Extending ArrayAdapter in android

Question

I need to override a getFilter() method from the class ArrayAdapter and i found the source code from here in the github

//package         


        

Answer 1

Perhaps this may help you:

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import android.content.Context;
import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.Filter;

public class CustomAdapter extends ArrayAdapter {

    private final ArrayList mOriginalValues;
    private List mObjects;
    private CustomFilter mFilter;
    private final Object mLock = new Object();
    public CustomAdapter(Context context, int textViewResourceId, T[] objects) {
        super(context, textViewResourceId, objects);

        mObjects = Arrays.asList(objects);
        mOriginalValues = (ArrayList) Arrays.asList(objects);
        // TODO Auto-generated constructor stub
    }

    @Override
    public Filter getFilter() {
        // TODO Auto-generated method stub
        if (mFilter == null) {
            mFilter = new CustomFilter();
        }
        return mFilter;
    }


    private class CustomFilter extends Filter {
        @Override
        protected FilterResults performFiltering(CharSequence prefix) {
            FilterResults results = new FilterResults();
            Log.d("bajji", "its ---> " + prefix);

            if (prefix == null || prefix.toString().trim().length() == 0) {
                ArrayList list;
                synchronized (mLock) {
                    list = new ArrayList(mOriginalValues);
                }
                results.values = list;
                results.count = list.size();
            } else {
                String prefixString = prefix.toString().toLowerCase();

                ArrayList values;
                synchronized (mLock) {
                    values = new ArrayList(mOriginalValues);
                }

                final int count = values.size();
                final ArrayList newValues = new ArrayList();
                final ArrayList approxValues = new ArrayList();
                final ArrayList secondApproxValues = new ArrayList();


                for (int i = 0; i < count; i++) {
                    final T value = values.get(i);
                    final String valueText = value.toString().toLowerCase();
                    boolean flag = true;
                    // First match against the whole, non-splitted value
                    if (valueText.startsWith(prefixString)) {
                        newValues.add(value);
                        flag = false;
                    } else {
                        final String[] words = valueText.split(" ");
                        final int wordCount = words.length;

                        // Start at index 0, in case valueText starts with space(s)
                        for (int k = 0; k < wordCount; k++) {
                            if (words[k].startsWith(prefixString)) {
                                newValues.add(value);
                                flag = false;
                                break;
                            } 
                        }
                    }

                    if(flag) {
                        if(approxMatch(valueText, prefixString) <= 3) { //change the stuff and do a levi work
                            approxValues.add(value);
                        }
                        else {
                            final String[] words = valueText.split(" ");
                            final int wordCount = words.length;

                            // Start at index 0, in case valueText starts with space(s)
                            for (int k = 0; k < wordCount; k++) {
                                if(approxMatch(words[k], prefixString) <= 3) {
                                    //leve work
                                    secondApproxValues.add(value);
                                    break;
                                }
                            }
                        }
                    }
                }
                newValues.addAll(approxValues);
                newValues.addAll(secondApproxValues);
                results.values = newValues;
                results.count = newValues.size();
            }
            return results;
        }
        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) {
            //noinspection unchecked
            mObjects = (List) results.values;
            notifyDataSetChanged();
            clear();
            for(T tmp : mObjects){
                add(tmp);
            }

            notifyDataSetChanged();
        }
    }

    private int approxMatch (String s, String t) {
          // an approxmimate string matching algo
          return p;
    }
}

Now in getView method of adapter, you need to refer to mObjects object to get recent available values for ListView