使用SWT创建GUI时Event.gc错误

Question

我在使用SWT中的PaintListeners和 GC将矩形打印到外壳时遇到问题。如有必要，我也可以发布主要方法，但所有方法都会产生一个输入屏幕，然后打开下面的shell。我认为这个错误在SimDisp中。

在下面的网站中使用该类，使用了相同的过程，并且实际显示了一个矩形。

http://www.java2s.com/Code/Java/SWT-JFace-Eclipse/HowtodrawdirectlyonanSWTControl.htm

有谁知道为什么GC GC = event.gc;产生错误？ - gc无法解析或不是字段。

import java.awt.event.PaintEvent; 
import org.eclipse.swt.SWT; 
import org.eclipse.swt.events.PaintListener; 
import org.eclipse.swt.events.MouseListener; 
import org.eclipse.swt.graphics.Color; 
import org.eclipse.swt.graphics.Font; 
import org.eclipse.swt.graphics.GC; 
import org.eclipse.swt.graphics.Rectangle; 
import org.eclipse.swt.widgets.Button; 
import org.eclipse.swt.widgets.Canvas; 
import org.eclipse.swt.widgets.Display; 
import org.eclipse.swt.widgets.Event; 
import org.eclipse.swt.widgets.Listener; 
import org.eclipse.swt.widgets.Shell; 
import org.eclipse.swt.widgets.Text; 
import java.util.ResourceBundle; 

public static Shell SimDisp (Shell s1){ 

    final Shell shell2 = new Shell(s1.getDisplay()); 
    shell2.setText("Linear Magnetic Accelerator Simulation"); 

    /* 
    Canvas canvas = new Canvas(shell2, SWT.NONE); 
    LightweightSystem lws = new LightweightSystem(canvas); 
    RectangleFigure rect = new RectangleFigure(); 
    rect.setBounds(new org.eclipse.draw2d.geometry.Rectangle(20,20,100,100)); 
    rect.setBackgroundColor(ColorConstants.green); 
    rect.setForegroundColor(ColorConstants.gray); 
    lws.setContents(rect); 
    */ 

    /* 
    Canvas canvas = new Canvas(shell2, SWT.NONE); 
    Rectangle rect = new Rectangle (20,20,100,100); 
    GC gc = new GC (canvas); 
    gc.drawRectangle(rect); 
    */ 



    final Color red = new Color(s1.getDisplay(), 0xFF, 0, 0); 
    shell2.addPaintListener(new PaintListener() { 
     public void paintControl(PaintEvent event) { 
     GC gc = event.gc; // This line produces an error - gc cannot be resolved or is not a field. 
     gc.setForeground(red); 
     Rectangle rect = shell2.getClientArea(); 
     gc.drawRectangle(rect.x + 10, rect.y + 10, rect.width - 20, 
      rect.height - 20); 
     gc.drawString("Hello_world", rect.x + 20, 
      rect.y + 20);} 

    @Override 
    public void paintControl(org.eclipse.swt.events.PaintEvent e) { 
     // TODO Auto-generated method stub 

    }}); 


    return shell2;} 

Answer 1

因为你进口java.awt.event.PaintEvent，而不是org.eclipse.swt.events.PaintEvent。