【发布时间】：2015-01-04 00:03:21
【问题描述】：
我的任务是创建一个自定义摆动组件。我的组件在包含用于放大和缩小图像的 JSlider 的测试应用程序中正常运行。但是，我需要以模型、UIDelegate 和组件类格式呈现我的自定义组件，我完全不知道如何转换我的代码以使其遵循这种格式。这是我的测试应用程序的代码。
package test;
import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
import javax.swing.event.*;
import java.io.File;
import java.net.URL;
import javax.imageio.ImageIO;
public class ZoomDemo extends JComponent implements ChangeListener {
JPanel gui;
/**
* Displays the image.
*/
JLabel imageCanvas;
Dimension size;
double scale = 1.0;
private BufferedImage image;
public ZoomDemo() {
size = new Dimension(10, 10);
setBackground(Color.black);
try {
image = ImageIO.read(new File("car.jpg"));
} catch (Exception ex) {
ex.printStackTrace();
}
}
public void setImage(Image image) {
imageCanvas.setIcon(new ImageIcon(image));
}
public void initComponents() {
if (gui == null) {
gui = new JPanel(new BorderLayout());
gui.setBorder(new EmptyBorder(5, 5, 5, 5));
imageCanvas = new JLabel();
JPanel imageCenter = new JPanel(new GridBagLayout());
imageCenter.add(imageCanvas);
JScrollPane imageScroll = new JScrollPane(imageCenter);
imageScroll.setPreferredSize(new Dimension(300, 100));
gui.add(imageScroll, BorderLayout.CENTER);
}
}
public Container getGui() {
initComponents();
return gui;
}
public void stateChanged(ChangeEvent e) {
int value = ((JSlider) e.getSource()).getValue();
scale = value / 100.0;
paintImage();
}
protected void paintImage() {
int imageWidth = image.getWidth();
int imageHeight = image.getHeight();
BufferedImage bi = new BufferedImage(
(int)(imageWidth*scale),
(int)(imageHeight*scale),
image.getType());
Graphics2D g2 = bi.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
AffineTransform at = AffineTransform.getTranslateInstance(0, 0);
at.scale(scale, scale);
g2.drawRenderedImage(image, at);
setImage(bi);
}
public Dimension getPreferredSize() {
int w = (int) (scale * size.width);
int h = (int) (scale * size.height);
return new Dimension(w, h);
}
private JSlider getControl() {
JSlider slider = new JSlider(JSlider.HORIZONTAL, 1, 500, 50);
slider.setMajorTickSpacing(50);
slider.setMinorTickSpacing(25);
slider.setPaintTicks(true);
slider.setPaintLabels(true);
slider.addChangeListener(this);
return slider;
}
public static void main(String[] args) {
ZoomDemo app = new ZoomDemo();
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setContentPane(app.getGui());
app.setImage(app.image);
// frame.getContentPane().add(new JScrollPane(app));
frame.getContentPane().add(app.getControl(), "Last");
frame.setSize(700, 500);
frame.setLocation(200, 200);
frame.setVisible(true);
}
}
以下代码是我需要遵循的类格式
组件类
package component;
import javax.swing.JComponent;
import javax.swing.JSlider;
import javax.swing.plaf.ComponentUI;
public class ProgressBar extends JComponent {
public static ComponentUI createUI(JComponent c) {
return new ZoomUI();
}
public void installUI(JComponent c){
}
public void uninstallUI (JComponent c){
}
}
模型类
public class ZoomModel extends JSLider {
}
UIDelegate 类
public class ZoomUI extends ComponentUI implements ChangeListener{
}
任何有关如何以这种格式实现自定义组件的帮助将不胜感激。我对 Swing 非常陌生，我在自定义组件上找到的文档非常混乱且帮助不大。
测试应用
package test;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
import javax.swing.border.LineBorder;
import javax.swing.event.*;
import java.io.File;
import java.net.URL;
import javax.imageio.ImageIO;
import component.ZoomComponent;
public class ZoomDemo extends JPanel implements PropertyChangeListener, ActionListener {
ZoomComponent zoomer;
JPanel board;
private BufferedImage image;
public ZoomDemo( ) {
super(true);
setLayout(new BorderLayout( ));
board = new JPanel(true);
board.setPreferredSize(new Dimension(300, 300));
board.setBorder(new LineBorder(Color.black, 5));
zoomer = new ZoomComponent();
add(board, BorderLayout.NORTH);
add(zoomer, BorderLayout.SOUTH);
}
@Override
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void propertyChange(PropertyChangeEvent arg0) {
// TODO Auto-generated method stub
}
public static void main(String[] args) {
UIManager.getDefaults().put("ZoomComponentUI", "component.BasicZoomUI");
ZoomDemo s= new ZoomDemo();
JFrame frame = new JFrame("Sample Sketch Application");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setContentPane(s);
frame.pack( );
frame.setVisible(true);
}
}
【问题讨论】：
-
您的模型类不正确，它应该对数据、UI 进行建模，因此可能包含图像和缩放级别，例如......
-
对于模型，您应该重用或扩展现有的 Swing 模型。 UIdelegate（“用户界面”类）扩展了 ComponentUI。它负责绘制组件并解释用户的鼠标或键盘操作，因此它应该实现适当的侦听器和接口。 Component 类扩展了 JComponent。这些是我收到的说明，但不明白如何使其工作。
-
“你应该重用或扩展现有的 Swing 模式” 喜欢什么？
-
我认为这意味着像在我的代码中那样扩展现有模型，例如“JSLider”
-
JSlider不是模型，而是组件；)
标签： java swing model-view-controller custom-component