java - 如何设置背景图片 "under"所有miglayout的单元格

Question

这是我没有使用 miglayout 的背景

private void initialize() {
        frame = new JFrame();
        frame.setSize(800, 500);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JLabel background=new JLabel(new ImageIcon("pic1.jpg"));
        frame.add(background); 
}

看起来很不错

---

但是我想用MigLayout

这是代码

private void initialize() {
    frame = new JFrame();
    frame.setSize(800, 500);
    frame.setLocationRelativeTo(null);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().setLayout(new MigLayout("", "[800px]", "[500px]"));

    JLabel background=new JLabel(new ImageIcon("pic1.jpg"));
    frame.getContentPane().add(background, "cell 0 0,grow"); 
            // also tried the following to force background "under" all cells 
            // frame.getContentPane().add(background); 
 }

看起来很糟糕那些顶部和右侧的白色寄宿生来自哪里？为什么图像没有完全显示？

Answer 1

• frame.setSize(800, 500);包含Borders，然后绝对协调new MigLayout("", "[800px]", "[500px]") 在 MigLayout 中用作常量大于 JFrame 没有/减去 Borders，你的图像的一部分画出屏幕，

• 您可以使用 frame.setLayout(new MigLayout("debug", "[400px]", "[300px]")); 代替 frame 进行模拟.setLayout(new MigLayout("", "[400px]", "[300px]"));

• 在JFrame.setVisible(true)

  之前使用JFrame.pack()

• 使用了您代码中的大部分细节

编辑

通过删除默认间隙

import java.awt.Color;
import java.awt.GradientPaint;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.image.BufferedImage;
import java.util.Random;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
import net.miginfocom.swing.MigLayout;


public class MigAndIcon {

    private JLabel label = new JLabel();
    private Random random = new Random();
    private Timer backTtimer;
    private JFrame frame = new JFrame("Test");

    public MigAndIcon() {
        //frame.setLayout(new MigLayout("", "[400px]", "[300px]"));
        frame.setLayout(new MigLayout("insets 0, debug", "[400px]", "[300px]"));
        frame.add(label, "cell 0 0, grow"); 
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        startBackground();
        frame.setVisible(true);
    }

    private void startBackground() {
        backTtimer = new javax.swing.Timer(1500, updateBackground());
        backTtimer.start();
        backTtimer.setRepeats(true);
    }

    private Action updateBackground() {
        return new AbstractAction("Background action") {
            private final long serialVersionUID = 1L;

            @Override
            public void actionPerformed(ActionEvent e) {
                label.setIcon(new ImageIcon(getImage()));
            }
        };
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                MigAndIcon t = new MigAndIcon();
            }
        });
    }

    public BufferedImage getImage() {
        int w = label.getWidth();
        int h = label.getHeight();
        GradientPaint gp = new GradientPaint(0f, 0f, new Color(
                127 + random.nextInt(128),
                127 + random.nextInt(128),
                127 + random.nextInt(128)),
                w, w,
                new Color(random.nextInt(128), random.nextInt(128), random.nextInt(128)));
        BufferedImage bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2d = bi.createGraphics();
        g2d.setPaint(gp);
        g2d.fillRect(0, 0, w, h);
        g2d.setColor(Color.BLACK);
        return bi;
    }
}