小编Tah*_*aha的帖子

我有两个类:其中一个是活动类,另一个是非活动类.我调用一个非活动类中的方法来返回mac Adress.

活动类:

public class Control extends Activity {
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    deneme d = new deneme(this); // i has tried (getApplicatonContext)
    String x = d.macadress();
    Toast.makeText(getApplicationContext(), x, Toast.LENGTH_LONG).show();
}}

和非活动类:

public class deneme {
Context mcontext ;
WifiManager wm;

public deneme(Context mcontext){
    this.mcontext = mcontext;
}

public String macadress(){
    wm = (WifiManager)mcontext.getSystemService(Context.WIFI_SERVICE);
    String m_szWLANMAC = wm.getConnectionInfo().getMacAddress();
    return m_szWLANMAC;

}}

但该方法返回null.我有权限ACCESS_WIFI_STATE.