JavaFX - populating data from TableView selection to dialog box - javafx

Question

I am learning to get data from selected row of TableView and prepopulate dialog box with that data. No matter what I do while loading dialog box I get NullPointerException in Controller.java -> showEditContactDialog()-> editController.setItem(item)).Somehow I am not able to pass selected data to another class and have it displayed by dialog box. Appreciate someone point me to the right direction. Here is the code:
Main.java:
package sample;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
import sample.datamodel.ContactData;
public class Main extends Application {
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) throws Exception{
Parent root = FXMLLoader.load(getClass().getResource("MainWindow.fxml"));
primaryStage.setTitle("Address Book");
primaryStage.setScene(new Scene(root, 1280, 500));
primaryStage.show();
}
#Override
public void stop(){
ContactData.getInstance().saveContacts();
}
}
Controller.java:
package sample;
#FXML
private TableView<Contact> tableView;
#FXML
private BorderPane mainBorderPane;
private Contact item;
public Controller() {
}
#FXML
public TableView<Contact> getTableView() {
return tableView;
}
#FXML
public void initialize(){
loadContacts();
tableView.setOnMouseClicked((MouseEvent event) -> {
if (event.getClickCount() > 0) {
item = tableView.getSelectionModel().getSelectedItem(); // *** get selection from TableView ***
}
});
}
#FXML
public void handleExit(){
ContactData.getInstance().saveContacts();
Platform.exit();
}
public void saveContacts() {
ContactData.getInstance().saveContacts();
}
public void loadContacts() {
ContactData.getInstance().loadContacts();
tableView.setItems(ContactData.getInstance().getContacts());
}
public void deleteContact(){
ContactData.getInstance().deleteContact(item);
}
public void showAddContactDialog(ActionEvent event) throws IOException {
Dialog<ButtonType> dialog = new Dialog<>();
dialog.initOwner(mainBorderPane.getScene().getWindow());
FXMLLoader fxmlLoader = new FXMLLoader();
fxmlLoader.setLocation(getClass().getResource("addContact.fxml"));
try{
dialog.getDialogPane().setContent(fxmlLoader.load());
}catch(IOException e){
System.out.println("Couldn't load the dialog");
e.printStackTrace();
return;
}
Optional<ButtonType> result = dialog.showAndWait();
if(result.isPresent()){
Dialog controller = fxmlLoader.getController();
}
}
public void showEditContactDialog() throws Exception {
Dialog<ButtonType> dialog = new Dialog<>();
dialog.initOwner(mainBorderPane.getScene().getWindow());
FXMLLoader fxmlLoader = new FXMLLoader();
fxmlLoader.setLocation(getClass().getResource("editContact.fxml"));
EditContactController editController = fxmlLoader.<EditContactController>getController();
editController.setItem(item); // ****** trying to pass "item" but get NullPointerException *********
try{
dialog.getDialogPane().setContent(fxmlLoader.load());
} catch (IOException e) {
System.out.println("Couldn't load the dialog");
e.printStackTrace();
return;
}
Optional<ButtonType> result = dialog.showAndWait();
}
}
EditContactController.java
package sample;
import javafx.fxml.FXML;
import javafx.scene.control.TextArea;
import javafx.scene.control.TextField;
import javafx.stage.Stage;
import sample.datamodel.Contact;
public class EditContactController{
#FXML
private TextField fName;
#FXML
private TextField lName;
#FXML
private TextField pNumber;
#FXML
private TextArea nNotes;
#FXML
private javafx.scene.control.Button cancelButton;
#FXML
private Contact item;
public void setItem(Contact item) {
this.item = item;
}
#FXML
public void initialize(){
try {
fName.setText(item.getFirstName());
}catch(NullPointerException e) {
System.out.println("null point --> " + e.getMessage());
e.printStackTrace();
}
}
//#FXML
public void cancelButtonAction(){
// get a handle to the stage
Stage stage = (Stage) cancelButton.getScene().getWindow();
stage.close();
}
}
editContact.fxml:
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.geometry.Insets?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.control.TextArea?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.layout.ColumnConstraints?>
<?import javafx.scene.layout.GridPane?>
<?import javafx.scene.layout.HBox?>
<?import javafx.scene.layout.RowConstraints?>
<?import javafx.scene.text.Font?>
<GridPane prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/8.0.121" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.EditContactController">
<HBox GridPane.columnSpan="2">
<Label text="Edit contact">
<font>
<Font name="System Bold" size="17.0" />
</font>
<padding>
<Insets bottom="10.0" left="10.0" />
</padding></Label>
</HBox>
<Label text="First Name" GridPane.columnIndex="0" GridPane.hgrow="ALWAYS" GridPane.rowIndex="1">
<GridPane.margin>
<Insets left="10.0" />
</GridPane.margin>
<padding>
<Insets bottom="5.0" />
</padding></Label>
<Label text="Last Name" GridPane.columnIndex="0" GridPane.rowIndex="2">
<GridPane.margin>
<Insets bottom="5.0" left="10.0" />
</GridPane.margin></Label>
<Label text="Phone number" GridPane.columnIndex="0" GridPane.rowIndex="3">
<GridPane.margin>
<Insets bottom="5.0" left="10.0" />
</GridPane.margin></Label>
<Label text="Notes" GridPane.columnIndex="0" GridPane.rowIndex="4">
<GridPane.margin>
<Insets bottom="5.0" left="10.0" />
</GridPane.margin></Label>
<TextField fx:id="fName" GridPane.columnIndex="1" GridPane.rowIndex="1">
<GridPane.margin>
<Insets bottom="5.0" />
</GridPane.margin></TextField>
<TextField fx:id="lName" GridPane.columnIndex="1" GridPane.rowIndex="2">
<GridPane.margin>
<Insets bottom="5.0" />
</GridPane.margin></TextField>
<TextField fx:id="pNumber" GridPane.columnIndex="1" GridPane.rowIndex="3">
<GridPane.margin>
<Insets bottom="5.0" />
</GridPane.margin></TextField>
<TextArea fx:id="nNotes" GridPane.columnIndex="1" GridPane.rowIndex="4">
<GridPane.margin>
<Insets bottom="5.0" />
</GridPane.margin></TextArea>
<HBox alignment="TOP_RIGHT" spacing="5.0" GridPane.columnIndex="1" GridPane.rowIndex="5">
<Button text="Edit">
<opaqueInsets>
<Insets />
</opaqueInsets></Button>
<Button fx:id="cancelButton" cancelButton="true" onAction="#cancelButtonAction" text="Cancel" />
<opaqueInsets>
<Insets />
</opaqueInsets>
<GridPane.margin>
<Insets />
</GridPane.margin>
<padding>
<Insets bottom="5.0" left="5.0" right="5.0" />
</padding>
</HBox>
<columnConstraints>
<ColumnConstraints maxWidth="288.0" minWidth="22.0" prefWidth="129.0" />
<ColumnConstraints maxWidth="578.0" minWidth="312.0" prefWidth="471.0" />
</columnConstraints>
<rowConstraints>
<RowConstraints />
<RowConstraints />
<RowConstraints />
<RowConstraints />
<RowConstraints />
<RowConstraints />
</rowConstraints>
<padding>
<Insets left="5.0" right="5.0" top="5.0" />
</padding>
<opaqueInsets>
<Insets />
</opaqueInsets>
</GridPane>
Stack:
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1774)
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1657)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Node.fireEvent(Node.java:8413)
at javafx.scene.control.Button.fire(Button.java:185)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:182)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:96)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:89)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3757)
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3485)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2494)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:394)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$353(GlassViewEventHandler.java:432)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:431)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1771)
... 48 more
Caused by: java.lang.NullPointerException
at sample.Controller.showEditContactDialog(Controller.java:105)
... 58 more

