java - 如何使用 JFrame/JComponent 通过一次按键移动由多个对象组成的图形

Question

我是一个真正的初学者，所以请原谅我在这方面的愚蠢。我正在尝试创建一个程序，该程序将根据输入 validator 的单个按键沿连续方向移动图形，直到它超出框架。这是我到目前为止所拥有的:

具有主要方法的框架构建类:

import javax.swing.JFrame;
import javax.swing.Timer;

public class EmptyFrameViewer 
{
public static void main(String[] args)
{
    JFrame frame = new JFrame();
    frame.setSize(300,  400);
    frame.setTitle("Alien Faces");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);

    FaceComponent face1 = new FaceComponent();
    frame.add(face1);
    frame.setVisible(true);

    FaceComponentTwo face2 = new FaceComponentTwo();
    frame.add(face2);
    frame.setVisible(true);

}

这是绘画课:

}

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.geom.AffineTransform;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Line2D;
import javax.swing.JComponent;

/*
 * This component will draw an "Alien" face
 */ 

public class FaceComponent extends JComponent 
{

public void paintComponent(Graphics g)
{
    //Recover Graphics2D
    super.paintComponent(g);
    Graphics2D g2 = (Graphics2D) g;

    //Construct the alien face

    //Draw the  head
    Ellipse2D.Double head = new Ellipse2D.Double (5, 80, 100, 150);
    g2.draw(head);

    //Draw the set of eyes
    g2.setColor(Color.GREEN);
    Rectangle eye = new Rectangle(25, 140, 15, 15);
    g2.fill(eye);
    eye.translate(50, 0);
    g2.fill(eye);

    //Draw the mouth
    Line2D.Double mouth = new Line2D.Double(30, 180, 80, 180);
    g2.setColor(Color.RED);
    g2.draw(mouth);

    //Draw the greeting
    g2.setColor(Color.BLUE);
    g2.drawString("Hello, World!", 20, 245);
}


}

这是 Movement 类的框架，但我觉得需要进行大量修改:

import javax.swing.*;


/*
 * This class will invoke the methods that move the 
 * objects in different directions.
 */

public class Movement extends FaceComponent
{
//List of fields that are used within this class.
int x = 0, y = 0, velX = 7, velY = 7;


//Constructor, that creates two brand new instances of the alien faces.
public Movement()
{
    FaceComponent face1 = new FaceComponent();
    FaceComponentTwo face2 = new FaceComponentTwo();
    repaint();
}

//List of methods that will be invoking different movements which are based on the user's inputs.


//Method that will move the first face(left) to the right until it is out of frame.
public void moveRight(int x, int y)
{

}


//Method that will move the second face(right) to the left until it is out of frame.
public void moveLeft(int x, int y)
{
    while(x > 0 || x <= 550)
    {
        x += velX;
        repaint();
    }
}


//Method that will move the first face(left) up until it is out of frame.
public void moveUp(int x, int y)
{

}


//Method that will move the second face(right) until it is out of frame.
public void moveDown(int x, int y)
{

}


//Method that will move the first face(left) in a downwards-right angle until it is out of frame.
public void moveDownRight(int x, int y)
{

}


//Method that will move the second face(right) in a downwards-left angle until it is out of frame.
public void moveDownLeft(int x, int y)
{

}


}

可能是以错误的方式来解决这个问题的，而且我之前曾多次问过这个问题，但我没有以正确的方式提出问题。原谅我的无知，感谢任何帮助。

Answer 1

首先，您可能想要学习如何在按下按键时移动组件。查看 Motion Using the Keyboard 中的 MotionWithKeyBindings 示例代码有关如何使用键绑定(bind)执行此操作的示例。

一旦理解了这一点，您将需要修改Action，因为您现在需要使用Swing Timer来安排连续事件。因此，您无需使用 Action 直接更改组件的位置，而是启动 Timer。然后，当Timer触发时，您将更改组件的位置。

查看 Swing 教程中 How to Use Swing Timers 的部分了解更多信息和示例。

您还可以查看:Update a Label with a Swing Timer有关 Swing 计时器的简单示例。