201771010101白玛次仁《面向对象程序设计（java）》第十二周实验总结
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实验十二 图形程序设计
实验时间 2018-11-14
学习总结：
1.Java的抽象口工具箱（ Abstract WindowToolkit, AWT)包含在java.awt包中，它提供了许多用来设计GUI的组件类和容器类。
2.AWT库处理用户界面元素的方法：把图形元素的创建和行为委托给本地GUI工具箱进行处理。
3.Swing用户界面库是非基于对等体的GUI工具箱。Swing具有更丰富并且更方便的用户界面元素集合。Swing对底层平台的依赖很少，因此与平台相关的bug很少。Swing会带来交叉平台上的统一视觉体验。Swing类库被放在 javax.swing 包里。
4.大部分AWT组件都有其 Swing的等价组件。Swing组件的名字一般是在AWT组件名前面添加一个字母“J”，如：JButton,JFrame,JPanel等。
5.通常把由Component类的子类或间接子类创建的对象称为一个组件。
6.组件类的常用API
java.awt.Component 1.0
– boolean isVisible() 检查组件是否可见
– void setVisible(boolean b) 设置组件可见
– void setSize(int width,int height) 把组件缩放到指定宽度和高度
– void setBounds(int x,int y,intwidth,int height) 移动并缩放组件
– Dimension getSize() 得到组件的大小
– void setSize(Dimension d) 把组件缩放到指定的大小
– void setLocation(int x,int y)
7.容器是Java中能容纳和排列组件的组件。常用的容器是框架（Frame,JFrame)
8.java.awt.Frame 类的常用API
void setResizable(boolean b) 缩放框架
void setTitle(String s) 设置框架标题
void setIconImage(Image image) 将Image用作框架图标
9.Container类提供了一个方法add(),用来在容器类组件对象中添加其他组件。容器本身也是一个组件，可以把一个容器添加到另一个容器里，实现容器嵌套。
10.定位：常用Component类的setLocation和setBounds方法
11.创建框架时的常用类及API
java.awt.Component 1.0
– boolean isVisible() 检查组件是否可见
– void setVisible(boolean b) 设置组件可见
– void setSize(int width,int height) 把组件缩放到指定宽度和高度
– void setBounds(int x,int y,intwidth,int height) 移动并缩放组件
– Dimension getSize() 得到组件的大小
– void setSize(Dimension d) 把组件缩放到指定的大小
12.Java SE了包含一个Java 2D库，该库提供了一个非常强大的图形操作集。
13.Graphics 2D类是Graphics类的子类，Graphics。2D类对象通常可用Graphics对象转换而来。
14.Java 2D图形类使用浮点数坐标系，这样可为坐标指定单位。
15.图像：（1）在Java应用程序中，一旦图像保存在本地或因特网的某个位置上，就可以将它们直接读入到java应用程序中。（2）完成将一个图像文件加载到程序中，再调用Graphics类提供的DrawImage()显示它。
1、实验目的与要求
(1) 掌握Java GUI中框架创建及属性设置中常用类的API；
(2) 掌握Java GUI中2D图形绘制常用类的API；
(3) 了解Java GUI中2D图形中字体与颜色的设置方法；
(4) 了解Java GUI中2D图像的载入方法。
2、实验内容和步骤
实验1： 导入第10章示例程序，测试程序并进行代码注释。
测试程序1：
l 运行下列程序，观察程序运行结果。
|
import javax.swing.*; public class SimpleFrameTest { public static void main(String[] args) { JFrame frame = new JFrame(); frame.setBounds(0, 0,300, 200); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); } } |
l 在elipse IDE中调试运行教材407页程序10-1，结合程序运行结果理解程序；与上面程序对比，思考异同；
l 掌握空框架创建方法；
l 了解主线程与事件分派线程概念；
l 掌握GUI顶层窗口创建技术。
package simpleFrame;
import java.awt.*;
import javax.swing.*;
/**
* @version 1.33 2015-05-12
* @author Cay Horstmann
*/
public class SimpleFrameTest
{
public static void main(String[] args)
{
EventQueue.invokeLater(() ->
{
SimpleFrame frame = new SimpleFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}
class SimpleFrame extends JFrame
{
private static final int DEFAULT_WIDTH = 300;
private static final int DEFAULT_HEIGHT = 200;
public SimpleFrame()
{
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
}
}
package simpleFrame;
import java.awt.*;
import javax.swing.*;
/**
* @version 1.33 2015-05-12
* @author Cay Horstmann
*/
public class SimpleFrameTest
{
public static void main(String[] args)
{
EventQueue.invokeLater(() ->
{
SimpleFrame frame = new SimpleFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}
class SimpleFrame extends JFrame
{
private static final int DEFAULT_WIDTH = 300;
private static final int DEFAULT_HEIGHT = 200;
public SimpleFrame()
{
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
}
}
测试程序2：
l 在elipse IDE中调试运行教材412页程序10-2，结合程序运行结果理解程序；
