在 Java 中为新图形清除屏幕 (awt)
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【中文标题】在 Java 中为新图形清除屏幕 (awt)【英文标题】：Clearing the screen for new graphics in Java (awt) 【发布时间】：2022-01-06 18:56:16 【问题描述】：我有这段代码，它基本上是一个带有两个可点击矩形的主菜单。
开始游戏 信息开始游戏工作正常。 信息是没有真正起作用的。按下时，会出现信息屏幕，但主菜单按钮仍然存在，虽然不可见（可以单击）.. 似乎当信息菜单出现时，主菜单按钮没有被清除。 此外，信息菜单上的任何点都是可点击的，并将再次显示主菜单。 （不是预期的，只有后退按钮应该这样做）。
我该如何解决这些问题？
package test;
import javax.swing.*;
import java.awt.*;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.font.FontRenderContext;
import java.awt.font.TextLayout;
import java.awt.geom.Rectangle2D;
import java.awt.image.ImageObserver;
import java.awt.image.ImageProducer;
public class HomeMenu extends JComponent implements MouseListener, MouseMotionListener
private static final String GAME_TITLE = "BRICK DESTROY";
private static final String START_TEXT = "START";
private static final String INFO_TEXT = "INFO";
private static final String howtoPlay = """
1- Click Start\n
2- Choose the mode\n
3- Each mode has 3 levels\n
4- To play/pause press space, use 'A' and 'D' to move\n
5- To open pause menu press 'ESC'\n
6- To open DebugPanel press 'ALT-SHIFT-F1'""";
private static final String backText = "BACK";
private static final Color BORDER_COLOR = new Color(200,8,21); //Venetian Red
private static final Color DASH_BORDER_COLOR = new Color(255, 216, 0);//school bus yellow
private static final Color TEXT_COLOR = new Color(255, 255, 255);//white
private static final Color CLICKED_BUTTON_COLOR = Color.ORANGE.darker();;
private static final Color CLICKED_TEXT = Color.ORANGE.darker();
private static final int BORDER_SIZE = 5;
private static final float[] DASHES = 12,6;
private Rectangle menuFace;
private Rectangle infoFace;
private Rectangle startButton;
private Rectangle infoButton;
private Rectangle backButton;
private BasicStroke borderStoke;
private BasicStroke borderStoke_noDashes;
private Image img = Toolkit.getDefaultToolkit().createImage("1.jpeg");
private Font gameTitleFont;
private Font infoFont;
private Font buttonFont;
private Font howtoPlayFont;
private GameFrame owner;
private boolean startClicked;
private boolean infoClicked = false;
private boolean backClicked = false;
public HomeMenu(GameFrame owner,Dimension area)
this.setFocusable(true);
this.requestFocusInWindow();
this.addMouseListener(this);
this.addMouseMotionListener(this);
this.owner = owner;
menuFace = new Rectangle(new Point(0,0),area);
infoFace = new Rectangle(new Point(0,0),area);
this.setPreferredSize(area);
Dimension btnDim = new Dimension(area.width / 3, area.height / 12);
startButton = new Rectangle(btnDim);
infoButton = new Rectangle(btnDim);
backButton = new Rectangle(btnDim);
borderStoke = new BasicStroke(BORDER_SIZE,BasicStroke.CAP_ROUND,BasicStroke.JOIN_ROUND,0,DASHES,0);
borderStoke_noDashes = new BasicStroke(BORDER_SIZE,BasicStroke.CAP_ROUND,BasicStroke.JOIN_ROUND);
gameTitleFont = new Font("Calibri",Font.BOLD,28);
infoFont = new Font("Calibri",Font.BOLD,24);
buttonFont = new Font("Calibri",Font.BOLD,startButton.height-2);
howtoPlayFont = new Font("Calibri",Font.PLAIN,14);
public void paint(Graphics g)
drawMenu((Graphics2D)g);
public void drawMenu(Graphics2D g2d)
if(infoClicked)
drawInfoMenu(g2d);
return;
else
drawContainer(g2d);
Color prevColor = g2d.getColor();
Font prevFont = g2d.getFont();
double x = menuFace.getX();
