rectmover.java

书籍"Java_面向事件编程"的附带光盘代码

import objectdraw.*;

// class to animate the vertical motion of members of a
// collection of FilledRects
public class RectMover extends ActiveObject {
    
    // the delay between moves
    private final double DELAY = 400;
    
    // the collection whose rects should be moved
    private RectCollection theRects;
    
    // how far to move in one step
    private double dropSize;
    
    // create an ActiveObject to slowly move all the rectangles
    // in a collection up or down on the screen
    public RectMover (RectCollection rects, double dy) {
        dropSize = dy;
        theRects = rects;
        start();
    }
    
    public void run() {
        
        while (true){
            
            theRects.goToFirst();
            while ( theRects.rectsLeft() ){
                theRects.getNextRect().move(0,dropSize);
                pause( DELAY);
            }
            
        }
    }
}