Java 方法调用另一个类
我的Java 方法调用另一个类,java,swing,paintcomponent,repaint,Java,Swing,Paintcomponent,Repaint,我的Java代码中的repaint()方法有问题。我想在另一个类中调用它,但我不能,有些东西根本不起作用。我在论坛上搜索过,但没有什么能帮到我 我的Main课程: public class Main { public static Main main; public static JFrame f; public Main(){ } public static void main(String[] args) { main = new Main(); f = new JF
Java代码中的repaint()
方法有问题。我想在另一个类中调用它,但我不能,有些东西根本不起作用。我在论坛上搜索过,但没有什么能帮到我
我的Main课程
:
public class Main {
public static Main main;
public static JFrame f;
public Main(){
}
public static void main(String[] args) {
main = new Main();
f = new JFrame();
Ball b = new Ball();
f.getContentPane().setBackground(Color.GRAY);
f.add(b);
f.setSize(500, 500);
f.setLocationRelativeTo(null);
f.setTitle("Test");
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.addMouseMotionListener(b);
f.addKeyListener(new Key());
}
}
Ball类
我为移动形状创建了二维图形:
public class Ball extends JLabel implements MouseMotionListener{
public Ball(){
}
public static double x = 10;
public static double y = 10;
public static double width = 40;
public static double height = 40;
String nick;
boolean isEllipse = true;
public void paintComponent(Graphics g){
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
if(isEllipse){
Ellipse2D e2d = new Ellipse2D.Double(x, y, width, height);
g2d.setColor(Color.RED);
g2d.fill(e2d);
}
else{
Rectangle2D r2d = new Rectangle2D.Double(x, y, width, height);
g2d.setColor(Color.GREEN);
g2d.fill(r2d);
}
}
@Override
public void mouseDragged(MouseEvent e) {
isEllipse = false;
x = e.getX() - 30;
y = e.getY() - 40;
this.repaint();
}
@Override
public void mouseMoved(MouseEvent e) {
x = e.getX() - 30;
y = e.getY() - 40;
isEllipse = true;
this.repaint();
}
}
和键类
我放置键侦听器
的位置,通过按键移动形状:
public class Key extends Ball implements KeyListener {
public Key() {
}
@SuppressWarnings("static-access")
@Override
public void keyPressed(KeyEvent e) {
if(e.getKeyCode() == KeyEvent.VK_W){
super.x += 10;
super.repaint();
System.out.println("x: " + super.x);
}
}
@Override
public void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
@Override
public void keyTyped(KeyEvent e) {
// TODO Auto-generated method stub
}
}
但是这段代码有点问题:super方法不适用于键类
。Ball课程中的所有内容都运行良好。问题出在哪里?Super工作正常,但您对它的解释是错误的。您的问题是,您试图使用继承来解决继承无法解决的问题。您需要在实际的可视化和使用的Ball实例上调用repaint()
,而不是在某个完全不同的类Key的实例上,该类不适当地从Ball扩展。首先,让Key不延伸球,将一个真实的球参考传给Key,解决方案就会从中消失
或许可以这样做:
f.addKeyListener(new Key(b));
及
请注意,我自己,我会使用键绑定,而不是一个键侦听器,因为这样我就不必再专注于键盘了
例如:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.event.*;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.SwingUtilities;
public class MoveBall {
private static final int PREF_W = 500;
private static final int PREF_H = PREF_W;
private static void createAndShowGui() {
BallPanel ballPanel = new BallPanel(PREF_W, PREF_H);
MyMouse myMouse = new MyMouse(ballPanel);
ballPanel.addMouseListener(myMouse);
ballPanel.addMouseMotionListener(myMouse);
new CreateKeyBindings(ballPanel);
JFrame frame = new JFrame("MoveBall");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(ballPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
createAndShowGui();
});
}
}
@SuppressWarnings("serial")
class BallPanel extends JPanel {
private static final Color ELLIPSE_COLOR = Color.RED;
private static final Color SQUARE_COLOR = Color.GREEN;
private static final int BALL_WIDTH = 40;
private int prefW;
private int prefH;
private boolean isEllipse = true;
private int ballX;
private int ballY;
public BallPanel(int prefW, int prefH) {