double y = menuFace.getY();
g2d.translate(x,y);
//methods calls
drawText(g2d);
drawButton(g2d);
//end of methods calls
g2d.translate(-x,-y);
g2d.setFont(prevFont);
g2d.setColor(prevColor);
Toolkit.getDefaultToolkit().sync();
private void drawContainer(Graphics2D g2d)
Color prev = g2d.getColor();
//g2d.setColor(BG_COLOR);
g2d.drawImage(img,0,0,menuFace.width,menuFace.height,this);
//g2d.fill(menuFace);
Stroke tmp = g2d.getStroke();
g2d.setStroke(borderStoke_noDashes);
g2d.setColor(DASH_BORDER_COLOR);
g2d.draw(menuFace);
g2d.setStroke(borderStoke);
g2d.setColor(BORDER_COLOR);
g2d.draw(menuFace);
g2d.setStroke(tmp);
g2d.setColor(prev);
private void drawText(Graphics2D g2d)
g2d.setColor(TEXT_COLOR);
FontRenderContext frc = g2d.getFontRenderContext();
Rectangle2D gameTitleRect = gameTitleFont.getStringBounds(GAME_TITLE,frc);
int sX,sY;
sY = (int)(menuFace.getHeight() / 4);
sX = (int)(menuFace.getWidth() - gameTitleRect.getWidth()) / 2;
sY += (int) gameTitleRect.getHeight() * 1.1;//add 10% of String height between the two strings
g2d.setFont(gameTitleFont);
g2d.drawString(GAME_TITLE,sX,sY);
private void drawButton(Graphics2D g2d)
FontRenderContext frc = g2d.getFontRenderContext();
Rectangle2D txtRect = buttonFont.getStringBounds(START_TEXT,frc);
Rectangle2D mTxtRect = buttonFont.getStringBounds(INFO_TEXT,frc);
g2d.setFont(buttonFont);
int x = (menuFace.width - startButton.width) / 2;
int y =(int) ((menuFace.height - startButton.height) * 0.5);
startButton.setLocation(x,y);
x = (int)(startButton.getWidth() - txtRect.getWidth()) / 2;
y = (int)(startButton.getHeight() - txtRect.getHeight()) / 2;
x += startButton.x;
y += startButton.y + (startButton.height * 0.9);
if(startClicked)
Color tmp = g2d.getColor();
g2d.setColor(CLICKED_BUTTON_COLOR);
g2d.draw(startButton);
g2d.setColor(CLICKED_TEXT);
g2d.drawString(START_TEXT,x,y);
g2d.setColor(tmp);
else
g2d.draw(startButton);
g2d.drawString(START_TEXT,x,y);
x = startButton.x;
y = startButton.y;
y *= 1.3;
infoButton.setLocation(x,y);
x = (int)(infoButton.getWidth() - mTxtRect.getWidth()) / 2;
y = (int)(infoButton.getHeight() - mTxtRect.getHeight()) / 2;
x += infoButton.getX();
y += infoButton.getY() + (startButton.height * 0.9);
if(infoClicked)
Color tmp = g2d.getColor();
g2d.setColor(CLICKED_BUTTON_COLOR);
g2d.draw(infoButton);
g2d.setColor(CLICKED_TEXT);
g2d.drawString(INFO_TEXT,x,y);
g2d.setColor(tmp);
else
g2d.draw(infoButton);
g2d.drawString(INFO_TEXT,x,y);
private void drawInfoMenu(Graphics2D g2d)
FontRenderContext frc = g2d.getFontRenderContext();
Rectangle2D infoRec = infoFont.getStringBounds(INFO_TEXT,frc);
Color prev = g2d.getColor();
Stroke tmp = g2d.getStroke();
g2d.setStroke(borderStoke_noDashes);
g2d.setColor(DASH_BORDER_COLOR);
g2d.draw(infoFace);
g2d.setStroke(borderStoke);
g2d.setColor(BORDER_COLOR);
g2d.draw(infoFace);
g2d.fillRect(0,0,infoFace.width,infoFace.height);
g2d.setStroke(tmp);
g2d.setColor(prev);
g2d.setColor(TEXT_COLOR);
int sX,sY;
sY = (int)(infoFace.getHeight() / 15);
sX = (int)(infoFace.getWidth() - infoRec.getWidth()) / 2;
sY += (int) infoRec.getHeight() * 1.1;//add 10% of String height between the two strings
g2d.setFont(infoFont);
g2d.drawString(INFO_TEXT,sX,sY);
TextLayout layout = new TextLayout(howtoPlay, howtoPlayFont, frc);
String[] outputs = howtoPlay.split("\n");
