将搜索框添加到listview

Question

• 

我正在尝试添加搜索框..

我知道搜索框代码如下所示。但是我很困惑如何添加和放置... .MainActvity类无法访问listview，因为它是在CountryXmlParser中创建的，而CountryXmlParser类不会扩展Actvity？I我发布了MainActvity和CountryXmlParser的代码

SearchBox代码

searchBox.addTextChangedListener(new TextWatcher() {

         public void onTextChanged(CharSequence s, int start, int before, int count) {
               //get the text in the EditText
               String searchString=searchBox.getText().toString();
               int textLength=searchString.length();

                      //clear the initial data <span class="h9umc81m835" id="h9umc81m835_8">set</span>
                      list.clear();

               for(int i=0;i<originalValues.size();i++)
               {
              String countryName=originalValues.get(i).get("country").toString();
              if(textLength<=countryName.length()){
              //compare the String in EditText with Names in the ArrayList
                if(searchString.equalsIgnoreCase(countryName.substring(0,textLength)))
                searchResults.add(originalValues.get(i));
              }
               }

               adapter.notifyDataSetChanged();
             }
public void beforeTextChanged(CharSequence s, int start, int count,
     int after) {


   }

   public void afterTextChanged(Editable s) {


   }
  });

MainActvity.java

Public class MainActivity extends Activity {
 EditText searchBox;
ArrayList<HashMap<String, Object>> searchResults;
ArrayList<HashMap<String, Object>> originalValues;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
   searchBox = (EditText)findViewById(R.id.searchBox);

        /** This is the XML data to be parsed */
        String xmlData = "<countries>" +
                            "<country name='India' flag='"+Integer.toString(R.drawable.india) +"'>" +
                                "<language>Hindi</language>" +
                                "<capital city='New Delhi' />" +
                                "<currency code='INR'>Indian Rupee</currency>" +
                            "</country>" +

                            "<country name='Pakistan' flag='"+Integer.toString(R.drawable.pakistan) +"'>" +
                                "<language>Urdu</language>" +
                                "<capital city='Islamabad' />" +
                                "<currency code='PKR'>Pakistani Rupee</currency>" +
                            "</country>" +

                            "<country name='Sri Lanka' flag='"+Integer.toString(R.drawable.srilanka) +"'>" +
                                "<language>Sinhala</language>" +
                                "<capital city='Sri Jayawardenapura Kotte' />" +
                                "<currency code='LKR'>Sri Lankan Rupee</currency>" +
                            "</country>" +

                            "<country name='China' flag='"+Integer.toString(R.drawable.china) +"'>" +
                                "<language>Chineese</language>" +
                                "<capital city='Beijing' />" +
                                "<currency code='CNY'>Renminbi</currency>" +
                            "</country>" +

                            "<country name='Bangladesh' flag='"+Integer.toString(R.drawable.bangladesh) +"'>" +
                                "<language>Bangla</language>" +
                                "<capital city='Dhaka' />" +
                                "<currency code='BDT'>Taka</currency>" +
                            "</country>" +

                            "<country name='Nepal' flag='"+Integer.toString(R.drawable.nepal) +"'>" +
                                "<language>Nepal Bhasa</language>" +
                                "<capital city='Kathmandu' />" +
                                "<currency code='NPR'>Nepalese rupee</currency>" +
                            "</country>" +

                            "<country name='Afghanistan' flag='"+Integer.toString(R.drawable.afghanistan) +"'>" +
                                "<language>Dari Persian</language>" +
                                "<capital city='Kabul' />" +
                                "<currency code='AFN'>Afghani</currency>" +
                            "</country>" +

                            "<country name='North Korea' flag='"+Integer.toString(R.drawable.nkorea) +"'>" +
                                "<language>Korean</language>" +
                                "<capital city='Pyongyang' />" +
                                "<currency code='KPW'>North Korean won</currency>" +
                            "</country>" +

