為從服務器檢索為JSON的數據實現搜索過濾器

Question

為從服務器檢索為JSON的數據實現搜索過濾器

1. 鏈接1
2. 鏈接2

我能做什么

當我通過向其添加一些數據來考慮簡單數組時，便能夠執行搜索過濾器

ListOfContacts.java

public class ListOfContacts extends Activity {
    // Declare Variables
    JSONObject jsonobject;
    JSONArray jsonarray;
    ListView listview;
    ListViewAdapter adapter;
    ProgressDialog mProgressDialog;
    ArrayList<HashMap<String, String>> arraylist;
    static String NAME = "rank";
    static String FLAG = "flag";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // Get the view from listview_main.xml
        setContentView(R.layout.listview_main);


        // Locate the listview in listview_main.xml
        listview = (ListView) findViewById(R.id.listview);

        // Execute DownloadJSON AsyncTask
        new DownloadJSON().execute();
    }

    // DownloadJSON AsyncTask
    private class DownloadJSON extends AsyncTask<Void, Void, Void> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            // Create a progressdialog
            mProgressDialog = new ProgressDialog(ListOfContacts.this);
            // Set progressdialog title
            //mProgressDialog.setTitle("Fetching the information");
            // Set progressdialog message
            mProgressDialog.setMessage("Loading...");
            mProgressDialog.setIndeterminate(false);
            // Show progressdialog
            mProgressDialog.show();
        }

        @Override
        protected Void doInBackground(Void... params) {
            // Create an array
            arraylist = new ArrayList<HashMap<String, String>>();
            // Retrieve JSON Objects from the given URL address
            jsonobject = JSONfunctions.getJSONfromURL("http://54.218.73.244:7004/DescriptionSortedPrice/");

            try {
                // Locate the array name in JSON
                jsonarray = jsonobject.getJSONArray("restaurants");

                for (int i = 0; i < jsonarray.length(); i++) {
                    HashMap<String, String> map = new HashMap<String, String>();
                    jsonobject = jsonarray.getJSONObject(i);
                    // Retrive JSON Objects
                    map.put(ListOfContacts.NAME, jsonobject.getString("Person_Name"));
                    map.put(ListOfContacts.FLAG, "http://54.218.73.244:7004/"+jsonobject.getString("Image_Name"));



                    // Set the JSON Objects into the array
                    arraylist.add(map);
                }
            } catch (JSONException e) {
                Log.e("Error", e.getMessage());
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(Void args) {
            // Pass the results into ListViewAdapter.java
            adapter = new ListViewAdapter(ListOfContacts.this, arraylist);
            // Set the adapter to the ListView
            listview.setAdapter(adapter);
            // Close the progressdialog
            mProgressDialog.dismiss();
        }
    }
}

---

listview_main.xml

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

    <!-- Editext for Search -->
    <EditText android:id="@+id/inputSearch"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:hint="Search Here"
        android:inputType="textVisiblePassword"/>

    <ListView
        android:id="@+id/listview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
    </ListView>

</LinearLayout>

---

ListViewAdapter.java

public class ListViewAdapter extends BaseAdapter {

    // Declare Variables
    Context context;
    LayoutInflater inflater;
    ArrayList<HashMap<String, String>> data;
    ImageLoader imageLoader;
    HashMap<String, String> resultp = new HashMap<String, String>();

    public ListViewAdapter(Context context,
            ArrayList<HashMap<String, String>> arraylist) {
        this.context = context;
        data = arraylist;
        imageLoader = new ImageLoader(context);
    }

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

    @Override
    public Object getItem(int position) {
        return null;
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

    public View getView(final int position, View convertView, ViewGroup parent) {
        // Declare Variables
        TextView name;
        ImageView flag;

        inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        View itemView = inflater.inflate(R.layout.listview_item, parent, false);
        // Get the position
        resultp = data.get(position);

        // Locate the TextViews in listview_item.xml
        name = (TextView) itemView.findViewById(R.id.RestaurantNameID);
        flag = (ImageView) itemView.findViewById(R.id.flag);

        name.setText(resultp.get(MainActivity.NAME));
        imageLoader.DisplayImage(resultp.get(MainActivity.FLAG), flag);
        // Capture ListView item click

        return itemView;
    }
}

---

ImageLoader.java

public class ImageLoader {

    MemoryCache memoryCache = new MemoryCache();
    FileCache fileCache;
    private Map<ImageView, String> imageViews = Collections
            .synchronizedMap(new WeakHashMap<ImageView, String>());
    ExecutorService executorService;
    // Handler to display images in UI thread
    Handler handler = new Handler();

    public ImageLoader(Context context) {
        fileCache = new FileCache(context);
        executorService = Executors.newFixedThreadPool(5);
    }

    final int stub_id = R.drawable.ic_launcher;

    public void DisplayImage(String url, ImageView imageView) {
        imageViews.put(imageView, url);
        Bitmap bitmap = memoryCache.get(url);
        if (bitmap != null)
            imageView.setImageBitmap(bitmap);
        else {
            queuePhoto(url, imageView);
            imageView.setImageResource(stub_id);
        }
    }

    private void queuePhoto(String url, ImageView imageView) {
        PhotoToLoad p = new PhotoToLoad(url, imageView);
        executorService.submit(new PhotosLoader(p));
    }

    private Bitmap getBitmap(String url) {
        File f = fileCache.getFile(url);

