23.01.05(Java)

1. 생성자

• 상속

package ch06;

import java.awt.Color;
import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

public class Mframe extends Frame {
	public Mframe() {
		setSize(300,300);
		setBackground(Color.ORANGE);
		addWindowListener(new WindowAdapter() {
			public void windowClosing(WindowEvent e) {
				System.exit(0);
			}
		});
		setVisible(true);
	}
	
}

package ch06;

import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

public class MyFrame {
	public static void main(String[] args) {
		Frame f=new Frame();
		f.setSize(300, 300);
		f.setVisible(true);
	
		Mframe m=new Mframe();
	}
}

package ch06;


class SuperClass4{
	//super 라는 키워드 부모를 지칭하는 것.
	//super()는 반드시 첫번째 라인에 삽입(생략)
//	public SuperClass4() {
//	}
	
	public SuperClass4(int i) {
		//super();
		System.out.println("오류");
	}
}

class SubClass4 extends SuperClass4{
	public SubClass4() {
		super(22);//생략: 반드시 생성자의 첫번째 라인
		System.out.println("Sub 생성자");
	}
	
}

public class ConstructorEx4 {
	public static void main(String[] args) {
		SubClass4 s1=new SubClass4();
		
	}
}

package ch06;

import java.awt.Color;
import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.security.DomainCombiner;

public class MFrame extends Frame {
	public MFrame() {
		this(300,300,new Color(220,220,220),false);
	}
	public MFrame(int w, int h) {
		this(h,w,new Color(220,220,220),false);
	}
	public MFrame(Color c) {
		this(300,300,c,false);
	}
	
	public MFrame(int w, int h, Color c, boolean flag) {	
		setSize(w,h);
		setBackground(c);
		addWindowListener(new WindowAdapter() {
			public void windowClosing(WindowEvent e) {
				System.exit(0);
			}
		});
		setResizable(flag);
		setVisible(true);
	}
	public static void main(String []args) {
		//new MFrame();
		//new MFrame(Color.cyan);
		new MFrame(500,500,new Color(100,200,100),true);
	}
}

package ch06;

import java.awt.Color;
import java.awt.Graphics;
import java.util.Random;

public class MyFrame extends MFrame{
	Random r;
	
	public MyFrame() {
		super(500, 500, Color.WHITE,false);	
		r = new Random();
	}
	
	public void paint(Graphics g){
		
		if(r==null)
			return;
//		g.drawString("반갑습니다", 50, 50);
		for (int i = 0; i < 10000; i++) {
			g.setColor(rColor());//붓에 노란색 물감 셋팅
			int x=r.nextInt(500);
			int y=r.nextInt(500);
			int w=r.nextInt(10)+5;
			int h=r.nextInt(10)+5;
//			g.drawRect(x,y,w,h);
			g.fillRect(x,y,w,h);
			
			try {
				Thread.sleep(10);
			} catch (InterruptedException e) {}
		}	//--for
	} //--paint
	public Color rColor(){
		int rr = r.nextInt(256);
		int gg = r.nextInt(256);
		int bb = r.nextInt(256);
		return new Color(rr,gg,bb);
	}
	public static void main(String[] args) {
		new MyFrame();
	}
}

this
-> 자신의 생성자
-> 인스턴스 변수(필드)를 지칭
-> 자신의 객체 주소값 or 자신객체

package ch06;

import java.awt.Button;
import java.awt.Color;
import java.awt.Dialog;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class ThisEx2 extends MFrame
implements ActionListener{
	Button btn;
	
	public ThisEx2() {
		super(500,350,Color.green,true);
		btn=new Button("my Button");
		add(btn,"South");
		btn.addActionListener(this);
	}
	
	public void actionPerformed(ActionEvent e) {
		//System.out.println("보이나요?");
		MDialog md=new MDialog(this, "보이나요");
	}
	
	class MDialog extends Dialog 
	implements ActionListener{
		Button mbtn;
		ThisEx2 f;
		public MDialog(ThisEx2 f,String title) {
			super(f,title,true);
			this.f=f;
			setLayout(new FlowLayout());
			setSize(150,100);
			mbtn=new Button("Click!");
			mbtn.addActionListener(this);
			add(mbtn);
			setVisible(true);
		}
		
		@Override
		public void actionPerformed(ActionEvent e) {
			f.btn.setBackground(Color.red);
			dispose();			
		}		
	}
	
	public static void main(String[] args) {
		new ThisEx2();
	}
}