fallingtomato.java

来自「书籍"Java_面向事件编程"的附带光盘代码」· Java 代码 · 共 47 行

import java.awt.Color;

import objectdraw.DrawingCanvas;
import objectdraw.FilledOval;

// makes a falling tomato

public class FallingTomato extends FallingObject {
    
    // size of a tomato
    private static final int SIZE = 40;
    private static final int SPLATTER_DELAY = 1000;
    
    private DrawingCanvas canvas;
    
    // initialize the instance variables and start the active object
    public FallingTomato(DrawingCanvas aCanvas, double x, double aSpeed, int aScreenHeight) {
        // first, call "up" to the constructor of the FallingObject class
        super(aScreenHeight - SIZE / 2, aSpeed);
        
        canvas = aCanvas;
        
        object = new FilledOval(x, -SIZE, SIZE, SIZE, canvas);
        object.setColor(Color.RED);
        
        start();
    }
    
    // we override the hitBottom method from FallingObject
    // since we want extra functionality
    protected void hitBottom() {
        
        // first, remember our x position
        double x = object.getX();
        
        object.removeFromCanvas();
        
        // but then a little extra
        FilledOval splat = 
            new FilledOval(x - SIZE / 2, fallToPos, SIZE * 2, 
                           SIZE / 2, canvas);
        splat.setColor(Color.red);
        pause(SPLATTER_DELAY);
        splat.removeFromCanvas();
    }
}