java Swing Basic tutorial graphical example code
Unlike multithreading, generics, etc., Swing is mainly used.
The following is mainly code and comments, less talk.
(1) Basic framework
package Swing;
import java.awt.*;
import javax.swing.*;
/**
*
* @author QuinnNorris
* The basic framework
*/
public class FrameTest {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
// open 1 Three threads, all of them Swing Components must be configured by the event dispatch thread that transfers mouse click and keystroke control to the user interface component.
EventQueue.invokeLater(new Runnable() {
// Anonymous inner class, yes 1 a Runnable An instance of the interface run methods
public void run() {
SimpleFrame frame = new SimpleFrame();
// Create the following self-defined ones SimpleFrame Class object so that constructor methods can be called
frame.setExtendedState(Frame.MAXIMIZED_BOTH);
// Maximize the window
// Other optional properties: Frame.NORMAL ICONIFIED MAXIMIZED_HORIZ MAXIMIZED_VERT
// MAXIMIZED_BOTH
frame.setTitle("Christmas");
// Set window title
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Select the action to take when the user closes the framework In some cases, you need to hide the window, you can't exit directly, you need this method
frame.setVisible(true);
// Make the window visible so that the user is in control 1 We can add content to the window before we see it again
}
});
}
// main When it ends, the program doesn't end, but ends the main thread until all the frames are closed or called System.exit The procedure is terminated only after the event
}
class SimpleFrame extends JFrame {
public SimpleFrame() {
Toolkit kit = Toolkit.getDefaultToolkit();
// Modify the position of the window at the top of the screen, changing the window size
// Toolkit Class contains many methods for interacting with a local window
Dimension screenSize = kit.getScreenSize();
// Toolkit Gets the screen size of the method returned 1 a Dimension The class object
setSize((int) (screenSize.getWidth()), (int) (screenSize.getHeight()));
// setBounds(0,0,(int)(screenSize.getWidth()),(int)(screenSize.getHeight()));
// Define the location and size of the window
// setLocation(0,0); Position the window from the upper-left corner
// setLocationByPlatform(true); Let the window system control the window position and distance 1 A small offset for a window
// Replace window ICONS with images
Image img = new ImageIcon("D:/icon.png").getImage();
setIconImage(img);
}
}The output: a box that fills the entire screen. The title bar is called Christmas.
(2) Output text
package Swing;
import java.awt.*;
import javax.swing.*;
/**
*
* @author QuinnNorris
* The output text
*/
public class HelloWorld {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
// open 1 Three threads, all of them Swing Components must be configured by the event dispatch thread that transfers mouse click and keystroke control to the user interface component
EventQueue.invokeLater(new Runnable() {
// Anonymous inner class, yes 1 a Runnable An instance of the interface run methods
public void run() {
JFrame frame = new HelloWorldFrame();
// HelloworldFrame Defined below, inherited JFrame, Use one of the constructor methods
frame.setTitle("HelloWrold");
// Set the title
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Select the action to take when the user closes the framework In some cases, you need to hide the window, you can't exit directly, you need this method
frame.setVisible(true);
// Make the window visible so that the user is in control 1 We can add content to the window before we see it again
}
});
}
}
// Authoring inherits JFrame Class, our work is carried out here
class HelloWorldFrame extends JFrame {
public HelloWorldFrame() {
add(new HelloWorldComponent());
// Add to it 1 The implementation of the instantiation JComponent A subclass of a class
pack();
// Call the preferred size of the framework component, or we can use SetSize Method to replace it
}
}
class HelloWorldComponent 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;
/**
* We overwrite this to use for writing
*
* @param g
* Graphics Object holds Settings for drawing images and text
*/
public void paintComponent(Graphics g) {
g.drawString("Hello World!", MESSAGE_X, MESSAGE_Y);
// Parameter: Write content, the first in the string 1 The characters are located from left to right 75 Pixel, the first in a string 1 Two characters from top to bottom 100 pixel
}
/**
* We override this method to indicate the size of the component of the class
*
* @return Returns how big the component of the class itself should be
*/
public Dimension getPreferredSize() {
return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT);
// return 1 a Dimension Object that represents the size of the component
}
}Output: A small window called HelloWrold in the upper left corner and “Hello World!” in the middle. With the words.
(3) Print graphics
package Swing;
import java.awt.EventQueue;
import javax.swing.*;
import java.awt.*;
import java.awt.geom.*;
/**
*
* @author QuinnNorris
* Print graphics
*/
public class DrawTest {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
// open 1 Three threads, all of them Swing Components must be configured by the event dispatch thread that transfers mouse click and keystroke control to the user interface component.
