How to Use Objects: Code and Concepts by Holger Gast

Author:Holger Gast [Gast, Holger]
Language: eng
Format: epub, azw3, pdf
Publisher: Pearson Education
Published: 2015-12-25T23:00:00+00:00

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public String getImageName()

public void setImageName(String name)

public boolean isImageShown()

public void setImageShown(boolean show)

public void addSelectionListener(SelectionListener l)

public void removeSelectionListener(SelectionListener l)

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The imageName is a property rather than a parameter to the constructor because the WindowBuilder does not handle such constructors well. 7.5

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Painting on the screen is event-driven.

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The central question is, of course, how to paint on the Canvas. In other frameworks, such as Swing and the Graphical Editing Framework’s Draw2D 214 layer, the solution is to override one or several methods that are responsible for drawing different parts of a figure in an application of the TEMPLATE 1.4.9 METHOD pattern. SWT instead lets you register PaintListeners that are called back whenever some part of the Canvas needs re-drawing. The MemoryCard’s constructor sets this up, as shown in the next example. We choose to delegate to the outer class here, because painting is one of the 2.1.3 MemoryCard’s tasks and the PaintListener is only a technical necessity.

swt.custom.MemoryCard.MemoryCard

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