哪种布局可以做到这一点？

Question

我正在尝试在我的应用程序中布局一些JLabel,如下例所示:

我一直有此JLabel在中间,其他的JLabel数量变量可以通过选择好的数列/行,并在空格设置一些空的JLabel,但我去从1到30我曾尝试网格布局无法获得良好的结果,并且无法找到如何使用MigLayout,任何人都有一个良好的布局解决方案或任何其他解决方案.

PS:我不想展示圆圈,只是为了表明JLabel排成一个圆圈.

Answer 1

您不需要专门支持此功能的布局管理器.您可以使用一些相当简单的三角函数自己计算x,y位置,然后使用常规布局,例如SpringLayout.

import java.awt.Point;
import java.util.ArrayList;
import java.util.List;

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

public class CircleLayout {

  /**
   * Calculate x,y positions of n labels positioned in
   * a circle around a central point. Assumes AWT coordinate
   * system where origin (0,0) is top left.
   * @param args
   */
  public static void main(String[] args) {
    int n = 6;  //Number of labels
    int radius = 100;
    Point centre = new Point(200,200);

    double angle = Math.toRadians(360/n);
    List<Point> points = new ArrayList<Point>();
    points.add(centre);

    //Add points
    for (int i=0; i<n; i++) {
      double theta = i*angle;
      int dx = (int)(radius * Math.sin(theta));
      int dy = (int)(-radius * Math.cos(theta));
      Point p = new Point(centre.x + dx, centre.y + dy);
      points.add(p);
    }

    draw(points);
  }

  private static void draw(List<Point> points) {
    JFrame frame = new JFrame("Labels in a circle");
    frame.setSize(500, 500);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

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

    int count = 0;
    for (Point point : points) {
      JLabel label = new JLabel("Point " + count);
      panel.add(label);
      count++;
      layout.putConstraint(SpringLayout.WEST, label, point.x, SpringLayout.WEST, panel);
      layout.putConstraint(SpringLayout.NORTH, label, point.y, SpringLayout.NORTH, panel);
    }

    panel.setLayout(layout);

    frame.add(panel);
    frame.setVisible(true);

  }
}

Answer 2

我怀疑你的要求是如此专业,以至于没有可以满足你需要的LayoutManager.尝试创建自己的!

Answer 3

JH实验室有一个ClockLayout:

这是一个非常愚蠢的布局,为特殊目的而创建.它只是将组件放在一个圆圈中,从顶部顺时针方向.

Answer 4

我喜欢@Baqueta 和@sacha 的想法：

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

public class CircleLayoutTest {
  public JComponent makeUI() {
    JPanel panel = new JPanel() {
      @Override protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Insets i = getInsets();
        g.translate(i.left, i.top);
        g.setColor(Color.RED);
        int w = getWidth() - i.left - i.right;
        int h = getHeight() - i.top - i.bottom;
        g.drawOval(0, 0, w, h);
        g.translate(-i.left, -i.top);
      }
    };
    panel.setLayout(new FlowLayout() {
      @Override public void layoutContainer(Container target) {
        synchronized(target.getTreeLock()) {
          int nmembers  = target.getComponentCount();
          if(nmembers<=0) return;
          Insets i = target.getInsets();
          double cx = .5 * target.getWidth();
          double cy = .5 * target.getHeight();
          Component m = target.getComponent(0);
          Dimension d = m.getPreferredSize();
          m.setSize(d.width, d.height);
          m.setLocation((int)(cx+.5-.5*d.width),(int)(cy+.5-.5*d.height));
          if(nmembers-1<=0) return;
          double rw = .5 * (target.getWidth() - i.left - i.right);
          double rh = .5 * (target.getHeight() - i.top - i.bottom);
          double x = 0, y = 0, r = 0;
          double radian = 2.0 * Math.PI / (nmembers-1);
          for(int j=1; j<nmembers; j++) {
            m = target.getComponent(j);
            if(m.isVisible()) {
              d = m.getPreferredSize();
              m.setSize(d.width, d.height);
              x = cx + rw * Math.cos(r) - .5 * d.width;
              y = cy + rh * Math.sin(r) - .5 * d.height;
              m.setLocation((int)(x+.5), (int)(y+.5));
              r += radian;
            }
          }
        }
      }
    });
    JPanel p = new JPanel(new BorderLayout());
    p.add(initPanel(panel));
    return p;
  }
  private static JComponent initPanel(JComponent p) {
    p.setBorder(BorderFactory.createEmptyBorder(50,50,50,50));
    for(int i=0; i<6; i++) {
      p.add(new JLabel("No."+i));
    }
    return p;
  }
  public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
      @Override public void run() {
        createAndShowGUI();
      }
    });
  }
  public static void createAndShowGUI() {
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    f.getContentPane().add(new CircleLayoutTest().makeUI());
    f.setSize(320 ,320);
    f.setLocationRelativeTo(null);
    f.setVisible(true);
  }
}