我正在嘗試創(chuàng)建一個通用的圖形導(dǎo)出工具,它通過實現(xiàn)Graphics接口來工作,并攔截和解釋對其各種方法的調(diào)用.但是,雖然我可以成功地為單個組件執(zhí)行此操作,但當我在包含其他組件的組件上使用它時,我的Graphics類正在被替換.奇怪的是,這只發(fā)生在

Windows和

Linux上.在OSX上它工作正常.

任何人都可以建議我如何確保它是我的原始Graphics類傳遞給所有子組件？

我有一個簡短的腳本,演示了根本問題.當我使用MyGraphics的實例顯式調(diào)用paint時,我沒有在JPanel中看到MyGraphics – 只是sun.java2d.SunGraphics2D.

import java.awt.*;

import java.awt.image.*;

import java.text.AttributedCharacterIterator;

import javax.swing.*;

public class GraphicsTest {

public static void main(String[] args) {

new GraphicsTest();

}

public GraphicsTest () {

JFrame frame = new JFrame();

frame.getContentPane().add(new MyPanel());

frame.setSize(500,500);

frame.setVisible(true);

try {

Thread.sleep(2000);

} catch (InterruptedException e) {}

System.out.println("Using my graphics - expect to see 'MyGraphics' next");

frame.paint(new MyGraphics());

}

class MyPanel extends JPanel {

public void paint (Graphics g) {

super.paint(g);

System.out.println("Graphics is "+g);

g.fillRect(10, 10, 20, 20);

}

}

class MyGraphics extends Graphics {

public String toString () {

return "MyGraphics";

}

public Graphics create() {

return this;

}

// I've left out the huge list of abstract methods from the original script

// since they're unchanged from the defaults and don't really matter here.

}

在我的Windows系統(tǒng)上,輸出是：

Graphics is sun.java2d.SunGraphics2D[font=javax.swing.plaf.FontUIResource[family=Dialog,name=Dialog,style=plain,size=12],color=sun.swing.PrintColorUIResource[r=51,g=51,b=51]]

Using my graphics - expect to see 'MyGraphics' next

Graphics is sun.java2d.SunGraphics2D[font=javax.swing.plaf.FontUIResource[family=Dialog,name=Dialog,style=plain,size=12],color=sun.swing.PrintColorUIResource[r=51,g=51,b=51]]

而在OSX下,我得到了我的預(yù)期,即：

Graphics is sun.java2d.SunGraphics2D[font=apple.laf.CUIAquaFonts$DerivedUIResourceFont[family=LucidaGrande,name=LucidaGrande,style=plain,size=13],color=javax.swing.plaf.ColorUIResource[r=0,g=0,b=0]]

Using my graphics - expect to see 'MyGraphics' next

Graphics is MyGraphics

那么我能做些什么來確保在所有情況下我都將’MyGraphics’傳遞給相應(yīng)的子組件？

總結(jié)

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