
+ " while retrieving bitmap from " + url);
return null;
}
final HttpEntity entity = response.getEntity();
if (entity != null) {
InputStream inputStream = null;
try {
inputStream = entity.getContent();
final Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
return bitmap;
} finally {
if (inputStream != null) {
inputStream.close();
}
entity.consumeContent();
}
}
} catch (Exception e) {
// Could provide a more explicit error message for IOException or
// IllegalStateException
getRequest.abort();
Log.w("ImageDownloader", "Error while retrieving bitmap from " + url);
} finally {
if (client != null) {
client.close();
}
}
return null;
}
我曾尝试使用 ViewHolder 但 ImageView 不断重复，并发现 ListView 回收其视图以保持较低的内存占用。但我不明白如何解决这个问题。
【问题讨论】：
-
在您的适配器中覆盖 getCount() 方法有帮助吗？在这里，您基本上返回 newsContainer.size();
标签： android listview android-listview android-imageview