Using a JFileChooser to get absolute path of a file

Hi Guys,

I am developing a program for data analysis. I am using Netbeans to develop a simple Desktop Application. I want to be able to make a JButton which opens a JFileChooser. I then want to be able to use the absolute path of the chosen file in another method which reads the data file.

So to clarify things I have a class ReadData with a method called readFile(String filename), The filename is a string of the absolute path to the file.

I have another class which is storing all the Graphical user interface components (JFrame, JPanel, JMenu). Now somehow I want to learn how to add a button to the GUI class which opens a file chooser popup box and the selected file path is passed on to the other method readFile(String filename) on class ReadData.

I know how to make the button open a file chooser but I don't know how to add this button to the Graphical User Interface and I do not know how to use the result from the ActionListener . Below is some of the code that I have generated. I kind of understand how things work on their own but I don't know how to put them together. Any help is greatly appreciated as ever. :)

Where would I create this button: In the ReadData Class and than add it to the GUI class or in the Gui Class and than use it's result in the ReadData Class?

Code:

---

//declare new button
 static JButton button1 = new javax.swing.JButton();

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
        JFileChooser chooser = new JFileChooser();
        int returnName = chooser.showOpenDialog(null);
        String path;

        if (returnName == JFileChooser.APPROVE_OPTION) {
            File f = chooser.getSelectedFile();
            if (f != null) { // Make sure the user didn't choose a directory.

                path = f.getAbsolutePath();//get the absolute path to selected file
                //below line to test the file chooser
                //System.out.println(path);
            }
        }
    }

    public void main(){
      // System.out.println(getFilePath());
        button1.setAction(null);
        button1.setName("Choose File");
        button1.addActionListener(new java.awt.event.ActionListener() {

            public void actionPerformed(ActionEvent e) {
                throw new UnsupportedOperationException("Not supported yet.");
            }
        });


    }

---

You've got your Model, the ReadFile class, and your View, the GUI classes which all indicate a good separation of functionality into separate entities, now you will need to join them together with a Control class(es). Hang on a second and I'll show you an example of what I mean, an example of Model, View, Control or MVC...

First of all, assume for example purposes that your ReadData class is quite simple, something like so...

Code:

---

class ReadData {
    public void readFile(String fileName) {
        System.out.println("reading from " + fileName);
    }

    // overload the method so we can call it with a File parameter as well.
    public void readfile(File file) {
        System.out.println("reading from " + file.getAbsolutePath());
    }
}

---

And assume that your GUI is also very simple, something like so:

Code:

---

class GuiPanel extends JPanel {
    private Controller controller; // this will tie things together


    // pass a reference to the Controller in the GUI constructor
    GuiPanel(Controller controller) {
        this.controller = controller;
       
        JButton readFileBtn = new JButton("Read File");
        readFileBtn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                readFileBtnActionPerformed();
            }
        });
        JButton writeFileBtn = new JButton("Write File");
        writeFileBtn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                writeFileBtnActionPerformed();
            }
        });
       
        add(readFileBtn);
        add(writeFileBtn);
    }

    // call the Controller methods in the button's actionPerformed methods
    private void writeFileBtnActionPerformed() {
        if (controller != null) {
            controller.writeFileAction();
        }
    }

    // call the Controller methods in the button's actionPerformed methods
    private void readFileBtnActionPerformed() {
        if (controller != null) {
            controller.readFileAction();
        }
    }
}

---

And the Control class that ties all together could look something like so:

Code:

---

class Controller {
    private ReadData readData; // holds a reference to the "model", the ReadData object


    // set the Model's reference in the constructor
    public Controller(ReadData readData) {
        this.readData = readData;
    }

    public void readFileAction() {
        JFileChooser chooser = new JFileChooser();
        int returnName = chooser.showOpenDialog(null);
        String path;
        if (returnName == JFileChooser.APPROVE_OPTION) {
            File f = chooser.getSelectedFile();
            if (f != null) {
                path = f.getAbsolutePath();
                readData.readFile(path);
            }
        }
    }
   
    public void writeFileAction() {
        //.... code to write to file
        System.out.println("write to file");
    }
}

---

A Main class to create the JFrame and tie all together

Code:

---

public class Main {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createGui();
            }
        });
    }

    private static void createGui() {
        ReadData readData = new ReadData();
        Controller controller = new Controller(readData);
        GuiPanel guiPanel = new GuiPanel(controller);
       
        JFrame frame = new JFrame("App");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(guiPanel);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }
}

---

Dear Fubarable,

Thank You for your very informative reply. I will now be trying to make it work. I suspect the autogenerated code from Netbeans Desktop Application will give me some headache. I will keep you updated.

Regards,
Jetnor.

Hello Fubarable,

I am stuck in one problem. Your code works very well and I have adapted it to work on my project.
What I am stuck on is that I need to use the read file in another method called draw graph. This method runs when I add it to the Controller class but I want to be able to view the graph on a new JPanel object which I have created on the GuiPanel class. So the code with the draw graph method on the controller class is as below:

Code:

---

class Controller {
    private ReadData readData; // holds a reference to the "model", the ReadData object


    // set the Model's reference in the constructor
    public Controller(ReadData readData) {
        this.readData = readData;
    }

    public void readFileAction() {
        JFileChooser chooser = new JFileChooser();
        MatrixToGraph draw = new MatrixToGraph();
        int returnName = chooser.showOpenDialog(null);
        String path;
        if (returnName == JFileChooser.APPROVE_OPTION) {
            File f = chooser.getSelectedFile();
            if (f != null) {
                path = f.getAbsolutePath();

                double[][]rawData=ReadData.readDataMatrix(path, ",");
                double[][]corrMatrix=CorrelationMatrix.readCorrMatrix(rawData);
              draw.matixToGr(corrMatrix);

            }
        }
    }

    public void writeFileAction() {
        //.... code to write to file
        System.out.println("write to file");
    }
}//End Class

---

The updated controller class is as below:

Code:

---

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package fubarable;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JPanel;

/**
 *
 * @author  PC Admin
 */
class GuiPanel extends JPanel {
    private Controller controller; // this will tie things together


    // pass a reference to the Controller in the GUI constructor
    GuiPanel(Controller controller) {
        this.controller = controller;

        JButton readFileBtn = new JButton("Read File");
        readFileBtn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                readFileBtnActionPerformed();
            }
        });
        JButton writeFileBtn = new JButton("Write File");
        writeFileBtn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                writeFileBtnActionPerformed();
            }
        });
       
      JPanel graph1panel=new JPanel();//create a JPanel as a container for the graph
      graph1panel.setName("graph1 panel"); // NOI18N
        MatrixToGraph graph1=new MatrixToGraph();//instance of graph drawing class which takes as input a 2 dimensional array
        graph1 = new MatrixToGraph();
      graph1.matixToGr(edges);
        graph1panel.add(graph1);//add the



        add(graph1panel);
        add(readFileBtn);
        add(writeFileBtn);
    }

    // call the Controller methods in the button's actionPerformed methods
    private void writeFileBtnActionPerformed() {
        if (controller != null) {
            controller.writeFileAction();
        }
    }

    // call the Controller methods in the button's actionPerformed methods
    private void readFileBtnActionPerformed() {
        if (controller != null) {
            controller.readFileAction();
        }



    }
}

---

On the MatrixToGraph class i have a method which takes input the read file matrix. The method is called matixToGr(double[][] edges).
At the end of this method I have created a jPanel which gets the graph added to it.

Code:

---

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package fubarable;

/**
 *
 * @author  PC Admin
 */

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ItemEvent;
import java.lang.reflect.InvocationTargetException;
import java.util.HashMap;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.swing.JFrame;


import org.apache.commons.collections15.Factory;
import cern.colt.matrix.DoubleMatrix2D;
import cern.colt.matrix.impl.SparseDoubleMatrix2D;
import edu.uci.ics.jung.graph.DirectedSparseMultigraph;
import edu.uci.ics.jung.graph.Graph;
import edu.uci.ics.jung.graph.SparseGraph;
import edu.uci.ics.jung.graph.SparseMultigraph;
import edu.uci.ics.jung.graph.DirectedGraph;
import edu.uci.ics.jung.graph.DirectedSparseGraph;
import edu.uci.ics.jung.graph.DirectedOrderedSparseMultigraph;
import edu.uci.ics.jung.graph.UndirectedGraph;
import edu.uci.ics.jung.graph.UndirectedSparseGraph;
import edu.uci.ics.jung.graph.UndirectedOrderedSparseMultigraph;
import edu.uci.ics.jung.graph.UndirectedSparseMultigraph;
import edu.uci.ics.jung.algorithms.matrix.GraphMatrixOperations;
import edu.uci.ics.jung.algorithms.layout.AbstractLayout;
import edu.uci.ics.jung.algorithms.layout.BalloonLayout;
import edu.uci.ics.jung.algorithms.layout.FRLayout;
import edu.uci.ics.jung.algorithms.layout.ISOMLayout;
import edu.uci.ics.jung.algorithms.layout.KKLayout;
import edu.uci.ics.jung.algorithms.layout.Layout;
import edu.uci.ics.jung.algorithms.layout.CircleLayout;
import edu.uci.ics.jung.algorithms.layout.SpringLayout;
import edu.uci.ics.jung.visualization.decorators.EdgeShape;
import edu.uci.ics.jung.visualization.decorators.ToStringLabeller;
import edu.uci.ics.jung.visualization.*;
import edu.uci.ics.jung.visualization.decorators.*;
import java.awt.event.ActionListener;
import java.awt.event.ItemListener;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class MatrixToGraph extends JPanel implements ActionListener, ItemListener {

    public void matixToGr(double[][] edges) {



        Map<String, Number> weights = new HashMap<String, Number>();

        Factory<Graph<String, String>> graphFactory = new Factory<Graph<String, String>>() {

            public Graph<String, String> create() {

                return new SparseGraph<String, String>();

            }
        };
        Factory<DirectedGraph<String, String>> directedGraphFactory = new Factory<DirectedGraph<String, String>>() {

            //public DirectedOrderedSparseMultigraph<String, String> create() {
            public DirectedOrderedSparseMultigraph<String, String> create() {
                return new DirectedOrderedSparseMultigraph<String, String>();
                //        return new DirectedOrderedSparseMultigraph<String, String>();

            }
        };

        Factory<UndirectedGraph<String, String>> undirectedGraphFactory = new Factory<UndirectedGraph<String, String>>() {

            public UndirectedOrderedSparseMultigraph<String, String> create() {
                return new UndirectedOrderedSparseMultigraph<String, String>();
            }
        };


        Factory<String> vertexFactory = new Factory<String>() {

            int n = 0;

            public String create() {

                return "V" + n++;

            }
        };

        Factory<String> edgeFactory = new Factory<String>() {

            int i = 0;

            public String create() {

                return "E" + i++;

            }
        };
        //change 2D array to DoubleMatrix2D
        DoubleMatrix2D m = new SparseDoubleMatrix2D(edges);
        //method to build graph from matrix
        Graph<String, String> g = GraphMatrixOperations.<String, String>matrixToGraph(m, undirectedGraphFactory, vertexFactory, edgeFactory);

        for (String anEdge : weights.keySet()) {

            double aWeight = (Double) weights.get(anEdge);

            System.out.println(anEdge + " " + aWeight);

        }
        Layout<String, String> layout = new CircleLayout(g);

        layout.setSize(new Dimension(300, 300));

        BasicVisualizationServer<String, String> vv = new BasicVisualizationServer<String, String>(
                layout);

        vv.setPreferredSize(new Dimension(320, 320));

        //vv.getRenderContext().setEdgeLabelTransformer(nEdgeStringer);

        vv.getRenderContext().setVertexLabelTransformer(new ToStringLabeller());

        vv.getRenderContext().setEdgeShapeTransformer(new EdgeShape.Line());

//build panel to hold the graph

        JPanel graphPanel = new JPanel();

        graphPanel.setPreferredSize(new Dimension(320, 320));
        graphPanel.add(vv);//vv is the graph being built by the method.
        JLabel graphLabel1 = new JLabel("First Graph");
        graphPanel.add(graphLabel1);
        add(graphPanel);

    }//end main

    public void actionPerformed(ActionEvent e) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    public void itemStateChanged(ItemEvent e) {
        throw new UnsupportedOperationException("Not supported yet.");
    }
}

---

Could you please help me solve this issue I am having. Do I add the graph to the readFileAction() method already in the controller or how would you suggest I go about this.

Thanks in advance for your help,
Jetnor.