我的程序是将字母转换为某些信号。我的主要方法是生成一些随机字母。该字母被传递给另一个方法，该方法根据生成的Letter调用repaint（）方法.PaintComponent（）方法用于绘制一个填充白色的圆。当我执行程序时，我只得到一个Jframe。我没有看到圆圈。请帮助。
package morsecode;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.Random;
import java.awt.*;
public class MorseCode extends Frame {
public static void main(String[] args) {
MorseCode mc = new MorseCode();
MorseCode frame = new MorseCode();
final String chars = "abcdefghijklmnopqrstuvwxyz1234567890";
char word;
for(int i=1;i<=1;i++)
{
Random rand = new Random();
int x = rand.nextInt(36);
word = chars.charAt(x);
System.out.print(word);
frame.setBackground(Color.BLACK);
frame.addWindowListener(
new WindowAdapter()
{
@Override
public void windowClosing(WindowEvent we)
{
System.exit(0);
}
}
);
frame.setSize(400, 400);
frame.setVisible(true);
mc.toMorseCode(word);
}
}
void toMorseCode(char letter)
{
switch(letter)
{
case 'A' | 'a':
repaint();
Thread.sleep(1000);
repaint();
Thread.sleep(2000);
break;
case 'B' | 'b':
repaint();
Thread.sleep(1000);
repaint();
Thread.sleep(1000);
repaint();
Thread.sleep(1000);
repaint();
Thread.sleep(2000);
break; ..............
}
}
public void paintComponent(Graphics g) {
Graphics2D ga = (Graphics2D)g;
ga.setColor(Color.white);
ga.fillOval(125,125,150,150);
}
}
答案 0 :(得分：3)
两件事......
首先，在Event Dispatching Thread中调用Thread.sleep(2000);将阻止EDT处理事件队列上的事件，包括绘制事件。
其次，Frame没有paintComponent。
添加@Override注释并尝试调用super.paintComponent会突出显示此问题，因为代码无法编译。
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
首先，首先使用JPanel来保存核心逻辑并执行自定义绘画。
其次，使用javax.swing.Timer执行动画。有关详细信息，请参阅How to use Swing Timers
<强>更新
基本概念相对简单。您需要某种第二/后台线程，它可以在输出中产生更改之间的延迟。然后，您需要在每次延迟之前根据您尝试显示的信息类型更新UI。
实现变得棘手，因为与大多数GUI框架一样，Swing是单线程的而不是线程安全的。
这意味着，您无法阻止GUI线程，这样做会阻止UI重新绘制，除此之外，还必须在GUI线程的上下文中更新任何UI组件的状态。
这意味着虽然您可以使用Thread在后台运行，但您必须确保对UI的所有更改/修改仅在EDT内执行。
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingWorker;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class MorseCodeTest {
public static void main(String[] args) {
new MorseCodeTest();
}
public MorseCodeTest() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public static final int GAP = 500;
public static final int DOT = 1000;
public static final int DASH = 4000;
public interface Transmitter {
public void setTap(boolean tap);
}
public class TestPane extends JPanel implements Transmitter {
private MorseCode code;
private boolean tapped;
public TestPane() {
code = MorseCode.create('A').addDot().addDash();
addMouseListener(new MouseAdapter() {
@Override
public void mouseClicked(MouseEvent e) {
Signalar signalar = new Signalar(TestPane.this, code);
signalar.execute();
}
});
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (tapped) {
Graphics2D g2d = (Graphics2D) g.create();
int diameter = Math.min(getWidth(), getHeight()) / 2;
int x = (getWidth() - diameter) / 2;
int y = (getHeight() - diameter) / 2;
g2d.fillOval(x, y, diameter, diameter);
g2d.dispose();
}
}
@Override
public void setTap(boolean tap) {
tapped = tap;
repaint();
}
}
public class Signalar extends SwingWorker<Void, Boolean> {
private final MorseCode code;
private final Transmitter transmitter;
public Signalar(Transmitter transmitter, MorseCode code) {
this.code = code;
this.transmitter = transmitter;
}
@Override
protected void process(List<Boolean> chunks) {
transmitter.setTap(chunks.get(chunks.size() - 1));
}
@Override
protected Void doInBackground() throws Exception {
for (Tone tone : code.getTones()) {
publish(true);
Thread.sleep(tone.getDelay());
publish(false);
Thread.sleep(GAP);
}
return null;
}
}
public static class Tone {
private final int delay;
public Tone(int delay) {
this.delay = delay;
}
public int getDelay() {
return delay;
}
}
public static class DashTone extends Tone {
public DashTone() {
super(DASH);
}
}
public static class DotTone extends Tone {
public DotTone() {
super(DOT);
}
}
public static class MorseCode {
private final char value;
private final List<Tone> tones;
public static MorseCode create(char value) {
MorseCode code = new MorseCode(value);
return code;
}
public MorseCode(char value) {
this.value = value;
this.tones = new ArrayList<>(25);
}
public char getValue() {
return value;
}
public MorseCode addDash() {
return addTone(new DashTone());
}
public MorseCode addDot() {
return addTone(new DotTone());
}
public MorseCode addTone(Tone tone) {
tones.add(tone);
return this;
}
public Iterable<Tone> getTones() {
return tones;
}
}
}