我有一个带有图像和按钮的listview应用程序。但是，一旦我单击holder.RSVP并执行了RemoteDataTask，该应用程序就会运行，如果我尝试继续将列表视图向下滚动到其他图像，则该应用程序将崩溃。日志猫读取“无效索引3，java.util.Arraylist.throwIndexOutofBoundsException的大小为0”。我的猜测是该错误发生在内部PostComment类中（成功== 1）。
public class ListViewAdapter4 extends BaseAdapter {
public ListViewAdapter4(Context context,
List<WorldPopulation2> worldpopulationlist) {
this.context = context;
this.worldpopulationlist = worldpopulationlist;
inflater = LayoutInflater.from(context);
this.arraylist = new ArrayList<WorldPopulation2>();
this.arraylist.addAll(worldpopulationlist);
}
public class ViewHolder {
TextView Username;
TextView Filename;
ImageView flag;
ImageView success;
TextView location;
TextView message;
ImageView event;
Button button1;
Layout mLayout;
ImageButton RSVP;
ImageButton done;
TextView responses;
}
@Override
public int getCount() {
return worldpopulationlist.size();
}
@Override
public Object getItem(int position) {
return worldpopulationlist.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
public View getView(final int position, View view, ViewGroup parent) {
final ViewHolder holder;
if (view == null) {
holder = new ViewHolder();
view = inflater.inflate(R.layout.dialogprofile, null);
// Locate the TextViews in listview_item.xml
ParseUser currentUser = ParseUser.getCurrentUser();
struser = currentUser.getUsername().toString();
holder.RSVP = (ImageButton) view.findViewById(R.id.rsvp);
holder.success = (ImageView) view.findViewById(R.id.humble);
holder.Username = (TextView) view.findViewById(R.id.username);
holder.location = (TextView) view.findViewById(R.id.location);
holder.message = (TextView) view.findViewById(R.id.message1);
holder.event = (ImageView) view.findViewById(R.id.imageView1);
holder.done = (ImageButton) view.findViewById(R.id.done);
holder.done.setVisibility(View.INVISIBLE);
holder.responses = (TextView) view.findViewById(R.id.responses);
view.setTag(holder);
} else {
holder = (ViewHolder) view.getTag();
}
});
holder.RSVP.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
holder.done.setVisibility(View.VISIBLE);
holder.RSVP.setVisibility(View.INVISIBLE);
seconduser = worldpopulationlist.get(position).getUsername();
seconduserfile = worldpopulationlist.get(position).getFilename();
secondlocation = worldpopulationlist.get(position).getLocation();
new RemoteDataTask().execute();
}
});
private class RemoteDataTask extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// mProgressDialog.show();
}
@Override
protected Void doInBackground(Void... params) {
worldpopulationlist = new ArrayList<WorldPopulation2>();
mCommentList = new ArrayList<HashMap<String, String>>();
JSONParser jParser = new JSONParser();
JSONObject json = jParser.getJSONFromUrl(READ_COMMENTS_URL);
try {
mComments = json.getJSONArray(TAG_POSTS);
Map<String, Object> example = new HashMap<String, Object>();
// looping through all posts according to the json object returned
for (int i = 0; i < mComments.length(); i++) {
JSONObject c = mComments.getJSONObject(i);
if (c.getString(TAG_USERNAME).contentEquals(struser)) {
username = c.getString(TAG_USERNAME);
filename = c.getString(TAG_FILENAME);
}
}
new PostComment().execute();
}catch (JSONException e) {
e.printStackTrace();
}
return null;
}
class PostComment extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
//pDialog.show();
}
@Override
protected String doInBackground(String... args) {
// TODO Auto-generated method stub
// Check for success tag
int success;
try {
// Building Parameters
message = username + " has RSVP'd to " + seconduser + "'s activity at " + secondlocation;
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("username", username));
params.add(new BasicNameValuePair("useronefile", filename));
params.add(new BasicNameValuePair("message", message));
params.add(new BasicNameValuePair("location", secondlocation));
params.add(new BasicNameValuePair("usernameone", seconduser));
params.add(new BasicNameValuePair("seconduserfile", seconduserfile));
Log.d("request!", "starting");
// Posting user data to script
JSONObject json = jsonParser.makeHttpRequest(POST_COMMENT_URL1,
"POST", params);
// full json response
Log.d("Post Comment attempt", json.toString());
// json success element
success = json.getInt(TAG_SUCCESS);
if (success == 1) {
} else {
Log.d("Comment Failure!", json.getString(TAG_MESSAGE));
return json.getString(TAG_MESSAGE);
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(String file_url) {
// dismiss the dialog once product deleted
//pDialog.dismiss();
if (file_url != null) {
}
}
}
}
}
Logcat：
FATAL EXCEPTION: main
Process: com.example PID:
java.lang.IndexOutOfBoundsException: Invalid index 2, size is 0
at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
at java.util.ArrayList.get(ArrayList.java:308)
at com.example.chronospect.ListViewAdapter4.getView(ListViewAdapter4.java:130)
at android.widget.AbsListView.obtainView(AbsListView.java:2255)
at android.widget.ListView.makeAndAddView(ListView.java:1790)
at android.widget.ListView.fillDown(ListView.java:691)
at android.widget.ListView.fillGap(ListView.java:655)
at android.widget.AbsListView.trackMotionScroll(AbsListView.java:5143)
at android.widget.AbsListView$FlingRunnable.run(AbsListView.java:4254)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
at android.view.Choreographer.doCallbacks(Choreographer.java:574)
at android.view.Choreographer.doFrame(Choreographer.java:543)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5086)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
最佳答案
当您调用RemoteDataTask时，您正在重置worldpopulationlist，因此一旦被调用，列表视图中的项目数将变为零，并且您会得到Exception