l 掌握确定框架常用属性的设置方法。
package sizedFrame;
import java.awt.*;
import javax.swing.*;
/**
* @version 1.34 2015-06-16
* @author Cay Horstmann
*/
public class SizedFrameTest
{
public static void main(String[] args)
{
EventQueue.invokeLater(() ->
{
JFrame frame = new SizedFrame();
frame.setTitle("SizedFrame");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}
class SizedFrame extends JFrame
{
public SizedFrame()
{
// get screen dimensions
Toolkit kit = Toolkit.getDefaultToolkit();
Dimension screenSize = kit.getScreenSize();
int screenHeight = screenSize.height;
int screenWidth = screenSize.width;
// set frame width, height and let platform pick screen location
setSize(screenWidth / 2, screenHeight / 2);
setLocationByPlatform(true);
// set frame icon
Image img = new ImageIcon("icon.gif").getImage();
setIconImage(img);
}
}
package sizedFrame;
import java.awt.*;
import javax.swing.*;
/**
* @version 1.34 2015-06-16
* @author Cay Horstmann
*/
public class SizedFrameTest
{
public static void main(String[] args)
{
EventQueue.invokeLater(() ->
{
JFrame frame = new SizedFrame();
frame.setTitle("SizedFrame");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}
class SizedFrame extends JFrame
{
public SizedFrame()
{
// get screen dimensions
Toolkit kit = Toolkit.getDefaultToolkit();
Dimension screenSize = kit.getScreenSize();
int screenHeight = screenSize.height;
int screenWidth = screenSize.width;
// set frame width, height and let platform pick screen location
setSize(screenWidth / 2, screenHeight / 2);
setLocationByPlatform(true);
// set frame icon
Image img = new ImageIcon("icon.gif").getImage();
setIconImage(img);
}
}
测试程序3：
l 在elipse IDE中调试运行教材418页程序10-3，结合运行结果理解程序；
l 掌握在框架中添加组件；
l 掌握自定义组件的用法。
package notHelloWorld;
import javax.swing.*;
import java.awt.*;
/**
* @version 1.33 2015-05-12
* @author Cay Horstmann
*/
public class NotHelloWorld
{
public static void main(String[] args)
{
EventQueue.invokeLater(() ->
{
JFrame frame = new NotHelloWorldFrame();
frame.setTitle("NotHelloWorld");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}
/**
* A frame that contains a message panel
*/
class NotHelloWorldFrame extends JFrame
{
public NotHelloWorldFrame()
{
add(new NotHelloWorldComponent());
pack();
}
}
/**
* A component that displays a message.
*/
class NotHelloWorldComponent extends JComponent
{
public static final int MESSAGE_X = 75;
public static final int MESSAGE_Y = 100;
private static final int DEFAULT_WIDTH = 300;
private static final int DEFAULT_HEIGHT = 200;
public void paintComponent(Graphics g)
{
g.drawString("Not a Hello, World program", MESSAGE_X, MESSAGE_Y);
}
public Dimension getPreferredSize() { return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT); }
}
package notHelloWorld;
import javax.swing.*;
import java.awt.*;
/**
* @version 1.33 2015-05-12
* @author Cay Horstmann
*/
public class NotHelloWorld
{
public static void main(String[] args)
{
EventQueue.invokeLater(() ->
{
JFrame frame = new NotHelloWorldFrame();
frame.setTitle("NotHelloWorld");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}
/**
* A frame that contains a message panel
*/
class NotHelloWorldFrame extends JFrame
{
public NotHelloWorldFrame()
{
add(new NotHelloWorldComponent());
pack();
}
}
/**
* A component that displays a message.