        Bitmap b = decodeFile(f);
        if (b != null)
            return b;

        // Download Images from the Internet
        try {
            Bitmap bitmap = null;
            URL imageUrl = new URL(url);
            HttpURLConnection conn = (HttpURLConnection) imageUrl
                    .openConnection();
            conn.setConnectTimeout(30000);
            conn.setReadTimeout(30000);
            conn.setInstanceFollowRedirects(true);
            InputStream is = conn.getInputStream();
            OutputStream os = new FileOutputStream(f);
            Utils.CopyStream(is, os);
            os.close();
            conn.disconnect();
            bitmap = decodeFile(f);
            return bitmap;
        } catch (Throwable ex) {
            ex.printStackTrace();
            if (ex instanceof OutOfMemoryError)
                memoryCache.clear();
            return null;
        }
    }

    // Decodes image and scales it to reduce memory consumption
    private Bitmap decodeFile(File f) {
        try {
            // Decode image size
            BitmapFactory.Options o = new BitmapFactory.Options();
            o.inJustDecodeBounds = true;
            FileInputStream stream1 = new FileInputStream(f);
            BitmapFactory.decodeStream(stream1, null, o);
            stream1.close();

            // Find the correct scale value. It should be the power of 2.
            // Recommended Size 512
            final int REQUIRED_SIZE = 70;
            int width_tmp = o.outWidth, height_tmp = o.outHeight;
            int scale = 1;
            while (true) {
                if (width_tmp / 2 < REQUIRED_SIZE
                        || height_tmp / 2 < REQUIRED_SIZE)
                    break;
                width_tmp /= 2;
                height_tmp /= 2;
                scale *= 2;
            }

            // Decode with inSampleSize
            BitmapFactory.Options o2 = new BitmapFactory.Options();
            o2.inSampleSize = scale;
            FileInputStream stream2 = new FileInputStream(f);
            Bitmap bitmap = BitmapFactory.decodeStream(stream2, null, o2);
            stream2.close();
            return bitmap;
        } catch (FileNotFoundException e) {
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    // Task for the queue
    private class PhotoToLoad {
        public String url;
        public ImageView imageView;

        public PhotoToLoad(String u, ImageView i) {
            url = u;
            imageView = i;
        }
    }

    class PhotosLoader implements Runnable {
        PhotoToLoad photoToLoad;

        PhotosLoader(PhotoToLoad photoToLoad) {
            this.photoToLoad = photoToLoad;
        }

        @Override
        public void run() {
            try {
                if (imageViewReused(photoToLoad))
                    return;
                Bitmap bmp = getBitmap(photoToLoad.url);
                memoryCache.put(photoToLoad.url, bmp);
                if (imageViewReused(photoToLoad))
                    return;
                BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad);
                handler.post(bd);
            } catch (Throwable th) {
                th.printStackTrace();
            }
        }
    }

    boolean imageViewReused(PhotoToLoad photoToLoad) {
        String tag = imageViews.get(photoToLoad.imageView);
        if (tag == null || !tag.equals(photoToLoad.url))
            return true;
        return false;
    }

    // Used to display bitmap in the UI thread
    class BitmapDisplayer implements Runnable {
        Bitmap bitmap;
        PhotoToLoad photoToLoad;

        public BitmapDisplayer(Bitmap b, PhotoToLoad p) {
            bitmap = b;
            photoToLoad = p;
        }

        public void run() {
            if (imageViewReused(photoToLoad))
                return;
            if (bitmap != null)
                photoToLoad.imageView.setImageBitmap(bitmap);
            else
                photoToLoad.imageView.setImageResource(stub_id);
        }
    }

    public void clearCache() {
        memoryCache.clear();
        fileCache.clear();
    }

}

---

我的JSON結構 ::

{
  "restaurants": [
    {
      "Sl_no": 1,
      "Person_Name": "salmanKhan",
      "Image_Name": "image.jpg"
    },
    {
      "Sl_no": 2,
      "Person_Name": "AmirKhan",
      "Image_Name": "c92beeaf5ba50e65.jpg"
    },
    {
      "Sl_no": 3,
      "Person_Name": "carl",
      "Image_Name": "f2d835b73945ded2.jpg"
    },

