Java:无法从同一包中的其他类访问静态变量 [英] Java: cannot access static variable from a different class in the same package

问题描述

这很奇怪，因为我有一个可以访问Frame.dimension.getWidth();的Character类.及其伙伴getHeight()，但是当我想在Map类中使用它时，eclipse会对其加下划线，并且无法给我反馈.无论如何运行该程序都会导致Java错误，表明它们找不到Map对象的X值.

This is quite odd, because I have a Character class that can access Frame.dimension.getWidth(); and its partner getHeight(), however when I wanted to use this in the Map class eclipse underlines it and cannot give me feedback. Running the program anyways ends up in java errors stating they can't find the X value of a Map object.

这是Frame类:

package Core;

import java.awt.Dimension;
import java.awt.Rectangle;
import javax.swing.JFrame;


public class Frame
{
static int width = 800, height = 600;
static Dimension dimension;

public static void main(String[]args){
    JFrame frame= new JFrame("RETRO");
    frame.add(new Screen());

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(width,height);
    frame.setVisible(true);
    frame.setResizable(false);
    dimension = frame.getContentPane().getSize();
}
}

还有Map类:

package Core;

import java.awt.Frame;
import java.awt.Image;
import java.awt.Rectangle;
import javax.swing.ImageIcon;
import java.awt.Dimension;

public class Map
{
    double x, y;

Image map;
ImageIcon background = new ImageIcon("images/Maps/maze.jpg");

public Map(){
    map = background.getImage();
}

public void move(double moveX, double moveY){
        x += moveX;
        y += moveY;
}

//////////Gets
public Image getMap(){
    return map;
}
public double getX(){
    if(x<0)
        x=0;
    else if(x>Frame.dimension.getWidth())
        x=Frame.dimension.getWidth();

    return x;
}

public double getY(){
    if(y<0)
        y=0;
    else if(y>Frame.dimension.getHeight())
        y=Frame.dimension.getHeight();

    return y;
}

public int getHeight(){
    return map.getHeight(null);
}

public int getWidth(){
    return map.getWidth(null);
}
}

我可以提供Character类，但此刻它很长而且很混乱..但是，单词Frame仅用于Frame.dimension.getWidth()/getHeight();

I could provide the Character class but it is very long and messy at the moment.. however the word Frame was only used in the calling of Frame.dimension.getWidth()/getHeight();

推荐答案

您在 x = Frame.dimension.getWidth(); 中引用的Frame类是 java.awt.Frame.请注意，您导入了此类.尝试显式提及: Core.Frame ，或者如果不使用此类，则删除 import java.awt.Frame; 行.

the Frame class you refer to in x=Frame.dimension.getWidth(); is java.awt.Frame. note that you imported this class. Try mentioning explicitly: Core.Frame instead or remove the line import java.awt.Frame; if you don't use this class.

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