java - 使用update时Jlabel文本相乘和重叠(图形)

Question

我编写了这段代码来更新我的进度条进度消息。基本上，当我有在 for() 循环上运行的 length 进程时，我将其放入循环中，并使用 prog = i 和 max = 数组 max 对其进行更新。

for(int i = 1; i <= array.length-1; i++){
//Process
setPrg(this.lbl, ths.prg, i, array.length-1, "Doing so process");
}

-

public void setPrg(JLabel lbl, JProgressBar prg, int prog, int max, String msg) {
    prg.setMaximum(max);
    if (prog <= max) {
        prg.setValue(prog);
    }
    prg.update(prg.getGraphics());
    if (prog >= max) {
        setMessage(lbl, "");
    } else {
        setMessage(lbl, msg);
    }
}

    public void setMessage(JLabel lbl, String msg) {
        lbl.setText(msg);
        lbl.update(lbl.getGraphics());
    }

我使用多个连续的 for() 循环来执行此操作，每个循环都有描述该过程的唯一消息。

问题是，出于某种原因，标签文本与自身重叠。例如，如果我有一个运行此代码的循环:

setPrg(this.lbl, ths.prg, i, array.length-1, "This is process 1");

还有一个运行这段代码的:

setPrg(this.lbl, ths.prg, i, array.length-1, "The second process this is");

然后，一旦第二个进程开始，两条消息的文本就会重叠，而不是“这是进程 1”消失。

另一方面，如果我不包括这一行:

lbl.update(lbl.getGraphics());

在循环期间根本不会显示任何文本，只有为标签设置的最后一个文本会在循环后显示。

非常感谢帮助!

完整程序如下:

package test;

import javax.swing.JLabel;
import javax.swing.JProgressBar;

public class Main extends javax.swing.JFrame {

    public Main() {
        initComponents();
    }
 public void setPrg(JLabel lbl, JProgressBar prg, int prog, int max, String msg) {
        prg.setMaximum(max);
        if (prog <= max) {
            prg.setValue(prog);
        }
        prg.update(prg.getGraphics());
        if (prog >= max) {
            setMessage(lbl, "");
        } else {
            setMessage(lbl, msg);
        }
    }

    public void setMessage(JLabel lbl, String msg) {
        lbl.setText(msg);
        lbl.update(lbl.getGraphics());
    }

    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jButton1 = new javax.swing.JButton();
        jProgressBar1 = new javax.swing.JProgressBar();
        jLabel1 = new javax.swing.JLabel();
        jTextField1 = new javax.swing.JTextField();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jButton1.setText("Button");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        jLabel1.setText("jLabel1");

        jTextField1.setText("jTextField1");

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addGap(246, 246, 246)
                        .addComponent(jLabel1))
                    .addGroup(layout.createSequentialGroup()
                        .addGap(226, 226, 226)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                            .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addComponent(jButton1)))
                    .addGroup(layout.createSequentialGroup()
                        .addContainerGap()
                        .addComponent(jProgressBar1, javax.swing.GroupLayout.PREFERRED_SIZE, 540, javax.swing.GroupLayout.PREFERRED_SIZE)))
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap(108, Short.MAX_VALUE)
                .addComponent(jButton1)
                .addGap(22, 22, 22)
                .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 31, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(18, 18, 18)
                .addComponent(jProgressBar1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(40, 40, 40))
        );

        pack();
    }// </editor-fold>                        

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        for (int i = 1; i <= 10000; i++) {
            this.setPrg(jLabel1, jProgressBar1, i, 10000, "Message 1");
        }
                for (int i = 1; i <= 10000; i++) {
            this.setPrg(jLabel1, jProgressBar1, i, 10000, "Second Message");
        }
    }                                        

    public static void main(String args[]) {
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new Main().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    public javax.swing.JButton jButton1;
    public javax.swing.JLabel jLabel1;
    public javax.swing.JProgressBar jProgressBar1;
    public javax.swing.JTextField jTextField1;
    // End of variables declaration                   
}

Answer 1

当您使用 Swing 时，您自动处于多线程环境中。一个是主线程，Swing 使用 EDT 进行 UI 重绘。

使用 SwingUtilities.invokeLater() 在 EventDispatchThread 上执行 JProgressBar.setValue() 和 JLabel.setValue()。这可确保它们得到相应更新。

如何使用 SwingUtilities 的示例片段。

    final JProgressBar prg = new JProgressBar();
    final JLabel lbl = new JLabel();

    SwingUtilities.invokeLater(new Runnable() {

        @Override
        public void run() {
            prg.setValue(70);
            lbl.setText("Text");
        }
    });

您会看到，不再需要调用lbl.update(lbl.getGraphics());。