ERROR/AndroidRuntime(363): FATAL EXCEPTION: main
 ERROR/AndroidRuntime(363): java.lang.RuntimeException: Unable to start activity ComponentInfo{dongguk.ac/dongguk.ac.rssiScan}: java.lang.NullPointerException
 ERROR/AndroidRuntime(363):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
 ERROR/AndroidRuntime(363):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
 ERROR/AndroidRuntime(363):     at android.app.ActivityThread.access$2300(ActivityThread.java:125)
 ERROR/AndroidRuntime(363):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
 ERROR/AndroidRuntime(363):     at android.os.Handler.dispatchMessage(Handler.java:99)
 ERROR/AndroidRuntime(363):     at android.os.Looper.loop(Looper.java:123)
 ERROR/AndroidRuntime(363):     at android.app.ActivityThread.main(ActivityThread.java:4627)
 ERROR/AndroidRuntime(363):     at java.lang.reflect.Method.invokeNative(Native Method)
 ERROR/AndroidRuntime(363):     at java.lang.reflect.Method.invoke(Method.java:521)
 ERROR/AndroidRuntime(363):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
 ERROR/AndroidRuntime(363):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
 ERROR/AndroidRuntime(363):     at dalvik.system.NativeStart.main(Native Method)
 ERROR/AndroidRuntime(363): Caused by: java.lang.NullPointerException
 ERROR/AndroidRuntime(363):     at dongguk.ac.rssiScan.onCreate(rssiScan.java:40)
 ERROR/AndroidRuntime(363):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
 ERROR/AndroidRuntime(363):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
 ERROR/AndroidRuntime(363):     ... 11 more


이클립스 상에 에러는 없는데 에뮬레이터 실행시 접속이 되지않습니다.

LogCat 에러 를 보니 이렇게 나오는데 잘 이해가 가지않아 올립니다.

고수님들의 가르침을 좀 받고 싶습니다.

 

 

ERROR/AndroidRuntime(363):     at dongguk.ac.rssiScan.onCreate(rssiScan.java:40)

이부분이 자꾸 선택이되던데... 어떻게 수정을 해야할지 모르겟습니다..

해당위치는 노란색으로 가르켜놓겟습니다.

 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState); 
  setContentView(R.layout.main); 
  // Setup UI 
  textStatus = (TextView) findViewById(R.id.textStatus); 
  buttonScan = (Button) findViewById(R.id.buttonScan); 
  buttonScan.setOnClickListener(this); 
  // Setup WiFi 
  wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
  // List<ScanResult>
  List<ScanResult> results = wifiDemo.wifi.getScanResults();
  ArrayList<Integer> maxsignal = new ArrayList <Integer> ();
  ScanResult bestSignal = null; 
  for (ScanResult result : results) {   
   if (bestSignal == null         
     || WifiManager.compareSignalLevel(bestSignal.level, result.level) < 0){       
    maxsignal.add(result.level);
    bestSignal = result;
   }
  }   
  java.util.Collections.sort(maxsignal);
  textStatus.append("\n\nWiFi Status: " + maxsignal.toString());
    // Get WiFi status
  WifiInfo info = wifi.getConnectionInfo(); 
  textStatus.append("\n\nWiFi Status: " +
    "\nSSID : " + info.getSSID() +
    "\nMacAddress : " + info.getMacAddress() +
    "\nRssi : " + info.getRssi());
  // List available networks 
  List<WifiConfiguration> configs = wifi.getConfiguredNetworks();
  for (WifiConfiguration config : configs) {  
   textStatus.append("\n\n" + config.SSID); 
  } 
  // Register Broadcast Receiver 
  if (receiver == null)  
   receiver = new WiFiScanReceiver(this);
   registerReceiver(receiver, new IntentFilter(
    WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
  Log.d(TAG, "onCreate()");
 }