Answer 1

Your controller class is specified in the FXML file, so the FXMLLoader cannot instantiate it until it reads that file. This means the controller is only created during the call to load(), and calling fxmlLoader.getController() prior to that will return null.
So you need to move the code that retrieves the controller and acts on it so that it is executed after you call load():
public void showEditContactDialog() throws Exception {
Dialog<ButtonType> dialog = new Dialog<>();
dialog.initOwner(mainBorderPane.getScene().getWindow());
FXMLLoader fxmlLoader = new FXMLLoader();
fxmlLoader.setLocation(getClass().getResource("editContact.fxml"));
try {
Parent dialogContent = fxmlLoader.load();
EditContactController editController = fxmlLoader.<EditContactController>getController();
editController.setItem(item);
dialog.getDialogPane().setContent(dialogContent);
} catch (IOException e) {
System.out.println("Couldn't load the dialog");
e.printStackTrace();
return;
}
Optional<ButtonType> result = dialog.showAndWait();
}
The initialize() method in the controller is also called during the call to FXMLLoader.load(). So, as a consequence of these changes, initialize() is now called before you call setItem(...) on the EditContactController. So you need to move the code that depends on the item from the initialize() method to the setItem() method:
public void setItem(Contact item) {
this.item = item;
fName.setText(item.getFirstName());
}
#FXML
public void initialize(){
}