EventQueue.invokeLater(new Runnable()
{
// Anonymous inner class, yes 1 a Runnable An instance of the interface run methods
public void run(){
JFrame frame = new DrawFrame();
// Create the following self-defined ones SimpleFrame Class object so that constructor methods can be called
frame.setTitle("DrawTest");
// Set the title
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Select the action to take when the user closes the framework In some cases, you need to hide the window, you can't exit directly, you need this method
frame.setVisible(true);
// Make the window visible so that the user is in control 1 We can add content to the window before we see it again
}
});
}
}
class DrawFrame extends JFrame
{
public DrawFrame(){
add(new DrawComponent());
// Add to it 1 The implementation of the instantiation JComponent A subclass of a class
pack();
// Call the preferred size of the framework component, or we can use SetSize Method to replace it
}
}
class DrawComponent extends JComponent
{
private static final int DEFAULT_WIDTH = 400;
private static final int DEFAULT_HEIGHT = 400;
/**
* We overwrite this to print the graph
*
* @param g
* Graphics Objects are what we need to use Graphics2D The parent class
*/
public void paintComponent(Graphics g){
Graphics2D g2 = (Graphics2D)g;
// instantiation Graphics2D The object of this class, which is the argument Graphics2D the 1 A subclass
double leftX = 100;
double topY = 100;
double width = 200;
double height = 150;
// We set the rectangle 4 A property
Rectangle2D rect = new Rectangle2D.Double(leftX,topY,width,height);
// create 1 a Rectangle2D This object inherits Sharp interface
//Double Is one of the 1 A static inner class that we need to be in when we initialize Double Set parameters in
g2.draw(rect);
// The incoming 1 An implementation Sharp An instance of the interface and draw it on the canvas
Ellipse2D ellipse = new Ellipse2D.Double();
// create 1 An instance of an ellipse
ellipse.setFrame(rect);
// Ellipses and rectangles are siblings because they have the same way of judging boundaries
// Here we're going to use it directly rect To describe the ellipse (through the enclosing rectangle of the ellipse)
g2.draw(ellipse);
// The incoming 1 An implementation Sharp An instance of the interface and draw it on the canvas
g2.draw(new Line2D.Double(leftX,topY,leftX+width,topY+height));
// Draw on the canvas 1 A straight line
double centerX = rect.getCenterX();
double centerY = rect.getCenterY();
double radius = 150;
// Define the center coordinates and the radius
Ellipse2D circle = new Ellipse2D.Double();
// create 1 An example of a circle
circle.setFrameFromCenter(centerX, centerY, centerX+radius, centerY+radius);
// Set the coordinates and the radius
g2.draw(circle);
// Draw on the canvas 1 A round
}
/**
* We override this method to indicate the size of the component of the class
*
* @return Returns how big the component of the class itself should be
*/
public Dimension getPreferredSize(){
return new Dimension(DEFAULT_WIDTH,DEFAULT_HEIGHT);
// return 1 a Dimension Object that represents the size of the component
}
}The window in the upper left corner has an ellipse, an outer rectangle, a straight line from the upper left corner of the rectangle to the lower right corner, and a circle with a radius of 150 pixels starting from the center of the rectangle.
(4) Graphics coloring
Rectangle2D rect = new Rectangle2D.Double(leftX,topY,width,height);
// create 1 a Rectangle2D This object inherits Sharp interface
//Double Is one of the 1 A static inner class that we need to be in when we initialize Double Set parameters in
g2.setColor(Color.BLUE);
// for g2 Object to set 1 Fill color , It affects the color of the line
g2.fill(rect);
// Fill in the color we selected rect Represents a closed graph
g2.draw(rect);
// The incoming 1 An implementation Sharp An instance of the interface and draw it on the canvasInsert these two lines of code (insert 2 and 3 lines of code between the original position of 1 and 4) without changing the rest of the previous code. Get the coloring effect.
Output: A blue rectangle in the middle, with the center of the rectangle as the origin, and a circle with a blue line as the radius of 150 pixels.
(5) Special font
package Swing;
import javax.swing.*;
import java.awt.*;
import java.awt.font.*;
import java.awt.geom.*;
/**
*
* @author QuinnNorris Special font
*/
public class FontTest {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
// open 1 Three threads, all of them Swing Components must be configured by the event dispatch thread that transfers mouse click and keystroke control to the user interface component.
