Java Swing：管理多个 SpringLayout

Question

我想管理一个复杂的容器结构作为 SpringLayouts 的组合（一系列独立的 SpringLayout 一个在另一个里面）

特别是，由包含 JPanel 的主 SpringLayout 管理的 JFrame：每个 JPanel 都应由其自己的 SpringLayout 管理。

不幸的是，如果我尝试应用两个不同的 SpringLayout，框架上不会出现任何内容

我编写了这个简单的代码来向您展示问题所在。代码包含：

• 一个 JFrame 和它的 SprilgLayout
• 一个 JPanel 及其 SpringLayout
• JPanel 中的一个简单 JButton

代码如下：

import java.awt.Container;
import java.awt.Dimension;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SpringLayout;

public class SpringLayout_cobination {

    // THE OBJECTS
    static JFrame frame;// The frame
    static JPanel panel;        // The container
    static JButton Button;      // Object

    // THE LayOuts
    static SpringLayout LayOut_Frame;
    static SpringLayout LayOut_panel;
    static Container contentPane;

    public static void main(String[] args) {

        // Start frame and componets
        frame=new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
        frame.setSize(830, 420); 

        panel=new JPanel();
        Button=new JButton("ok");

        panel.add(Button);
        panel.setSize(new Dimension(100,100));
        frame.add(panel);

        // Set the layouts
        LayOut_Frame=new SpringLayout(); // Frame LayOut
        frame.setLayout(LayOut_Frame);
        contentPane=frame.getContentPane(); // Main Container of the frame

        LayOut_panel=new SpringLayout();
        panel.setLayout(LayOut_panel);

        LayOut_Frame.putConstraint(SpringLayout.NORTH, panel,30,SpringLayout.NORTH, contentPane);
        LayOut_Frame.putConstraint(SpringLayout.WEST, panel,30,SpringLayout.WEST , contentPane);

        LayOut_panel.putConstraint(SpringLayout.NORTH, contentPane,30,SpringLayout.NORTH, Button);
        LayOut_panel.putConstraint(SpringLayout.WEST, contentPane,30,SpringLayout.WEST , Button);

        frame.setVisible(true);
    }

}

Answer 1

应用两个不同的SpringLayout

如果我理解您的要求，我认为可以将SpringLayouts 组合如下：

import java.awt.*;
import javax.swing.*;

public class SpringLayoutCobinationTest {
  private static Component makeSubPanel() {
    JButton button = new JButton("ok");

    SpringLayout layout = new SpringLayout();
    JPanel pnl = new JPanel(layout);

    layout.putConstraint(SpringLayout.NORTH, button, 10, SpringLayout.NORTH, pnl);
    layout.putConstraint(SpringLayout.WEST, button, 10, SpringLayout.WEST, pnl);

    pnl.add(button);
    pnl.setBorder(BorderFactory.createLineBorder(Color.RED));

    return pnl;
  }
  public Component makeUI() {
    Component sub = makeSubPanel();

    SpringLayout layout = new SpringLayout();
    SpringLayout.Constraints c = layout.getConstraints(sub);
    c.setWidth(Spring.constant(100));
    c.setHeight(Spring.constant(100));

    JPanel panel = new JPanel(layout);
    layout.putConstraint(SpringLayout.NORTH, sub, 30, SpringLayout.NORTH, panel);
    layout.putConstraint(SpringLayout.WEST, sub, 30, SpringLayout.WEST, panel);
    panel.add(sub);

    return panel;
  }
  public static void main(String[] args) {
    EventQueue.invokeLater(() -> {
      JFrame f = new JFrame();
      f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
      f.add(new SpringLayoutCobinationTest().makeUI());
      f.setSize(420, 420);
      f.setLocationRelativeTo(null);
      f.setVisible(true);
    });
  }
}

Answer 2

我忘记的部分代码是：

SpringLayout.Constraints c = LayOut_Frame.getConstraints(panel);
c.setWidth(Spring.constant(200));
c.setHeight(Spring.constant(100));

似乎每次在主框架中导入组件时都必须施加一个约束维度

在我的示例中，当我导入 最终代码为：

import java.awt.Container;
import java.awt.Dimension;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Spring;
import javax.swing.SpringLayout;

public class SpringLayout_cobination {

    // THE OBJECTS
    static JFrame frame;// The frame
    static JPanel panel;        // The container
    static JButton Button;      // Object

    // THE LayOuts
    static SpringLayout LayOut_Frame;
    static SpringLayout LayOut_panel;
    static Container contentPane;

    public static void main(String[] args) {

        // Start frame and componets
        frame=new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
        frame.setSize(830, 420); 

        panel=new JPanel();
        Button=new JButton("ok");

        panel.add(Button);
        panel.setSize(new Dimension(100,100));
        frame.add(panel);

        // Set the layouts
        LayOut_Frame=new SpringLayout(); // Frame LayOut
        frame.setLayout(LayOut_Frame);
        contentPane=frame.getContentPane(); // Main Container of the frame

        LayOut_panel=new SpringLayout();
        panel.setLayout(LayOut_panel);
        LayOut_panel.putConstraint(SpringLayout.NORTH, contentPane,30,SpringLayout.NORTH, Button);
        LayOut_panel.putConstraint(SpringLayout.WEST, contentPane,30,SpringLayout.WEST , Button);

        SpringLayout.Constraints c = LayOut_Frame.getConstraints(panel);
        c.setWidth(Spring.constant(200));
        c.setHeight(Spring.constant(100));

        LayOut_Frame.putConstraint(SpringLayout.NORTH, panel,30,SpringLayout.NORTH, contentPane);
        LayOut_Frame.putConstraint(SpringLayout.WEST, panel,30,SpringLayout.WEST , contentPane);



        frame.setVisible(true);
    }

}