慢慢地打印文本从字符串的JLabel？

Question

我试图做一个口袋妖怪式的打印一个JLabel里面，但由于其局限性，所以我一直无法成功地做到这一点。我能够完成这个任务简单地使用下面的代码打印到控制台：

for(int i = 0; i < test.length(); i++) {
        System.out.print(test.charAt(i));
        Thread.sleep(35);
    }

然而，因为一个JLabel不能接受char数据类型，这种做法是行不通的。正因为如此，我尝试设置一个字符串，利用这一点，字符：

while (pos < text.length() - 1) {
            char test = text.charAt(pos);
            String print = String.valueOf(test);
            label.setText(print);
            try {
                Thread.sleep(35);
            } catch (InterruptedException e1) {
                e1.printStackTrace();
            }
            pos++;
        }

然而，我再跑进不添加到期间通过环上一次是什么有文字的问题。

有另一种方式我可以做到的打印速度缓慢文字这个任务？

Answer 1

Swing不是线程安全的，是单线程的。

你不能阻止事件指派线程，否则没有东西画，你不应该更新UI或任何用户界面从EDT上下文之外依靠

• 不应该被用来Concurrency in Swing为什么当前解决方案不起作用/
• How to Use Swing Timers为解决您的问题

Runnable example

import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;

public class Test {

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

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        private String text = "All your base belong to us";
        private int index;

        private JLabel label = new JLabel("");

        public TestPane() {
            setLayout(new GridBagLayout());
            add(label);

            Timer timer = new Timer(35, new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent evt) {
                    label.setText(text.substring(0, index));
                    index++;
                    if (index > text.length()) {
                        ((Timer) evt.getSource()).stop();
                    }
                }
            });
            timer.start();
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(400, 200);
        }

    }

}

Answer 2

我赶紧点击共同的东西应该像你所需要的：

/**
 *
 * @author Kai
 */
public class Pokemon extends javax.swing.JFrame {

    String text = "someTesttext";
    StringBuffer current = new StringBuffer();

    /**
     * Creates new form Pokemon
     */
    public Pokemon() {
        initComponents();
        new javax.swing.Timer(150, event -> {
            if (current.length() == text.length()) {
                current.setLength(0);
            } else {
                current.append(text.charAt(current.length()));
            }
            this.jLabel1.setText(current.toString());

        }).start();
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jLabel1 = new javax.swing.JLabel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setMinimumSize(new java.awt.Dimension(400, 400));
        getContentPane().setLayout(null);
        getContentPane().add(jLabel1);
        jLabel1.setBounds(41, 23, 240, 30);

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

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new Pokemon().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JLabel jLabel1;
    // End of variables declaration                   
}

Answer 3

你不能只是把字符串while循环外面，然后添加到它。事情是这样的：

String print = ""; // add this line
while (pos < text.length() - 1) {
            char test = text.charAt(pos);
            print = print + String.valueOf(test); // add to the print
            label.setText(print);
            try {
                Thread.sleep(35);
            } catch (InterruptedException e1) {
                e1.printStackTrace();
            }
            pos++;
        }