改变框架，调整内容大小

Question

我正在做一个分配，有一些问题，当我的框架打开时，当我运行我的程序，它没有打开到它的完整尺寸，700x100。为什么呢?此外，如何使框架内的内容可调整大小?

这是我的。

package hw06;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.MouseAdapter;
import java.awt.geom.Ellipse2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class TargetLogoUI {
/**
 * @param args the command line arguments
 */
public static void main(String[] args) {
   JFrame frame = new JFrame();
    JTextField TargetMessagePanel = new JTextField();
    TargetMessagePanel.setBackground(new java.awt.Color(204, 204, 204));
    TargetMessagePanel.setFont(new java.awt.Font("Helvetica", 1, 72)); // NOI18N
    TargetMessagePanel.setText("Welcome to Target");
    frame.add(TargetMessagePanel, BorderLayout.NORTH);
    final TargetLogoPanel panel = new TargetLogoPanel();
    panel.addMouseListener(new MouseAdapter() {
        @Override
        public void mouseClicked(java.awt.event.MouseEvent e) {
            panel.setTarget(true);
            panel.repaint();
        }
    });
    frame.add(panel);
    frame.setSize(700, 100);
    frame.setVisible(true);
}
 }
 class TargetLogoPanel extends JPanel {
private boolean isTarget;
public void paintComponent(Graphics g) {
    super.paintComponent(g); // erase back
    Graphics2D g2 = (Graphics2D) g;
    Color c = null;
    if (isTarget) {
        c = Color.BLUE;
    } else {
        c = Color.RED;
    }
    g2.setColor(c);
    g2.fill(new Ellipse2D.Double(250, 50, 160, 160));
    g2.setColor(Color.WHITE);
    g2.fill(new Ellipse2D.Double(275, 75, 110, 110));
    g2.setColor(c);
    g2.fill(new Ellipse2D.Double(300, 100, 60, 60));
}
public boolean isTarget() {
    return isTarget;
}
public void setTarget(boolean isTarget) {
    this.isTarget = isTarget;
}

}

Answer 1

我正在做一个作业，有一些问题，当我的帧打开时当我运行我的程序时，它没有打开到它的完整尺寸，700x100

实际上它的尺寸是700 * 100。

我建议您不要这样做，而是重写JPanel的getPreferredSize()方法，然后在可视化JFrame之前在JFrame上调用pack()。比如:

class TargetLogoPanel extends JPanel {
   private static final int PREF_W = 700; //!!
   private static final int PREF_H = 300;
   private boolean isTarget;
   public void paintComponent(Graphics g) {
      super.paintComponent(g); // erase back
      Graphics2D g2 = (Graphics2D) g;
      // rendering your circles smoothly
      g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
      Color c = null;
      if (isTarget) {
         c = Color.BLUE;
      } else {
         c = Color.RED;
      }
      g2.setColor(c);
      g2.fill(new Ellipse2D.Double(250, 50, 160, 160));
      g2.setColor(Color.WHITE);
      g2.fill(new Ellipse2D.Double(275, 75, 110, 110));
      g2.setColor(c);
      g2.fill(new Ellipse2D.Double(300, 100, 60, 60));
   }
   @Override  //!!
   public Dimension getPreferredSize() {
      return new Dimension(PREF_W, PREF_H);
   }
   public boolean isTarget() {
      return isTarget;
   }
   public void setTarget(boolean isTarget) {
      this.isTarget = isTarget;
   }
}

另外，我如何使框架内的内容可调整大小?

请详细说明您的意思。