I need to override a getFilter()
method from the class ArrayAdapter
and i found the source code from here in the github
//package name
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;
import android.widget.Filterable;
public class CustomAdapter<T> extends ArrayAdapter<T> implements Filterable{
private ArrayList<T> mOriginalValues;
private List<T> 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);
// 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 (mOriginalValues == null) {
synchronized (mLock) {
mOriginalValues = new ArrayList<T>(mObjects);
}
}
if (prefix == null || prefix.length() == 0) {
ArrayList<T> list;
synchronized (mLock) {
list = new ArrayList<T>(mOriginalValues);
}
results.values = list;
results.count = list.size();
} else {
String prefixString = prefix.toString().toLowerCase();
ArrayList<T> values;
synchronized (mLock) {
values = new ArrayList<T>(mOriginalValues);
}
final int count = values.size();
final ArrayList<T> newValues = new ArrayList<T>();
final ArrayList<T> approxValues = new ArrayList<T>();
final ArrayList<T> secondApproxValues = new ArrayList<T>();
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<T>) results.values;
if (results.count > 0) {
notifyDataSetChanged();
} else {
notifyDataSetInvalidated();
}
}
}
private int approxMatch (String s, String t) {
// an approxmimate string matching algo
return p;
}
}
The problem is the getFilter method has a object of a private inner class ArrayFilter
which has a method peformFiltering
and i need to put a different code there so i have to overide the class. And i get an exception in the method.
In the derived class which extends ArrayAdapter i created a private inner class which is similar to ArrayFilter
and called it MyFilter
and i get the same exception again in the method performFiltering
.
I found a solution to solve my problem. I copied all the code in ArrayAdapter
class and created a new class called MyAdapter
and i altered some code inside the inner class ArrayFilter
and the app works the way i wanted it to. But i feel its not the best solution.
Android has various api levels so if the array adapter is changed in different api level then i have to add those changes in my codes to. So i feel the best way is to extend the class ArrayAdapter
to create MyAdapter
rather than just copying and pasting the code from the ArrayAdapter
How can i override the inner private class of a parent class..?
Edit: The exception i get..
Edit2: Now i added the full code in the question. and it works perfectly if i copy and edit the array adapter.. the problem is only when i extend..!! now the code and search is working perfectly. I checked it with Log.i
.. but the drop down list for auto complete suggestion in UI is not working.. i only get for the first character i type the next character filtering takes place but UI update is not taking place.
After some help from stackoverflow community i removed the exception and later i found out that the suggestions that are returned doesn't really change because the mObjects
was returned from the super class or base class. The problem was the there were two public methods getCount()
and getItem(int position)
which gets the count and fetches the list from mObjects from the base class. So i just have to add those two methods in my class..
public int getCount() {
return mObjects.size();
}
public T getItem(int position) {
return mObjects.get(position);
}
Now mObjects
of the derived class will be returned. Which are the updated in the dropdown list in the UI.
I am not a java expert, but this solves my problem. If you have any suggestions to make the code better please add it in comments or feel free to edit the answer.!