Help with assignment and JFileChooser

[Austin Trower]

I have an upcoming assignment Here is the List of things to accomplish which is difficult to understand in the first place.

Here is one way to say it.

have two buttons in the SOUTH frame. One says Get Student Names, which when clicked will read in the Student Names File and display the lines in the textArea; and one that says "Get Student Grades" that when clicked will display the student Id, names, and average grade in the text area. Include the student object from P_Supplemental_9 with an arraylist for the grades.

Requirements:
1 frame with BorderLayout
2 buttons on Panel
1 Panel with GridLayout to put the two buttons on in the SOUTH region
1 FileChooser in a new frame
1 TextArea in the CENTRAL region
1 Label telling what the program does in the NORTH region



here is another

for P_Supplemental_11. When the first button is pressed, it should open up the FileChooser that's explained on page 329 in the book. With this, choose the studentNames.txt file and read it into the JTextArea.
When the second button is pressed, it should have you browse to the studentScores.txt file, import it, do the magic, and display the same output as P_Supplemental_9 in the JTextArea.


Here is my entire code:

import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class P_Supplemental_10 extends JFrame {
JPanel jpnl1 = new JPanel ();
JPanel jpnl2 = new JPanel();
JButton jbtReadFile = new JButton ("Get Student Grades");
JButton jbtFileChoose = new JButton ("Get Student Names");
JTextField jtxtFilePath = new JTextField();
JLabel jlb1Desc = new JLabel ("Enter the file name here");
JTextArea jtxtAfileContents = new JTextArea ();
	
P_Supplemental_10 () {
	this.setLayout(new BorderLayout(5,10));
	jpnl1.setLayout(new GridLayout(2,2));
	jpnl1.add(jlb1Desc);
	jpnl1.add(jtxtFilePath);
	add(jpnl1,BorderLayout.NORTH);
	add(jtxtAfileContents, BorderLayout.CENTER);
	add(jbtReadFile, BorderLayout.SOUTH);
	add(jbtFileChoose, BorderLayout.SOUTH);
	
	jbtReadFile.addActionListener(new ActionListener () {
		public void actionPerformed (ActionEvent evt) {
			jbtReadFileActionPerformed(evt);
		}
	});
}// end Constructor
private void jbtReadFileActionPerformed(ActionEvent evt) {
	
	File inFile = new File ("c:/temp/transactions.txt");
	try {
		Scanner input = new Scanner (inFile);
		
		String fileContents = "";
		while(input.hasNext()){
			fileContents+= input.nextLine() + "\n";
		}
		jtxtAfileContents.setText(fileContents);
	} catch (FileNotFoundException e) {
	
		Logger.getLogger(P_Supplemental_10.class.getName()).log(Level.SEVERE, null);
	}
	
	
}//end action method for jbtReadFile button
	

public static void main(String[] args) throws Exception{
P_Supplemental_10 frame = new P_Supplemental_10();
frame.setTitle("P_Supplemental_10");
frame.setVisible(true);
frame.setSize(410, 520);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
/*JFileChooser fileChooser = new JFileChooser();
if (fileChooser.showOpenDialog(null)
		==JFileChooser.APPROVE_OPTION) {
	//get file
	java.io.File file = fileChooser.getSelectedFile();
	
	//Scanner for file
	Scanner input = new Scanner(file);
	
	//Read text form file 
	while (input.hasNext()) {
		System.out.println(input.nextLine());
	}
	
	//close file
	input.close();
}
else{
	System.out.println("No file selected");*/
	}//else
}//main
//}

So my first question is how do I get The two buttons to display next to eachother in the SOUTH of the frame in the BorderLayout

P_Supplemental_10 () {
	this.setLayout(new BorderLayout(5,10));
	jpnl1.setLayout(new GridLayout(2,2));
	jpnl1.add(jlb1Desc);
	jpnl1.add(jtxtFilePath);
	add(jpnl1,BorderLayout.NORTH);
	add(jtxtAfileContents, BorderLayout.CENTER);
	add(jbtReadFile, BorderLayout.SOUTH);
	add(jbtFileChoose, BorderLayout.SOUTH);

And second how do attach the JFile chooser to the buttons?

[Kemal Sokolovic]

So my first question is how do I get The two buttons to display next to eachother in the SOUTH of the frame in the BorderLayout

You already have the answer to that one here.

And second how do attach the JFile chooser to the buttons?

Read How to Use File Choosers, there are some great examples that suit your needs.

