我正在尝试解析xml文件，并尝试加载图像和文本视图，并将其显示在列表视图中，但每当我尝试在getView方法中加载图像时，即使尝试快速滚动，也会关闭应用程序。我厌倦了在线程和异步任务中做5个小时。如果有人能解决这个问题，请帮忙。这是我的两个类文件。
class NewsRowAdapter
public class NewsRowAdapter extends ArrayAdapter<Item>
{
LoadingImage loadingImage;
Bitmap bitmap = null;
private Activity activity;
private List<Item> items;
private Item objBean;
private int row;
public NewsRowAdapter(Activity act, int resource, List<Item> arrayList)
{
super(act, resource, arrayList);
this.activity = act;
this.row = resource;
this.items = arrayList;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent)
{
View view = convertView;
final ViewHolder holder;
if (view == null)
{
LayoutInflater inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = inflater.inflate(row, null);
holder = new ViewHolder();
view.setTag(holder);
} else
{
holder = (ViewHolder) view.getTag();
}
if ((items == null) || ((position + 1) > items.size()))
return view;
objBean = items.get(position);
holder.tvTitle = (TextView) view.findViewById(R.id.tvtitle);
holder.tvDesc = (TextView) view.findViewById(R.id.tvdesc);
holder.tvDate = (TextView) view.findViewById(R.id.tvdate);
holder.imgView = (ImageView) view.findViewById(R.id.image);
holder.pbar = (ProgressBar) view.findViewById(R.id.pbar);
if (holder.tvTitle != null && null != objBean.getTitle() && objBean.getTitle().trim().length() > 0)
{
holder.tvTitle.setText(Html.fromHtml(objBean.getTitle()));
}
if (holder.tvDesc != null && null != objBean.getDesc() && objBean.getDesc().trim().length() > 0)
{
holder.tvDesc.setText(Html.fromHtml(objBean.getDesc()));
}
if (holder.tvDate != null && null != objBean.getPubdate() && objBean.getPubdate().trim().length() > 0)
{
holder.tvDate.setText(Html.fromHtml(objBean.getPubdate()));
}
if (holder.imgView != null)
{
if (null != objBean.getLink() && objBean.getLink().trim().length() > 0)
{
final ProgressBar pbar = holder.pbar;
pbar.setVisibility(View.INVISIBLE);
//---------CHANGES MADE FOR LOADING IMAGE----------//
Log.d("IMAGE NULL----------", objBean.getLink());
//loadBitmap(objBean.getLink());
/*new Thread()
{
public void run()
{*/
try
{
URL linkurl = new URL(objBean.getLink());
bitmap = BitmapFactory.decodeStream(linkurl.openConnection().getInputStream());
holder.imgView.setImageBitmap(bitmap);
} catch (MalformedURLException e)
{
e.printStackTrace();
} catch (IOException e)
{
e.printStackTrace();
}
/*}
}.start();*/
} else
{
holder.imgView.setImageResource(R.drawable.ic_launcher);
}
}
return view;
}
//------LOADING IMAGE FROM URL------//
public static Bitmap loadBitmap(String url)
{
Bitmap bitmap = null;
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.d("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();
bitmap = BitmapFactory.decodeStream(inputStream);
} 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.d("Error while retrieving bitmap from " + url, e.toString());
} finally
{
if (client != null)
{
client.close();
}
}
return bitmap;
}
public class ViewHolder
{
public TextView tvTitle, tvDesc, tvDate;
private ImageView imgView;
private ProgressBar pbar;
}
}
主要类别为：
类主活动
public class MainActivity extends Activity implements OnItemClickListener
{
private static final String rssFeed = /*"https://www.dropbox.com/s/t4o5wo6gdcnhgj8/imagelistview.xml?dl=1"*/"http://78.46.34.27/kapapps/newparsedtransaction.xml";
List<Item> arrayOfList;
ListView listView;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.mainnewtransaction);
listView = (ListView) findViewById(R.id.listview);
listView.setOnItemClickListener(this);
if (Utils.isNetworkAvailable(NewTransactionActivity.this))
{
new MyTask().execute(rssFeed);
} else
{
showToast("No Network Connection!!!");
}
}
// My AsyncTask start...
class MyTask extends AsyncTask<String, Void, Void>
{
ProgressDialog pDialog;
@Override
protected void onPreExecute()
{
super.onPreExecute();
pDialog = new ProgressDialog(NewTransactionActivity.this);
pDialog.setTitle("Latest Transaction");
pDialog.setMessage("Loading... Please wait");
pDialog.show();
}
@Override
protected Void doInBackground(String... params)
{
arrayOfList = new NamesParser().getData(params[0]);
return null;
}
@Override
protected void onPostExecute(Void result)
{
super.onPostExecute(result);
if (null == arrayOfList || arrayOfList.size() == 0)
{
showToast("No data found from web!!!");
NewTransactionActivity.this.finish();
} else
{
// check data...
/*
* for (int i = 0; i < arrayOfList.size(); i++)
* {
* Item item = arrayOfList.get(i); System.out.println(item.getId());
* System.out.println(item.getTitle());
* System.out.println(item.getDesc());
* System.out.println(item.getPubdate());
* System.out.println(item.getLink());
* }
*/
for(int i = 0 ; i < arrayOfList.size() ; i++)
{
Item item = arrayOfList.get(i);
Log.d("ID NEWTRANSACTION ACTIVITY ------>" , item.getId());
Log.d("TITLE NEWTRANSACTION ACTIVITY ------>" , item.getTitle());
Log.d("DESC NEWTRANSACTION ACTIVITY ------>", item.getDesc());
Log.d("LINK NEWTRANSACTION ACTIVITY ------>", item.getLink());
}
setAdapterToListview();
}
if (null != pDialog && pDialog.isShowing())
{
pDialog.dismiss();
}
}
}
@Override
public void onItemClick(AdapterView<?> parent , View view , int position , long id)
{
Item item = arrayOfList.get(position);
Intent intent = new Intent(NewTransactionActivity.this, DetailActivity.class);
intent.putExtra("url", item.getLink());
intent.putExtra("title", item.getTitle());
intent.putExtra("desc", item.getDesc());
Log.d("IMAGE_URL------>" , item.getLink());
startActivity(intent);
}
public void setAdapterToListview()
{
NewsRowAdapter objAdapter = new NewsRowAdapter(NewTransactionActivity.this , R.layout.row, arrayOfList);
listView.setAdapter(objAdapter);
}
public void showToast(String msg)
{
}
}
在另一个线程中执行图像检索逻辑。加载图像花费了太多时间，这就是您获得ANR的原因。
使用单个工作线程，并使其可以在活动的onPause（）中停止。好的方法是使用单线程执行器服务来加载图像。
下面是一个例子https://stackoverflow.com/a/14579365/1366471
我建议使用Prime库中的RemoteImageView。这大大减少了你的工作量。
在布局中，将ImageView替换为com.handlerexploit.prime.widgets.RemoteImageView，在代码中，将holder类中的ImageView更改为RemoteImageView。
在getView方法中，
holder.imgView = (RemoteImageView) view.findViewById(R.id.image);
//...
holder.imgView.setImageURL(objBean.getLink());