this.prefW = prefW;
this.prefH = prefH;
}
public boolean isEllipse() {
return isEllipse;
}
public void setEllipse(boolean isEllipse) {
this.isEllipse = isEllipse;
}
public int getBallX() {
return ballX;
}
public void setBallX(int ballX) {
this.ballX = ballX;
}
public void setXY(int x, int y) {
ballX = x;
ballY = y;
repaint();
}
public void setXYCenter(int x, int y) {
ballX = x - BALL_WIDTH / 2;
ballY = y - BALL_WIDTH / 2;
repaint();
}
public void setXYCenter(Point p) {
setXYCenter(p.x, p.y);
}
public int getBallY() {
return ballY;
}
public void setBallY(int ballY) {
this.ballY = ballY;
}
public void incrementBallX(int x) {
ballX += x;
repaint();
}
public void incrementBallY(int y) {
ballY += y;
repaint();
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
if (isEllipse) {
g2.setColor(ELLIPSE_COLOR);
g2.fillOval(ballX, ballY, BALL_WIDTH, BALL_WIDTH);
} else {
g2.setColor(SQUARE_COLOR);
g2.fillOval(ballX, ballY, BALL_WIDTH, BALL_WIDTH);
}
}
@Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(prefW, prefH);
}
}
class MyMouse extends MouseAdapter {
private BallPanel ballPanel;
public MyMouse(BallPanel ballPanel) {
this.ballPanel = ballPanel;
}
@Override
public void mousePressed(MouseEvent e) {
ballPanel.setXYCenter(e.getPoint());
}
@Override
public void mouseDragged(MouseEvent e) {
ballPanel.setXYCenter(e.getPoint());
}
@Override
public void mouseReleased(MouseEvent e) {
ballPanel.setXYCenter(e.getPoint());
}
}
enum Direction {
UP(KeyEvent.VK_UP), DOWN(KeyEvent.VK_DOWN), LEFT(KeyEvent.VK_LEFT), RIGHT(KeyEvent.VK_RIGHT);
private int key;
private Direction(int key) {
this.key = key;
}
public int getKey() {
return key;
}
}
// Actions for the key binding
@SuppressWarnings("serial")
class MyKeyAction extends AbstractAction {
private static final int STEP_DISTANCE = 5;
private BallPanel ballPanel;
private Direction direction;
public MyKeyAction(BallPanel ballPanel, Direction direction) {
this.ballPanel = ballPanel;
this.direction = direction;
}
@Override
public void actionPerformed(ActionEvent e) {
switch (direction) {
case UP:
ballPanel.incrementBallY(-STEP_DISTANCE);
break;
case DOWN:
ballPanel.incrementBallY(STEP_DISTANCE);
break;
case LEFT:
ballPanel.incrementBallX(-STEP_DISTANCE);
break;
case RIGHT:
ballPanel.incrementBallX(STEP_DISTANCE);
break;
default:
break;
}
}
}
class CreateKeyBindings {
private BallPanel ballPanel;
public CreateKeyBindings(BallPanel ballPanel) {
this.ballPanel = ballPanel;
int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;
InputMap inputMap = ballPanel.getInputMap(condition);
ActionMap actionMap = ballPanel.getActionMap();
for (Direction direction : Direction.values()) {
KeyStroke keyStroke = KeyStroke.getKeyStroke(direction.getKey(), 0);
String keyString = keyStroke.toString();
inputMap.put(keyStroke, keyString);
actionMap.put(keyString, new MyKeyAction(ballPanel, direction));
}
}
}
哦,谢谢,现在开始工作了。:)我之所以使用KeyListener是因为我不打算做什么大事,事实上,自2014年以来我就没有使用过“clear”Java(没有游戏插件的扩展库),现在我必须从一开始就提醒这一点:D
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.event.*;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.SwingUtilities;
public class MoveBall {
private static final int PREF_W = 500;
private static final int PREF_H = PREF_W;
private static void createAndShowGui() {
BallPanel ballPanel = new BallPanel(PREF_W, PREF_H);
MyMouse myMouse = new MyMouse(ballPanel);
ballPanel.addMouseListener(myMouse);
ballPanel.addMouseMotionListener(myMouse);
