In my application I have create a custom list view and I want to implement a filter so that the list can be filtered according to the text entered in the EditText. I am using a BaseAdapter as a separate class and I am calling that class in my Main Activity. I have also implemented the addTextChangedListener() in my main activity and I have also implemented the getFilter() in my BaseAdapter class. But I don't know how can I use getFilter() and can filter my list accordingly. In the list I am adding the values from a JSON URL. Please help me in letting me know that how can I use the getFilter() in order to filter my List.
The code of Activity class:
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
lv = (ListView)findViewById(R.id.listView1);
et1 = (EditText)findViewById(R.id.editText1);
inflator = getLayoutInflater();
et1.addTextChangedListener(this);
JsonParser jParser = new JsonParser();
JSONObject json = jParser.getJSONfromUrl(url);
try
{
JSONArray explore = json.getJSONArray("explore");
for(int i=0; i<explore.length(); i++)
{
JSONObject exp = explore.getJSONObject(i);
list.add(exp.getString("username"));
}
}
catch(JSONException e)
{
e.printStackTrace();
}
srchadptr = new SearchAdapter(this, inflator, list);
lv.setAdapter(srchadptr);
}
public void afterTextChanged(Editable s) {
// TODO Auto-generated method stub
srchadptr.getFilter().filter(s);
}
public void beforeTextChanged(CharSequence s, int start, int count,
int after) {
// TODO Auto-generated method stub
}
public void onTextChanged(CharSequence s, int start, int before, int count) {
// TODO Auto-generated method stub
}
The code of BaseAdapter class:
public class SearchAdapter extends BaseAdapter implements Filterable {
Context context;
LayoutInflater inflater;
Button btn;
View vw;
ArrayList<String> list = new ArrayList<String>();
public SearchAdapter(Context context, LayoutInflater inflater, ArrayList<String> list) {
// TODO Auto-generated constructor stub
this.context = context;
this.inflater = inflater;
this.list = list;
}
/*public CharSequence filter(CharSequence cs) {
return cs;
}*/
public int getCount() {
// TODO Auto-generated method stub
return list.size();
}
public Object getItem(int position) {
// TODO Auto-generated method stub
return position;
}
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
public View getView(final int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
LinearLayout ll = (LinearLayout) vw;
final EditText edt = ((EditText)ll.getChildAt(0));
vw = inflater.inflate(R.layout.list_items, null);
ImageView img = (ImageView)vw.findViewById(R.id.imageView1);
TextView tv = (TextView)vw.findViewById(R.id.textView1);
btn = (Button)vw.findViewById(R.id.button1);
tv.setText(String.valueOf(list.get(position)));
btn.setText(String.valueOf(list.get(position)));
btn.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
Toast.makeText(context, list.get(position), Toast.LENGTH_LONG).show();
}
});
return vw;
}
public android.widget.Filter getFilter() {
// TODO Auto-generated method stub
return new android.widget.Filter() {
@Override
protected void publishResults(CharSequence constraint, FilterResults results) {
// TODO Auto-generated method stub
}
@Override
protected FilterResults performFiltering(CharSequence constraint) {
// TODO Auto-generated method stub
return null;
}
};
}
}
Thanks in advance...
i hope this example could help you
in the Main_Activity
EditText etSearch;
BaseAdapterFilterable adapter;
etSearch.addTextChangedListener(new TextWatcher() {
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
// Listview name of the class
Listview.this.adapter.getFilter().filter(s);
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count,
int after) {
// TODO Auto-generated method stub
}
@Override
public void afterTextChanged(Editable s) {
// TODO Auto-generated method stub
}
});
in your adapter put this class to use it in getfilter method
public class filter_here extends Filter{
@Override
protected FilterResults performFiltering(CharSequence constraint) {
// TODO Auto-generated method stub
FilterResults Result = new FilterResults();
// if constraint is empty return the original names
if(constraint.length() == 0 ){
Result.values = Original_Names;
Result.count = Original_Names.size();
return Result;
}
ArrayList<String> Filtered_Names = new ArrayList<String>();
String filterString = constraint.toString().toLowerCase();
String filterableString;
for(int i = 0; i<Original_Names.size(); i++){
filterableString = Original_Names.get(i);
if(filterableString.toLowerCase().contains(filterString)){
Filtered_Names.add(filterableString);
}
}
Result.values = Filtered_Names;
Result.count = Filtered_Names.size();
return Result;
}
@Override
protected void publishResults(CharSequence constraint,FilterResults results) {
// TODO Auto-generated method stub
Names = (ArrayList<String>) results.values;
notifyDataSetChanged();
}
}
also in your adapter return instance from filter_here class
@Override
public Filter getFilter() {
// TODO Auto-generated method stub
return filter;
}
In your BaseAdapter, store two copies of the list, one original, and one filtered. And change all references in your BaseAdapter, to only use the filtered list.
1) in your activity, activate the filter on your ListView: lv.setTextFilterEnabled(true);
2) in your textWatcher, trigger the filter on your listadapter srchadptr.getFilter().filter(s)
3) Update your baseadapter to store two copies of the data, and change references to refer to the filtered list instead of the original list.
public class SearchAdapter extends BaseAdapter implements Filterable {
List<String> list = new ArrayList<String>();
List<String> listFiltered = new ArrayList<String>();
public SearchAdapter(Context context, ArrayList<String> list) {
this.context = context;
this.inflater = LayoutInflater.from(context)
this.list = list;
this.listFiltered=list;
}
public int getCount() {
return listFiltered.size();//note the change
}
public Object getItem(int position) {
return listFiltered.get(position);//note the change
}
//only altered lines shown in this function (change ``list`` to ``listFiltered``)
public View getView(final int position, View convertView, ViewGroup parent) {
tv.setText(String.valueOf(listFiltered.get(position)));
btn.setText(String.valueOf(listFiltered.get(position)));
btn.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
Toast.makeText(context, listFiltered.get(position), Toast.LENGTH_LONG).show();
}
});
}
//now write your filter function
@Override
public Filter getFilter() {
return new Filter() {
@Override
protected FilterResults performFiltering(CharSequence constraint) {
FilterResults results = new FilterResults();
if (constraint == null || constraint.length() == 0) {
//no constraint given, just return all the data. (no search)
results.count = list.size();
results.values = list;
} else {//do the search
List<String> resultsData = new ArrayList<>();
String searchStr = constraint.toString().toUpperCase();
for (String s : list)
if (s.toUpperCase().contains(searchStr)) resultsData.add(s);
results.count = resultsData.size();
results.values = resultsData;
}
return results;
}
@Override
protected void publishResults(CharSequence constraint, FilterResults results) {
listFiltered = (ArrayList<String>) results.values;
notifyDataSetChanged();
}
};
}
I find working with filters not all that convenient.. How i do it is:
((EditText)findViewById(R.id.etSearch)).addTextChangedListener(new TextWatcher(){
private boolean mCountIncreased;
@Override
public void afterTextChanged(Editable s) {
if (s.toString().length() == 0){
mDisplayedList.clear();
mDisplayedList.addAll(mFullList);
mListAdapter.notifyDataSetChanged();
return;
}
if (mCountIncreased){
mDisplayedList.clear();
mDisplayedList.addAll(mFullList);
}
List<Item> toRemove = new ArrayList<Item>();
for (Item item : mDisplayedList){
if (someCondition)
toRemove.add(currency);
}
}
mDisplayedList.removeAll(toRemove);
mListAdapter.notifyDataSetChanged();
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
mCountIncreased = after <= count;
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {}
});
}
Note that you'll have to change your adapter to work with the mDisplayedList instead of the mFullList.. and that's it.
This might give some overhead when your list contains ALOT of entries.. but i've worked like this with a list of +-300 items and i didn't notice anything.
Hope it helps, Vlad
来源：https://stackoverflow.com/questions/12456525/how-to-filter-listview-using-getfilter-in-baseadapter