Student Grade Calculator using Java Swing

Last Updated : 01 Sep, 2020

Consider the following scenario. We need to create a GUI based application which calculates grade of students according to marks obtained in 4 subjects. Below are the range of marks for different grades.

Marks	Grade
>90%	A
Between 85% – 90%	B
Between 80% – 85%	C
Between 70% – 80%	D
Between 60% – 70%	E
Between 50% – 60%	Poor

We will be using Netbeans to create GUI applications since it’s a well crafted open-source IDE that provides features of a Component inspector, Drag-and-Drop of widgets, Debugger, Object browser, etc.

Steps to create the Student Grade Calculator

1. Create a new Java application by clicking on New Project -> Java -> Java Application and give a suitable project name. Eg: GeeksForGeeks and click Finish.

2. To create a New File under the same Java project GeeksForGeeks, right-click on the project name on the left-hand side of the window, click New -> JFrame Form and give a suitable file name. Eg. Grade_Calulator.java and click Finish.

Creating New File in existing Java Application Project

3. Now from the palette situated at the right-hand side of the window, start dragging the toolkit widgets as per requirements. To change the background color of the frame, we need to first insert a JPanel and change its properties.

Drag the panel to fit the frame size

4. Click anywhere on the panel area, go to properties -> background.

5. Double click on the background option and select any color of your choice. Then click OK.

6. After setting background color, drag other widgets onto the design area. To display student details like Student ID, Name, Grade in a separate Dialog Box, drag a JOptionPane widget from the palette. First it overlaps the existing design. Go to navigator on left-hand side of the screen, then drag and move the JOptionPane component from JFrame to Other Components. It will go behind.

7. Let us now quickly go through the usage of each component in the program tabulated below.

Object Type	Object Name	Description
Label	jLabel1: ABC Public School, Mumbai	Describes title of the application
	jLabel2: Student ID	Defines Student ID
	jLabel3: Student Name	Defines Student Name
	jLabel4: Section	Defines Section
	jLabel5: Physics	Defines marks in subject 1
	jLabel6: Chemistry	Defines marks in subject 2
	jLabel7: Maths	Defines marks in subject 3
	jLabel8: English	Defines marks in subject 4
	jLabel9: Total Marks	Defines total marks
	jLabel10: Percentage	Defines percentage obtained
	jLabel11: Grade	Defines grade achieved
TextBox	jTextField1	Variable 1
	jTextField2	Variable 2
	jTextField3	Variable 3
	jTextField4	Variable 4
	jTextField5	Variable 5
	jTextField6	Variable 6
	jTextField7	Variable 7
	jTextField8	Variable 8
	jTextField9	Variable 9
	jTextField10	Variable 10
Panel	jPanel1	Container to hold components
Command Button	jButton1: Calculate	Calculates grade
	jButton2: Clear	Clears content of all components
	jButton3: Exit	Exists application
OptionPane	JOptionPane1	Displays additional information

8. Now to type the code, double click on jButton1, you will be directed to the source tab. Here type in the following code.

Java

// Initialize variables 
int s_id = Integer.parseInt(jTextField1.getText()); 
String s_name = jTextField2.getText(); 
String s_sec = jTextField7.getText(); 
double phy = Double.parseDouble(jTextField3.getText()); 
double chem = Double.parseDouble(jTextField4.getText()); 
double maths = Double.parseDouble(jTextField8.getText()); 
double eng = Double.parseDouble(jTextField9.getText()); 
  
// Calculates total marks 
double total = phy + chem + maths + eng; 
jTextField5.setText("" + total); 
  
// Calculates percentage 
double per = (total / 400) * 100; 
jTextField10.setText("" + per); 
String grade = null; 
  
// Grade calculation 
if (per > 90) { 
    grade = "A"; 
} else if ((per > 85) && (per < 90)) { 
    grade = "B"; 
} else if ((per > 80) && (per < 85)) { 
    grade = "C"; 
} else if ((per > 70) && (per < 80)) { 
    grade = "D"; 
} else if ((per > 60) && (per < 70)) { 
    grade = "E"; 
} else if ((per > 50) && (per < 60)) { 
    grade = "Poor"; 
} 
  
// Displays result in TextField 
jTextField6.setText("" + grade); 
  
// Displays result in new Dialog Box 
jOptionPane1.showMessageDialog(null, "Hello: " + s_name + " of class: " + s_sec + 
    "\nYour Grade is: " + grade); 

9. Now to clear all textfields write the following code under the jButton2 ActionPerformed option which can be achieved by clicking twice on Clear Button in the design area.

Java

jTextField1.setText(""); 
jTextField2.setText(""); 
jTextField3.setText(""); 
jTextField4.setText(""); 
jTextField5.setText(""); 
jTextField6.setText(""); 
jTextField7.setText(""); 
jTextField8.setText(""); 
jTextField9.setText(""); 
jTextField10.setText("");

10. Now to exit from the system, use the following statement under the jButton3 ActionPerformed option which can be achieved by clicking twice on exit button in the design area.

 System.exit(0)

11. Now, right-click anywhere on the screen and select Run File option from the drop-down menu. The final output is shown below. Input necessary details and the application is ready!