Question

我正在制作这个绘图程序项目，（更像是，扩展它），我遇到了一个讨厌的bug。我在BorderLayout南边的JPanel上添加了一个JLabel，但不仅没有添加到JPanel的南部，在我在JPanel上绘制内容后它也变得模糊了。我不明白为什么会发生这两件事。

班级代码：

import java.awt.BorderLayout;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class Painter extends JPanel{

private int pointCount = 0; // count the number of points

// array of 10000 java.awt.Point references
private Point[] points = new Point[10000];
JLabel myCount = new JLabel();

// set up GUI and register mouse event handler
public Painter() {

    myCount.setText("Points so far: " + pointCount);
    add(myCount, BorderLayout.SOUTH);

    // handle frame mouse motion event
    addMouseMotionListener(
            new MouseMotionAdapter() { // anonymous inner class
                public void mouseDragged(MouseEvent event) {
                    if (pointCount < points.length) {
                        points[pointCount] = event.getPoint(); // find the point
                        ++pointCount; // increment number of points in the array
                        repaint();
                        myCount.setText("Points so far: " + pointCount);
                    } // end if     
            } // end of mouseDragged method
        } // end anonymous inner class
    ); // end of addMouseMotionListener
}// end Painter constructor

// draw ovals in a 4-by-4 bounding box at specified locations on window
public void paintComponent(Graphics g) {
    super.paintComponents(g); // clears drawing area

    // draw all points in the array
    for (int i = 0; i < pointCount; i++) {
        g.fillOval(points[i].x, points[i].y, 12, 12);
    } // end for loop
} // end method paintComponent
} // end of Painter class

Answer 1

第一个问题可以通过调用setLayout（new BorderLayout）来解决;作为构造函数的第一行

第二个问题可以通过从paintComponents中删除's'并只调用paintComponent

来解决

我有一个JLabel和JPanel的BorderLayout的问题

1 个答案: