Java筆記丨09-1 兩個例子
阿新 • • 發佈：2018-12-22
一個自動出題並判分的小程式和一個顯示99個圓圈的小程式
·AutoScore.java自動出題並判分
import java.awt.*; import javax.swing.*; public class AutoScore extends JFrame { public AutoScore(){ init();//初始化 setSize( 400,350 );//設定大小 setDefaultCloseOperation(EXIT_ON_CLOSE); setVisible( true );//顯示 } public void init() { //{{INIT_CONTROLS setLayout(null); //沒有佈局 setSize(400,350); //設定大小 btnNew.setLabel("出題"); //設定文字 getContentPane().add(btnNew); //文字新增到介面 btnNew.setBackground(java.awt.Color.lightGray);//設定顏色 btnNew.setBounds(36,96,98,26); //設位置寬度高度 btnJudge.setLabel("判分"); getContentPane().add(btnJudge); btnJudge.setBackground(java.awt.Color.lightGray); btnJudge.setBounds(216,96,94,25); lblA.setText("text"); getContentPane().add(lblA); lblA.setFont(new Font("Dialog", Font.PLAIN, 24)); lblA.setBounds(36,24,36,36); lblOp.setText("text"); getContentPane().add(lblOp); lblOp.setFont(new Font("Dialog", Font.PLAIN, 24)); lblOp.setBounds(72,24,36,36); lblB.setText("text"); getContentPane().add(lblB); lblB.setFont(new Font("Dialog", Font.PLAIN, 24)); lblB.setBounds(108,24,33,36); label5.setText("="); getContentPane().add(label5); label5.setFont(new Font("Dialog", Font.PLAIN, 24)); label5.setBounds(168,24,34,36); getContentPane().add(txtAnswer); txtAnswer.setFont(new Font("Dialog", Font.PLAIN, 24)); txtAnswer.setBounds(216,24,85,42); listDisp.setFont(new Font("Dialog", Font.PLAIN, 16)); getContentPane().add(listDisp); listDisp.setBounds(36,144,272,106); //}} //{{REGISTER_LISTENERS 按鈕與函式關聯起來——新增事件的註冊 SymAction lSymAction = new SymAction(); btnNew.addActionListener(lSymAction); btnJudge.addActionListener(lSymAction); //}} } //{{DECLARE_CONTROLS 介面元素 java.awt.Button btnNew = new java.awt.Button();//按鈕 java.awt.Button btnJudge = new java.awt.Button(); java.awt.Label lblA = new java.awt.Label();//標籤用來顯示題目 java.awt.Label lblOp = new java.awt.Label(); java.awt.Label lblB = new java.awt.Label(); java.awt.Label label5 = new java.awt.Label(); java.awt.TextField txtAnswer = new java.awt.TextField();//文字框，輸入 java.awt.List listDisp = new java.awt.List(0);//顯示答案正確與錯誤 //}} class SymAction implements java.awt.event.ActionListener { public void actionPerformed(java.awt.event.ActionEvent event) { Object object = event.getSource(); if (object == btnNew)//出題 btnNew_ActionPerformed(event); else if (object == btnJudge)//判斷 btnJudge_ActionPerformed(event); } } void btnNew_ActionPerformed(java.awt.event.ActionEvent event) { // to do: code goes here. a = (int)(Math.random()*9+1); //隨機產生兩個數 b = (int)(Math.random()*9+1); int c = (int)(Math.random()*4); switch( c )//隨機產生符號 { case 0: op="+"; result=a+b; break; case 1: op="-"; result=a-b; break; case 2: op="*"; result=a*b;break; case 3: op="/"; result=a/b;break; //這裡只考慮整數除法 } lblA.setText(""+a); lblB.setText(""+b); lblOp.setText(""+op); txtAnswer.setText("");//將剛剛隨機產生的新增進去，即出題 } int a=0,b=0; //兩個數字a和b String op=""; //存符號 double result=0;//存正確的結果 void btnJudge_ActionPerformed(java.awt.event.ActionEvent event) { String str = txtAnswer.getText();//得到使用者的輸入 double d = Double.valueOf(str).doubleValue();//字串轉成實數 String disp = "" + a + op + b+"="+ str +" "; if( d == result ) disp += "☆"; else disp += "╳"; listDisp.add( disp );//把資訊加入到列表框裡 } public static void main(String [] args) { AutoScore f = new AutoScore(); } }
·Circle99Frame.java
import java.awt.*; import javax.swing.*; public class Circle99Frame extends JFrame { public static void main(String[]argv) { JFrame frame = new Circle99Frame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//設定關閉操作 frame.setSize( 600, 600 );//設定大小 frame.setVisible(true);//顯示 } public void paint(Graphics g)// { g.drawString("circle 99", 20, 20);//畫圖的位置（橫向和縱向的位置） int x0 = getSize().width /2;//根據大小和寬度設定中心位置 int y0 = getSize().height /2; for( int r=0 ; r<getSize().height/2; r+=10 ) { g.setColor( getRandomColor() );//加上隨機的顏色 g.drawOval( x0-r,y0-r/2, r*2, r*2 );//去掉這裡的y0後面的/2則為同心圓 } } Color getRandomColor()//紅綠藍三個顏色隨機 { return new Color( (int)( Math.random() * 256 ), (int)( Math.random() * 256 ), (int)( Math.random() * 256 ) ); } }
