change value in combobox ["example"] to "example" in javafx - javafx

Question

i am using a combobox to get data from the database on stage.show(), so far i can retrieve the data and also implement my changelistener on the combobox.
the problem is that i am getting ["example"] from the database instead of "example". its my first time of using javafx and don;t know how the output is supposed to look like, but this one is strange to me.
below is a screenshot of it and also my code
[http://i.stack.imgur.com/QWawZ.png]
package libman;
import java.sql.*;
import javafx.application.Application;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.*;
import javafx.scene.Scene;
import javafx.scene.layout.*;
import javafx.stage.Stage;
import javafx.stage.*;
import javafx.scene.control.*;
import javafx.scene.text.*;
import javafx.collections.*;
/**
/**
*
* #author kels
*/
public class BorrowMenu extends Application {
private ObservableList<ObservableList> data;
DBOperator login;
ResultSet rs;
Statement stat;
private String getval;
#Override
#SuppressWarnings({"static-access", "Convert2Lambda"})
public void start(Stage primaryStage){
//define the UI elements
Label lblID = new Label("Name: ");
Label lblTitle = new Label("Book Title: ");
Label lblauthor = new Label("Author: ");
Label lblissue = new Label("Issue Date: ");
Label lblreturn = new Label("Return Date: ");
ComboBox title = new ComboBox();
TextField txtid = new TextField();
TextField txtitle = new TextField();
TextField txtauthor = new TextField();
TextField txtissue = new TextField();
TextField txtreturn = new TextField();
//set prompt text
txtid.setPromptText("Enter Borrower's Name");
txtitle.setPromptText("Enter Book Title");
txtauthor.setPromptText("Enter Author's Name");
txtissue.setPromptText("Enter Issue Date");
txtreturn.setPromptText("Enter Return Date");
title.setPromptText("Fills books from database");
//ToolTip ttip = new ToolTip("Back Menu");
Button btn = new Button("Borrow Book");
Button btnexit = new Button("Menu>>");
btnexit.setTooltip(new Tooltip("Back to Menu"));
//set the gripane to add in components
GridPane gridpane = new GridPane();
gridpane.setPadding(new Insets(20));
gridpane.setHgap(5);
gridpane.setVgap(5);
//set components
gridpane.setHalignment(lblID, HPos.RIGHT);
gridpane.add(lblID, 0,0);
gridpane.setHalignment(txtid, HPos.RIGHT);
gridpane.add(txtid,1,0);
gridpane.setHalignment(lblTitle, HPos.RIGHT);
gridpane.add(lblTitle, 0,1);
gridpane.setHalignment(title, HPos.RIGHT);
gridpane.add(title, 1,1);
gridpane.setHalignment(lblauthor, HPos.RIGHT);
gridpane.add(lblauthor, 0,2);
gridpane.setHalignment(txtauthor, HPos.RIGHT);
gridpane.add(txtauthor, 1,2);
gridpane.setHalignment(lblissue, HPos.RIGHT);
gridpane.add(lblissue, 0,3);
gridpane.setHalignment(txtissue, HPos.RIGHT);
gridpane.add(txtissue, 1,3);
gridpane.setHalignment(lblreturn, HPos.RIGHT);
gridpane.add(lblreturn, 0,4);
gridpane.setHalignment(txtreturn, HPos.RIGHT);
gridpane.add(txtreturn, 1,4);
gridpane.setHalignment(btn, HPos.RIGHT);
gridpane.add(btn, 1,5);
gridpane.setHalignment(btnexit, HPos.RIGHT);
gridpane.add(btnexit, 2,5);
//display the values from db to combobox on windows launch
data = FXCollections.observableArrayList();
primaryStage.setOnShowing(new EventHandler<WindowEvent>(){
#Override
public void handle(WindowEvent event){
try{
login = new DBOperator();
stat = login.getStatement();
rs=stat.executeQuery("SELECT * FROM BOOKDB");
while(rs.next()){
ObservableList<String> row =FXCollections.observableArrayList();
row.add(rs.getString("Title"));
// row.add(rs.getString("Author"));
data.add(row);
}
title.setItems(data);
rs.close();
}
catch(SQLException ex){
System.out.println("Driver Not Found!!!" + ex);
System.exit(0);
}
}
});
//add the gridpane to the stackpane
StackPane root = new StackPane();
root.getChildren().add(gridpane);
//title.setO
Scene scene = new Scene(root, 380,220);
primaryStage.setTitle("Borrow Menu");
primaryStage.setScene(scene);
primaryStage.setResizable(false);
primaryStage.show();
//System.out.println(row);
//activate the combo listener at selection
title.getSelectionModel().selectedItemProperty().addListener(new ChangeListener<Object>(){
#Override
public void changed(ObservableValue<? extends Object> observable, Object oldvalue, Object newvalue){
System.out.println(newvalue.toString());
// txtauthor.setText(newvalue.toString());
}
});
}
public static void main(String [] args){
launch(args);
}
}
Please help thanks

Answer 1

You are getting the correct result for what you are actually doing: ObservableList<ObservableList> data bundles two collections.
For each item of the comboBox you will have a collection, so that's why you see "[ ]" when it is rendered.
This minimum sample reproduces your case:
#Override
public void start(Stage primaryStage) {
ComboBox title = new ComboBox();
StackPane root = new StackPane();
root.getChildren().add(title);
ObservableList<ObservableList> data = FXCollections.observableArrayList();
List<String> test = Arrays.asList("Test", "Example");
for(String s : test) {
ObservableList<String> row =FXCollections.observableArrayList();
row.add(s);
data.add(row);
}
title.setItems(data);
Scene scene = new Scene(root, 300, 250);
primaryStage.setScene(scene);
primaryStage.show();
}
with the same result you have:
You need to simplify your collection: ObservableList<String> data.
#Override
public void start(Stage primaryStage) {
ComboBox<String> title = new ComboBox();
StackPane root = new StackPane();
root.getChildren().add(title);
ObservableList<String> data = FXCollections.observableArrayList();
List<String> test = Arrays.asList("Test", "Example");
for(String s : test) {
data.add(s);
}
title.setItems(data);
Scene scene = new Scene(root, 300, 250);
primaryStage.setScene(scene);
primaryStage.show();
}
And you will have the expected result:
EDIT
In the case you want to add several items from the database to each item of the combo, you just need to provide a way to render the data, using ComboBox.setCellFactory(), so you can override the default method that produces the string [item1, item2, ... ].