[Maneesh Godbole]

Austin Trower wrote:
1 FileChooser in a new frame

Are you sure you got this one right?

[Austin Trower]

Austin Trower wrote:
1 FileChooser in a new frame


Are you sure you got this one right?

No that why I asked the Question how do I set that to open on a button click and why it is currently commented out

[Austin Trower]

You already have the answer to that one here

Im glad to see Im not the only one in my class having problems Thanks for the links

[Austin Trower]

K first problem solved

P_Supplemental_10 () {
	this.setLayout(new BorderLayout(5,10));
	jpnl1.setLayout(new GridLayout(2,2));
	jpnl1.add(jlb1Desc);
	jpnl1.add(jtxtFilePath);
	add(jpnl1,BorderLayout.NORTH);
	add(jtxtAfileContents, BorderLayout.CENTER);
	jpnl2.add(jbtReadFile);
	jpnl2.add(jbtFileChoose);
	add(jpnl2, BorderLayout.SOUTH);

[Austin Trower]

My next Question is how do i get the JFileChooser to display the selected files text inside the original GUI box instead of to the Console?

private void jbtReadFileActionPerformed(ActionEvent evt) throws Exception {
	
	//File inFile = new File ("c:/temp/transactions.txt");
	JFileChooser fileChooser = new JFileChooser();
	if (fileChooser.showOpenDialog(null)
			==JFileChooser.APPROVE_OPTION) {
		//get file
		java.io.File file = fileChooser.getSelectedFile();
		
		//Scanner for file
    	Scanner input = new Scanner(file);
		try {
			input = new Scanner(file);
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			Logger.getLogger(P_Supplemental_10.class.getName()).log(Level.SEVERE, null);
		}
		
		
		
		//Read text form file 
		while (input.hasNext()) {
			System.out.println(input.nextLine());
		}
		
		//close file
		input.close();
	}
	
	
	
	else{
		System.out.println("No file selected"); }

[Kemal Sokolovic]

If you've read the tutorial I gave you on how to use JFileChooser (and seems like you did read some of it), then you know how to choose a file, open it and read its content (that code you already have).

The only thing you have to do now is to replace the code that prints lines to the console:

// Read text from file
while(input.hasNext())
{
    System.out.println(input.nextLine());
}

with appropriate method that would append each line to JTextArea in your GUI. Check the API for JTextArea#append(String str) method and that would solve your problem.

[Austin Trower]

All right got that done i will have to work on making the out put fit in the frame better but got it to print inside the GUI

String fileContents = "";
		while (input.hasNext()) {
			fileContents+= input.next() +  "\n";
		}
		jtxtAfileContents.setText(fileContents);

Now Im going to need advice on this; When the second button is pressed, it should have you browse to the studentScores.txt file, import it, do the magic, and display the same output as P_Supplemental_9 in the JTextArea.

Instructor also clarified thusly; When the first file is read in, you will want to not just display it but add it to the student arraylist at that time. When the second file is read in, you will run the collect grades method (for each student) and add that to the corresponding student object.

This kind of splits up the code from P_Supplemental_9 but should help you understand the differences between working with the console and the GUI.

Seeing as how I don't know any magic I cant even pull my thumb off properly. Im going to keep reading but If their is any advice you guys could give to keep nudging me in the right direction it would be appreciated.

public class P_Supplemental_10 extends JFrame {
JPanel jpnl1 = new JPanel ();
JPanel jpnl2 = new JPanel();
JButton jbtReadFile = new JButton ("Get Student Grades");
JButton jbtFileChoose = new JButton ("Get Student Names");
JTextField jtxtFilePath = new JTextField();
JLabel jlb1Desc = new JLabel ("Enter the file name here");
JTextArea jtxtAfileContents = new JTextArea ();
	
P_Supplemental_10 () {
	this.setLayout(new BorderLayout(5,10));
	jpnl1.setLayout(new GridLayout(2,2));
	jpnl1.add(jlb1Desc);
	jpnl1.add(jtxtFilePath);
	add(jpnl1,BorderLayout.NORTH);
	add(jtxtAfileContents, BorderLayout.CENTER);
	jpnl2.add(jbtFileChoose);
	jpnl2.add(jbtReadFile);
	add(jpnl2, BorderLayout.SOUTH);
	
	
	jbtReadFile.addActionListener(new ActionListener () {
		public void actionPerformed (ActionEvent evt) {
			try {
				jbtReadFileActionPerformed(evt);
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	});
	jbtFileChoose.addActionListener(new ActionListener () {
		public void actionPerformed (ActionEvent evt) {
			try {
				jbtFileChooseActionPerformed(evt);
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	});
}// end Constructor
private void jbtReadFileActionPerformed(ActionEvent evt) throws Exception {
	
