risingsun.java

书籍"Java_面向事件编程"的附带光盘代码

import objectdraw.*;
import java.awt.*;

// A program that produces an animation of the sun rising.
// The animation is driven by clicking the mouse button.
// The faster the mouse is clicked, the faster the sun will rise.
public class RisingSun extends WindowController{

    private FilledOval sun;     // Circle that represents the sun
    private Text instructions;  // Display of instructions

    // Place the sun and some brief instructions on the screen
    public void begin() {
        sun = new FilledOval( 50, 150, 100, 100, canvas);
        instructions = new Text( "Please click the mouse repeatedly", 20, 20, canvas);
    }

    // Move the sun up a bit each time the mouse is clicked
    public void onMouseClick(Location point) {
        sun.move(0, -5);
        instructions.hide();
    }
    
    // Move the sun back to its starting position and redisplay
    // the instructions
    public void onMouseExit(Location point){
        sun.moveTo( 50, 150 );
        instructions.show();
    }
}