JavaGUI开发：Sketcher应用的功能增强与架构设计

### Java GUI开发：Sketcher应用的功能增强与架构设计 在Java GUI开发中，我们可以对应用程序进行一系列功能增强，如添加菜单项图标、工具提示以及采用模型/视图架构等。下面将详细介绍这些功能的实现方法和原理。 #### 1. 添加菜单项图标 为了让应用程序的GUI更加丰富，我们可以为菜单项添加图标。具体操作步骤如下： - **定义图标**：在SketcherConstants类中定义菜单项的图标，示例代码如下： ```java // Menu item icons public final static Icon NEW16 = new ImageIcon(imagePath + "new16.gif"); public final static Icon OPEN16 = new ImageIcon(imagePath + "Open16.gif"); public final static Icon SAVE16 = new ImageIcon(imagePath + " Save16.gif"); public final static Icon SAVEAS16 = new ImageIcon(imagePath + "SaveAs16.gif"); public final static Icon PRINT16 = new ImageIcon(imagePath + "print16.gif"); public final static Icon LINE16 = new ImageIcon(imagePath + "Line16.gif"); public final static Icon RECTANGLE16 = new ImageIcon(imagePath + "Rectangle16.gif"); public final static Icon CIRCLE16 = new ImageIcon(imagePath + "Circle16.gif"); public final static Icon CURVE16 = new ImageIcon(imagePath + "Curve16.gif"); public final static Icon RED16 = new ImageIcon(imagePath + "Red16.gif"); public final static Icon GREEN16 = new ImageIcon(imagePath + "Green16.gif"); public final static Icon BLUE16 = new ImageIcon(imagePath + "Blue16.gif"); public final static Icon YELLOW16 = new ImageIcon(imagePath + "Yellow16.gif"); ``` 这些图标大小为16×16像素，与菜单项相匹配。 - **使用图标**：在创建菜单项的方法中，为Action对象添加小图标。例如，在`createFileMenuActions()`方法中添加如下代码： ```java private void createFileMenuActions() { // Code to create action objects as before... // Code to add large icons to the action objects as before... // Add menu item actions newAction.putValue(SMALL_ICON, NEW16); openAction.putValue(SMALL_ICON, OPEN16); saveAction.putValue(SMALL_ICON, SAVE16); saveAsAction.putValue(SMALL_ICON,SAVEAS16); printAction.putValue(SMALL_ICON, PRINT16); } ``` 对于Elements菜单项和颜色菜单项，也可以采用类似的方法添加图标。在`createElementTypeActions()`方法末尾添加： ```java lineAction.putValue(SMALL_ICON, LINE16); rectangleAction.putValue(SMALL_ICON, RECTANGLE16); circleAction.putValue(SMALL_ICON, CIRCLE16); curveAction.putValue(SMALL_ICON, CURVE16); ``` 在`createElementColorActions()`方法中添加： ```java redAction.putValue(SMALL_ICON, RED16); blueAction.putValue(SMALL_ICON, BLUE16); greenAction.putValue(SMALL_ICON, GREEN16); yellowAction.putValue(SMALL_ICON, YELLOW16); ``` - **控制图标显示**：如果不想在菜单项上显示图标，可以使用`setIcon(null)`方法，示例如下： ```java menuItem.setIcon(null); ``` #### 2. 添加工具提示 工具提示是当鼠标悬停在GUI元素上时自动显示的小文本提示。在Java中实现工具提示非常简单，利用Action对象的`SHORT_DESCRIPTION`键即可。具体操作步骤如下： - **添加工具提示文本**：在`createFileMenuActions()`方法中添加工具提示文本，示例代码如下： ```java private void createFileMenuActions() { // Code to create action objects as before... // Code to add large icons to the action objects as before... // Code to add small icons to the action objects as before... // Add tooltip text newAction.putValue(SHORT_DESCRIPTION, "Create a new sketch"); openAction.putValue(SHORT_DESCRIPTION, "Read a sketch from a file"); saveAction.putValue(SHORT_DESCRIPTION, "Save the current sketch to file"); saveAsAction.putValue(SHORT_DESCRIPTION, "Save the current sketch to a new file"); printAction.putValue(SHORT_DESCRIPTION, "Print the current sketch"); } ``` 在`createElementTypeActions()`方法末尾添加： ```java lineAction.putValue(SHORT_DESCRIPTION, "Draw lines"); rectangleAction.putValue(SHORT_DESCRIPTION, "Draw rectangles"); circleAction.putValue(SHORT_DESCRIPTION, "Draw circles"); curveAction.putValue(SHORT_DESCRIPTION, "Draw curves"); ``` 在`createElementColorActions()`方法中添加： ```java redAction.putValue(SHORT_DESCRIPTION, "Draw in red"); blueAction.putValue(SHORT_DESCRIPTION, "Draw in blue"); greenAction.putValue(SHORT_DESCRIPTION, ```