java JPanel 如何固定大小
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java JPanel How to fixed sizes
提问by ManInMoon
I want to have a resizable panel, that always has the top green panel of a fixed depth. i.e. all changes in height should effect the yellow panel only.
我想要一个可调整大小的面板，它始终具有固定深度的顶部绿色面板。即高度的所有变化应该只影响黄色面板。
My code below is almost OK, except the green panel varies in size a little.
我下面的代码几乎没问题，只是绿色面板的大小略有不同。
How do I do this?
我该怎么做呢？
Panel.setLayout(new BoxLayout(Panel, BoxLayout.Y_AXIS));
Panel.setAlignmentX(Component.LEFT_ALIGNMENT);
JPanel TopPanel = new JPanel();
TopPanel.setPreferredSize(new Dimension(80,150));
TopPanel.setVisible(true);
TopPanel.setBackground(Color.GREEN);
JPanel MainPanel = new JPanel();
MainPanel.setPreferredSize(new Dimension(80,750));
MainPanel.setVisible(true);
MainPanel.setOpaque(true);
MainPanel.setBackground(Color.YELLOW);
Panel.add(TopPanel);
Panel.add(MainPanel);
采纳答案by jzd
Your question didn't restrict the solution to a BoxLayout, so I am going to suggest a different layout manager.
您的问题并未将解决方案限制为 a BoxLayout，因此我将建议使用不同的布局管理器。
I would attack this with a BorderLayoutand put the green panel in the PAGE_START location. Then put the yellow panel in the CENTER location without a preferredSizecall.
我会用 a 攻击它BorderLayout并将绿色面板放在 PAGE_START 位置。然后将黄色面板放在 CENTER 位置，无需preferredSize调用。
http://docs.oracle.com/javase/tutorial/uiswing/layout/border.html
http://docs.oracle.com/javase/tutorial/uiswing/layout/border.html
Here is an SSCCE example of the solution:
这是解决方案的 SSCCE 示例：
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class TestPad extends JFrame {
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.getContentPane().setLayout(new BorderLayout());
JPanel green = new JPanel();
green.setPreferredSize(new Dimension(80, 150));
green.setBackground(Color.GREEN);
JPanel yellow = new JPanel();
yellow.setBackground(Color.YELLOW);
frame.getContentPane().add(green, BorderLayout.PAGE_START);
frame.getContentPane().add(yellow, BorderLayout.CENTER);
frame.pack();
frame.setVisible(true);
frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
}
}
回答by gla3dr
If you make your Paneluse BorderLayoutinstead of BoxLayoutand put TopPanelin BorderLayout.NORTHand MainPanelin BorderLayout.CENTER, then they will both resize horizontally, but only the MainPanelwill resize vertically.
如果你让你Panel使用BorderLayout的不是BoxLayout，并把TopPanel在BorderLayout.NORTH和MainPanel中BorderLayout.CENTER，那么他们都将调整大小的水平，但只有MainPanel将垂直调整。
See the BorderLayout documentation