我無法做的事情：當我們從服務器檢索數據並填充列表視圖時，如何實現搜索過濾器

---

{編輯}

package com.example.datapostingproject;

import java.util.ArrayList;
import java.util.HashMap;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.text.Editable;
import android.util.Log;
import android.widget.EditText;
import android.widget.ListView;

public class ListOfContacts extends Activity {
    // Declare Variables
    JSONObject jsonobject;
    JSONArray jsonarray;
    ListView listview;
    ListViewAdapter adapter;
    ProgressDialog mProgressDialog;
    ArrayList<HashMap<String, String>> arraylist;
    static String NAME = "rank";
    static String FLAG = "flag";
    EditText mEditText;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // Get the view from listview_main.xml
        setContentView(R.layout.listview_main);


        // Locate the listview in listview_main.xml
        listview = (ListView) findViewById(R.id.listview);
        mEditText = (EditText) findViewById(R.id.inputSearch);
        // Execute DownloadJSON AsyncTask
        new DownloadJSON().execute();

        mEditText = (EditText) findViewById(R.id.inputSearch);
        mEditText.addTextChangedListener(new TextWatcher()
        {

            public void afterTextChanged(Editable s)
            {

            }

            public void beforeTextChanged(CharSequence s, int start,int count, int after)
            {

            }

            public void onTextChanged(CharSequence s, int start,int before, int count)
            {

                ArrayList<HashMap<String, String>> arrayTemplist= new ArrayList<HashMap<String,String>>();
                String searchString =mEditText.getText().toString();
                for (int i = 0; i < arraylist.size(); i++)
                {
                    String currentString =arraylist.get(i).get(ListOfContacts.NAME);
                    if (searchString.equalsIgnoreCase(currentString)
                    {
                        arrayTemplist.add(arraylist.get(i));
                    }
                }
                adapter = new ListViewAdapter(ListOfContacts.this, arrayTemplist);
                listview.setAdapter(adapter);
             }
            });
        }
    }

    // DownloadJSON AsyncTask
    class DownloadJSON extends AsyncTask<Void, Void, Void> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            // Create a progressdialog
            mProgressDialog = new ProgressDialog(ListOfContacts.this);
            // Set progressdialog title
            //mProgressDialog.setTitle("Fetching the information");
            // Set progressdialog message
            mProgressDialog.setMessage("Loading...");
            mProgressDialog.setIndeterminate(false);
            // Show progressdialog
            mProgressDialog.show();
        }

        @Override
        protected Void doInBackground(Void... params) {
            // Create an array
            arraylist = new ArrayList<HashMap<String, String>>();
            // Retrieve JSON Objects from the given URL address
            jsonobject = JSONfunctions.getJSONfromURL("http://54.218.73.244:7004/DescriptionSortedPrice/");

            try {
                // Locate the array name in JSON
                jsonarray = jsonobject.getJSONArray("restaurants");

                for (int i = 0; i < jsonarray.length(); i++) {
                    HashMap<String, String> map = new HashMap<String, String>();
                    jsonobject = jsonarray.getJSONObject(i);
                    // Retrive JSON Objects
                    map.put(ListOfContacts.NAME, jsonobject.getString("Person_Name"));
                    map.put(ListOfContacts.FLAG, "http://54.218.73.244:7004/"+jsonobject.getString("Image_Name"));



                    // Set the JSON Objects into the array
                    arraylist.add(map);
                }
            } catch (JSONException e) {
                Log.e("Error", e.getMessage());
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(Void args) {
            // Pass the results into ListViewAdapter.java
            adapter = new ListViewAdapter(ListOfContacts.this, arraylist);
            // Set the adapter to the ListView
            listview.setAdapter(adapter);
            // Close the progressdialog
            mProgressDialog.dismiss();
        }
    }
}

---

Answer 1

在ListOfContacts.java OnCreate（）方法中添加以下代碼

mEditText = (EditText) findViewById(R.id.inputSearch);
        mEditText.addTextChangedListener(new TextWatcher()
        {

            public void afterTextChanged(Editable s)
            {

            }

            public void beforeTextChanged(CharSequence s, int start,int count, int after)
            {

            }

            public void onTextChanged(CharSequence s, int start,int before, int count)
            {

                ArrayList<HashMap<String, String>> arrayTemplist= new ArrayList<HashMap<String,String>>();
                String searchString =mEditText.getText().toString();
                for (int i = 0; i < arraylist.size(); i++)
                {
                    String currentString =arraylist.get(i).get(ListOfContacts.NAME);
                    if (searchString.equalsIgnoreCase(currentString)
                    {
                        arrayTemplist.add(arraylist.get(i));
                    }
                }
                adapter = new ListViewAdapter(ListOfContacts.this, arrayTemplist);
                listview.setAdapter(adapter);
             }
            });
        }