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我花了最近幾天試圖瞭解在Java中的2D圖形,我開始得到它的竅門。我經歷了一個教程,現在我明白如何畫線(或其他物體)到JFrame
。但是,我遇到了一個心理障礙。我想在框架上創建一個網格,並且將必要的邏輯嵌入代碼的paintComponent()
部分,但它不起作用。我知道我可以一遍又一遍地寫下drawLine()
,但爲什麼如果我在評論的章節中添加代碼,代碼是不會工作的?自動繪圖與paintComponent()不工作的邏輯
import javax.swing.SwingUtilities;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.BorderFactory;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
public class SwingPaintDemo2 {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
private static void createAndShowGUI() {
JFrame f = new JFrame("Line Test");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new MyPanel());
f.pack();
f.setVisible(true);
}
}
class MyPanel extends JPanel {
public int x = 50;
public MyPanel() {
setBorder(BorderFactory.createLineBorder(Color.black));
}
public Dimension getPreferredSize() {
return new Dimension(250,250);
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
//while(x<250){
g.drawLine(0,x,250,x);
g.drawLine(x,0,x,250);
//x = x+50;}
}
}