Was thinking about getting rid of RocketUtils since it's only used by android app; there's no harm in leaving it...

android/src/net/sf/openrocket/android/rocket/#Overview.java#

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+package net.sf.openrocket.android.rocket;
+
+import net.sf.openrocket.R;
+import net.sf.openrocket.aerodynamics.AerodynamicCalculator;
+import net.sf.openrocket.aerodynamics.BarrowmanCalculator;
+import net.sf.openrocket.aerodynamics.FlightConditions;
+import net.sf.openrocket.aerodynamics.WarningSet;
+import net.sf.openrocket.android.CurrentRocketHolder;
+import net.sf.openrocket.android.util.AndroidLogWrapper;
+import net.sf.openrocket.document.OpenRocketDocument;
+import net.sf.openrocket.masscalc.BasicMassCalculator;
+import net.sf.openrocket.masscalc.MassCalculator;
+import net.sf.openrocket.masscalc.MassCalculator.MassCalcType;
+import net.sf.openrocket.rocketcomponent.Configuration;
+import net.sf.openrocket.rocketcomponent.Rocket;
+import net.sf.openrocket.unit.Unit;
+import net.sf.openrocket.unit.UnitGroup;
+import net.sf.openrocket.util.Coordinate;
+import android.content.SharedPreferences;
+import android.os.Bundle;
+import android.preference.PreferenceManager;
+import android.support.v4.app.Fragment;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.AdapterView;
+import android.widget.TextView;
+
+public class Overview extends Fragment
+implements SharedPreferences.OnSharedPreferenceChangeListener
+{
+
+	/* Calculation of CP and CG */
+	private AerodynamicCalculator aerodynamicCalculator = new BarrowmanCalculator();
+	private MassCalculator massCalculator  = new BasicMassCalculator();
+
+	private MotorConfigSpinner configurationSpinner;
+
+
+	@Override
+	public View onCreateView(LayoutInflater inflater, ViewGroup container,
+			Bundle savedInstanceState) {
+		AndroidLogWrapper.d(Overview.class, "Created View");
+		View v = inflater.inflate(R.layout.rocket_overview, container, false);
+		configurationSpinner = (MotorConfigSpinner) v.findViewById(R.id.openrocketviewerConfigurationSpinner);
+
+		return v;
+	}
+
+	@Override
+	public void onActivityCreated(Bundle savedInstanceState) {
+		super.onActivityCreated(savedInstanceState);
+
+		SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getActivity());
+		prefs.registerOnSharedPreferenceChangeListener(this);
+
+	}
+
+	@Override
+	public void onResume() {
+		super.onResume();
+		setup();
+
+	}
+
+	@Override
+	public void onDestroy() {
+		super.onDestroy();
+
+		SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getActivity());
+		prefs.unregisterOnSharedPreferenceChangeListener(this);
+	}
+
+	@Override
+	public void onSharedPreferenceChanged(SharedPreferences arg0, String arg1) {
+		if ( this.isVisible() ) {
+			setup();
+		}
+	}
+
+	private void setup() {
+		final OpenRocketDocument rocketDocument = CurrentRocketHolder.getCurrentRocket().getRocketDocument();
+		Rocket rocket = rocketDocument.getRocket();
+
+		// Find the index of the default configuration so we can preselect it.
+		Configuration defaultConfiguration = rocketDocument.getDefaultConfiguration();
+		configurationSpinner.createAdapter(rocket);
+		AndroidLogWrapper.d(Overview.class, "configurationSpinner = " + configurationSpinner);
+
+		if ( defaultConfiguration != null ) {
+			configurationSpinner.setSelectedConfiguration(defaultConfiguration.getMotorConfigurationID());
+		}
+		configurationSpinner.setOnItemSelectedListener( new AdapterView.OnItemSelectedListener() {
+
+			/* (non-Javadoc)
+			 * @see android.widget.AdapterView.OnItemSelectedListener#onItemSelected(android.widget.AdapterView, android.view.View, int, long)
+			 */
+			@Override
+			public void onItemSelected(AdapterView<?> arg0, View arg1,
+					int arg2, long arg3) {
+
+				String selectedConfigId = rocketDocument.getRocket().getMotorConfigurationIDs()[arg2];
+				Configuration config = new Configuration(rocketDocument.getRocket());
+				config.setMotorConfigurationID(selectedConfigId);
+				Coordinate cp = aerodynamicCalculator.getWorstCP(config,
+						new FlightConditions(config),
+						new WarningSet());
+
+				Coordinate cg = massCalculator.getCG(config, MassCalcType.LAUNCH_MASS);
+
+				Unit lengthUnit = UnitGroup.UNITS_LENGTH.getDefaultUnit();
+				Unit massUnit = UnitGroup.UNITS_MASS.getDefaultUnit();
+				Unit stabilityUnit = UnitGroup.stabilityUnits(config).getDefaultUnit();
+
+				((TextView)getActivity().findViewById(R.id.openrocketviewerCP)).setText(lengthUnit.toStringUnit(cp.x));
+				((TextView)getActivity().findViewById(R.id.openrocketviewerCG)).setText(lengthUnit.toStringUnit(cg.x));
+				((TextView)getActivity().findViewById(R.id.openrocketviewerLiftOffWeight)).setText(massUnit.toStringUnit(cg.weight));
+				((TextView)getActivity().findViewById(R.id.openrocketviewerStabilityMargin)).setText(stabilityUnit.toStringUnit(cp.x-cg.x));
+
+			}
+
+			/* (non-Javadoc)
+			 * @see android.widget.AdapterView.OnItemSelectedListener#onNothingSelected(android.widget.AdapterView)
+			 */
+			@Override
+			public void onNothingSelected(AdapterView<?> arg0) {
+				((TextView)getActivity().findViewById(R.id.openrocketviewerCP)).setText("");
+				((TextView)getActivity().findViewById(R.id.openrocketviewerCG)).setText("");
+				((TextView)getActivity().findViewById(R.id.openrocketviewerLiftOffWeight)).setText("");
+				((TextView)getActivity().findViewById(R.id.openrocketviewerStabilityMargin)).setText("");
+			}
+
+		});
+
+		Unit lengthUnit = UnitGroup.UNITS_LENGTH.getDefaultUnit();
+		Unit massUnit = UnitGroup.UNITS_MASS.getDefaultUnit();
+
+		Coordinate cg = RocketUtils.getCG(rocket, MassCalcType.NO_MOTORS);
+		double length = RocketUtils.getLength(rocket);
+		((TextView)getActivity().findViewById(R.id.openrocketviewerDesigner)).setText(rocket.getDesigner());
+		((TextView)getActivity().findViewById(R.id.openrocketviewerLength)).setText(lengthUnit.toStringUnit(length));
+		((TextView)getActivity().findViewById(R.id.openrocketviewerMass)).setText(massUnit.toStringUnit(cg.weight));
+		((TextView)getActivity().findViewById(R.id.openrocketviewerStageCount)).setText(String.valueOf(rocket.getStageCount()));
+	}
+
+}

android/src/net/sf/openrocket/android/rocket/.#Overview.java

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+joseph@snowball.10017:1560187057

core/src/net/sf/openrocket/rocketcomponent/RocketUtils.java

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+// this class is only used by the Android application
+package net.sf.openrocket.rocketcomponent;
+
+import java.util.Collection;
+
+import net.sf.openrocket.util.Coordinate;
+
+public abstract class RocketUtils {
+	
+	public static double getLength(Rocket rocket) {
+		return rocket.getSelectedConfiguration().getLength();
+	}
+}