android: ui update. fixed arcore java driver not stopping in background

app/android/jni/tango-gl/gesture_camera.cpp

@@ -199,8 +199,8 @@ void GestureCamera::SetCameraType(CameraType camera_index) {
       SetRotation(glm::quat(1.0f, 0.0f, 0.0f, 0.0f));
       cam_cur_dist_ = kThirdPersonFollow?kThirdPersonFollowCameraDist:kThirdPersonCameraDist;
       anchor_offset_ = glm::vec3(0.0f,0.0f,0.0f);
-      cam_cur_angle_.x = -M_PI / 6.0f;
-      cam_cur_angle_.y = kThirdPersonFollow?0:M_PI / 4.0f;
+      cam_cur_angle_.x = -M_PI / 12.0f;
+      cam_cur_angle_.y = kThirdPersonFollow?0:M_PI / 2.0f;
       cam_cur_target_rot_ = glm::quat(1,0,0,0);
       StartCameraToCurrentTransform();
       break;

app/android/res/layout/activity_rtabmap.xml

@@ -163,6 +163,7 @@
         android:layout_height="100dp"
         android:layout_alignLeft="@+id/button_library"
         android:layout_below="@+id/button_library"
+        android:layout_marginTop="20dp"
         android:text="@string/new_scan" />
 
 </RelativeLayout>        

app/android/src/com/introlab/rtabmap/RTABMapActivity.java

@@ -2314,6 +2314,15 @@ public class RTABMapActivity extends FragmentActivity implements OnClickListener
 
 		updateState(State.STATE_IDLE);
 
+		if(mArCoreCamera != null)
+		{
+			synchronized (this) {
+				mRenderer.setCamera(null);
+				mArCoreCamera.close();
+				mArCoreCamera = null;
+			}
+		}
+		
 		Thread stopThread = new Thread(new Runnable() {
 			public void run() {
 				if(!DISABLE_LOG) Log.i(TAG, String.format("setPausedMapping()"));