ArcGIS Engine Developer Guide

BUILDING APPLICATIONS WITH VISUAL JAVABEANS
3. The onCreate method is passed a reference to the control that the command
works with. In this case, it can be a MapBean, PageLayoutBean, or
ToolbarBean. Rather than adding logic in the onCreate method to determine
the type of object passed to the hook method, you will use the HookHelper
class to handle this. A command or tool needs to know how to handle the
hook it gets passed, so a check is needed to determine the type of ArcGIS
control that has been passed. The HookHelper is used to hold the hook and
return the ActiveView regardless of the type of hook (in this case either a
MapBean, PageLayoutBean, or ToolbarBean).
Import the HookHelper class and add the hookHelper member variable to the
AddDateCommand class:
import com.esri.arcgis.systemUI.ITool;
import com.esri.arcgis.controlcommands.HookHelper;
public class AddDateCommand implements ICommand, ITool{
HookHelper hookHelper;
4. In the onCreate method, construct the hookhelper and use the setHookByRef
method to pass the controls object.
public void onCreate(Object obj) throws IOException, AutomationException
{
// To be added later. Delete this line.
hookHelper = new HookHelper();
hookHelper.setHookByRef( obj );
}
5. Add implementation for all methods defined in the ITool interface to the
AddDateCommand class. Not all methods will be used, but they need to be
implemented to be able to compile the class. In the following code, pay attention
to the onMouseDown method, as this method creates a TextElement
with the current date as its text and adds it to the graphics container of the
hook object.
/*
* see com.esri.arcgis.systemUI.ITool#getCursor()
*/
public int getCursor() throws IOException, AutomationException {
return 0;
}
/*
* see com.esri.arcgis.systemUI.ITool#onMouseDown(int, int, int,
int)
*/
public void onMouseDown(int button, int shift, int x, int y)
throws IOException, AutomationException {
Date today = new Date();
// Format the date in the form "Wed 27 Aug, 2003".
SimpleDateFormat formatter;
formatter = new SimpleDateFormat("EEE d MMM, yyyy");
Chapter 6 • Developer scenarios • 323