*/
class NotHelloWorldComponent extends JComponent
{
public static final int MESSAGE_X = 75;
public static final int MESSAGE_Y = 100;
private static final int DEFAULT_WIDTH = 300;
private static final int DEFAULT_HEIGHT = 200;
public void paintComponent(Graphics g)
{
g.drawString("Not a Hello, World program", MESSAGE_X, MESSAGE_Y);
}
public Dimension getPreferredSize() { return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT); }
}
package notHelloWorld;
import javax.swing.*;
import java.awt.*;
/**
* @version 1.33 2015-05-12
* @author Cay Horstmann
*/
public class NotHelloWorld
{
public static void main(String[] args)
{
EventQueue.invokeLater(() ->
{
JFrame frame = new NotHelloWorldFrame();
frame.setTitle("NotHelloWorld");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}
/**
* A frame that contains a message panel
*/
class NotHelloWorldFrame extends JFrame
{
public NotHelloWorldFrame()
{
add(new NotHelloWorldComponent());
pack();
}
}
/**
* A component that displays a message.
*/
class NotHelloWorldComponent extends JComponent
{
public static final int MESSAGE_X = 75;
public static final int MESSAGE_Y = 100;
private static final int DEFAULT_WIDTH = 300;
private static final int DEFAULT_HEIGHT = 200;
public void paintComponent(Graphics g)
{
g.drawString("Not a Hello, World program", MESSAGE_X, MESSAGE_Y);
}
public Dimension getPreferredSize() { return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT); }
}
测试程序4：
l 在elipse IDE中调试运行教材424 -425页程序10-4，结合程序运行结果理解程序；
l 掌握2D图形的绘制方法。
package draw;
import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;
/**
* @version 1.33 2007-05-12
* @author Cay Horstmann
*/
public class DrawTest
{
public static void main(String[] args)
{
EventQueue.invokeLater(() ->
{
JFrame frame = new DrawFrame();
frame.setTitle("DrawTest");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}
/**
* A frame that contains a panel with drawings
*/
class DrawFrame extends JFrame
{
public DrawFrame()
{
add(new DrawComponent());
pack();
}
}
/**
* A component that displays rectangles and ellipses.
*/
class DrawComponent extends JComponent
{
private static final int DEFAULT_WIDTH = 400;
private static final int DEFAULT_HEIGHT = 400;
public void paintComponent(Graphics g)
{
Graphics2D g2 = (Graphics2D) g;
// draw a rectangle
double leftX = 100;
double topY = 100;
double width = 200;
double height = 150;
Rectangle2D rect = new Rectangle2D.Double(leftX, topY, width, height);
g2.draw(rect);
// draw the enclosed ellipse
Ellipse2D ellipse = new Ellipse2D.Double();
ellipse.setFrame(rect);
g2.draw(ellipse);
// draw a diagonal line
g2.draw(new Line2D.Double(leftX, topY, leftX + width, topY + height));
// draw a circle with the same center
double centerX = rect.getCenterX();
double centerY = rect.getCenterY();
double radius = 150;
Ellipse2D circle = new Ellipse2D.Double();
circle.setFrameFromCenter(centerX, centerY, centerX + radius, centerY + radius);
g2.draw(circle);
}
public Dimension getPreferredSize() { return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT); }
}
package draw;
import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;
/**
* @version 1.33 2007-05-12
* @author Cay Horstmann
*/
public class DrawTest
{
public static void main(String[] args)
{
EventQueue.invokeLater(() ->
{
JFrame frame = new DrawFrame();
frame.setTitle("DrawTest");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}
/**
* A frame that contains a panel with drawings
*/
class DrawFrame extends JFrame
{
public DrawFrame()
{
add(new DrawComponent());
pack();
}
}
/**
* A component that displays rectangles and ellipses.
*/
class DrawComponent extends JComponent
{
private static final int DEFAULT_WIDTH = 400;
private static final int DEFAULT_HEIGHT = 400;
public void paintComponent(Graphics g)
{
Graphics2D g2 = (Graphics2D) g;
// draw a rectangle
double leftX = 100;
double topY = 100;
double width = 200;
double height = 150;
Rectangle2D rect = new Rectangle2D.Double(leftX, topY, width, height);
g2.draw(rect);
// draw the enclosed ellipse
Ellipse2D ellipse = new Ellipse2D.Double();
ellipse.setFrame(rect);
g2.draw(ellipse);
// draw a diagonal line
g2.draw(new Line2D.Double(leftX, topY, leftX + width, topY + height));
// draw a circle with the same center
double centerX = rect.getCenterX();
double centerY = rect.getCenterY();
double radius = 150;
Ellipse2D circle = new Ellipse2D.Double();
circle.setFrameFromCenter(centerX, centerY, centerX + radius, centerY + radius);
g2.draw(circle);
}
public Dimension getPreferredSize() { return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT); }
}
package draw;
import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;
/**
* @version 1.33 2007-05-12
* @author Cay Horstmann
*/
public class DrawTest
{
public static void main(String[] args)
{
EventQueue.invokeLater(() ->
{
JFrame frame = new DrawFrame();
frame.setTitle("DrawTest");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}
/**
* A frame that contains a panel with drawings
*/
class DrawFrame extends JFrame
{
public DrawFrame()
{
add(new DrawComponent());
pack();
}
}
/**
* A component that displays rectangles and ellipses.
*/
class DrawComponent extends JComponent
{
private static final int DEFAULT_WIDTH = 400;
private static final int DEFAULT_HEIGHT = 400;
public void paintComponent(Graphics g)
{
Graphics2D g2 = (Graphics2D) g;
// draw a rectangle
double leftX = 100;
double topY = 100;
double width = 200;
double height = 150;
Rectangle2D rect = new Rectangle2D.Double(leftX, topY, width, height);
g2.draw(rect);
// draw the enclosed ellipse
Ellipse2D ellipse = new Ellipse2D.Double();
ellipse.setFrame(rect);
g2.draw(ellipse);
// draw a diagonal line
g2.draw(new Line2D.Double(leftX, topY, leftX + width, topY + height));
// draw a circle with the same center
double centerX = rect.getCenterX();
double centerY = rect.getCenterY();
double radius = 150;
Ellipse2D circle = new Ellipse2D.Double();
circle.setFrameFromCenter(centerX, centerY, centerX + radius, centerY + radius);
g2.draw(circle);
}
public Dimension getPreferredSize() { return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT); }
}
测试程序5：
l 在elipse IDE中调试运行教材432页-433程序10-5，结合程序运行结果理解程序；
l 了解2D图形中字体的设置的方法；
package font; import java.awt.*; import java.awt.font.*; import java.awt.geom.*; import javax.swing.*;
/** * @version 1.34 2015-05-12 * @author Cay Horstmann */ public class FontTest { public static void main(String[] args) { EventQueue.invokeLater(() -> { JFrame frame = new FontFrame(); frame.setTitle("FontTest"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); }); } } /** * A frame with a text message component */ class FontFrame extends JFrame { public FontFrame() { add(new FontComponent()); pack(); } } /** * A component that shows a centered message in a box. */ class FontComponent extends JComponent { private static final int DEFAULT_WIDTH = 300; private static final int DEFAULT_HEIGHT = 200; public void paintComponent(Graphics g) { Graphics2D g2 = (Graphics2D) g; String message = "Hello, World!";
Font f = new Font("Serif", Font.BOLD, 36); g2.setFont(f); // measure the size of the message FontRenderContext context = g2.getFontRenderContext(); Rectangle2D bounds = f.getStringBounds(message, context); // set (x,y) = top left corner of text double x = (getWidth() - bounds.getWidth()) / 2; double y = (getHeight() - bounds.getHeight()) / 2; // add ascent to y to reach the baseline double ascent = -bounds.getY(); double baseY = y + ascent; // draw the message g2.drawString(message, (int) x, (int) baseY); g2.setPaint(Color.LIGHT_GRAY); // draw the baseline g2.draw(new Line2D.Double(x, baseY, x + bounds.getWidth(), baseY)); // draw the enclosing rectangle Rectangle2D rect = new Rectangle2D.Double(x, y, bounds.getWidth(), bounds.getHeight()); g2.draw(rect); } public Dimension getPreferredSize() { return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT); } }
package font;
import java.awt.*;
import java.awt.font.*;
import java.awt.geom.*;
import javax.swing.*;
/**
* @version 1.34 2015-05-12
* @author Cay Horstmann
*/
public class FontTest
{
public static void main(String[] args)
{
EventQueue.invokeLater(() ->
{
JFrame frame = new FontFrame();
frame.setTitle("FontTest");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}
/**
* A frame with a text message component
*/
class FontFrame extends JFrame
{
public FontFrame()
{
add(new FontComponent());
pack();
}
}
/**
* A component that shows a centered message in a box.
