How to implement getfilter() with custom adapter that extends baseadapter

Question

here is my main activity

package com.javacodegeeks.android.lbs;

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.Toast;
import lbs.promotion.*;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import org.apache.http.NameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.AdapterView.OnItemClickListener;

public class Curve extends Activity {

    private ProgressDialog pDialog;
     JSONParser jParser = new JSONParser();
     ArrayList<HashMap<String, String>> DaftarPromotion = new ArrayList<HashMap<String, String>>();

     private static String url_daftar_promotion = "http://10.0.2.2/webserver_maaug/promotion/daftar_promotion.php";

     String lon = "101.5178";
     String lat = "3.0724";

     public static final String TAG_SUCCESS = "success";
     public static final String TAG_DAFTAR_PROMOTION = "daftar_promotion";
     public static final String TAG_ID_PROMO = "PromoID";
     public static final String TAG_NAMA_PROMO = "PromoName";
     public static final String TAG_LINK_IMAGE_PROMO = "PromoImage";
     public static final String TAG_DESC_PROMO= "PromoDesc";
     public static final String TAG_CATE_PROMO = "PromoCate";
     public static final String TAG_CONT_PROMO = "PromoContact";
     public static final String TAG_DATES_PROMO = "PromoDateStart";
     public static final String TAG_DATEE_PROMO = "PromoDateEnd";

     JSONArray daftar_promotion = null;

     ListView list;

     PromotionListAdapter adapter;

     EditText inputSearch;

     private Curve activity;

     @Override
     public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.activity_curve);
     DaftarPromotion = new ArrayList<HashMap<String, String>>();

      new Activity().execute();
      activity = this;
      list = (ListView) findViewById(R.id.list);

      inputSearch = (EditText) findViewById(R.id.search_box);

      inputSearch.addTextChangedListener(new TextWatcher() {

            @Override
            public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) {
                // When user changed the Text
                Curve.this.adapter.getFilter().filter(cs);
            }

            @Override
            public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
                    int arg3) {
                // TODO Auto-generated method stub

            }

            @Override
            public void afterTextChanged(Editable arg0) {
                // TODO Auto-generated method stub
            }
        }); 




      list.setOnItemClickListener(new OnItemClickListener() {
      @Override
      public void onItemClick(AdapterView<?> parent, View view,
      int position, long id) {
          HashMap<String, String> map = DaftarPromotion.get(position);
          String pna = map.get(TAG_NAMA_PROMO);
          String pde = map.get(TAG_DESC_PROMO);
          String pca = map.get(TAG_CATE_PROMO);
          String pcon = map.get(TAG_CONT_PROMO);
          String pds = map.get(TAG_DATES_PROMO);
          String pdae = map.get(TAG_DATEE_PROMO);



            Toast.makeText(Curve.this, pna +"\n" + pde +"\n" + pca +"\n" + pds +" to " + pdae +"\n" + pcon,Toast.LENGTH_LONG).show();

      }
      }); 



      }


     public boolean onCreateOptionsMenu(Menu menu) {
            MenuInflater inflater = getMenuInflater();
            inflater.inflate(R.menu.smenu, menu);
            return true;
        }
     public boolean onOptionsItemSelected(MenuItem item) {
         switch (item.getItemId()) {
            case R.id.about:
                 Toast.makeText(Curve.this,"Mobile Advertising Application Using GPS V1.0",Toast.LENGTH_LONG).show();
            return true;
            case R.id.search:{
                 Intent intent = new Intent(Curve.this, Search.class);
                 intent.putExtra("lon",lon);
                 intent.putExtra("lat",lat);
                 startActivity(intent);
            //startActivity(new Intent(this, Search.class));

            }
            return true;
            default:
            return super.onOptionsItemSelected(item);
        }
        }

      public void SetListViewAdapter(ArrayList<HashMap<String, String>> daftar) {
      adapter = new PromotionListAdapter(activity, daftar);
      list.setAdapter(adapter);
      }

      @Override
      protected void onActivityResult(int requestCode, int resultCode, Intent data) {
      super.onActivityResult(requestCode, resultCode, data);
      if (resultCode == 100) {
      Intent intent = getIntent();
      finish();
      startActivity(intent);
      }
      }

      class Activity extends AsyncTask<String, String, String> {

      @Override
      protected void onPreExecute() {
      super.onPreExecute();
      pDialog = new ProgressDialog(Curve.this);
      pDialog.setMessage("Please Wait...");
      pDialog.setIndeterminate(false);
      pDialog.setCancelable(false);
      pDialog.show();
      }

      protected String doInBackground(String... args) {
      List<NameValuePair> params = new ArrayList<NameValuePair>();
      JSONObject json = jParser.makeHttpRequest(url_daftar_promotion, "GET",params);

      Log.d("All Products: ", json.toString());
      try {
      int success = json.getInt(TAG_SUCCESS);
      if (success == 1) {
           daftar_promotion = json.getJSONArray(TAG_DAFTAR_PROMOTION);
           for (int i = 0; i < daftar_promotion.length();i++){
           JSONObject c = daftar_promotion.getJSONObject(i);
           String PromoID = c.getString(TAG_ID_PROMO);
           String PromoName = c.getString(TAG_NAMA_PROMO);
           String pat = "http://10.0.2.2/webserver_maaug/";
           String PromoImage = pat + c.getString(TAG_LINK_IMAGE_PROMO);
           String PromoDesc = c.getString(TAG_DESC_PROMO);
           String PromoCate = c.getString(TAG_CATE_PROMO);
           String PromoDateStart = c.getString(TAG_DATES_PROMO);
           String PromoDateEnd = c.getString(TAG_DATEE_PROMO);
           String PromoContact = c.getString(TAG_CONT_PROMO);

           HashMap<String, String> map = new HashMap<String, String>();

           map.put(TAG_ID_PROMO, PromoID);
           map.put(TAG_NAMA_PROMO, PromoName);
           map.put(TAG_LINK_IMAGE_PROMO, PromoImage);
           map.put(TAG_DESC_PROMO, PromoDesc);
           map.put(TAG_CATE_PROMO, PromoCate);
           map.put(TAG_DATES_PROMO, PromoDateStart);
           map.put(TAG_DATEE_PROMO, PromoDateEnd);
           map.put(TAG_CONT_PROMO, PromoContact);

           DaftarPromotion.add(map);
           }

           } else {
           }
           } catch (JSONException e) {
           e.printStackTrace();
           }
           return null;
           }

           protected void onPostExecute(String file_url) {
           pDialog.dismiss();
           runOnUiThread(new Runnable() {
           public void run() {

           SetListViewAdapter(DaftarPromotion);




                }
           });
        }
    }
    }

and this is my custom adapter, it is a very simple one, without an object class of it's own

package lbs.promotion;

import java.util.ArrayList;
import java.util.HashMap;

import com.javacodegeeks.android.lbs.Curve;
import com.javacodegeeks.android.lbs.R;

import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Filter;
import android.widget.Filterable;
import android.widget.ImageView;
import android.widget.TextView;

public class PromotionListAdapter extends BaseAdapter {

 private Activity activity;
 private ArrayList<HashMap<String, String>> data;
 private static LayoutInflater inflater = null;
 public ImageLoader imageLoader;

 public PromotionListAdapter(Activity a, ArrayList<HashMap<String, String>> d) {

 activity = a;
 data = d;
 inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
 imageLoader = new ImageLoader(activity.getApplicationContext());
 }

 public int getCount() {
 return data.size();
 }

 public Object getItem(int position) {
 return position;
 }

 public long getItemId(int position) {
 return position;
 }

 public View getView(int position, View convertView, ViewGroup parent) {

     View vi = convertView;
      if (convertView == null)vi = inflater.inflate(R.layout.item_list_promotion, null);

      TextView PromoID = (TextView) vi.findViewById(R.id.PromoID);
      TextView PromoName = (TextView) vi.findViewById(R.id.PromoName);
      TextView PromoImage = (TextView) vi.findViewById(R.id.PromoImage);
      TextView PromoDesc = (TextView) vi.findViewById(R.id.PromoDesc);
      TextView PromoCate = (TextView) vi.findViewById(R.id.PromoCate);
      TextView PromoContact = (TextView) vi.findViewById(R.id.PromoContact);
      TextView PromoDateStart = (TextView) vi.findViewById(R.id.PromoDateStart);
      TextView PromoDateEnd = (TextView) vi.findViewById(R.id.PromoDateEnd);
      ImageView thumb_image = (ImageView) vi.findViewById(R.id.image_promo);