	//File inFile = new File ("c:/temp/transactions.txt");
	JFileChooser fileChooser = new JFileChooser();
	if (fileChooser.showOpenDialog(null)
			==JFileChooser.APPROVE_OPTION) {
		//get file
		java.io.File file = fileChooser.getSelectedFile();
		
		//Scanner for file
    	Scanner input = new Scanner(file);
		try {
			input = new Scanner(file);
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			Logger.getLogger(P_Supplemental_10.class.getName()).log(Level.SEVERE, null);
		}
		
		
		
		//Read text form file 
		String fileContents = "";
		while (input.hasNext()) {
			fileContents+= input.next() +  "\n";
		}
		jtxtAfileContents.setText(fileContents);
		
		//close file
		input.close();
	}
	
	
	
	else{
		System.out.println("No file selected"); }
	
/*try {
	Scanner input = new Scanner (inFile);
		
		String fileContents = "";
		while(input.hasNext()){
		fileContents+= input.next() + "\n";
		}
		jtxtAfileContents.setText(fileContents);
	} catch (FileNotFoundException e) {
	
		Logger.getLogger(P_Supplemental_10.class.getName()).log(Level.SEVERE, null);
	}
	*/
	
	
}//end action method for jbtReadFile button
private void jbtFileChooseActionPerformed(ActionEvent evt) throws Exception {
	
	//File inFile = new File ("c:/temp/transactions.txt");
	JFileChooser fileChooser = new JFileChooser();
	if (fileChooser.showOpenDialog(null)
			==JFileChooser.APPROVE_OPTION) {
		//get file
		java.io.File file = fileChooser.getSelectedFile();
		
		//Scanner for file
    	Scanner input = new Scanner(file);
		try {
			input = new Scanner(file);
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		
		
		//Read text form file 
		String fileContents = "";
		while (input.hasNext()) {
			fileContents+= input.next() +  "\n";
		}
		jtxtAfileContents.setText(fileContents);
		
		//close file
		input.close();
	}
	
	
	
	else{
		System.out.println("No file selected"); }
	
}
	

public static void main(String[] args) throws Exception{
P_Supplemental_10 frame = new P_Supplemental_10();
frame.setTitle("P_Supplemental_10");
frame.setVisible(true);
frame.setSize(410, 520);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}//main
}//class

These are the baby steps I have taken so far Thanks Kemal

[Kemal Sokolovic]

And what is P_Supplemental_9?

From the description you gave, you should extend the code you already have. Since I don't know what are the formats of files you are reading, I will make an assumption.

Suppose the first file (containing data about students) is formatted as:

student_id first_name last_name

In this case your Student class should have these three fields. You would read the file just as you did in the code you already have, but in addition you would have to parse each line you read to extract values for each of these fields (see java.util.StringTokenizer). Once you have extracted all three values from the current line you read, you would instantiate a Student class with those values.

Until you provide more details about how files are structured, I can't give you any more hints, but what I wrote above would be some basic idea on how to handle that task.

[Campbell Ritchie]

Surely you would use String#split rather than a Tokenizer, which is legacy code.

[Kemal Sokolovic]

Surely you would use String#split rather than a Tokenizer, which is legacy code.

I missed that, what was I thinking?

[Austin Trower]

Sorry I have been away from a computer for a while I hope you guys are out there i will try and clarify, and take your input that you already given into consideration this is P_Supplemental_9

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;
import java.util.logging.Level;
import java.util.logging.Logger;


public class P_Supplemental_9 {
	  public static void main(String[] args) throws FileNotFoundException {
	        File inFile = new File ("c:/temp/studentNames.txt");
	        Scanner input = new Scanner(inFile);
	        ArrayList <Student> students = new ArrayList();
	       Student grade[] = new Student[3];
	       for (int i =0; i < grade.length; i ++)
	           
	        while (input.hasNext ()){
	        students.add(new Student(input.nextInt(),input.nextLine()));
	        }//end while loop
	        for (int o =0; o < students.size(); o++){
	        students.get(o).setGrades(collectGrades(students.get(o).getStuId()));	
	        System.out.printf("%-10d %-20s %.2f  avg " , students.get(o).getStuId(),students.get(o).getStuName(), 
	        		averageGrade(students.get(o). getGrades()));
	                }
	        