                            "<country name='South Korea' flag='"+Integer.toString(R.drawable.skorea) +"'>" +
                                "<language>Korean</language>" +
                                "<capital city='Seoul' />" +
                                "<currency code='KRW'>South Korean won</currency>" +
                            "</country>" +

                            "<country name='Japan' flag='"+Integer.toString(R.drawable.japan) +"'>" +
                                "<language>Japanese</language>" +
                                "<capital city='Tokyo' />" +
                                "<currency code='JPY'>Yen</currency>" +
                            "</country>" +
                        "</countries>";

        /** The parsing of the xml data is done in a non-ui thread */
        ListViewLoaderTask listViewLoaderTask = new ListViewLoaderTask();

        /** Start parsing xml data */
        listViewLoaderTask.execute(xmlData);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

    private class ListViewLoaderTask extends AsyncTask<String, Void, SimpleAdapter>{

        /** Doing the parsing of xml data in a non-ui thread */
        @Override
        protected SimpleAdapter doInBackground(String... xmlData) {
            StringReader reader = new StringReader(xmlData[0]);

            CountryXmlParser countryXmlParser = new CountryXmlParser();

            List<HashMap<String, String>> countries = null;

            try{
                /** Getting the parsed data as a List construct */
                countries = countryXmlParser.parse(reader);
            }catch(Exception e){
                Log.d("Exception",e.toString());
            }

            /** Keys used in Hashmap */
            String[] from = { "country","flag","details"};

            /** Ids of views in listview_layout */
            int[] to = { R.id.tv_country,R.id.iv_flag,R.id.tv_country_details};

            /** Instantiating an adapter to store each items
            *  R.layout.listview_layout defines the layout of each item
            */
            SimpleAdapter adapter = new SimpleAdapter(getBaseContext(), countries, R.layout.lv_layout, from, to);

            return adapter;
        }

        @Override
       protected void onPostExecute(SimpleAdapter adapter) {

        /** Getting a reference to listview of main.xml layout file */
        ListView listView = ( ListView ) findViewById(R.id.lv_countries);
        adapter = adapter;
        originalValues=new ArrayList<HashMap<String,Object>>();
        originalValues.add(hm);
        searchResults=new ArrayList<HashMap<String,Object>>(originalValues);
        searchBox.addTextChangedListener(new TextWatcher() {

            public void onTextChanged(CharSequence s, int start, int before, int count) {
                  //get the text in the EditText
                  String searchString=searchBox.getText().toString();
                  int textLength=searchString.length();

                         //clear the initial data <span class="h9umc81m835" id="h9umc81m835_8">set</span>
                         searchResults.clear();

                  for(int i=0;i<originalValues.size();i++)
                  {
                 String countryName=originalValues.get(i).get("country").toString();
                 if(textLength<=countryName.length()){
                 //compare the String in EditText with Names in the ArrayList
                   if(searchString.equalsIgnoreCase(countryName.substring(0,textLength)))
                   searchResults.add(originalValues.get(i));
                 }
                  }

                  adapter.notifyDataSetChanged();
                }
   public void beforeTextChanged(CharSequence s, int start, int count,
        int after) {


      }

      public void afterTextChanged(Editable s) {


      }
     });
        /** Setting the adapter containing the country list to listview */
        listView.setAdapter(adapter);
    }       
}

}

CountryXmlParser.java

public class CountryXmlParser { {

    private static final String ns = null;

    /** This is the only function need to be called from outside the class */
    public List<HashMap<String, String>> parse(Reader reader)
            throws XmlPullParserException, IOException{
        try{
            XmlPullParser parser = Xml.newPullParser();
            parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
            parser.setInput(reader);
            parser.nextTag();
            return readCountries(parser);
        }finally{
        }
    }

    /** This method read each country in the xml data and add it to List */
    private List<HashMap<String, String>> readCountries(XmlPullParser parser)
            throws XmlPullParserException,IOException{

        List<HashMap<String, String>> list = new ArrayList<HashMap<String,String>>();

        parser.require(XmlPullParser.START_TAG, ns, "countries");

        while(parser.next() != XmlPullParser.END_TAG){
            if(parser.getEventType() != XmlPullParser.START_TAG){
                continue;
            }

            String name = parser.getName();
            if(name.equals("country")){
                list.add(readCountry(parser));
            }
            else{
                skip(parser);
            }
        }
        return list;
    }

    /** This method read a country and returns its corresponding HashMap construct */
    private HashMap<String, String> readCountry(XmlPullParser parser)
            throws XmlPullParserException, IOException{

        parser.require(XmlPullParser.START_TAG, ns, "country");

        String countryName = parser.getAttributeValue(ns, "name");
        String flag = parser.getAttributeValue(ns, "flag");
        String language="";
        String capital="";
        String currencyCode="";
        String currency="";

        while(parser.next() != XmlPullParser.END_TAG){
            if(parser.getEventType() != XmlPullParser.START_TAG){
                continue;
            }

            String name = parser.getName();

            if(name.equals("language")){
                language = readLanguage(parser);
            }else if(name.equals("capital")){
                capital = parser.getAttributeValue(ns, "city");
                readCapital(parser);
            }else if(name.equals("currency")){
                currencyCode = parser.getAttributeValue(ns, "code");
                currency = readCurrency(parser);
            }else{
                skip(parser);
            }
        }

        String details =    "Language : " + language + "\n" +
                            "Capital : " + capital + "\n" +
                            "Currency : " + currency + "(" + currencyCode + ")";

        HashMap<String, String> hm = new HashMap<String, String>();
        hm.put("country", countryName);
        hm.put("flag", flag);
        hm.put("details",details);

        return hm;
    }

    /** Process language tag in the xml data */
    private String readLanguage(XmlPullParser parser)
            throws IOException, XmlPullParserException {
        parser.require(XmlPullParser.START_TAG, ns, "language");
        String language = readText(parser);
        return language;
    }

    /** Process Capital tag in the xml data */
    private void readCapital(XmlPullParser parser)
            throws IOException, XmlPullParserException {
        parser.require(XmlPullParser.START_TAG, ns, "capital");
        parser.nextTag();
    }

    /** Process Currency tag in the xml data */
    private String readCurrency(XmlPullParser parser)
            throws IOException, XmlPullParserException {
        parser.require(XmlPullParser.START_TAG, ns, "currency");
        String currency = readText(parser);
        return currency;
    }

    /** Getting Text from an element */
    private String readText(XmlPullParser parser)
            throws IOException, XmlPullParserException{
        String result = "";
        if(parser.next()==XmlPullParser.TEXT){
            result = parser.getText();
            parser.nextTag();
        }
        return result;
    }

    private void skip(XmlPullParser parser)
            throws XmlPullParserException, IOException {
        if (parser.getEventType() != XmlPullParser.START_TAG) {
           throw new IllegalStateException();
        }
        int depth = 1;
        while (depth != 0) {
            switch (parser.next()) {
                case XmlPullParser.END_TAG:
                    depth--;
                    break;
                case XmlPullParser.START_TAG:
                    depth++;
                    break;
            }
        }
    }
}

Answer 1

保留对适配器的引用并告诉它过滤结果：

adapter.getFilter().filter(sometext);

如果从getFilter()返回的过滤器不适合您，您可以通过覆盖Filterable interface.

中的方法返回适合您的过滤器

编辑： 尝试这样的事情： 在您的Activity中，在onCreate之前将ListView，Adapter和searchbox定义为类变量。在onCreate中，找到searchBox。

Public class MainActivity extends Activity {
    ListView listView;
    SimpleAdapter adapter;
    EditText searchBox;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        setContentView(..);
        searchBox = (EditText)findViewById(...);
    ...

在ListViewLoaderTask onPostExecute保存这些引用并添加侦听器：

listView = ( ListView ) findViewById(R.id.lv_countries);
adapter = adapter;
/** Setting the adapter containing the country list to listview */
listView.setAdapter(adapter);
//set textwatcher
searchBox.addTextChangeListener(...)

在前面提到的textwatcher afterTextChanged过滤结果中