formlayouteditpolicy.java

基于eclipse的工具开发代码

package com.cownew.uidesigner.policies;

import org.eclipse.draw2d.geometry.Dimension;
import org.eclipse.draw2d.geometry.Rectangle;
import org.eclipse.gef.EditPart;
import org.eclipse.gef.Request;
import org.eclipse.gef.commands.Command;
import org.eclipse.gef.editpolicies.XYLayoutEditPolicy;
import org.eclipse.gef.requests.ChangeBoundsRequest;
import org.eclipse.gef.requests.CreateRequest;

import com.cownew.uidesigner.commands.ComponentSetConstraintCommand;
import com.cownew.uidesigner.commands.CreateComponentCommand;
import com.cownew.uidesigner.model.Component;
import com.cownew.uidesigner.model.Form;
import com.cownew.uidesigner.parts.ComponentPart;

public class FormLayoutEditPolicy extends XYLayoutEditPolicy
{
	protected Command createAddCommand(EditPart child, Object constraint)
	{
		return null; // no support for adding
	}

	protected Command createChangeConstraintCommand(
			ChangeBoundsRequest request, EditPart child, Object constraint)
	{
		if (child instanceof ComponentPart && constraint instanceof Rectangle)
		{
			Component component = (Component) child.getModel();
			Rectangle rect = (Rectangle) constraint;
			// return a command that can move and/or resize a Shape
			return new ComponentSetConstraintCommand(component, request, rect);
		}
		return super.createChangeConstraintCommand(request, child, constraint);
	}

	protected Command createChangeConstraintCommand(EditPart child,
			Object constraint)
	{
		return null;
	}

	protected Command getCreateCommand(CreateRequest request)
	{
		Form form = (Form) getHost().getModel();
		Component component = (Component) request.getNewObject();
		Rectangle constraint = (Rectangle) getConstraintFor(request);
		component.setBounds(constraint);

		CreateComponentCommand command = new CreateComponentCommand(form,
				component);
		return command;
	}

	protected Object getConstraintFor(CreateRequest request)
	{
		Dimension size = request.getSize();
		// 当控件被拖放上去或者用户没有拖出方框的时候size会为空
		if (size == null || size.isEmpty())
		{
			Dimension newSize = new Dimension();
			newSize.width = 60;
			newSize.height = 22;
			request.setSize(newSize);
		}
		return super.getConstraintFor(request);
	}

	protected Command getDeleteDependantCommand(Request request)
	{
		return null; // no support for deleting a dependant
	}
}