      HashMap<String, String> daftar_promotion = new HashMap<String, String>();
      daftar_promotion = data.get(position);

      PromoID.setText(daftar_promotion.get(Curve.TAG_ID_PROMO));

      PromoName.setText(daftar_promotion.get(Curve.TAG_NAMA_PROMO));

      PromoImage.setText(daftar_promotion.get(Curve.TAG_LINK_IMAGE_PROMO));

      PromoDesc.setText(daftar_promotion.get(Curve.TAG_DESC_PROMO));

      PromoCate.setText(daftar_promotion.get(Curve.TAG_CATE_PROMO));

      PromoContact.setText(daftar_promotion.get(Curve.TAG_CONT_PROMO));

      PromoDateStart.setText(daftar_promotion.get(Curve.TAG_DATES_PROMO));

      PromoDateEnd.setText(daftar_promotion.get(Curve.TAG_DATEE_PROMO));

      imageLoader.DisplayImage(daftar_promotion.get(Curve.TAG_LINK_IMAGE_PROMO),thumb_image);

      return vi;

      }




}

here is my layout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >

 <!-- Editext for Search -->
    <EditText android:id="@+id/search_box"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:hint="type to search"
        android:inputType="text"
        android:maxLines="1"/>

<ListView
android:id="@+id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:divider="#040404"
android:dividerHeight="1dp"
android:listSelector="@drawable/list_selector" />

</LinearLayout>

how do i get the getfilter() function working? or is there any simpler way to implement filtering in my listview? i want to filter based on my PromoName

Answer 1

A Filter has two major components, the performFiltering(CharSequence) method and the publishResults(CharSequence, FilterResults) method. In your PromotionListAdapter, you'll need to implement the Filterable interface then Override the getFilter() method to return a new Filter that has these methods implemented.

The performFiltering(CharSequence) method is where you'll do the bulk of your work. The CharSequence argument is the data which you're filtering on. Here, you'll first want to determine if the list should even be filtered as the base case. Once you've decided to perform the filtering, create a new ArrayList for your filtered dataset (in your case, a new ArrayList>), and loop through your complete set of list items, adding the values that match the filter to your new ArrayList.

The return type for the performFiltering method is FilterResults. FilterResults is a simple object with two variables, int count and Object results. Once performFiltering has created the new ArrayList with the filtered data, create a new FilterResults, setting your new ArrayList as results and the size of that ArrayList as count.

The publishResults(CharSequence, FilterResults) method is called after performFiltering() returns. The CharSequence parameter is the same String you were filtering on. The FilterResults parameter is the return from performFiltering(). In this method, you'll want to set your new ArrayList as the data source for your List and then call notifyDataSetChanged() to update the UI.

In order to implement this, I've had success when my Adapter keeps track of both the original ArrayList of data and a filtered ArrayList of what is currently being shown. Here's some boilerplate code based on your adapter that can help get you started. I've commented above important lines.

public class PromotionListAdapter extends BaseAdapter implements Filterable
{
    private Activity activity;
    private static LayoutInflater inflater = null;
    public ImageLoader imageLoader;

    //Two data sources, the original data and filtered data
    private ArrayList<HashMap<String, String>> originalData;
    private ArrayList<HashMap<String, String>> filteredData;

    public PromotionListAdapter(Activity a, ArrayList<HashMap<String, String>> d) 
    {
        activity = a;
        inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        imageLoader = new ImageLoader(activity.getApplicationContext());

        //To start, set both data sources to the incoming data
        originalData = d;
        filteredData = d;
    }

    //For this helper method, return based on filteredData
    public int getCount() 
    {
        return filteredData.size();
    }

