在半透明框架/面板/組件上重新塗漆。

Question

我正在嘗試在OSX上創建一個帶有Java的半透明窗口並向其添加JLabel 。

這個JLabel每秒都會更改它的文本....

然而，該組件不能很好地重新粉刷。

我怎么解決這個問題？

我找到了這些 文章 ，但我無法弄清楚如何解決它。

如果可能的話，請粘貼修復源代碼，這是我的：

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JLabel;
import java.awt.Color;
import java.awt.Font;
import java.util.Timer;
import java.util.TimerTask;

public class Translucent {
    public static void main( String [] args ) {

        JFrame frame = new JFrame();

        frame.setBackground( new Color( 0.0f,0.0f,0.0f,0.3f));

        final JLabel label =  new JLabel("Hola");
        label.setFont( new Font( label.getFont().getFamily(), Font.PLAIN, 46 ) );
        label.setForeground( Color.white );

        frame.add( label );
        frame.pack();
        frame.setLocationRelativeTo( null );
        frame.setVisible( true );

        Timer timer = new Timer();
        timer.schedule( new TimerTask(){
            int i = 0;
            public void run() {
                label.setText("Hola "+ i++ );
            }
        }, 0, 1000 );


    }   
}

Answer 1

我有幸運行JLabel並實現Icon ，以便按照我想要的方式運行半透明組件。 您可以在此AlphaCompositeDemo中查看各種規則組合的結果。 以下示例為50％黑色的100％白色。

附錄：請注意此示例如何在半透明框架背景上的透明屏幕外背景上合成不透明文本。

附錄：這是一種使整個框架半透明的方法 。 不幸的是，它也使內容變暗。

import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;

public class Translucent extends JPanel implements ActionListener {

    private static final int W = 300;
    private static final int H = 100;
    private static final Font font =
        new Font("Serif", Font.PLAIN, 48);
    private static final SimpleDateFormat df =
        new SimpleDateFormat("HH:mm:ss");
    private final Date now = new Date();
    private final Timer timer = new Timer(1000, this);
    private BufferedImage time;
    private Graphics2D timeG;

    public Translucent() {
        super(true);
        this.setPreferredSize(new Dimension(W, H));
        timer.start();
    }

    @Override
    protected void paintComponent(Graphics g) {
        Graphics2D g2d = (Graphics2D) g;
        g2d.setRenderingHint(
            RenderingHints.KEY_ANTIALIASING,
            RenderingHints.VALUE_ANTIALIAS_ON);
        int w = this.getWidth();
        int h = this.getHeight();
        g2d.setComposite(AlphaComposite.Clear);
        g2d.fillRect(0, 0, w, h);
        g2d.setComposite(AlphaComposite.Src);
        g2d.setPaint(g2d.getBackground());
        g2d.fillRect(0, 0, w, h);
        renderTime(g2d);
        int w2 = time.getWidth() / 2;
        int h2 = time.getHeight() / 2;
        g2d.setComposite(AlphaComposite.SrcOver);
        g2d.drawImage(time, w / 2 - w2, h / 2 - h2, null);
    }

    private void renderTime(Graphics2D g2d) {
        g2d.setFont(font);
        String s = df.format(now);
        FontMetrics fm = g2d.getFontMetrics();
        int w = fm.stringWidth(s);
        int h = fm.getHeight();
        if (time == null && timeG == null) {
            time = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
            timeG = time.createGraphics();
            timeG.setRenderingHint(
                RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON);
            timeG.setFont(font);
        }
        timeG.setComposite(AlphaComposite.Clear);
        timeG.fillRect(0, 0, w, h);
        timeG.setComposite(AlphaComposite.Src);
        timeG.setPaint(Color.green);
        timeG.drawString(s, 0, fm.getAscent());
    }

    private static void create() {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setBackground(new Color(0f, 0f, 0f, 0.3f));
        f.setUndecorated(true);
        f.add(new Translucent());
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        now.setTime(System.currentTimeMillis());
        this.repaint();
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                create();
            }
        });
    }
}

Answer 2

問題可能還與您從不是事件調度線程的線程設置JLabel的文本這一事實有關。

有兩種方法可以解決這個問題。 在沒有測試你的問題的情況下，我將使用javax.swing.Timer類而不是java.util.Timer類來解決它。 javax.swing.Timer將確保在調度線程上觸發事件。

所以（未經測試的代碼）：

final ActionListener labelUpdater = new ActionListener() {
  private int i;
  @Override
  public final void actionPerformed(final ActionEvent event) {
    label.setText("Hola " + this.i++);
  }
};
final javax.swing.Timer timer = new javax.swing.Timer(1000L, labelUpdater);

另一種解決方法是繼續使用java.util.Timer但要確保使用EventQueue.invokeLater(Runnable)以確保在EDT上對標簽進行更新。

Answer 3

我不知道問題是否已經解決，但我在我的應用程序中用“Frame.repaint（）;”解決了它。

所以每一秒我的畫面都會被重新粉刷，而我的JLabel將會根據實際時間進行更新。

Answer 4

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

package mreg;

import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JWindow;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;

/**
 *
 * @author Manoj
 */
public class TranscluentWindow {

 public static void main(String[] args) {
        new TranscluentWindow();
    }

    public TranscluentWindow() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    try {
                        UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                    } catch (Exception ex) {
                    }

                    JWindow frame = new JWindow();
                    frame.setAlwaysOnTop(true);
                    frame.addMouseListener(new MouseAdapter() {



                    });
                    frame.setBackground(new Color(0,0,0,0));
                    frame.setContentPane(new TranslucentPane());
                    frame.add(new JLabel(new ImageIcon(ImageIO.read(getClass().getResource("/124742-high-school-collection/png/image_4.png")))));
                    frame.pack();
                    frame.setLocationRelativeTo(null);
                    frame.setVisible(true);

                       new Thread(new Runnable() {
            public void run() {

                    try {

                        Thread.sleep(2500);
                    } catch (InterruptedException ex) {
                    }

                frame.dispose();
                new loging().setVisible(true);
            }
        }).start();






                } catch (IOException ex) {
                    ex.printStackTrace();
                }

            }
        });
    }

    public class TranslucentPane extends JPanel {

        public TranslucentPane() {
            setOpaque(false);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g); 

            Graphics2D g2d = (Graphics2D) g.create();
            g2d.setComposite(AlphaComposite.SrcOver.derive(0.0f));
            g2d.setColor(getBackground());
            g2d.fillRect(0, 0, getWidth(), getHeight());

        }

    }   



}