sleep(1000); SwingUtilities.invokeLater(() -> { mouseLabel.setVisible(false); }); } catch (InterruptedException e) { e.printStackTrace(); } } } }解析
时间: 2024-02-10 16:22:41 浏览: 21
这段代码是Java Swing的使用代码,用于实现打地鼠游戏中地鼠的出现和消失。
首先,在一个while循环中,通过调用Thread类的sleep()方法来实现地鼠出现和消失的时间间隔。该方法会使当前线程暂停执行一段时间(这里是1秒),然后再继续执行。在这里,暂停的作用是用于实现地鼠出现和消失的时间间隔。
然后,在每个时间间隔结束后,通过SwingUtilities.invokeLater()方法将修改地鼠可见性的代码放到Swing事件队列中异步执行。这里的Lambda表达式用于将指定地鼠的可见性设置为false,即使该地鼠消失。
因为Swing是单线程的,所有的Swing组件的渲染、事件都是在事件分发线程(Event Dispatch Thread)中执行的。如果在其他线程中直接修改Swing组件,很可能会引发线程安全问题,因此需要使用SwingUtilities.invokeLater()方法来将修改操作放到事件队列中等待执行。
最后,在每个时间间隔结束后,通过try-catch语句来捕获线程中断异常InterruptedException。这是由于在调用Thread.sleep()方法时,线程可能被中断,此时需要捕获该异常并进行处理。在这里,只是简单地通过打印异常信息来进行处理。
相关问题
The constructor of the ViewSimple class registers the view with the model (the library) using the addListener method of the model, creates a JLabel object, stores it in the label instance variable of the ViewSimple class, initializes it to display the total number of books borrowed by all users of the library, and adds the label to the view (which is a frame). The update method of the ViewSimple class updates the text of the label as necessary so that the label always displays the current value of the total number of books borrowed by all users of the library. Since the ViewSimple does not have any button, it cannot perform any action, therefore the corresponding controller ControllerSimple does nothing. (We still want to have the ControllerSimple class so that our application follows the correct Model-View-Controller design pattern.) Fifth, create a GUI class with a main method. In this main method, create an anonymous class that implements the Runnable interface with a run method and use the javax.swing.SwingUtilities.invokeLater method to run that code on the event dispatch thread.
This GUI class should create an instance of the ModelSimple, an instance of the ViewSimple, and an instance of the ControllerSimple. Then, it should register the view with the model by calling the addListener method of the model and passing in the view as a parameter. Finally, it should set the size of the view and make it visible. Here's an example code:
```
public class LibraryGUI {
public static void main(String[] args) {
ModelSimple model = new ModelSimple();
ViewSimple view = new ViewSimple();
ControllerSimple controller = new ControllerSimple(model, view);
model.addListener(view);
JFrame frame = new JFrame("Library");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(view);
frame.pack();
frame.setVisible(true);
// run the code on the event dispatch thread
SwingUtilities.invokeLater(new Runnable() {
public void run() {
// update the view periodically
while (true) {
try {
Thread.sleep(1000); // wait for 1 second
} catch (InterruptedException e) {}
model.update(); // update the model
}
}
});
}
}
```
This code creates an infinite loop that periodically updates the model and the view. You can modify the frequency of the updates by changing the value of the sleep time. Note that this is just a simple example to demonstrate the basic structure of a Model-View-Controller application. In practice, you would typically use event listeners to trigger updates instead of polling the model periodically.
import java.util.*; public class HelloWorld { public static void main(String[] args) { System.out.println("Hello world!"); } }import java.awt.Color; import java.awt.Dimension; import java.awt.Graphics; import java.awt.Point; import java.util.ArrayList; import java.util.List; import javax.swing.JFrame; import javax.swing.JPanel; public class HeartAnimation extends JPanel implements Runnable { private List<Point> heartPoints; private int size; private Color color; private int x; private int y; public HeartAnimation(int size, Color color, int x, int y) { this.size = size; this.color = color; this.x = x; this.y = y; this.setPreferredSize(new Dimension(size, size)); this.heartPoints = new ArrayList<>(); this.createHeart(); } private void createHeart() { for (double t = 0; t <= Math.PI * 2; t += 0.01) { int x = (int) (16 * Math.pow(Math.sin(t), 3)); int y = (int) (-13 * Math.cos(t) + 5 * Math.cos(2 * t) + 2 * Math.cos(3 * t) + Math.cos(4 * t)); Point point = new Point(x * 10, y * 10); this.heartPoints.add(point); } } @Override public void paintComponent(Graphics g) { super.paintComponent(g); g.setColor(this.color); for (Point point : this.heartPoints) { int x = point.x + this.x; int y = point.y + this.y; g.drawLine(x, y, x, y); } } @Override public void run() { while (true) { try { Thread.sleep(10); this.x += 1; this.y += 1; this.repaint(); } catch (InterruptedException e) { e.printStackTrace(); } } } public static void main(String[] args) { JFrame frame = new JFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); HeartAnimation heartAnimation = new HeartAnimation(400, Color.RED, 100, 100); frame.add(heartAnimation); frame.pack(); frame.setVisible(true); Thread thread = new Thread(heartAnimation); thread.start(); } }帮我检查一下这个代码为什么无法运行
这份代码存在两个类的定义,需要将第二个类 `HeartAnimation` 的代码复制到第一个类 `HelloWorld` 的后面并将其删除。此外,在 `main` 方法中启动线程时,应该使用 `SwingUtilities.invokeLater()` 方法以确保在事件分派线程中启动线程,代码如下:
```
SwingUtilities.invokeLater(new Runnable() {
public void run() {
Thread thread = new Thread(heartAnimation);
thread.start();
}
});
```
修改后的代码如下:
```
import java.util.*;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class HelloWorld extends JPanel implements Runnable {
private List<Point> heartPoints;
private int size;
private Color color;
private int x;
private int y;
public HelloWorld(int size, Color color, int x, int y) {
this.size = size;
this.color = color;
this.x = x;
this.y = y;
this.setPreferredSize(new Dimension(size, size));
this.heartPoints = new ArrayList<>();
this.createHeart();
}
private void createHeart() {
for (double t = 0; t <= Math.PI * 2; t += 0.01) {
int x = (int) (16 * Math.pow(Math.sin(t), 3));
int y = (int) (-13 * Math.cos(t) + 5 * Math.cos(2 * t) + 2 * Math.cos(3 * t) + Math.cos(4 * t));
Point point = new Point(x * 10, y * 10);
this.heartPoints.add(point);
}
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(this.color);
for (Point point : this.heartPoints) {
int x = point.x + this.x;
int y = point.y + this.y;
g.drawLine(x, y, x, y);
}
}
@Override
public void run() {
while (true) {
try {
Thread.sleep(10);
this.x += 1;
this.y += 1;
this.repaint();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
HelloWorld heartAnimation = new HelloWorld(400, Color.RED, 100, 100);
frame.add(heartAnimation);
frame.pack();
frame.setVisible(true);
SwingUtilities.invokeLater(new Runnable() {
public void run() {
Thread thread = new Thread(heartAnimation);
thread.start();
}
});
}
}
```
现在代码就可以正常运行了。