histogram.java

管理系统实现的源代码,

package 学生成绩管理系统;

import java.awt.*;
import javax.swing.*;

public class Histogram extends javax.swing.JInternalFrame {
    public Histogram(int[] data) {
        int[] data1=data;
        BarChart chart1 = new BarChart();
//        int[] data1 = {20, 10, 30, 40,70};
        String[] dataName1 = {"<60分:"+data1[0]+"人", "60-69分:"+data1[1]+"人", 
        "70-79分:"+data1[2]+"人", "80-89分:"+data1[3]+"人",">=90分:"+data1[4]+"人"};
        chart1.setData( data1,dataName1);
        getContentPane().add(chart1);
  }
    
    class BarChart extends JPanel{
        private int[] data;
        private String[] dataName;
        //private String[] dataName;
        private double sum=0;
        public void setData(int[] data,String[] dataName){
            this.data=data;
            this.dataName=dataName;
            for(int i=0;i<data.length;i++){
                sum+=data[i];
            }
            //repaint();
        }
        
        //Paint the histogram
        @Override
        protected void paintComponent(Graphics g){
            if(data==null) return;
            
            super.paintComponent(g);
            
            int width=getWidth();
            int height=getHeight();
            int interval=(int)((width-40)/(2*data.length+1));
            int x=40+interval;
            //Draw  base line
            g.drawLine(10, height-45, width, height-45);
            g.drawLine(10, height-45, 10, 50);
            g.drawString("总人数："+(int)sum+"人", 5, 45);
            for(int i=0;i<data.length;i++){
                double a=((data[i]/sum)*(height-95));//a不为零，使barHeight不为零
                int barHeight=(int)a;
                g.drawRect(x, height-45-barHeight, interval, barHeight);
                //Display a letter on the top of the rec
                g.drawString(dataName[i], x-15, height-45-barHeight-10);
                x+=2*interval;
            }
        }
        
    }

}