Java开发网 - swt 问题求助

Topic: swt 问题求助

1.swt 问题求助

Posted by: poorbug
Posted on: 2004-06-02 17:30

我想实现通过一个按钮来控制字符串的变化,写出的代码如下.问题是我怎么才
能够让字符串不重叠?即显示第二个字符串时自动消去第一个,如此循环.
我想了好久都没解决,请高手指点,Thanks!!!
***************************************
import org.eclipse.swt.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.events.*;
public class Test602{
  private static Display display=new Display();
  private static Shell parent= new Shell(display);
  private Label label1;
  private Button button1;
private String string=new String();
  private GC gc =new GC(parent);
  private boolean bool = false;
public Test602(Shell parent,int sytle) {
}
public static void main(String[] args) {
  showGUI();
}
public static void showGUI(){
  Test602 Test = new Test602(parent,SWT.NULL);
  Test.open();

}
public void open() {
  parent.setBounds(0,0,800,600);
  parent.open();
  button1=new Button(parent,SWT.NULL);
  button1.setBounds(100,100,100,40);
  button1.setText("CHANGE");
  SelectionAdapter a1 = new SelectionAdapter() {
  public void widgetSelected(SelectionEvent arg0) {
    System.out.println("click");
    if(bool==false) {
      string="hi!";
      gc.drawText(string,0,0);
      bool=true;
            }
      else {
      string="hello!";
      gc.drawText(string,0,0);
     bool=false;

         }


    }

  };

  button1.addSelectionListener(a1);

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

}

2.Re:swt 问题求助 [Re: poorbug]	Copy to clipboard
Posted by: Jay Posted on: 2004-06-05 19:31 再你调用drawText()的时候需要完全覆盖掉上一次画出的区域你可以这样做：首先取得最长字符串的长和宽 Point size=gc.textExtent("hello"); 在绘制短字符串之前先填充长字符串的区域 gc.fillRectangle(0,0,size.x,size.y); gc.drawText("hi", 0, 0,false);