In my JavaFx application I want to update my BarChart whenever calculate button is clicked. The problem is that I am getting:
java.lang.NullPointerException at
application.StatController.setActivityData(StatController.java:47)
It is always pointing to:`xAxis.setCategories(optionsNames);
But it has elements on the list (See printscreen:https://image.ibb.co/b9YO8Q/Capture.png
In my StatController class I have setActivityData which is called from FormController class.
StatController class:
public class StatController {
#FXML
private BarChart<String, Double> barChart;
#FXML
private CategoryAxis xAxis;
Activities activities = new Activities();
private Map<String, List<Double>> uniqueActivityOptions = new HashMap<>();
private ObservableList<String> optionsNames = FXCollections.observableArrayList();
public StatController(){}
#FXML
private void initialize() {
}
public void setActivityData(Activities activitiesList) {
for(Activity activity : activities.getActivityList()) {
String optionName = activity.getOption();
if(uniqueActivityOptions.containsKey(optionName)) {
uniqueActivityOptions.get(optionName).add((double) activity.getNumber());
} else {
List<Double> activityOptionList = new ArrayList<>();
activityOptionList.add((double) activity.getNumber());
uniqueActivityOptions.put(optionName, activityOptionList);
}
}
for (Map.Entry<String, List<Double>> entry : uniqueActivityOptions.entrySet()) {
optionsNames.add(entry.getKey());
}
xAxis.setCategories(optionsNames);
XYChart.Series<String, Double> series = new XYChart.Series<>();
for (Map.Entry<String, List<Double>> entry : uniqueActivityOptions.entrySet()) {
Double average = calculateAverage(entry.getValue());
series.getData().add(new XYChart.Data<>(entry.getKey().toString(), average));
}
barChart.getData().add(series);
}
private double calculateAverage(List<Double> values) {
double result = 0;
for (Double value : values) {
result += value;
}
return result / values.size();
}
}
FormController class:
public class FormController {
Activities act = new Activities();
List<Activity> activities = act.getActivityList();
private ObservableList<String> opt = FXCollections.observableArrayList(
"Option 1",
"Option 2",
"Option 3"
);
#FXML
private Button calculateButton;
#FXML
private TextField numberField;
#FXML
private ComboBox<String> options;
private String selectedOption;
#FXML
private void initialize() {
options.getItems().addAll(opt);
options.getSelectionModel().selectedItemProperty()
.addListener(new ChangeListener<String>() {
#Override
public void changed(ObservableValue<? extends String> observable, String oldValue, String newValue) {
selectedOption = newValue;
}
});
}
#FXML
public void calculateButtonClicked(){
activities.add(new Activity(selectedOption, Integer.parseInt(numberField.getText())));
StatController sc = new StatController();
sc.setActivityData(act);
}
}
I tested setActivityData method in StatsController and it is working correctly when I am passing Activities.
Please advise what to change in the code to pass and update BarChart.
I know that this is something trivial but I really don't know how to do it.
`
Thank you very much for the help!
Your problem is in FormController#calculateButtonClicked(). You create a new instance of StatController manually and then call the setActivityData() method. This is not how JavaFX works and will result in the xAxis member being null, hence your NullPointerException.
Controller members annotated with the #FXML annotation will be injected by the FXMLLoader class when you call the FXMLLoader#load() method. You will need to use the FXMLLoader class to load the .fxml file that corresponds to the StatController class, which will then create an instance of your StatController object for you and will also inject your xAxis and barChart instances.
Here's a quick (not production ready) example that you will have to adapt for your specific scenario:
FXMLLoader loader = new FXMLLoader();
loader.setLocation(filePath); // your path to the .fxml file
loader.load();
StatController controller = (StatController) loader.getController();
controller.setActivityData(activities); // your activities data
How and when you do that depends on how your scene graph is setup. Looking at your source code, I would suggest the following changes:
MainController.java
public class MainController
implements Initializable {
#FXML
private TabPane tabPane;
#FXML
private Tab formTabPage;
#FXML
private FormController formTabController; // change name to this
#FXML
private Tab statsTabPage;
#FXML
private StatController statsTabController; // change name to this
private MainApp mainApp;
public void setMainApp(MainApp mainApp) {
this.mainApp = mainApp;
}
#Override // rename your init() method to this
public void initialize(URL location, ResourceBundle resources) {
// add this line
formTabController.setStatController(statTabController);
}
}
FormController.java
public class FormController {
Activities act = new Activities();
List<Activity> activities = act.getActivityList();
private ObservableList<String> opt = FXCollections.observableArrayList(
"Option 1",
"Option 2",
"Option 3"
);
#FXML
private Button calculateButton;
#FXML
private TextField numberField;
#FXML
private ComboBox<String> options;
private String selectedOption;
private StatController statController; // add this member
#FXML
private void initialize() {
options.getItems().addAll(opt);
options.getSelectionModel().selectedItemProperty()
.addListener(new ChangeListener<String>() {
#Override
public void changed(ObservableValue<? extends String> observable, String oldValue, String newValue) {
selectedOption = newValue;
}
});
}
#FXML
public void calculateButtonClicked() {
// change this method here
statController.setActivityData(act);
}
// add this method here
public void setStatController(StatController statController) {
this.statController = statController;
}
}
There are other problems that occur, but this fixes your null pointer exception. The reason this works and your previous code didn't, is because you were manually creating a new instance of StatController and not using the instance that the FXMLLoader had already loaded and mapped to the user interface node for you. All I have done above, is capture a reference to the controller you needed, and provided it to the other through a setter method.