for(int i=0; i<outputs.length; i++)
g2d.setFont(howtoPlayFont);
g2d.drawString(outputs[i], 40, (int) (80 + i * layout.getBounds().getHeight() + 0.5));
backButton.setLocation(getWidth()/3,getHeight()-50);
int x = (int)(backButton.getWidth() - infoRec.getWidth()) / 2;
int y = (int)(backButton.getHeight() - infoRec.getHeight()) / 2;
x += backButton.x+11;
y += backButton.y + (layout.getBounds().getHeight() * 1.35);
backButton.setLocation(getWidth()/3,getHeight()-50);
if(backClicked)
Color tmp1 = g2d.getColor();
g2d.setColor(CLICKED_BUTTON_COLOR);
g2d.draw(backButton);
g2d.setColor(CLICKED_TEXT);
g2d.drawString(backText,x,y);
g2d.setColor(tmp1);
infoClicked = false;
repaint();
else
g2d.draw(backButton);
g2d.drawString(backText,x,y);
@Override
public void mouseClicked(MouseEvent mouseEvent)
Point p = mouseEvent.getPoint();
if(startButton.contains(p))
owner.enableGameBoard();
else if(infoButton.contains(p))
infoClicked = true;
else if(backButton.contains(p))
infoClicked = false;
repaint();
@Override
public void mousePressed(MouseEvent mouseEvent)
Point p = mouseEvent.getPoint();
if(startButton.contains(p))
startClicked = true;
repaint(startButton.x,startButton.y,startButton.width+1,startButton.height+1);
else if(infoButton.contains(p))
infoClicked = true;
else if(backButton.contains(p))
infoClicked = false;
repaint();
@Override
public void mouseReleased(MouseEvent mouseEvent)
if(startClicked)
startClicked = false;
repaint(startButton.x,startButton.y,startButton.width+1,startButton.height+1);
else if(infoClicked)
infoClicked = false;
else if(backClicked)
infoClicked = true;
repaint();
@Override
public void mouseEntered(MouseEvent mouseEvent)
@Override
public void mouseExited(MouseEvent mouseEvent)
@Override
public void mouseDragged(MouseEvent mouseEvent)
@Override
public void mouseMoved(MouseEvent mouseEvent)
Point p = mouseEvent.getPoint();
if(startButton.contains(p) || infoButton.contains(p) || backButton.contains(p))
this.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
else
this.setCursor(Cursor.getDefaultCursor());
这是两个窗口的图像 main menu
info menu, pressing anywhere = back to home menu, pressing roughly in the middle = start game or back to main menu too
【问题讨论】：
1.阅读 Performing Custom Painting 和 [在 AWT 和 Swing 中绘画](oracle.com/java/technologies/painting.html) 以更好地了解绘画的工作原理以及您应该如何使用它； 2. 将您的需求分解为单独的类/面板，并专注于他们的个人需求（即解耦和单一职责） 【参考方案1】：首先阅读Performing Custom Painting 和Painting in AWT and Swing，以更好地了解在 Swing 中绘画的工作原理以及您应该如何使用它。
但我已经有了……
public void paint(Graphics g)
drawMenu((Graphics2D)g);
否则会建议。说真的，请阅读这些链接，以便了解上述决定将为您带来的所有问题。
您正在使用 OO 语言进行操作，您需要利用它并解耦您的代码并专注于“单一职责”原则。
我有点厌倦了谈论它，所以你可以阅读一下：
https://softwareengineering.stackexchange.com/questions/244476/what-is-decoupling-and-what-development-areas-can-it-apply-to Cohesion and Decoupling, what do they represent? Single Responsibility Principle Single Responsibility Principle in Java with Examples SOLID Design Principles Explained: The Single Responsibility Principle这些是您真正需要了解的基本概念，因为它们将使您的 SOOO 生活变得更加轻松，并且可以应用于几乎任何语言。
例如，从您的代码中...
public HomeMenu(GameFrame owner,Dimension area)
//...
this.setPreferredSize(area);
没有充分的理由（除了懒惰（恕我直言））任何调用者都应该告诉组件它应该是什么大小，这不是他们的责任。组件有责任告诉父容器它希望有多大，而父组件则负责弄清楚它将如何实现（或视情况而定）。
您遇到的“基本”问题很简单。您的“上帝”课程只是试图做太多事情（即承担了太多责任）。现在我们“可以”在代码中添加十几个或更多标志来弥补这一点，这只会增加耦合和复杂性，使其更难理解和维护，或者我们可以退后一步，将其分解为各个责任领域并围绕这些领域构建解决方案，例如...
import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.Stroke;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.font.FontRenderContext;
import java.awt.font.TextLayout;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class Test
public static void main(String[] args)
new Test();
public Test()
EventQueue.invokeLater(new Runnable()
@Override
public void run()
JFrame frame = new JFrame();
frame.add(new HomePane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
);
public class HomePane extends JPanel
public HomePane()
setLayout(new BorderLayout());
navigateToMenu();
@Override
public Dimension getPreferredSize()
return new Dimension(400, 400);
protected void navigateToMenu()
removeAll();
HomeMenuPane pane = new HomeMenuPane(new HomeMenuPane.NavigationListener()
@Override
public void navigateToInfo(HomeMenuPane source)
HomePane.this.navigateToInfo();
@Override
public void navigateToStartGame(HomeMenuPane source)
startGame();
);
add(pane);
revalidate();
repaint();
protected void navigateToInfo()
removeAll();
HowToPlayPane pane = new HowToPlayPane(new HowToPlayPane.NavigationListener()
@Override
public void navigateBack(HowToPlayPane source)
navigateToMenu();
);
add(pane);
revalidate();
repaint();
protected void startGame()
removeAll();
add(new JLabel("This is pretty awesome, isn't it!", JLabel.CENTER));
revalidate();
repaint();
public abstract class AbstractBaseMenuPane extends JPanel
protected static final Color BORDER_COLOR = new Color(200, 8, 21); //Venetian Red
protected static final Color DASH_BORDER_COLOR = new Color(255, 216, 0);//school bus yellow
protected static final Color TEXT_COLOR = new Color(255, 255, 255);//white
protected static final Color CLICKED_BUTTON_COLOR = Color.ORANGE.darker();
protected static final Color CLICKED_TEXT = Color.ORANGE.darker();
protected static final int BORDER_SIZE = 5;
protected static final float[] DASHES = 12, 6;
private Rectangle border;
private BasicStroke borderStoke;
private BasicStroke borderStoke_noDashes;
private BufferedImage backgroundImage;
public AbstractBaseMenuPane()
borderStoke = new BasicStroke(BORDER_SIZE, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND, 0, DASHES, 0);
borderStoke_noDashes = new BasicStroke(BORDER_SIZE, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND);
border = new Rectangle(new Point(0, 0), getPreferredSize());
// You are now responsible for filling the background
setOpaque(false);
@Override
public Dimension getPreferredSize()
return new Dimension(400, 400);
@Override
protected void paintComponent(Graphics g)
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
BufferedImage backgroundImage = getBackgroundImage();
if (backgroundImage != null)
g2d.drawImage(backgroundImage, 0, 0, getWidth(), getHeight(), this);
Color prev = g2d.getColor();
Stroke tmp = g2d.getStroke();
g2d.setStroke(borderStoke_noDashes);
g2d.setColor(DASH_BORDER_COLOR);
g2d.draw(border);
g2d.setStroke(borderStoke);
g2d.setColor(BORDER_COLOR);
g2d.draw(border);
g2d.dispose();
public void setBackgroundImage(BufferedImage backgroundImage)
this.backgroundImage = backgroundImage;
repaint();
public BufferedImage getBackgroundImage()
return backgroundImage;
public class HomeMenuPane extends AbstractBaseMenuPane
public static interface NavigationListener
public void navigateToInfo(HomeMenuPane source);
public void navigateToStartGame(HomeMenuPane source);
private static final String GAME_TITLE = "BRICK DESTROY";
private static final String START_TEXT = "START";
private static final String INFO_TEXT = "INFO";
private Rectangle startButton;
private Rectangle infoButton;
private Font gameTitleFont;
private Font buttonFont;
// Don't do this, this just sucks (for so many reasons)
// Use ImageIO.read instead and save yourself a load of frustration
//private Image img = Toolkit.getDefaultToolkit().createImage("1.jpeg");
private Point lastClickPoint;
private NavigationListener navigationListener;
public HomeMenuPane(NavigationListener navigationListener)
this.navigationListener = navigationListener;
try
setBackgroundImage(ImageIO.read(getClass().getResource("/images/BrickWall.jpg")));
catch (IOException ex)
Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
this.addMouseListener(new MouseAdapter()
@Override
public void mousePressed(MouseEvent mouseEvent)
Point p = mouseEvent.getPoint();
lastClickPoint = p;
if (startButton.contains(p))
peformStartGameAction();
else if (infoButton.contains(p))
performInfoAction();
repaint();
@Override
public void mouseReleased(MouseEvent mouseEvent)
lastClickPoint = null;
repaint();
);
this.addMouseMotionListener(new MouseAdapter()
@Override
public void mouseMoved(MouseEvent mouseEvent)
Point p = mouseEvent.getPoint();
if (startButton.contains(p) || infoButton.contains(p))
setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
else
setCursor(Cursor.getDefaultCursor());
);
Dimension area = getPreferredSize();
Dimension btnDim = new Dimension(area.width / 3, area.height / 12);
startButton = new Rectangle(btnDim);
infoButton = new Rectangle(btnDim);
gameTitleFont = new Font("Calibri", Font.BOLD, 28);
buttonFont = new Font("Calibri", Font.BOLD, startButton.height - 2);
@Override
protected void paintComponent(Graphics g)
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
Color prevColor = g2d.getColor();
Font prevFont = g2d.getFont();
//methods calls
drawText(g2d);
drawButton(g2d);
//end of methods calls
g2d.setFont(prevFont);
g2d.setColor(prevColor);
g2d.dispose();
private void drawText(Graphics2D g2d)
g2d.setColor(TEXT_COLOR);
FontRenderContext frc = g2d.getFontRenderContext();
Rectangle2D gameTitleRect = gameTitleFont.getStringBounds(GAME_TITLE, frc);
int sX, sY;
sY = (int) (getHeight() / 4);
sX = (int) (getWidth() - gameTitleRect.getWidth()) / 2;
sY += (int) gameTitleRect.getHeight() * 1.1;//add 10% of String height between the two strings
g2d.setFont(gameTitleFont);
g2d.drawString(GAME_TITLE, sX, sY);
private void drawButton(Graphics2D g2d)
FontRenderContext frc = g2d.getFontRenderContext();
Rectangle2D txtRect = buttonFont.getStringBounds(START_TEXT, frc);
Rectangle2D mTxtRect = buttonFont.getStringBounds(INFO_TEXT, frc);
g2d.setFont(buttonFont);
int x = (getWidth() - startButton.width) / 2;
int y = (int) ((getHeight() - startButton.height) * 0.5);
startButton.setLocation(x, y);
x = (int) (startButton.getWidth() - txtRect.getWidth()) / 2;
y = (int) (startButton.getHeight() - txtRect.getHeight()) / 2;
x += startButton.x;
y += startButton.y + (startButton.height * 0.9);
if (lastClickPoint != null && startButton.contains(lastClickPoint))
Color tmp = g2d.getColor();
g2d.setColor(CLICKED_BUTTON_COLOR);
g2d.draw(startButton);
g2d.setColor(CLICKED_TEXT);
g2d.drawString(START_TEXT, x, y);
g2d.setColor(tmp);
else
g2d.draw(startButton);
g2d.drawString(START_TEXT, x, y);
x = startButton.x;
y = startButton.y;
y *= 1.3;
infoButton.setLocation(x, y);
x = (int) (infoButton.getWidth() - mTxtRect.getWidth()) / 2;
y = (int) (infoButton.getHeight() - mTxtRect.getHeight()) / 2;
x += infoButton.getX();
y += infoButton.getY() + (startButton.height * 0.9);
if (lastClickPoint != null && infoButton.contains(lastClickPoint))
Color tmp = g2d.getColor();
g2d.setColor(CLICKED_BUTTON_COLOR);
g2d.draw(infoButton);
g2d.setColor(CLICKED_TEXT);
g2d.drawString(INFO_TEXT, x, y);
g2d.setColor(tmp);
else
g2d.draw(infoButton);
g2d.drawString(INFO_TEXT, x, y);
protected void peformStartGameAction()
navigationListener.navigateToStartGame(this);
protected void performInfoAction()
navigationListener.navigateToInfo(this);
public class HowToPlayPane extends AbstractBaseMenuPane
public static interface NavigationListener
public void navigateBack(HowToPlayPane source);
private static final String HOW_TO_PLAY_TEXT = """
1- Click Start\n
2- Choose the mode\n
3- Each mode has 3 levels\n
4- To play/pause press space, use 'A' and 'D' to move\n
5- To open pause menu press 'ESC'\n
6- To open DebugPanel press 'ALT-SHIFT-F1'""";
private static final String BACK_TEXT = "BACK";
private static final String INFO_TEXT = "INFO";
private Rectangle backButton;
private boolean backClicked = false;
private Font infoFont;
private Font howtoPlayFont;
private NavigationListener navigationListener;
public HowToPlayPane(NavigationListener navigationListener)
this.navigationListener = navigationListener;
this.addMouseListener(new MouseAdapter()
@Override
public void mousePressed(MouseEvent mouseEvent)
Point p = mouseEvent.getPoint();
if (backButton.contains(p))
backClicked = true;
repaint();
performBackAction();
@Override
public void mouseReleased(MouseEvent e)
backClicked = false;
);
this.addMouseMotionListener(new MouseAdapter()
@Override
public void mouseMoved(MouseEvent mouseEvent)
Point p = mouseEvent.getPoint();
if (backButton.contains(p))
setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
else
setCursor(Cursor.getDefaultCursor());
);
Dimension btnDim = new Dimension(getPreferredSize().width / 3, getPreferredSize().height / 12);
backButton = new Rectangle(btnDim);
infoFont = new Font("Calibri", Font.BOLD, 24);
howtoPlayFont = new Font("Calibri", Font.PLAIN, 14);
@Override
public Dimension getPreferredSize()
return new Dimension(400, 400);
@Override
protected void paintComponent(Graphics g)
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setColor(BORDER_COLOR);
g2d.fillRect(0, 0, getWidth(), getHeight());
FontRenderContext frc = g2d.getFontRenderContext();
Rectangle2D infoRec = infoFont.getStringBounds(INFO_TEXT, frc);
//
// Color prev = g2d.getColor();
//
// Stroke tmp = g2d.getStroke();
//
// g2d.setStroke(borderStoke_noDashes);
// g2d.setColor(DASH_BORDER_COLOR);
// g2d.draw(infoFace);
//
// g2d.setStroke(borderStoke);
// g2d.setColor(BORDER_COLOR);
// g2d.draw(infoFace);
//
// g2d.fillRect(0, 0, infoFace.width, infoFace.height);
//
// g2d.setStroke(tmp);
//
// g2d.setColor(prev);
//
g2d.setColor(TEXT_COLOR);
int sX, sY;
sY = (int) (getHeight() / 15);
sX = (int) (getWidth() - infoRec.getWidth()) / 2;
sY += (int) infoRec.getHeight() * 1.1;//add 10% of String height between the two strings
g2d.setFont(infoFont);
g2d.drawString(INFO_TEXT, sX, sY);
TextLayout layout = new TextLayout(HOW_TO_PLAY_TEXT, howtoPlayFont, frc);
String[] outputs = HOW_TO_PLAY_TEXT.split("\n");
for (int i = 0; i < outputs.length; i++)
g2d.setFont(howtoPlayFont);
g2d.drawString(outputs[i], 40, (int) (80 + i * layout.getBounds().getHeight() + 0.5));
backButton.setLocation(getWidth() / 3, getHeight() - 50);
int x = (int) (backButton.getWidth() - infoRec.getWidth()) / 2;
int y = (int) (backButton.getHeight() - infoRec.getHeight()) / 2;
x += backButton.x + 11;
y += backButton.y + (layout.getBounds().getHeight() * 1.35);
backButton.setLocation(getWidth() / 3, getHeight() - 50);
if (backClicked)
Color tmp1 = g2d.getColor();
g2d.setColor(CLICKED_BUTTON_COLOR);
g2d.draw(backButton);
g2d.setColor(CLICKED_TEXT);
g2d.drawString(BACK_TEXT, x, y);
g2d.setColor(tmp1);
repaint();
else
g2d.draw(backButton);
g2d.drawString(BACK_TEXT, x, y);
g2d.dispose();
protected void performBackAction()
navigationListener.navigateBack(this);
现在，这个例子利用组件来呈现不同的视图（它甚至有一个很好的抽象实现来允许代码重用?），但我突然想到，如果你“真的”想要，你可以有一系列“画家”类，可用于将当前状态的绘画委托给，鼠标点击/移动可以委托给，这意味着您可以有一个组件，它可以简单地委托绘画（通过paintComponent 方法），painter 对其处于活动状态。
而且，你不知道吗，他们有一个设计原则，Delegation Pattern
上面的例子也使用了observer pattern，所以你可能也想看看
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