Question

Sorry if it’s a silly question…i m only a beginner in android programming.

i want to make an array of signal levels and access point mac addresses. Later my goal is to POST these two arrays to a server using JSON for getting a web service. i cannot find a right way to make the array..though i m able to retrieve the wifi information that android provides. see the commented out statements in the Onreceive method of the following code.

package com.example.jsonwifi;


public class JsonWifi extends Activity {
    TextView mainText;
    WifiManager mainWifi;
    WifiReceiver receiverWifi;
    List<ScanResult> wifiList;
    StringBuilder sb = new StringBuilder();
    String[] apmacs;
    String[] levels;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    mainText = (TextView) findViewById(R.id.mainText);
    mainWifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);

    receiverWifi = new WifiReceiver();
    registerReceiver(receiverWifi, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
    mainWifi.startScan();
    mainText.setText("\nStarting Scan...\n");
}

@Override
public boolean onCreateOptionsMenu(Menu mn) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.layout.menu, mn);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle item selection
    switch (item.getItemId()) {
    case R.id.refreshbt:
        mainWifi.startScan();
        mainText.setText("Starting Scan");
    default:
        return super.onOptionsItemSelected(item);
    }
}

protected void onPause() {
    unregisterReceiver(receiverWifi);

    super.onPause();
}

protected void onResume() {
    registerReceiver(receiverWifi, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
    Toast.makeText(getBaseContext(), "resumed", Toast.LENGTH_LONG).show();
    super.onResume();
}

class WifiReceiver extends BroadcastReceiver {

    public void onReceive(Context c, Intent intent) {
        sb = new StringBuilder();
        wifiList = mainWifi.getScanResults();
        for(int i = 0; i < wifiList.size(); i++){
            sb.append(new Integer(i+1).toString() + ".");
            sb.append(" SSID= ");
            sb.append((wifiList.get(i)).SSID.toString());
            sb.append("\n");
            sb.append("     BSSID= ");
            sb.append((wifiList.get(i)).BSSID.toString());
            sb.append(",");
            sb.append(" signal level= ");
            sb.append((wifiList.get(i)).level);
            sb.append("\n");

           // apmacs[]= (wifiList.get(i).BSSID);
           // levels[] = (wifiList.get(i).level);
        }
        mainText.setText(sb);
    }
}

}

Answer 1

seems like you want to build String arrays out of retrieved data stored in a List<ScanResult>.. I’d initialize the arrays to the size of the List and populate them in side the loop… like this

See if this works.

    public void onReceive(Context c, Intent intent) {
            sb = new StringBuilder();
            wifiList = mainWifi.getScanResults();

            // initialize arrays here!
            apmacs = new String[wifiList.size( )];
            levels = new String[wifiList.size( )];

            for(int i = 0; i < wifiList.size(); i++){
                sb.append(new Integer(i+1).toString() + ".");
..... more appends....

               // populate the arrays                       
               apmacs[i]= wifiList.get(i).BSSID;
               levels[i] = String.valueOf( wifiList.get(i).level );
            }