Android Application to scan wifi aps and display them in list view

Question

I am trying to make an simple android application which scans wifi aps and display them including SSID,BSSID, and Signal Strength in list view.

Although it might not be too difficult task, I am having a problem since I am very new to android development.

I wrote codes to do these basic tasks. But, somehow it doesn't display any result. It is not showing any error either. Would you help me to fix it and make it work?

public class MainActivity extends AppCompatActivity implements View.OnClickListener, CompoundButton.OnCheckedChangeListener{

// Declare View variables
private Button mRefreshButton;
private Switch mWifiSwitch;
private ListView mAPListView;
private List<ScanResult> mWifiList;
private List<String> mListOfProviders;
private ListAdapter mAdapter;
private WifiManager mWifiManager;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mListOfProviders = new ArrayList<String>();
    mAPListView = (ListView) findViewById(R.id.APListView);
    mRefreshButton = (Button) findViewById(R.id.refreshButton);
    mWifiSwitch = (Switch) findViewById(R.id.WiFiSwitch);
    mWifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);

    boolean wasEnabled = mWifiManager.isWifiEnabled();
    if (wasEnabled){
        mWifiSwitch.setChecked(true);
    }
    mWifiSwitch.setOnCheckedChangeListener(this);

    mWifiManager.startScan();
    mWifiList = mWifiManager.getScanResults();

    for (ScanResult result : mWifiList) {
        mListOfProviders.add(result.SSID); //This will add the SSID of the connection
    }
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, android.R.id.text1, mListOfProviders);
    mAPListView.setAdapter(adapter);

}


@Override
public void onClick(View view)
{

}

@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
    if (isChecked){
        mWifiManager.setWifiEnabled(true);
    }
    else {
        mWifiManager.setWifiEnabled(false);
    }
}
}

Answer 1

Try to add permissions into manifest.

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />