【JAVA语言程序设计基础篇】--图形-- 绘制封装表格类的思考

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开始用的方法没有体现类的封装性没有类的普遍性

package chapter15;import java.awt.*;import javax.swing.*;@SuppressWarnings("serial")public class exercise15_14 extends JFrame {    public exercise15_14() {    add(new barchart());  }  public static void main(String[] args) {    exercise15_14 frame = new exercise15_14();    frame.setTitle("Exercise15_14");    frame.setSize(500, 200);    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);    frame.setLocationRelativeTo(null); // Center the frame    frame.setVisible(true);  }}@SuppressWarnings("serial")class barchart extends JPanel{public barchart() {}String[] str = {"Project -- 20%", "Quizzes -- 10%","Midtems -- 30%", "Final -- 40%"};Color[] color = {Color.red,Color.yellow, Color.green, Color.blue};int[] number = {20,10,30,40};protected void paintComponent(Graphics g) {super.paintComponent(g);int max=0;for(int i=0;i<number.length;i++){max = Math.max(max, number[i]);}g.drawLine(5, getHeight()-10, getWidth()-10, getHeight()-10);int x = 15;int y = getHeight()-10;int singleWidth = (int)((getWidth()-10-5-20)/4);int maxHeight = getHeight()-50; for(int i=0;i<4;i++){g.setColor(color[i]);int newHeight = (int)(maxHeight *number[i]/max);g.fillRect(x, y-newHeight, singleWidth, newHeight);g.setColor(Color.black);g.drawString(str[i],x, y-newHeight-10);x+=singleWidth+5;}}}

对其进行封装改编使该表格类（barChart）具备普遍性

体现其封装性

package chapter15_编程练习题;import java.awt.*;import javax.swing.*;@SuppressWarnings("serial")public class Exercise15_14 extends JFrame {    public Exercise15_14() {    BarChart1 chart1 = new BarChart1();    double[] data1 = {20, 10, 30, 40};    String[] dataName1 = {"Project -- 20%", "Quizzes -- 10%",  "Midtems -- 30%", "Final -- 40%"};    chart1.setData(dataName1, data1);//传进关键词    add(chart1);  }  public static void main(String[] args) {    Exercise15_14 frame = new Exercise15_14();    frame.setTitle("Exercise15_14");    frame.setSize(500, 200);    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);    frame.setLocationRelativeTo(null); // Center the frame    frame.setVisible(true);  }}@SuppressWarnings("serial")class BarChart1 extends JPanel {BorderLayout borderLayout1 = new BorderLayout();Color[] colors = {Color.red, Color.yellow, Color.green, Color.blue,Color.cyan, Color.magenta, Color.orange, Color.pink,Color.darkGray};String[] dataName;double[] data;public void paintComponent(Graphics g) {super.paintComponent(g);// Find the maximum value in the datadouble max = data[0];for (int i=1; i<data.length; i++)max = Math.max(max, data[i]);int barWidth = (int)((getWidth() - 10.0) / data.length - 10);//设置单个宽度int maxBarHeight = getHeight() - 30;//设置表格中最大高度g.drawLine(5, getHeight() - 10, getWidth() - 5, getHeight() - 10);//底线int x = 15;for (int i = 0; i < data.length; i++) {g.setColor(colors[i % colors.length]);int newHeight = (int)(maxBarHeight * data[i] / max);//更新每个列的高度int y = getHeight() - 10 - newHeight;g.fillRect(x, y, barWidth, newHeight);g.setColor(Color.black);g.drawString(dataName[i], x, y - 7);x += barWidth + 10;//更新x轴坐标}}  public void setData(String[] dataName, double[] data) {//从类外传进值 使该类具有封装性 普遍性this.dataName = dataName;this.data = data;  }}

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