*/
class FontComponent extends JComponent
{
private static final int DEFAULT_WIDTH = 300;
private static final int DEFAULT_HEIGHT = 200;
public void paintComponent(Graphics g)
{
Graphics2D g2 = (Graphics2D) g;
String message = "Hello, World!";
Font f = new Font("Serif", Font.BOLD, 36);
g2.setFont(f);
// measure the size of the message
FontRenderContext context = g2.getFontRenderContext();
Rectangle2D bounds = f.getStringBounds(message, context);
// set (x,y) = top left corner of text
double x = (getWidth() - bounds.getWidth()) / 2;
double y = (getHeight() - bounds.getHeight()) / 2;
// add ascent to y to reach the baseline
double ascent = -bounds.getY();
double baseY = y + ascent;
// draw the message
g2.drawString(message, (int) x, (int) baseY);
g2.setPaint(Color.LIGHT_GRAY);
// draw the baseline
g2.draw(new Line2D.Double(x, baseY, x + bounds.getWidth(), baseY));
// draw the enclosing rectangle
Rectangle2D rect = new Rectangle2D.Double(x, y, bounds.getWidth(), bounds.getHeight());
g2.draw(rect);
}
public Dimension getPreferredSize() { return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT); }
}
package font;
import java.awt.*;
import java.awt.font.*;
import java.awt.geom.*;
import javax.swing.*;
/**
* @version 1.34 2015-05-12
* @author Cay Horstmann
*/
public class FontTest
{
public static void main(String[] args)
{
EventQueue.invokeLater(() ->
{
JFrame frame = new FontFrame();
frame.setTitle("FontTest");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}
/**
* A frame with a text message component
*/
class FontFrame extends JFrame
{
public FontFrame()
{
add(new FontComponent());
pack();
}
}
/**
* A component that shows a centered message in a box.
*/
class FontComponent extends JComponent
{
private static final int DEFAULT_WIDTH = 300;
private static final int DEFAULT_HEIGHT = 200;
public void paintComponent(Graphics g)
{
Graphics2D g2 = (Graphics2D) g;
String message = "Hello, World!";
Font f = new Font("Serif", Font.BOLD, 36);
g2.setFont(f);
// measure the size of the message
FontRenderContext context = g2.getFontRenderContext();
Rectangle2D bounds = f.getStringBounds(message, context);
// set (x,y) = top left corner of text
double x = (getWidth() - bounds.getWidth()) / 2;
double y = (getHeight() - bounds.getHeight()) / 2;
// add ascent to y to reach the baseline
double ascent = -bounds.getY();
double baseY = y + ascent;
// draw the message
g2.drawString(message, (int) x, (int) baseY);
g2.setPaint(Color.LIGHT_GRAY);
// draw the baseline
g2.draw(new Line2D.Double(x, baseY, x + bounds.getWidth(), baseY));
// draw the enclosing rectangle
Rectangle2D rect = new Rectangle2D.Double(x, y, bounds.getWidth(), bounds.getHeight());
g2.draw(rect);
}
public Dimension getPreferredSize() { return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT); }
}
测试程序6：
l 在elipse IDE中调试运行教材436页-437程序10-6，结合程序运行结果理解程序；
l 了解2D图形图像的显示方法。
package image;
import java.awt.*;
import javax.swing.*;
/**
* @version 1.34 2015-05-12
* @author Cay Horstmann
*/
public class ImageTest
{
public static void main(String[] args)
{
EventQueue.invokeLater(() ->
{
JFrame frame = new ImageFrame();
frame.setTitle("ImageTest");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
}
/**
* A frame with an image component
*/
class ImageFrame extends JFrame
{
public ImageFrame()
{
add(new ImageComponent());
pack();
}
}
/**
* A component that displays a tiled image
*/
class ImageComponent extends JComponent
{
private static final int DEFAULT_WIDTH = 300;
private static final int DEFAULT_HEIGHT = 200;
private Image image;
public ImageComponent()
{
image = new ImageIcon("blue-ball.gif").getImage();
}
public void paintComponent(Graphics g)
{
if (image == null) return;
int imageWidth = image.getWidth(null);
int imageHeight = image.getHeight(null);
// draw the image in the upper-left corner
g.drawImage(image, 0, 0, null);
// tile the image across the component
for (int i = 0; i * imageWidth <= getWidth(); i++)
for (int j = 0; j * imageHeight <= getHeight(); j++)
if (i + j > 0)
g.copyArea(0, 0, imageWidth, imageHeight, i * imageWidth, j * imageHeight);
}
public Dimension getPreferredSize() { return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT); }
}
实验总结 ：这次实验很明确地知道了，用java制作图的方法和很多不同的用法。
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