問(wèn)題描述

下面是我全部的代碼：

package day0411;import java.awt.*;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.awt.event.WindowAdapter;import java.awt.event.WindowEvent;import java.util.*;import java.util.Random;/** * Created by Administrator on 2017-4-11. */public class Farme1 { public static void main(String[] args) {//創(chuàng)建窗口對(duì)象Frame f1 = new Frame();Button btn = new Button('OOO!');f1.setVisible(true);//顯示窗口對(duì)象。f1.setBounds(200,500,550,350); //設(shè)置位置f1.setTitle('我的窗口程序！'); //設(shè)置窗口標(biāo)題。f1.setIconImage(Toolkit.getDefaultToolkit().getImage('F:L-我的圖片logoeyes-1059234.jpg'));//設(shè)置窗體左上角圖標(biāo)f1.setLayout(null);//制作界面時(shí)用的的布局函數(shù)btn.setBackground(Color.gray);btn.setSize(50, 30);btn.setLocation(10,30);btn.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) {NewButton(f1); }});f1.add(btn);CloseFrame(f1); } public static void CreatFrame(Frame f1,Button btn){ } public static int Random1(){//隨機(jī)函數(shù)生成0-255之間的數(shù)字、Random rd = new Random();int a= rd.nextInt(256);return a; } public static void NewButton(Frame f1){int x = 50;int y= 100;int count = 0;for (int i=0;i<9;i++){ Button bt1 = new Button('BT'+(i+1)); //隨機(jī)顏色。 bt1.setBackground(new Color(Random1(),Random1(),Random1())); bt1.setBounds(x, y, 50, 30); f1.add(bt1); x+=60; count++; if (count==3){y += 50;count =0;x=50;//System.out.println('AAAA'); } try {Thread.sleep(200); } catch (InterruptedException e1) {e1.printStackTrace(); }} } public static void CloseFrame(Frame f1){f1.addWindowListener(new WindowAdapter() { @Override public void windowClosing(WindowEvent e) {System.exit(0); }}); }}

我想到的是

boolean a =false;if(!a){ ... a=flase;}else{ ... a=true}"但是這樣好像并不對(duì)。。

問(wèn)題解答

可以使用一個(gè) List 保存當(dāng)前已經(jīng)存在的 顏色隨機(jī)的Button，然后每次點(diǎn)擊按鈕，都先將 Frame 上面在該 List 中的 Button 去掉。

/** * 用來(lái)保存那些顏色隨機(jī)的 Button */static java.util.List<Button> newButtons = new ArrayList<>();public static void NewButton(final Frame f1) { // 每次添加之前，先移除原來(lái)的顏色隨機(jī)按鈕 for (Button button : newButtons) {f1.remove(button); } int x = 50; int y = 100; int count = 0; for (int i = 0; i < 9; i++) {Button bt1 = new Button('BT' + (i + 1));//隨機(jī)顏色。bt1.setBackground(new Color(Random1(), Random1(), Random1()));bt1.setBounds(x, y, 50, 30);f1.add(bt1);x += 60;count++;if (count == 3) { y += 50; count = 0; x = 50; //System.out.println('AAAA');}newButtons.add(bt1); // 將 bt1 加入 newButtonstry { Thread.sleep(200);} catch (InterruptedException e1) { e1.printStackTrace();} }}