如何從另一個類的main方法訪問變量

Question

這可能是一個noob問題，但是哦，我需要從main方法中收集frameWidth和frameHeight變量

---

frame.java

public static void main(String[] args) { 
    .....
    .......                                                
    int frameWidth  = frame.getContentPane().getWidth();
    int frameHeight  = frame.getContentPane().getHeight();
}

Board.java

public class board extends JPanel {
    private frame Frame;

    public board() {
        Frame = new frame();
        int FrameWidth = frame.main().frameWidth;
        int FrameWidth = frame.main().frameHeight;
    }
}

---

訪問變量的正確方法是什么？

Answer 1

將它傳遞給構造函數：

private int width = 0, height= 0;
public Board(int width, int height){
  ...
  this.width = width;
  this.height = height;
}

然后在你的main ：

Board myBoard = new Board(FrameWidth, FrameHeight);

您的類現在可以分別訪問變量FrameWidth和FrameHeight作為width和height 。

Answer 2

你需要聲明Main類中的board（類應該是大寫B）對象，並為寬度和高度定義getter，如下所示：

public static void main(String[] args) { 
Board board = new Board();                                              
int frameWidth  = board.getWidth();
int frameHeight  = board.getHeight();
}

public class board extends JPanel {
private frame Frame;

public board() {
    Frame = new frame();
    int FrameWidth = frame.frameWidth;
    int FrameWidth = frame.frameHeight;
}
public int getWidth(){
     return frame.frameWidth;
}

public int getHeight(){
    return frame.frameHeight;

}
}