microcomponent.java

J2ME程序设计实例教程的源码

import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;

/**
 * 该类是一个抽象类，它是所有组件类的超类。
 */
public abstract class MicroComponent {
    //
    protected Display display;
    
    protected MicroComponent(Display display) {
        this.display = display;
    }
    
    public final void show() {
        if(getGUI() == null) {
            createModel();
            createGUI();
        }
        else {
            update();
        }
        
        display.setCurrent(getGUI());
    }
    
    protected abstract void createModel();
    protected abstract void createGUI();
    protected abstract Displayable getGUI();
    protected abstract void update();
}