title: NullPointerException since changing Google Maps API key
body: <p>I'm getting an error in my Android application. The application worked perfectly and then when I was building the apk I realised my Google Maps API key wasn't going to work for multiple users, so I made a new one following the Google tutorial. Now when I install my app I get a force close - could someone help me ?</p>
  
  <p>This is the logcat:</p>
  
  <pre><code>`03-20 15:42:45.209    3906-3906/project.sharethefare E/AndroidRuntime﹕ FATAL EXCEPTION: main
      Process: project.sharethefare, PID: 3906
      java.lang.RuntimeException: Unable to start activity ComponentInfo{project.sharethefare/project.sharethefare.CurrentLocation}: java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.android.gms.maps.GoogleMap com.google.android.gms.maps.SupportMapFragment.getMap()' on a null object reference
              at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2658)
              at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2725)
              at android.app.ActivityThread.access$900(ActivityThread.java:172)
              at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1422)
              at android.os.Handler.dispatchMessage(Handler.java:102)
              at android.os.Looper.loop(Looper.java:145)
              at android.app.ActivityThread.main(ActivityThread.java:5834)
              at java.lang.reflect.Method.invoke(Native Method)
              at java.lang.reflect.Method.invoke(Method.java:372)
              at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1388)
              at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1183)
       Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.android.gms.maps.GoogleMap com.google.android.gms.maps.SupportMapFragment.getMap()' on a null object reference
              at project.sharethefare.CurrentLocation.setUpMapIfNeeded(CurrentLocation.java:55)
              at project.sharethefare.CurrentLocation.onCreate(CurrentLocation.java:25)
              at android.app.Activity.performCreate(Activity.java:6221)
              at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)
              at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2611)
              at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2725)
              at android.app.ActivityThread.access$900(ActivityThread.java:172)
              at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1422)
              at android.os.Handler.dispatchMessage(Handler.java:102)
              at android.os.Looper.loop(Looper.java:145)
              at android.app.ActivityThread.main(ActivityThread.java:5834)
              at java.lang.reflect.Method.invoke(Native Method)
              at java.lang.reflect.Method.invoke(Method.java:372)
              at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1388)
              at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1183)
  `
  </code></pre>
  
  <p>This is the class:</p>
  
  <pre><code>    public class CurrentLocation extends FragmentActivity {
  
      private GoogleMap mMap; // Might be null if Google Play services APK is not available.
      //________________________________________________________________________________________
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {        //auto generated
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_current_location);
          setUpMapIfNeeded();                                     //part of google maps api
          mMap.setMyLocationEnabled(true);                               //creates a new HomeScreen
      }
  
  
      @Override
      protected void onResume() {                             //Auto Generated
          super.onResume();
          setUpMapIfNeeded();                                 //set up map if not already created
      }
  
      /**
       * Sets up the map if it is possible to do so (i.e., the Google Play services APK is correctly
       * installed) and the map has not already been instantiated.. This will ensure that we only ever
       * call {@link #setUpMap()} once when {@link #mMap} is not null.
       * &lt;p/&gt;
       * If it isn't installed {@link SupportMapFragment} (and
       * {@link com.google.android.gms.maps.MapView MapView}) will show a prompt for the user to
       * install/update the Google Play services APK on their device.
       * &lt;p/&gt;
       * A user can return to this FragmentActivity after following the prompt and correctly
       * installing/updating/enabling the Google Play services. Since the FragmentActivity may not
       * have been completely destroyed during this process (it is likely that it would only be
       * stopped or paused), {@link #onCreate(Bundle)} may not be called again so we should call this
       * method in {@link #onResume()} to guarantee that it will be called.
       */
      private void setUpMapIfNeeded() {
          // Do a null check to confirm that we have not already instantiated the map.
          if (mMap == null) {
              // Try to obtain the map from the SupportMapFragment.
              mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.curLocMap))
                      .getMap();
              // Check if we were successful in obtaining the map.
              if (mMap != null) {
                  setUpMap();
              }
          }
      }
  
      /**
       * This is where we can add markers or lines, add listeners or move the camera. In this case, we
       * just add a marker near Africa.
       * &lt;p/&gt;
       * This should only be called once and when we are sure that {@link #mMap} is not null.
       */
      //call the method to continuously check current location
      private void setUpMap() {
          mMap.setOnMyLocationChangeListener(myLocationChangeListener);
      }
  
      //called above. Used to constantly update the users position on the map
      private GoogleMap.OnMyLocationChangeListener myLocationChangeListener = new GoogleMap.OnMyLocationChangeListener() {
          @Override
          public void onMyLocationChange(Location location) {
              //create a new latitude and longitude point
              LatLng loc = new LatLng(location.getLatitude(), location.getLongitude());
              //make global variables on home screen == to current location
              HomeScreen.curLat = location.getLatitude();
              HomeScreen.curLong = location.getLongitude();
              HomeScreen.curLocSet = true;
              //animate the camera to zoom in on position when found
              mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(loc, 16.0f));
          }
      };
  
      public void backToHome(View view){ // called when button clicked. returns to homeScreen activity
          Intent intent = new Intent(CurrentLocation.this,HomeScreen.class);
          startActivity(intent);
      }
  
  }
  </code></pre>
  
  <p>Any help would be greatly appreciated. Thanks in advance</p>