Greenfoot：使用不同的钥匙移动两辆车

Question

我是 java 和 Greenfoot 的新手。我想以不同的方式移动两辆车，其中一辆使用 "up"、"down"、"left"、"right" 用于 car1 和 "w"、"s"、"a", "d" 分别。

我想为 moveForward()、Car.car1.isKeyDown("down") 和 Car.car2.isKeyDown("s") 为 moveBack() 等制作类似 Car.car1.isKeyDown("up") 和 Car.car2.isKeyDown("w") 的东西。如何我应该这样做吗？

这是我得到的：

/**
 * Class that models objects of type "car"
 *
 */

public class Car extends Actor
{
    // Attributes of the class Car
private static int numberWheels = 4;                                          
private boolean areHeadlightsOn = false;              


private String image1;
private String image2;

private boolean isKeyDown = false;

/**
 * Constructor
 */
public Car(String file1, String file2){
    setImage1(file1); // Sets the attribute image1 to file1
    setImage2(file2); // Sets the attribute image2 to file2

    setImage(file1);
    // Sets the image that appears in the screen at the beginning to the one in file1
}



/**
 * Method that is being always invoked when the program is running
 */
public void act(){
    moveForward();
    moveBack();
    turnLeft();
    turnRight();
    turnHeadlightsOn();
    turnHeadlightsOff();
}    

/**
 * Move the car forward every time the key "up" is pressed
 */
public void moveForward(){
    if (Greenfoot.isKeyDown("up")){
        move(5);
    }
}

/**
 * Move the car back every time the key "down" is pressed
 */
public void moveBack(){
    if (Greenfoot.isKeyDown("down")){
        move(-1);
    }
}    

/**
 * Turn the car to the left every time the key "left" is pressed
 */    
public void turnLeft(){
    if (Greenfoot.isKeyDown("left")){ 
        turn(-4);
    }
}

/**
 * Turn the car to the right every time the key "right" is pressed
 */      
public void turnRight(){
    if (Greenfoot.isKeyDown("right")){ 
        turn(4);
    }
}

/**
 * Turn the headlights on when the key "space" is pressed.
 * The attribute isKeyDown is used to prevent setting the headlights on and off when the key "space" is pressed (and remains pressed for some time)
 */
public void turnHeadlightsOn(){
    if (Greenfoot.isKeyDown("space") && !getIsKeyDown()){
        if (getAreHeadlightsOn() == false){
            setAreHeadlightsOn(true);
            setImage(getImage2());
            setIsKeyDown(true);
        }


    }
    if (!Greenfoot.isKeyDown("space") && getIsKeyDown()){
         setIsKeyDown(false);
    }           
}   


/**
 * Turn the headlights off when the key "space" is pressed.
 * The attribute isKeyDown is used to prevent setting the headlights off and on when the key "space" is pressed (and remains pressed for some time)
 */  
public void turnHeadlightsOff(){
    if (Greenfoot.isKeyDown("space") && !getIsKeyDown()){
        if (getAreHeadlightsOn() == true){
            setAreHeadlightsOn(false);
            setImage(getImage1());
            setIsKeyDown(true);
        }

    }
    if (!Greenfoot.isKeyDown("space") && getIsKeyDown()){
        setIsKeyDown(false);
    }           
}      


public void setAreHeadlightsOn(boolean areHeadlightsOn){
    this.areHeadlightsOn = areHeadlightsOn;
}

public boolean getAreHeadlightsOn(){
    return this.areHeadlightsOn;
}     

public void setImage1(String image1){
    this.image1 = image1;
}

public String getImage1(){
    return this.image1;
}    

public void setImage2(String image2){
    this.image2 = image2;
}

public String getImage2(){
    return this.image2;
}       

public void setIsKeyDown(boolean isKeyDown){
    this.isKeyDown = isKeyDown;
}

public boolean getIsKeyDown(){
    return this.isKeyDown;
    }          
}


 /*MyWorld class
  */


import greenfoot.*;

public class MyWorld extends World
{
  public MyWorld() 
  {
    super(800, 600, 1); 
    setBackground("road.jpg");
    populateWorld();
  }

public void populateWorld(){
    Car car1 = new Car(new String("car1.png"),
                           new String("car2.png");
    Car car2 = new Car(new String("car3.png"), 
                           new String("car4.png");

    addObject(car1, 120, 70);
    addObject(car2, 580, 30);  
   }
}

Answer 1

您只需将要用作参数的钥匙添加到汽车 class。例如

public class Mario {
    private upKey;

    public Mario(String upKey) {
         this.upKey = upKey;
    }

    public void jump(){
        if (Greenfoot.isKeyDown(upKey)){
            move(5);
        }
    }
}

然后就可以为每个对象设置跳转的key了！

 Mario player1 = new Mario("up");
 Mario player2 = new Mario("w");

您可以仅使用单个字母本身来跟踪任何字母键。 "s"、"a"、"d"。您可以添加更多键作为更多参数。希望这是有道理的。

如果您不想在构造函数中添加所有键，您还可以添加一个 'setKeys(String key)' 方法或其他方法。

Greenfoot：使用不同的钥匙移动两辆车

Greenfoot: Move two cars using different keys

java

greenfoot