title: SecurityException when getting Wifi Scan Results
body: <p>I'm working with Android Studio on an app that, when I push a button, gives me the results of wifi scan!
  If I test the code alone (only the part "wifi scan") it works... But when I put it in the complete app, the app crashs!
  Why?
  I post my code:</p>
  
  <p>//MAIN</p>
  
  <pre><code>    package com.example.pc1.tesiprova;
  
  import android.content.Intent;
  import android.support.v7.app.AppCompatActivity;
  import android.os.Bundle;
  import android.view.Menu;
  import android.view.MenuItem;
  import android.view.View;
  import android.widget.Button;
  
  public class MainActivity extends AppCompatActivity
  {
  
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
  
  //CERCO GLI ELEMENTI BUTTON E BUTTON2
  
          Button OutDoor = (Button) findViewById(R.id.button);
          Button InDoor = (Button) findViewById(R.id.button2);
  
  //CLICCANDO SU BUTTON FACCIO APRIRE UNA NUOVA ACTIVITY
  
          OutDoor.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View arg0) {
                  //DEFINISCO L'INTENZIONE DI APRIRE UNA NUOVA ACTIVITY
                  Intent openActivityO=new Intent(MainActivity.this,ActivityO.class);
                  //APRO L'ACTIVITY ACTIVITYO.JAVA
                  startActivity(openActivityO);
  
              }
          });
  
  //CLICCANDO SU BUTTON2 FACCIO APRIRE UNA NUOVA ACTIVITY
  
          InDoor.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View arg0) {
  
                  Intent openActivityI=new Intent(MainActivity.this,ActivityI.class);
                  startActivity(openActivityI);
  
              }
  
  
          });
      }
  </code></pre>
  
  <p>//ACTIVITYO (that contains wifi scan!)</p>
  
  <pre><code>    package com.example.pc1.tesiprova;
  
  import android.content.Context;
  import android.net.wifi.ScanResult;
  import android.net.wifi.WifiManager;
  import android.support.v7.app.AppCompatActivity;
  import android.os.Bundle;
  import android.view.Menu;
  import android.view.MenuItem;
  import android.widget.TextView;
  
  import java.util.List;
  
  public class ActivityO extends AppCompatActivity {
  
      public WifiManager wifi;
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_o);
  
          TextView text1 = (TextView)findViewById(R.id.textView);
          TextView text2 = (TextView)findViewById(R.id.textView2);
          TextView text3 = (TextView)findViewById(R.id.textView3);
  
          wifi=(WifiManager)getSystemService(Context.WIFI_SERVICE);
          for(int i=0;i&lt;5;i++);
  
          wifi.startScan();
          try{
              text1.setText("Sto cercando");
              Thread.sleep(3333);
          }
          catch(InterruptedException e)
          {
              e.printStackTrace();
          }
  
          List&lt;ScanResult&gt; results = wifi.getScanResults();
  
  
          String ssid1= results.get(0).SSID;
          String ssid2= results.get(1).SSID;
          String ssid3= results.get(2).SSID;
  
          Integer rssi1= results.get(0).level;
          Integer rssi2= results.get(1).level;
          Integer rssi3= results.get(2).level;
  
          text1.setText(ssid1+rssi1);
          text2.setText(ssid2+rssi2);
          text3.setText(ssid3+rssi3);
  </code></pre>
  
