Read Excel and show it on tableview. Populate TableView using 2D array or List of List

Question

My aim is to read the excel (which I am able to, via Apache POI) and display the excel on TableView (JavaFX). I am able to display column names on TableView, bu

Answer 1

I have created a demo that explains how to populate a TableView when the number of columns is unknown. Comments in the code.

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import javafx.application.Application;
import javafx.beans.property.ReadOnlyObjectWrapper;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.scene.Scene;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import org.apache.poi.EncryptedDocumentException;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.DataFormatter;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.ss.usermodel.WorkbookFactory;

/**
 *
 * @author blj0011
 */
public class JavaFXApplication124 extends Application
{
    @Override
    public void start(Stage primaryStage)
    {        
        ObservableList<ObservableList<String>> data = FXCollections.observableArrayList();        
        final List<List<String>> excelData = readExcelFile("fileName.xlsx");//Get data from excel file
        //Add excel data to an observable list
        for(int i = 0; i < excelData.size(); i++)
        {
            data.add(FXCollections.observableArrayList(excelData.get(i)));
        }

        TableView<ObservableList<String>> tableView = new TableView();
        tableView.setItems(data);

        //Create the table columns, set the cell value factory and add the column to the tableview.
        for (int i = 0; i < excelData.get(0).size(); i++) {
            final int curCol = i;
            final TableColumn<ObservableList<String>, String> column = new TableColumn<>(
                    "Col " + (curCol + 1)
            );
            column.setCellValueFactory(
                    param -> new ReadOnlyObjectWrapper<>(param.getValue().get(curCol))
            );
            tableView.getColumns().add(column);
        }

        VBox vbox = new VBox(tableView);

        Scene scene = new Scene(vbox);

        primaryStage.setScene(scene);

        primaryStage.show();

    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args)
    {
        launch(args);
    }

    public static List<List<String>> readExcelFile(String fileName)
    {
        List<List<String>> excelContent = new ArrayList();
        int columnCounter = 0;
        int rowCounter = 0;

        try (InputStream inputStream = new FileInputStream(fileName)) {
            DataFormatter formatter = new DataFormatter();

            Workbook workbook = WorkbookFactory.create(inputStream);
            Sheet sheet = workbook.getSheetAt(0);

            for (Row row : sheet) {
                List<String> tempList = new ArrayList();

                for (Cell cell : row) {
                    String text = formatter.formatCellValue(cell);
                    System.out.print(++columnCounter + ": " + text + " - ");
                    System.out.println(text.length());
                    tempList.add(text.length() == 0 ? "" : text);
                }
                columnCounter = 0;
                excelContent.add(tempList);

                ++rowCounter;
                if (rowCounter == 5) {
                    break;
                }
            }
        }
        catch (IOException | EncryptedDocumentException ex) {
            System.out.println(ex.toString());
        }

        return excelContent;
    }
}

I am going to go out on a limb and credit this answer to @jewelsea. https://coderanch.com/t/663384/java/Populating-TableView-method