我想在更新 listview 之前显示一个圆圈，一切正常，而异步任务的 doinbackground 从服务器获取数据时显示进度条，但是在更新 listview 时它会冻结一段时间，然后显示 listview，我想删除它更新前冻结进度条，这是我的代码
public class feeds extends AsyncTask<Void, Void, ArrayList<HashMap<String, String>>>{
protected void onPreExecute() {
// SHOW THE SPINNER WHILE LOADING FEEDS
linlaHeaderProgress.setVisibility(View.VISIBLE);
}
@Override
protected ArrayList<HashMap<String, String>> doInBackground(Void... params) {
new_request_feeds(); //here i am fetching data from server
return fetch;
}
protected void onPostExecute(ArrayList<HashMap<String, String>> result) {
// HIDE THE SPINNER AFTER LOADING FEEDS
linlaHeaderProgress.setVisibility(View.GONE);
if(result.size()!=0)
{
adapter=new CustomListAdapter(getActivity(), R.id.list_ongoing, result);
list.setAdapter(adapter);
}
else
{
Toast.makeText(getActivity(), "no feeds", 3000).show();
}// Here if you wish to do future process for ex. move to another activity do here
}
我的getview（）
@Override
public View getView(int position, View convertView, ViewGroup parent) {
final int pos=position;
System.out.println(position);
View v = convertView;
final ViewHolder holder;
if (v == null) {
LayoutInflater vi =
(LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.feed_row, null);
holder = new ViewHolder();
holder.like=(ImageButton) v.findViewById(R.id.like);
holder.share=(ImageButton) v.findViewById(R.id.share);
holder.report=(ImageButton) v.findViewById(R.id.report);
holder.headline_text = (TextView) v.findViewById(R.id.lar);
holder.topic_text = (TextView) v.findViewById(R.id.mt);
holder.count_likes = (TextView) v.findViewById(R.id.count_likes);
holder.count_shares = (TextView) v.findViewById(R.id.count_shares);
holder.image = (ImageView) v.findViewById(R.id.img1);
holder.image2 = (ImageView) v.findViewById(R.id.img2);
v.setTag(holder);
}
else
holder=(ViewHolder)v.getTag();
mSharedPreferences= v.getContext().getSharedPreferences("mypref", 0);
holder.headline_text.setText(" "+entries.get(pos).get(TAG_FFN)+" had a chance with "+entries.get(pos).get(TAG_IFN)+"! ");
holder.topic_text.setText(entries.get(pos).get(TAG_TOPIC));
holder.image.setTag(entries.get(pos).get(TAG_FTID));
holder.image2.setTag(entries.get(pos).get(TAG_ITID));
holder.count_likes.setText(entries.get(pos).get(TAG_LIKERS)+" likes");
holder.count_shares.setText(entries.get(pos).get(TAG_SHARERS)+" shares");
if(entries.get(pos).get(TAG_LIKED).equals("True"))
{
holder.like.setImageResource(R.drawable.like);
holder.like.setTag("True");
}
else
{
holder.like.setTag("False");
}
if(entries.get(pos).get(TAG_SHARED).equals("True"))
{
holder.share.setImageResource(R.drawable.share);
holder.share.setEnabled(false);
}
//=======================setting image of user==========================================//
// Loader image - will be shown before loading image
// whenever you want to load an image from url
// call DisplayImage function
// url - image url to load
// loader - loader image, will be displayed before getting image
// image - ImageView
imgLoader.DisplayImage((image_url.getimage(Long.parseLong(entries.get(pos).get(TAG_FTID))))[0],loader, holder.image);
imgLoader.DisplayImage((image_url.getimage(Long.parseLong(entries.get(pos).get(TAG_ITID))))[0],loader, holder.image2);
//====================================================================================//
holder.image.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if((holder.image.getTag()).equals(mSharedPreferences.getString("USERID", null)))
{
Toast.makeText(v.getContext(), "Your profile", Toast.LENGTH_LONG).show();
}
else
{
Intent i=new Intent(v.getContext(),OtherProfilePage.class);
i.putExtra("Image_id",entries.get(pos).get(TAG_FTID));
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
(v.getContext()).startActivity(i);
}
}
});
holder.image2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(holder.image2.getTag().equals(mSharedPreferences.getString("USERID", null)))
{
Toast.makeText(v.getContext(), "Your profile", Toast.LENGTH_LONG).show();
}
else
{
Intent i=new Intent(v.getContext(),OtherProfilePage.class);
i.putExtra("Image_id", entries.get(pos).get(TAG_ITID));
(v.getContext()).startActivity(i);
}
}
});
holder.like.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(holder.like.getTag()=="True")
{
holder.like.setImageResource(R.drawable.like_pressed);
holder.like.setTag("False");
new sendlikes().execute("link");
}
else
{ holder.like.setImageResource(R.drawable.like);
holder.like.setTag("True");
new sendlikes().execute("link");
}
}
});
holder.share.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
holder.share.setImageResource(R.drawable.share);
holder.share.setEnabled(false);
new sendlikes().execute("http://gangster.cloudapp.net/share/",entries.get(pos).get(TAG_CID),mSharedPreferences.getString("person_id",null));
}
});
return v;
}
imageloader 是我用来缓存图像的一个类。