  <p>And the errors are:</p>
  
  <pre><code>    10-23 08:30:04.257    2230-2230/com.example.pc1.tesiprova I/art﹕ Not late-enabling -Xcheck:jni (already on)
  10-23 08:30:04.257    2230-2230/com.example.pc1.tesiprova I/art﹕ Late-enabling JIT
  10-23 08:30:04.259    2230-2230/com.example.pc1.tesiprova I/art﹕ JIT created with code_cache_capacity=2MB compile_threshold=1000
  10-23 08:30:04.867    2230-2230/com.example.pc1.tesiprova W/System﹕ ClassLoader referenced unknown path: /data/app/com.example.pc1.tesiprova-1/lib/x86
  10-23 08:30:05.276    2230-2252/com.example.pc1.tesiprova D/OpenGLRenderer﹕ Use EGL_SWAP_BEHAVIOR_PRESERVED: true
  10-23 08:30:05.286    2230-2230/com.example.pc1.tesiprova D/﹕ HostConnection::get() New Host Connection established 0xac07fda0, tid 2230
  10-23 08:30:05.459    2230-2252/com.example.pc1.tesiprova D/﹕ HostConnection::get() New Host Connection established 0xac07feb0, tid 2252
  10-23 08:30:05.507    2230-2252/com.example.pc1.tesiprova I/OpenGLRenderer﹕ Initialized EGL, version 1.4
  10-23 08:30:05.576    2230-2252/com.example.pc1.tesiprova W/EGL_emulation﹕ eglSurfaceAttrib not implemented
  10-23 08:30:05.576    2230-2252/com.example.pc1.tesiprova W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xac130fc0, error=EGL_SUCCESS
  10-23 08:31:14.500    2230-2252/com.example.pc1.tesiprova W/EGL_emulation﹕ eglSurfaceAttrib not implemented
  10-23 08:31:14.500    2230-2252/com.example.pc1.tesiprova W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xac13f560, error=EGL_SUCCESS
  10-23 08:31:14.812    2230-2252/com.example.pc1.tesiprova E/Surface﹕ getSlotFromBufferLocked: unknown buffer: 0xac0763b0
  10-23 08:31:14.819    2230-2252/com.example.pc1.tesiprova D/OpenGLRenderer﹕ endAllStagingAnimators on 0xa42e1280 (RippleDrawable) with handle 0xac12fbd0
  10-23 08:31:16.517    2230-2252/com.example.pc1.tesiprova W/EGL_emulation﹕ eglSurfaceAttrib not implemented
  10-23 08:31:16.517    2230-2252/com.example.pc1.tesiprova W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xad9c7840, error=EGL_SUCCESS
  10-23 08:31:17.043    2230-2230/com.example.pc1.tesiprova I/Choreographer﹕ Skipped 30 frames!  The application may be doing too much work on its main thread.
  10-23 08:31:17.119    2230-2252/com.example.pc1.tesiprova E/Surface﹕ getSlotFromBufferLocked: unknown buffer: 0xac076c00
  10-23 08:31:18.646    2230-2242/com.example.pc1.tesiprova I/art﹕ Background sticky concurrent mark sweep GC freed 9604(599KB) AllocSpace objects, 0(0B) LOS objects, 53% free, 1148KB/2MB, paused 1.649ms total 139.305ms
  10-23 08:31:18.671    2230-2242/com.example.pc1.tesiprova W/art﹕ Suspending all threads took: 24.989ms
  10-23 08:31:22.070    2230-2230/com.example.pc1.tesiprova D/AndroidRuntime﹕ Shutting down VM
      --------- beginning of crash
  10-23 08:31:22.093    2230-2230/com.example.pc1.tesiprova E/AndroidRuntime﹕ FATAL EXCEPTION: main
      Process: com.example.pc1.tesiprova, PID: 2230
      java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.pc1.tesiprova/com.example.pc1.tesiprova.ActivityO}: java.lang.SecurityException: Need ACCESS_COARSE_LOCATION or ACCESS_FINE_LOCATION permission to get scan results
              at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
              at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
              at android.app.ActivityThread.-wrap11(ActivityThread.java)
              at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
              at android.os.Handler.dispatchMessage(Handler.java:102)
              at android.os.Looper.loop(Looper.java:148)
              at android.app.ActivityThread.main(ActivityThread.java:5417)
              at java.lang.reflect.Method.invoke(Native Method)
              at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
              at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
       Caused by: java.lang.SecurityException: Need ACCESS_COARSE_LOCATION or ACCESS_FINE_LOCATION permission to get scan results
              at android.os.Parcel.readException(Parcel.java:1599)
              at android.os.Parcel.readException(Parcel.java:1552)
              at android.net.wifi.IWifiManager$Stub$Proxy.getScanResults(IWifiManager.java:1066)
              at android.net.wifi.WifiManager.getScanResults(WifiManager.java:1311)
              at com.example.pc1.tesiprova.ActivityO.onCreate(ActivityO.java:44)
              at android.app.Activity.performCreate(Activity.java:6237)
              at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
              at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
              at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
              at android.app.ActivityThread.-wrap11(ActivityThread.java)
              at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
              at android.os.Handler.dispatchMessage(Handler.java:102)
              at android.os.Looper.loop(Looper.java:148)
              at android.app.ActivityThread.main(ActivityThread.java:5417)
              at java.lang.reflect.Method.invoke(Native Method)
              at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
              at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
  10-23 08:31:24.168    2230-2230/? I/Process﹕ Sending signal. PID: 2230 SIG: 9
  </code></pre>
  
  <p>I have used these permissions:</p>
  
  <pre><code>&lt;uses-permission android:name="android.permission.CHANGE_WIFI_STATE"/&gt;
  &lt;uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/&gt;
  &lt;uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/&gt;
  &lt;uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /&gt;
  &lt;uses-permission android:name="android.permission.INTERNET" /&gt;
  </code></pre>
  
  <p>Thank you very much!!!!</p>