android - 如何使用扩展 baseadapter 的自定义适配器实现 getfilter()

Question

这是我的主要 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);




                }
           });
        }
    }
    }

这是我的自定义适配器，它非常简单，没有自己的对象类

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;

      }




}

这是我的 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>

如何让 getfilter() 函数工作？或者有没有更简单的方法在我的 ListView 中实现过滤？我想根据我的 PromoName 进行过滤

Answer 1

过滤器有两个主要组件，performFiltering(CharSequence) 方法和 publishResults(CharSequence, FilterResults) 方法。在您的 PromotionListAdapter 中，您需要实现 Filterable 接口(interface)，然后重写 getFilter() 方法以返回已实现这些方法的新过滤器。

performFiltering(CharSequence) 方法是您完成大部分工作的地方。 CharSequence 参数是您要过滤的数据。在这里，您首先要确定是否应该将列表过滤为基本情况。决定执行过滤后，为过滤后的数据集创建一个新的 ArrayList(在您的情况下是一个新的 ArrayList>)，然后循环遍历您的完整列表项集，将与过滤器匹配的值添加到新的 ArrayList .

performFiltering 方法的返回类型是FilterResults。 FilterResults 是一个简单的对象，有两个变量，int count 和 Object results。一旦 performFiltering 使用过滤后的数据创建了新的 ArrayList，请创建一个新的 FilterResults，将新的 ArrayList 设置为结果，并将该 ArrayList 的大小设置为计数。

publishResults(CharSequence, FilterResults) 方法在performFiltering() 返回后调用。 CharSequence 参数与您过滤的字符串相同。 FilterResults 参数是 performFiltering() 的返回值。在此方法中，您需要将新的 ArrayList 设置为 List 的数据源，然后调用 notifyDataSetChanged() 来更新 UI。

为了实现这一点，当我的适配器同时跟踪数据的原始 ArrayList 和当前显示的过滤 ArrayList 时，我取得了成功。下面是一些基于您的适配器的样板代码，可以帮助您入门。我已经在重要的行上面发表了评论。

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();
            }
        };
    }
}

你有它!据我所知，您已经为您的 inputText EditText 正确设置了 TextWatcher，因此添加 getFilter() 方法并对您的 Adapter 进行一些其他小的更改应该会引导您一个解法。我相信你也可以在你的适配器上为你的过滤器创建一个成员变量，所以你不会在每次调用 getFilter() 时创建一个新的类实例，但是我从我以前的项目中复制/粘贴了这个确保它以这种方式工作。玩它，看看什么对你有用!希望这可以帮助!如果您需要澄清任何事情，请发表评论。