哪种布局可以做到这一点？ [英] Which layout can do this?

问题描述

我正在尝试在我的应用程序中布局一些JLabel，如下例所示：

I'm trying to layout some JLabels in my application as shown in this example:

我总是把这个JLabel放在中间，其他JLabel的数量是可变的，它可以去从1到30.我通过选择大量的列/行并在空白区域设置一些空的JLabel来尝试网格布局，但是我无法获得良好的结果，并且无法找到如何使用 MigLayout ，是否有任何人有一个良好的布局解决方案或任何其他解决方案。

I always have this JLabel at the middle and the number of the others JLabels is variable it can go from 1 to 30. I have tried Grid layout by choosing a good number of columns/rows and setting some empty JLabels in the white space but i can't get a good result, and can't find how to do it with MigLayout, did any one have a good layouting soulution or any other solution.

PS ：我不想显示圆圈，只是为了表明JLabel排成一个圆圈。

PS: I don't want to show the circle it's just to show that the JLabels are in a arranged in a circle.

推荐答案

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计算x，y位置，然后使用常规布局，例如 SpringLayout 。

You don't need a layout manager which specifically supports this. You can calculate the x, y positions yourself with some fairly simple trigonometry, then use a regular layout such as 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);

  }
}

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