java - No display - ListView using SimpleAdapter -

i'm trying display list of wifi ap's in range i.e. including same ssid's these not shown in default wifi settings.

this first attempt @ android sdk , i've gotten far:

package com.iiitd.wifistats;  import android.app.activity; import android.content.context; import android.net.wifi.scanresult; import android.net.wifi.wifimanager; import android.os.bundle; import android.view.menu; import android.view.view; import android.widget.button; import android.widget.listview; import android.widget.simpleadapter; import android.widget.toast;  import java.util.arraylist; import java.util.hashmap; import java.util.list; import java.util.map;  public class wifistats extends activity implements view.onclicklistener {      wifimanager wifi;     list<scanresult> scanresults;     arraylist<map<string, integer>> list;     simpleadapter adapter;     listview listview;      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);          wifi = (wifimanager) getsystemservice(context.wifi_service);         if (!wifi.iswifienabled()) {             toast.maketext(getapplicationcontext(), "turning on wifi...", toast.length_long).show();             wifi.setwifienabled(true);         }          carryon();     }      private void carryon(){         final button button = (button) findviewbyid(r.id.buttonscan);         button.setonclicklistener(new view.onclicklistener() {             public void onclick(view v) {                 wifi = (wifimanager) v.getcontext().getsystemservice(context.wifi_service);                 scanresults = wifi.getscanresults();                 toast.maketext(getapplicationcontext(), "scanning...", toast.length_short).show();                 list = builddata(scanresults);                 //toast.maketext(getapplicationcontext(), list.tostring(), toast.length_short).show();                 adapter = new simpleadapter(v.getcontext(), list, r.layout.listitem, new string[]{"bssid", "strength"}, new int[] {r.id.bssid, r.id.strength});                 //toast.maketext(getapplicationcontext(), adapter.tostring(), toast.length_short).show();                 listview = (listview) findviewbyid(r.id.list);                 listview.setadapter(adapter);             }         });     }      private arraylist<map<string, integer>> builddata(java.util.list<scanresult> s) {         arraylist<map<string, integer>> list = new arraylist<map<string, integer>>();         (scanresult result : s) {             list.add(putdata(result.bssid, result.level));         }         return list;     }      private hashmap<string, integer> putdata(string bssid, int level) {         hashmap<string, integer> item = new hashmap<string, integer>();         item.put(bssid, level);         return item;     }      @override     public boolean oncreateoptionsmenu(menu menu) {         getmenuinflater().inflate(r.menu.wi_fi_stats, menu);         return true;     }      @override     public void onclick(view view) {      } } 

this activity_xml:

    <relativelayout         android:layout_width="fill_parent"         android:layout_height="fill_parent"         xmlns:android="http://schemas.android.com/apk/res/android">      <button             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:text="scan"             android:id="@+id/buttonscan"             android:layout_alignparentbottom="true"             android:layout_centerhorizontal="true"/>      <listview             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:id="@+id/list"             android:layout_above="@+id/buttonscan"             android:layout_alignparentleft="true"             android:layout_marginbottom="14dp"/> </relativelayout> 

and listitem.xml:

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"                 android:layout_width="fill_parent"                 android:layout_height="?android:attr/listpreferreditemheight"                 android:padding="6dip">      <textview             android:id="@+id/strength"             android:layout_width="fill_parent"             android:layout_height="26dip"             android:layout_alignparentbottom="true"             android:layout_alignparentright="true"             android:ellipsize="marquee"             android:singleline="true"             android:text="description"             android:textsize="12sp"/>     <textview             android:id="@+id/bssid"             android:layout_width="fill_parent"             android:layout_height="wrap_content"             android:layout_above="@id/strength"             android:layout_alignparentright="true"             android:layout_alignparenttop="true"             android:layout_alignwithparentifmissing="true"             android:gravity="center_vertical"             android:text="example application"             android:textsize="16sp"/>  </relativelayout> 

there no list displayed when start scan. however, if use toast, can see list forming correctly. can guide me here? thanks.

take @ code here

adapter = new simpleadapter(v.getcontext(), list, r.layout.listitem, new string[]{"bssid", "strength"}, new int[] {r.id.bssid, r.id.strength}); 

the string array telling adapter keys used when accessing map define. in code, assigning values such

private hashmap<string, integer> putdata(string bssid, int level) {     hashmap<string, integer> item = new hashmap<string, integer>();     item.put(bssid, level);     return item; } 

this assigning int level key set string bssid. need change occurrences of hashmap in code take string value , string key hashmap< string, string >and replace method following

private hashmap<string, string> putdata(string bssid, int level) {     hashmap<string, string> item = new hashmap<string, string>();     item.put("bssid", bssid);     item.put("strength", integer.tostring(level));     return item; }