EventQueue.invokeLater(new Runnable() {
// Anonymous inner class, yes 1 a Runnable An instance of the interface run methods
public void run() {
JFrame frame = new FontFrame();
// Create the following self-defined ones SimpleFrame Class object so that constructor methods can be called
frame.setTitle("FontTest");
// Set the title
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Select the action to take when the user closes the framework In some cases, you need to hide the window, you can't exit directly, you need this method
frame.setVisible(true);
// Make the window visible so that the user is in control 1 We can add content to the window before we see it again
}
});
}
}
class FontFrame extends JFrame {
public FontFrame() {
add(new FontComponent());
// Add to it 1 The implementation of the instantiation JComponent A subclass of a class
pack();
// Call the preferred size of the framework component, or we can use SetSize Method to replace it
}
}
class FontComponent extends JComponent {
private static final int DEFAULT_WIDTH = 300;
private static final int DEFAULT_HEIGHT = 200;
/**
* We overwrite this to do that 1 Some work
*
* @param g
* Graphics Objects are what we need to use Graphics2D The parent class
*/
public void paintComponent(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
// instantiation Graphics2D The object of this class, which is the argument Graphics2D the 1 A subclass
String message = "Hello World!";
// Write the text that we want to manipulate
Font f = new Font("Dialog", Font.BOLD, 36);
// create 1 Font type, including font family, style type, size
// It is also possible to get a local font pack by means of a special method called load
g2.setFont(f);
// will f Set in the g2 Among the
FontRenderContext context = g2.getFontRenderContext();
// Get the description object of the screen device font property by calling the method
Rectangle2D bounds = f.getStringBounds(message, context);
// getStringBounds Method returns 1 A rectangle enclosing a string
double x = (DEFAULT_WIDTH - bounds.getWidth()) / 2;
// bounds.getWidth Method to obtain the width of the string
double y = (DEFAULT_HEIGHT - bounds.getHeight()) / 2;
// bounds.getHeight Method to obtain the height of the string
double ascent = -bounds.getY();
// Gets the upper slope of the font
double baseY = y + ascent;
// The base line position of the text
g2.drawString(message, (int) x, (int) y);
// Set string position
g2.setPaint(Color.LIGHT_GRAY);
// Set the line color to light gray
g2.draw(new Line2D.Double(x, baseY, x + bounds.getWidth(), baseY));
// Draw a line under the text 1 Horizontal lines
Rectangle2D rect = new Rectangle2D.Double(x, y, bounds.getWidth(),
bounds.getHeight());
g2.draw(rect);
}
/**
* We override this method to indicate the size of the component of the class
*
* @return Returns how big the component of the class itself should be
*/
public Dimension getPreferredSize() {
return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT);
// return 1 a Dimension Object that represents the size of the component
}
}Output: In the middle of the window is the text “Hello World”, surrounded by a gray rectangle with a horizontal line at the baseline.
(6) Add pictures
package Swing;
import javax.swing.*;
import java.awt.*;
/**
*
* @author QuinnNorris Add images
*/
public class ImageTest {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
// open 1 Three threads, all of them Swing Components must be configured by the event dispatch thread that transfers mouse click and keystroke control to the user interface component.
EventQueue.invokeLater(new Runnable() {
// Anonymous inner class, yes 1 a Runnable An instance of the interface run methods
public void run() {
JFrame frame = new ImageFrame();
// Create the following self-defined ones SimpleFrame Class object so that constructor methods can be called
frame.setTitle("ImageTest");
// Set the title
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Select the action to take when the user closes the framework In some cases, you need to hide the window, you can't exit directly, you need this method
frame.setVisible(true);
// Make the window visible so that the user is in control 1 We can add content to the window before we see it again
}
});
}
}
class ImageFrame extends JFrame {
public ImageFrame() {
add(new ImageComponent());
// Add to it 1 The implementation of the instantiation JComponent A subclass of a class
pack();
// Call the preferred size of the framework component, or we can use SetSize Method to replace it
}
}
class ImageComponent extends JComponent {
private static final int DEFAULT_WIDTH = 300;
private static final int DEFAULT_HEIGHT = 200;
private Image image;
/**
* ImageComponent Constructor to instantiate an image
*/
public ImageComponent(){
image = new ImageIcon("D:/image.jpg").getImage();
// Get the picture by the path
}
/**
* We overwrite this to do that 1 Some work
*
* @param g
*
*/
public void paintComponent(Graphics g) {
if(image == null ) return;
// If the image is incorrect, return it directly to avoid an error
g.drawImage(image, 0,0,null);
// Give the picture on the canvas
}
/**
* We override this method to indicate the size of the component of the class
*
* @return Returns how big the component of the class itself should be
*/
public Dimension getPreferredSize() {
return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT);
// return 1 a Dimension Object that represents the size of the component
}
}Output: Place your added image on the canvas starting at the top left corner.
Thank you for reading, I hope to help you, thank you for your support to this site!