How to scan wifi networks and list them in a listview?

Question

I need to scan for available wifi networks and list them in a clickable listview. Using some tutorial I found online, and repeated by meny people here, I managed to complete this code:

public class Wifi_list extends Activity implements OnClickListener
 {      
    WifiManager wifi;       
    ListView lv;
    TextView textStatus;
    Button buttonScan;
    Switch enable;
    int size = 0;
    List<ScanResult> results;

    String ITEM_KEY = "key";
    ArrayList<HashMap<String, String>> arraylist = new ArrayList<HashMap<String, String>>();
    SimpleAdapter adapter;

    /* Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.wifi_list);
        buttonScan = (Button) findViewById(R.id.button1);
        buttonScan.setOnClickListener(this);
        lv = (ListView)findViewById(R.id.listView1);

        wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
        enable.setChecked(wifi.isWifiEnabled());
        enable.setOnCheckedChangeListener(new OnCheckedChangeListener() {
            public void onCheckedChanged(CompoundButton compoundbutton, boolean flag) {
                wifi.setWifiEnabled(flag);
                if(flag){
                    arraylist.clear();
                    lv.setVisibility(View.VISIBLE);
                    buttonScan.setEnabled(true);
                    wifi.startScan();
                }else{
                    lv.setVisibility(View.INVISIBLE);
                    buttonScan.setEnabled(false);
                }
            }
        });
        this.adapter = new SimpleAdapter(Wifi_list.this, arraylist, R.layout.wifi_item, new String[] { ITEM_KEY }, new int[] { R.id.list_value });
        lv.setAdapter(this.adapter);
        lv.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                int a = lv.getSelectedItemPosition();

            }
        });

        registerReceiver(new BroadcastReceiver()
        {
            @Override
            public void onReceive(Context c, Intent intent) 
            {
               results = wifi.getScanResults();
               size = results.size();
               for(int i=size-1;i>=0;i--){
                   HashMap<String, String> item = new HashMap<String, String>();                       
                   item.put(ITEM_KEY, results.get(i).SSID);
                   arraylist.add(item);
               }
               if(size>0)
                   adapter.notifyDataSetChanged();
            }
        }, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));                    
    }

    public void onClick(View view) 
    {
        arraylist.clear();          
        wifi.startScan();
        Toast.makeText(this, "Scanning....", Toast.LENGTH_SHORT).show();

    }    
}

But I can't find what are R.layout.wifi_item and R.id.list_value, because I get errors on them. Can somebody help me figuring this out? Thanks.

Answer 1

But I can't find NOWHERE what in the god's name is R.layout.wifi_item and R.id.list_value, cause I get errors on them. Can somebody help me figurning this out? Thanks.

The files you named are layout files, defined in .xml

They can contain the UI-Components such as the ListView you want to use to display your WiFi Networks.

In your example you have 2 Layout files. One is the R.layout.wifi_list that contains a button (button1) and a ListView (listView1). The other one is R.layout.wifi_item, a custom layout file that represents the layout of one entry in the ListView.

Do display a simple String containing the name of the WiFi Network, you could use the Android-predefined layout "android.R.layout.simple_list_item_1" for your List-Adapter.