在android數組適配器中使用notifyDataSetChanged時出錯

Question

11-06 19：52：25.958：E / AndroidRuntime（29609）：java.lang.IllegalStateException：適配器的內容已更改，但ListView未收到通知。 確保不從后台線程修改適配器的內容，而只是從UI線程修改。 [在ListView（-1，類android.widget.ListPopupWindow $ DropDownListView）中使用Adapter（類com.example.parkfoxxlight_android.PlacesAutoCompleteAdapter）]

完整日志： http ： //pastebin.com/Hx7k28Rm

適配器的完整代碼： http ： //pastebin.com/TfH1bXE3我使用的是https://developers.google.com/places/training/autocomplete-android中的示例，它有相當的默認代碼，因此它似乎有一個谷歌代碼中的錯誤？

應用程序有時會崩潰，但上面的錯誤消息。

protected void publishResults(CharSequence constraint,
        FilterResults results) {

    if (results != null && results.count > 0) {
        notifyDataSetChanged();
    } else {
        notifyDataSetInvalidated();
    }
}

活動http://pastebin.com/FYzYtvXY ：

public class CityActivity extends Activity{

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.city);

            AutoCompleteTextView autoCompView = (AutoCompleteTextView) findViewById(R.id.autocomplete_city);

            PlacesAutoCompleteAdapter ad = new PlacesAutoCompleteAdapter(this);
            ProgressBar b = (ProgressBar)findViewById(R.id.progressBar1);
            ad.setLoadingIndicator(b);

            autoCompView.setAdapter(ad);
        }
}

任何想法如何解決這一問題？ 我在android 4.3上。

Answer 1

Filter的performFiltering()方法在后台線程上運行，並且從該方法更改適配器所基於的resultList 。 如果你更改了那個數據列表，那么ListView訪問適配器就會看到一些東西在沒有它知情的情況下發生了變化（並且不會很高興）。 您應該避免在performFiltering方法中使用resultList ，只需創建一個新的臨時列表：

// in the performFiltering method which runs on a background thread:
@Override
protected FilterResults performFiltering(CharSequence constraint) {
     FilterResults filterResults = new FilterResults();
     ArrayList<String> queryResults;
     if (constraint != null && constraint.length() > 0) {
         queryResults = autocomplete(constraint);
     } else {
         queryResults = new ArrayList<String>(); // empty list/no suggestions showing if there's no valid constraint
     }
     filterResults.values = queryResults;
     filterResults.count = queryResults.size();
     return filterResults; // ## Heading ##
}

private List<String> autocomplete(String input) {
   // don't use the here the resultList List on which the adapter is based!
   // some custom code to get items from http connection
     ArrayList<String> queryResults = new ArrayList<String>(); // new list
     queryResults.add("Some String");
     return queryResults;
}

@Override
protected void publishResults(CharSequence constraint, FilterResults results) {
     // update the data with the new set of suggestions
     resultList = (ArrayList<String>)results.values;
     if (results.count > 0) {
         notifyDataSetChanged();
     } else {
         notifyDataSetInvalidated();
     }
}

Answer 2

試試這個（只是一個猜測）：

@Override
    public Filter getFilter() {
        Filter filter = new Filter() {
            @Override
            protected FilterResults performFiltering(CharSequence constraint) {
                FilterResults filterResults = new FilterResults();
                if (constraint != null) {
                    ArrayList list = autocomplete(constraint.toString());
                    if (list != null) {
                        filterResults.values = list;
                        filterResults.count = list.size();
                    }
                }
                return filterResults;
            }

            @Override
            protected void publishResults(CharSequence constraint, FilterResults results) {
                if (results != null && results.count > 0) {
                    //change the underlying data immediately before notifying UI                        
                    resultList = (ArrayList)results.values; 
                    notifyDataSetChanged();
                }
                else {
                    notifyDataSetInvalidated();
                }
            }};
        return filter;
    }