new CreateKeyBindings(ballPanel);
JFrame frame = new JFrame("MoveBall");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(ballPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
createAndShowGui();
});
}
}
@SuppressWarnings("serial")
class BallPanel extends JPanel {
private static final Color ELLIPSE_COLOR = Color.RED;
private static final Color SQUARE_COLOR = Color.GREEN;
private static final int BALL_WIDTH = 40;
private int prefW;
private int prefH;
private boolean isEllipse = true;
private int ballX;
private int ballY;
public BallPanel(int prefW, int prefH) {
this.prefW = prefW;
this.prefH = prefH;
}
public boolean isEllipse() {
return isEllipse;
}
public void setEllipse(boolean isEllipse) {
this.isEllipse = isEllipse;
}
public int getBallX() {
return ballX;
}
public void setBallX(int ballX) {
this.ballX = ballX;
}
public void setXY(int x, int y) {
ballX = x;
ballY = y;
repaint();
}
public void setXYCenter(int x, int y) {
ballX = x - BALL_WIDTH / 2;
ballY = y - BALL_WIDTH / 2;
repaint();
}
public void setXYCenter(Point p) {
setXYCenter(p.x, p.y);
}
public int getBallY() {
return ballY;
}
public void setBallY(int ballY) {
this.ballY = ballY;
}
public void incrementBallX(int x) {
ballX += x;
repaint();
}
public void incrementBallY(int y) {
ballY += y;
repaint();
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
if (isEllipse) {
g2.setColor(ELLIPSE_COLOR);
g2.fillOval(ballX, ballY, BALL_WIDTH, BALL_WIDTH);
} else {
g2.setColor(SQUARE_COLOR);
g2.fillOval(ballX, ballY, BALL_WIDTH, BALL_WIDTH);
}
}
@Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(prefW, prefH);
}
}
class MyMouse extends MouseAdapter {
private BallPanel ballPanel;
public MyMouse(BallPanel ballPanel) {
this.ballPanel = ballPanel;
}
@Override
public void mousePressed(MouseEvent e) {
ballPanel.setXYCenter(e.getPoint());
}
@Override
public void mouseDragged(MouseEvent e) {
ballPanel.setXYCenter(e.getPoint());
}
@Override
public void mouseReleased(MouseEvent e) {
ballPanel.setXYCenter(e.getPoint());
}
}
enum Direction {
UP(KeyEvent.VK_UP), DOWN(KeyEvent.VK_DOWN), LEFT(KeyEvent.VK_LEFT), RIGHT(KeyEvent.VK_RIGHT);
private int key;
private Direction(int key) {
this.key = key;
}
public int getKey() {
return key;
}
}
// Actions for the key binding
@SuppressWarnings("serial")
class MyKeyAction extends AbstractAction {
private static final int STEP_DISTANCE = 5;
private BallPanel ballPanel;
private Direction direction;
public MyKeyAction(BallPanel ballPanel, Direction direction) {
this.ballPanel = ballPanel;
this.direction = direction;
}
@Override
public void actionPerformed(ActionEvent e) {
switch (direction) {
case UP:
ballPanel.incrementBallY(-STEP_DISTANCE);
break;
case DOWN:
ballPanel.incrementBallY(STEP_DISTANCE);
break;
case LEFT:
ballPanel.incrementBallX(-STEP_DISTANCE);
break;
case RIGHT:
ballPanel.incrementBallX(STEP_DISTANCE);
break;
default:
break;
}
}
}
class CreateKeyBindings {
private BallPanel ballPanel;
public CreateKeyBindings(BallPanel ballPanel) {
this.ballPanel = ballPanel;
int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;
InputMap inputMap = ballPanel.getInputMap(condition);
ActionMap actionMap = ballPanel.getActionMap();
for (Direction direction : Direction.values()) {
KeyStroke keyStroke = KeyStroke.getKeyStroke(direction.getKey(), 0);
String keyString = keyStroke.toString();
inputMap.put(keyStroke, keyString);
actionMap.put(keyString, new MyKeyAction(ballPanel, direction));
}
}
}