java - 处理 - 有面向对象的编程问题

Question

基本上，我的目标是创建一个类似于 MS Paint 软件的程序，我可以在其中通过鼠标拖动来绘制形状并更改其颜色。这是我的一个很长的脚本。我对 OOP 还很陌生，所以我在尝试使所有功能协同工作时遇到了困难。

主要

Button button1, button2, button3, button4, button5, button6, button7;
Rect rect;
Circle circle;
int mode = 1;

void setup() {
    size(900,600);
    smooth();
    rect = new Rect(0,0,0,0, new PImage());
    circle = new Circle(0,0,0,0, new PImage());
    color gray = color(234);
    color black = color(0);
    color white  = color(255);
    color red = color(255,0,0);
    color green = color(0,255,0);
    color blue = color(0,0,255);

    button1 = new Button(10, 60, 20, white, gray, black); //draw rectangle function
    button2 = new Button(10, 100, 20, white, gray, black); //draw circle function
    button3 = new Button(10, 140, 20, red, gray, black); //option of color red
    button4 = new Button(10, 160, 20, green, gray, black); //option of color green
    button5 = new Button(10, 180, 20, blue, gray, black); //option of color blue
    button6 = new Button(10, 220, 20, black, gray, black); //fill entire shape
    button7 = new Button(10, 240, 20, white, gray, black); //fill nothing
}

void draw() {
    button1.setp();
    button2.setp();
}

void mousePressed() {
    if (button1.press()) { mode = 1; }
    if (button2.press()) { mode = 2; }
    if (button3.press()) { mode = 3; }
    if (button4.press()) { mode = 4; }
    if (button5.press()) { mode = 5; }
    if (button6.press()) { mode = 6; }
    if (button7.press()) { mode = 7; }
}

void manageButtons() {
    button1.update();
    button2.update();
    button3.update();
    button4.update();
    button5.update();
    button6.update();
    button7.update();

    button1.display();
    button2.display();
    button3.display();
    button4.display();
    button5.display();
    button6.display();
    button7.display();
}

void mouseReleased() {
    button1.release();
    button2.release();
    button3.release();
    button4.release();
    button5.release();
    button6.release();
    button7.release();
}

void mouseDragged() {
    //rect.drag();
}

按钮类

class Button {
    int x, y; // the x- and y-coordinate
    int size; // dimension (width & height)
    color baseGray; // Default gray value
    color overGray; // Value when the mouse is over
    color pressGray; // Value when the mouse is pressed
    boolean over = false; // true when the mouse is over
    boolean pressed = false;// true when pressed 

    Button(int xp, int yp, int s, color b, color o, color p) {
        x = xp;
        y = yp;
        size = s;
        baseGray = b;
        overGray = o;
        pressGray = p;
    }

    void setp() {
        background(255);
        manageButtons();
        //stroke();
        if (mode == 1) {
            rect.drawing();
        } else if (mode == 2) {
            circle.drawing();
        }
    }

    void update() {
        if ((mouseX >= x) && (mouseX <= x + size) && (mouseY >= y) && (mouseY <= y + size)) {
            over = true;
        } else {
            over = false;
        }
    }

    boolean press() {
        if (over) {
            pressed = true;
            return true;
        } else {
            return false;
        }
    }

    void release() {
        pressed = false;
        rect.release();
        circle.release();
    }

    void display() {
        if (pressed) {
            fill(pressGray);
        } else if (over) {
            fill(overGray);
        } else {
            fill(baseGray);
        }

        stroke(0);
        rect(x, y, size, size);
    }
}

圈类

class Circle {
    int x, y;
    int xp, yp;
    PImage a;

    Circle(int dragx, int dragy, int movex, int movey, PImage image) {
        x = dragx;
        y = dragy;
        xp = movex;
        yp = movey;
        a = image;
    }

    void display() {
        smooth();
        background(255);
        a = get();
        stroke(0);
        fill(255); //255,255,10);
    }

    void drawing() {
        image(a, 0, 0); //background(a);
        float sizex = xp - x;
        float sizey = yp - y;
        if (mousePressed && mouseButton == LEFT) {
            ellipse(x, y, sizex, sizey);
        }
    }

    void press() {
        x = mouseX;
        y = mouseY;
    }

    void release() {
        xp = mouseX;
        yp = mouseY;
        noLoop();
        a = get();
        loop();
    }

    void drag() {
        xp = 80 + mouseX;
        yp = 80 + mouseY;
    }
}

矩形类

class Rect {
    int x, y;
    int xp, yp;
    PImage a;

    Rect(int dragx, int dragy, int movex, int movey, PImage image) {
        x = dragx;
        y = dragy;
        xp = movex;
        yp = movey;
        a = image;
    }

    void display() {
        smooth();
        background(255);
        a = get();
        stroke(0);
        fill(255); //255,255,10);
    }

    void drawing() {
        image(a, 0, 0); //background(a);
        float sizex = xp - x;
        float sizey = yp - y;
        if (mousePressed && mouseButton == LEFT) {
            rect(x, y, sizex, sizey);
        }
    }

    void press() {
        x = mouseX;
        y = mouseY;
    }

    void release() {
        xp = mouseX;
        yp = mouseY;
        noLoop();
        a = get();
        loop();
    }

    void drag() {
        xp = mouseX;
        yp = mouseY;
    }
}

使用上述处理脚本 (java)，我在让矩形和圆形类正确与我创建的按钮一起工作时遇到问题。按钮 1 应该绘制矩形，按钮 2 应该绘制圆形(到目前为止，只有这些功能应该起作用。我还需要为它们应用颜色)。

我知道矩形和圆形类可以正确地工作，因为我在将所有内容组合在一起之前分别对它们进行了测试。按钮(功能)工作但不正确(我应该使用鼠标将形状拖动到任何需要的位置，而这个程序只允许它们出现我放置它们的地方并且只能从角落，就好像我只是从 x 和 y 位置 (0,0) 拉伸(stretch)形状一样。我唯一的问题是我似乎无法正确地将按钮连接到形状函数，并使它们一起工作。

Answer 1

如果不看 main 方法，很难评估代码的正确性。您的“主”类的设置方式使得 mousePressed() 方法似乎旨在轮询按钮并根据按钮的状态设置绘图模式。

但是，如果不查看 main 方法，我不可能知道您是否正确轮询了按钮。

如果您希望使用面向对象的方法，您将需要使用 Observer pattern .本质上，您的按钮都将引用具有 buttonClicked(Button btn) 方法的“主”对象。单击按钮时，它会运行“主”对象的 buttonClicked(Button btn) 方法。提供的参数将是对被单击按钮的引用，以便主程序可以选择要使用的适当模式。演示代码如下:

在主类中:

//Give the button a reference to the main object
button1 = new button(this);

//receive notifications from the button
public buttonClicked(Button btn) {
    if(btn.equals(button1))
        mode = 1;
    if(...)
        ...
}