title: Null pointer exception when checking for permission with android.content.Context.checkPermission
body: <p>I need to check for permissions before querying the Android calendar for events.
  To do it, Android studio is warning that I need to follow a check before querying.
  The auto generated code is this piece:</p>
  
  <pre><code>if (ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_CALENDAR) != PackageManager.PERMISSION_GRANTED) {
          System.out.println("NO ACCESS TO CALENDAR!! Abort mission, abort mission!!");
      }
  </code></pre>
  
  <p>When trying to run it, I get this error: </p>
  
  <blockquote>
    <p>Attempt to invoke virtual method 'int<br>
        android.content.Context.checkPermission(java.lang.String, int, int)' 
        on a null object reference</p>
  </blockquote>
  
  <p>So it is clear that something is null at this point, and I tried to get the context of the app with a different way, but it's still the same error. 
  Other thing I tried was this code, which is supposed to handle the targets lower than Android 6:</p>
  
  <pre><code>if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_CALENDAR) != PackageManager.PERMISSION_GRANTED) {
  
          ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_CALENDAR},
                  MY_PERMISSIONS_REQUEST_READ_CONTACTS);
      }
  </code></pre>
  
  <p>Still get the same error, can anybody help me with this?</p>