    //This should return a data object, not an int
    public Object getItem(int position) 
    {
        return filteredData.get(position);
    }

    public long getItemId(int position) 
    {
        return position;
    }

    //The only change here is that we'll use filteredData.get(position)
    //Even better would be to use getItem(position), which uses the helper method (see the getItem() method above)
    public View getView(int position, View convertView, ViewGroup parent) 
    {

       View vi = convertView;
       if (convertView == null)vi = inflater.inflate(R.layout.item_list_promotion, null);

      TextView PromoID = (TextView) vi.findViewById(R.id.PromoID);
      TextView PromoName = (TextView) vi.findViewById(R.id.PromoName);
      TextView PromoImage = (TextView) vi.findViewById(R.id.PromoImage);
      TextView PromoDesc = (TextView) vi.findViewById(R.id.PromoDesc);
      TextView PromoCate = (TextView) vi.findViewById(R.id.PromoCate);
      TextView PromoContact = (TextView) vi.findViewById(R.id.PromoContact);
      TextView PromoDateStart = (TextView) vi.findViewById(R.id.PromoDateStart);
      TextView PromoDateEnd = (TextView) vi.findViewById(R.id.PromoDateEnd);
      ImageView thumb_image = (ImageView) vi.findViewById(R.id.image_promo);

      HashMap<String, String> daftar_promotion = new HashMap<String, String>();

      //Get data from filtered Data
      //This line can be replaced with:
      //     daftar_promotion = getItem(position);
      daftar_promotion = filteredData.get(position);

      PromoID.setText(daftar_promotion.get(Curve.TAG_ID_PROMO));

      PromoName.setText(daftar_promotion.get(Curve.TAG_NAMA_PROMO));

      PromoImage.setText(daftar_promotion.get(Curve.TAG_LINK_IMAGE_PROMO));

      PromoDesc.setText(daftar_promotion.get(Curve.TAG_DESC_PROMO));

      PromoCate.setText(daftar_promotion.get(Curve.TAG_CATE_PROMO));

      PromoContact.setText(daftar_promotion.get(Curve.TAG_CONT_PROMO));

      PromoDateStart.setText(daftar_promotion.get(Curve.TAG_DATES_PROMO));

      PromoDateEnd.setText(daftar_promotion.get(Curve.TAG_DATEE_PROMO));

      imageLoader.DisplayImage(daftar_promotion.get(Curve.TAG_LINK_IMAGE_PROMO),thumb_image);

      return vi;

    }

    @Override
    public Filter getFilter()
    {
       return new Filter()
       {
            @Override
            protected FilterResults performFiltering(CharSequence charSequence)
            {
                FilterResults results = new FilterResults();

                //If there's nothing to filter on, return the original data for your list
                if(charSequence == null || charSequence.length() == 0)
                {
                    results.values = originalData;
                    results.count = originalData.size();
                }
                else
                {
                    ArrayList<HashMap<String,String>> filterResultsData = new ArrayList<HashMap<String,String>>();

                    for(HashMap<String,String> data : originalData)
                    {
                        //In this loop, you'll filter through originalData and compare each item to charSequence.
                        //If you find a match, add it to your new ArrayList
                        //I'm not sure how you're going to do comparison, so you'll need to fill out this conditional
                        if(data matches your filter criteria)
                        {
                            filterResultsData.add(data);
                        }
                    }            

                    results.values = filterResultsData;
                    results.count = filteredResultsData.size();
                }

                return results;
            }

            @Override
            protected void publishResults(CharSequence charSequence, FilterResults filterResults)
            {
                filteredData = (ArrayList<HashMap<String,String>>)filterResults.values;
                notifyDataSetChanged();
            }
        };
    }
}

And there you have it! As far as I can tell, you've already implemented the TextWatcher for your inputText EditText set up properly, so adding the getFilter() method and making a few other minor changes to your Adapter should lead you to a solution. I believe you can also create a member variable on your Adapter for your Filter, so you're not creating a new instance of the class each time getFilter() is called, but I copy/pasted this from a previous project of mine and am sure it works this way. Play with it and see what works for you! Hope this helps! And please do comment if you need anything clarified.

Answer 2

you adapter needs to implement Filterable .

for more info about this (and about listView) , watch the video "the world of listView"

here's a sample code:

http://codetheory.in/android-filters/