Question

我刚刚开始学习swt，我正在尝试做一个我在课程中看到的例子并且它不起作用 - 它应该围绕鼠标的尖端创建一个圆圈并随身携带但圆圈不在正确的位置 - 他用鼠标移动但不在它的尖端

这是代码：

import java.awt.MouseInfo;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.events.MouseMoveListener;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class CanvasKeyEvent {

  public static void main(String[] args) {
    final Display display = new Display();
    Shell shell = new Shell(display);
    shell.setSize(370, 380);
    final Canvas c=new Canvas(shell,SWT.NONE);
    c.setSize(370,380);
    c.setLocation(21, 21);
    c.addPaintListener(new Example());

    c.addMouseMoveListener(new MouseMoveListener(){
         public void mouseMove(MouseEvent e) {
          c.redraw();
         }    
        });

    shell.open();
    while(!shell.isDisposed())
    {
        if (!display.readAndDispatch())
            display.sleep();            
    }

    display.dispose();

  }
  static class Example implements PaintListener {

    @Override
    public void paintControl(PaintEvent e) {
        int x  = MouseInfo.getPointerInfo().getLocation().x;
        int y = MouseInfo.getPointerInfo().getLocation().y;
        e.gc.drawOval(x , y , 20 , 20);

    }

  }
}

有人知道它为什么不能正常工作？

谢谢

Answer 1

最好不要将java.awt.MouseInfo与SWT一起使用 - 首选Display.getCurrent().getCursorLocation()。

您遇到的主要问题是找到相对于Canvas的鼠标位置。尝试这样的事情：

public void paintControl(PaintEvent e) {

    Canvas c = ((Canvas) e.getSource());

    Point pos = c.toDisplay(c.getLocation());

    Point relativePos = new Point(e.x - pos.x, e.y - pos.y);

    int x = Display.getCurrent().getCursorLocation().x + relativePos.x + 10;
    int y = Display.getCurrent().getCursorLocation().y + relativePos.y + 10;

    e.gc.drawOval(x, y, 20, 20);
}

swt中的java示例

1 个答案: