Filtering ListView with custom (object) adapter
You need to do a few things:
1) In your activity, register for a text change listener on your EditText that contains the value the user enters:
mSearchValue.addTextChangedListener(searchTextWatcher);
2) Create your searchTextWatcher and have it do something:
private TextWatcher searchTextWatcher = new TextWatcher() {
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
// ignore
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
// ignore
}
@Override
public void afterTextChanged(Editable s) {
Log.d(Constants.TAG, "*** Search value changed: " + s.toString());
adapter.getFilter().filter(s.toString());
}
};
3) Override getFilter() in your custom adapter and have it filter the results and notify the listview that the dataset has changed.
@Override
public Filter getFilter() {
return new Filter() {
@SuppressWarnings("unchecked")
@Override
protected void publishResults(CharSequence constraint, FilterResults results) {
Log.d(Constants.TAG, "**** PUBLISHING RESULTS for: " + constraint);
myData = (List<MyDataType>) results.values;
MyCustomAdapter.this.notifyDataSetChanged();
}
@Override
protected FilterResults performFiltering(CharSequence constraint) {
Log.d(Constants.TAG, "**** PERFORM FILTERING for: " + constraint);
List<MyDataType> filteredResults = getFilteredResults(constraint);
FilterResults results = new FilterResults();
results.values = filteredResults;
return results;
}
};
}
Here an interesting example
public Filter getFilter() {
return new Filter() {
@Override
protected FilterResults performFiltering(CharSequence constraint) {
final FilterResults oReturn = new FilterResults();
final ArrayList<station> results = new ArrayList<station>();
if (orig == null)
orig = items;
if (constraint != null) {
if (orig != null && orig.size() > 0) {
for (final station g : orig) {
if (g.getName().toLowerCase()
.contains(constraint.toString()))
results.add(g);
}
}
oReturn.values = results;
}
return oReturn;
}
@SuppressWarnings("unchecked")
@Override
protected void publishResults(CharSequence constraint,
FilterResults results) {
items = (ArrayList<station>) results.values;
notifyDataSetChanged();
}
};
}
public void notifyDataSetChanged() {
super.notifyDataSetChanged();
notifyChanged = true;
}
For those who don't need the Filterable
interface, there is a much simpler solution. This also handles notifyDataSetChanged()
correctly where the other solutions fail. Note that you need to add a getArray()
function to the BaseAdapter
that just returns the array object that was passed to the constructor.
public abstract class BaseFilterAdapter<T> extends BaseAdapter<T> {
private List<T> original;
private String lastFilter;
public BaseFilterAdapter(Context context, List<T> array) {
super(context, new LinkedList<T>());
original = array;
filter("");
}
protected abstract Boolean predicate(T element, String filter);
public void filter(String filter) {
lastFilter = filter;
super.getArray().clear();
for (T element : original)
if (predicate(element, filter))
super.getArray().add(element);
super.notifyDataSetChanged();
}
@Override
public List<T> getArray() {
return original;
}
@Override
public void notifyDataSetChanged() {
filter(lastFilter);
}
}