	        
	        
	        
	        
	}//end main
	  
	  public static ArrayList <Double> collectGrades(int inId) {
		  
		  ArrayList <Double> outGrade = new ArrayList();
		  try {
		  File inFile = new File ("c:/temp/studentScores.txt");
	        Scanner input = new Scanner(inFile);
	        while (input.hasNext()) {
	        int tmpInt = input.nextInt();
	        double tmpDbl = input.nextDouble();
	        if(tmpInt ==inId) {
	        	outGrade.add(tmpDbl);
	        }//end if
	        }//end while
	        
	       
	  } catch (FileNotFoundException ex) {
		  Logger.getLogger(P_Supplemental_9.class.getName()).log(Level.SEVERE, null, ex);
	  }
	  return outGrade;
	  }
	  public static double averageGrade(ArrayList <Double> gradeIn){
		  double outAvg = 0.0;
		  
		  for (int y =0; y < gradeIn.size (); y ++) {
			  outAvg+=gradeIn.get(y);
		  }
		  return outAvg/gradeIn.size();
	  }
	  
	  
	  
	  
	  
	}//end main class

	class Student{
	    private String stuName;
	    private int stuId;
	    private ArrayList<Double> grades;
	    
	    
	  
	Student (int idIn, String nameIn){

	this.stuId = idIn;
	this.stuName = nameIn;

	}//end student

	    /**
	     * @return the stuName
	     */
	    public String getStuName() {
	        return stuName;
	    }

	    /**
	     * @param stuName the stuName to set
	     */
	    public void setStuName(String stuName) {
	        this.stuName = stuName;
	    }

	    /**
	     * @return the stuId
	     */
	    public int getStuId() {
	        return stuId;
	    }

	    /**
	     * @param stuId the stuId to set
	     */
	    public void setStuId(int stuId) {
	        this.stuId = stuId;
	    }

	    /**
	     * @return the grades
	     */
	    public ArrayList getGrades() {
	        return grades;
	    }

	    /**
	     * @param grades the grades to set
	     */
	    public void setGrades(ArrayList grades) {
	        this.grades = grades;
	    }
	}//end student class

What i think i need to do is clickmy first button in my GUI that pops up and look up this file which is in a notepad format that has student names and ID numbers

3305 Smith Henry
5555 Eddy Olivia
8915 Johnson Luke

 File inFile = new File ("c:/temp/studentNames.txt");

then i need the code to do the afore mention "magic" so When I click the other button in my GUI and select the file that looks like this:

3305 92.0
5555 95.5
8915 98.5
3305 89.0
5555 90.5
8915 95.5
3305 78.5
5555 85.0
8915 82.0

and is list in the above code here

		  File inFile = new File ("c:/temp/studentScores.txt");

It sort of adds the two files together and prints out the student names and Average grades which is what the code in P_Supplemental_9 does, I just need to make it so it does the same action by clicking the two buttons in the GUI from the code that i originally posted. So in the end the print out looks like this.
3305 Smith Henry 86.50 avg,
5555 Eddy Olivia 90.33 avg,
8915 Johnson Luke 92.00 avg,

Inside the GUI text box

I hope that makes some sense.

[Austin Trower]

How do i change this so it is all a String?

 jtxtAfileContents.setText("%-10d %-20s %.2f  avg,  \n" , students.get(o).getStuId(),students.get(o).getStuName(), 
	        		averageGrade(students.get(o). getGrades()));

all night

[Austin Trower]

Where and how do I use StringBuilder in my code? I know that that is what I need to do and I think it is the last step. here is where i need to use it for the jtxtAfileContents.setText line

ArrayList <Student> students = new ArrayList();
	       Student grade[] = new Student[3];
	       for (int i =0; i < grade.length; i ++){}
              
            //Read text form file   
            String fileContents = "";  
           while(input.hasNext()) {
        students.add(new Student(input.nextInt(),input.nextLine()));

    } // end while
           for (int o =0; o < students.size(); o++){
	        students.get(o).setGrades(collectGrades(students.get(o).getStuId()));	
	      //  jtxtAfileContents.setText("%-10d %-20s %.2f  avg,  \n" , students.get(o).getStuId(),students.get(o).getStuName(), 
	        		averageGrade(students.get(o). getGrades()));

and I know it it needs to be set like this

 stringBuilder.append(String.format( "%-10d %-20s \n",students.get(i).getId(),students.get(i).getname()));

but I just dont know where or how to set the method for it