我正在像这样扩展 JFrame:
public GameFrame() {
this.setBounds(30, 30, 500, 500);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
initializeSquares();
}
private void initializeSquares(){
for(int i = 0; i < 5; i++){
this.getContentPane().add(new Square(i*10, i*10, 100, 100));
}
this.setVisible(true);
}
但是,屏幕上只绘制了一个正方形,有人知道为什么吗?
我的 Square 类也是这样的:
private int x;
private int y;
private int width;
private int height;
public Square(int x, int y, int width, int height){
this.x = x;
this.y = y;
this.width = width;
this.height = height;
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawRect(x, y, width, height);
}
最佳答案
JFrame 的 contentPane 默认使用 BorderLayout。当您向其中添加一个 Square 时,它会默认添加 BorderLayout.CENTER 并覆盖之前添加的任何 Square。您将需要阅读 Swing GUI 可用的所有布局管理器。
例如,从这里开始:Laying Out Components within a Container
但话虽如此,我会做不同的事情。我将只创建一个 JPanel 并使其能够绘制多个正方形。例如像这样:
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
public class GameFrame extends JFrame {
public GameFrame() {
super("Game Frame");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Squares squares = new Squares();
getContentPane().add(squares);
for (int i = 0; i < 15; i++) {
squares.addSquare(i * 10, i * 10, 100, 100);
}
pack();
setLocationRelativeTo(null);
setVisible(true);
}
public static void main(String[] args) {
new GameFrame();
}
}
class Squares extends JPanel {
private static final int PREF_W = 500;
private static final int PREF_H = PREF_W;
private List<Rectangle> squares = new ArrayList<Rectangle>();
public void addSquare(int x, int y, int width, int height) {
Rectangle rect = new Rectangle(x, y, width, height);
squares.add(rect);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
for (Rectangle rect : squares) {
g2.draw(rect);
}
}
}
关于java - 在java中的Jframe上绘制简单的矩形,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/9713432/