Related
I'm making an application with JavaFX and Scene Builder.
I have two controllers:Controller and FontController
I have Main class that launch my program and open Stage with first fontroller (Controller)
public class Main extends Application {
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) throws Exception {
try {
Parent root = FXMLLoader.load(getClass().getResource("/card/card.fxml"));
Scene scene = new Scene(root, 1600, 600);
primaryStage.setScene(scene);
scene.getStylesheets().add(getClass().getResource("style.css").toExternalForm());
primaryStage.initStyle(StageStyle.UNDECORATED);
primaryStage.setMaximized(true);
primaryStage.setResizable(true);
primaryStage.getIcons().add(new Image("card/resources/logo-icon.png"));
primaryStage.show();
//adding resize and drag primary stage
ResizeHelper.addResizeListener(primaryStage);
//assign ALT+ENTER to maximize window
final KeyCombination kb = new KeyCodeCombination(KeyCode.ENTER, KeyCombination.CONTROL_DOWN);
scene.addEventHandler(KeyEvent.KEY_PRESSED, new EventHandler<KeyEvent>() {
#Override
public void handle(KeyEvent event) {
if (kb.match(event)) {
primaryStage.setMaximized(!primaryStage.isMaximized());
primaryStage.setResizable(true);
}
}
});
} catch (Exception e) {
e.printStackTrace();
}
}
}
There is a label and a button in Controller. When I click on the button a method is called and new window with second controller appears(FontController):
#FXML private Button btnFont;
#FXML private Label category1
#FXML
void changeFont(ActionEvent event) {
try {
FXMLLoader fxmlLoader = new
FXMLLoader(getClass().getResource("font.fxml"));
Parent rootFont = (Parent) fxmlLoader.load();
Stage stage = new Stage();
stage.setTitle("Select Font");
stage.setScene(new Scene(rootFont));
stage.show();
} catch (Exception e) {
System.out.println("can't load new window");
}
}
There is the button "OK" and label in FontCOntroller:
#FXML private Label fontLabel;
#FXML private Button btnFontOk;
Please tell me, what should I do to send and apply text from label in FontController when I click on the burtton "OK" to label in Controller?
SOLUTION FOUND:
I created class "Context" in my project directory to make all controllers communicate each other. You can add as many controllers as you want there.
Here it looks like:
package card;
public class Context {
private final static Context instance = new Context();
public static Context getInstance() {
return instance;
}
private Controller controller;
public void setController(Controller controller) {
this.controller=controller;
}
public Controller getController() {
return controller;
}
private FontController fontController;
public void setFontController(FontController fontController) {
this.fontController=fontController;
}
public FontController getFontController() {
return fontController;
}
}
Controller:
I created getters and setters (ALT + Insert in IDEA) for Label that I wanna change
public Label getCategory1() {
return category1;
}
public void setCategory1(Label category1) {
this.category1 = category1;
}
To get FontController variables and methods through Context class I placed line of code
//getting FontController through Context Class
FontController fontCont = Context.getInstance().getFontController();
I registered Controller in Context class through my initialize method (my class implements Initializable)
#FXML
public void initialize(URL location, ResourceBundle resources) {
//register Controller in Context Class
Context.getInstance().setController(this);
}
FontController:
to get Controller variables and methods I placed this code:
//getting Controller variables and methods through Context class
Controller cont = Context.getInstance().getController();
I also registered FontController in Context class through initialize method:
#Override
public void initialize(URL location, ResourceBundle resources) {
//register FontController in Context Class
Context.getInstance().setFontController(this);
}
Method that send text and text color from label in this FontController to label in Controller when I click on button:
#FXML
void applyFont(ActionEvent event) {
cont.getCategory1().setText(fontLabel.getText());
cont.getCategory1().setTextFill(fontLabel.getTextFill());
}
*By creating Context class you can make controllers communicate each other and create as many controllers as you want there. Controllers see variables and methods of each other
I am currently experimenting with JavaFX and SceneBuilder in eclipse to create and design my own program. In my first class "StartController" I am using a method called makeFadeIn. Basically, when I click a button another page loads up with a fade effect.
This is the code from StartController.java (notice makeFadeIn):
public class StartController {
#FXML
private AnchorPane rootPane;
private void makeFadeIn() {
FadeTransition fadeTransition = new FadeTransition();
fadeTransition.setDuration(Duration.millis(1000));
fadeTransition.setNode(rootPane);
fadeTransition.setFromValue(0);
fadeTransition.setToValue(1);
fadeTransition.play();
}
#FXML
private void loadSecondPage(ActionEvent event) throws IOException {
AnchorPane startPage = FXMLLoader.load(getClass().getResource("SecondController.fxml"));
rootPane.getChildren().setAll(startPage);
makeFadeIn();
}
Next, my other class loads up called "SecondController.java". In this class, I'm using the exact same method makeFadeIn (but I had to write it twice since it didn't let me run the program).
This is the code from SecondController.java:
public class SecondController {
#FXML
private AnchorPane rootPane;
private void makeFadeIn() {
FadeTransition fadeTransition = new FadeTransition();
fadeTransition.setDuration(Duration.millis(1000));
fadeTransition.setNode(rootPane);
fadeTransition.setFromValue(0);
fadeTransition.setToValue(1);
fadeTransition.play();
}
#FXML
private void loadFirstPage(ActionEvent event) throws IOException {
AnchorPane startPage = FXMLLoader.load(getClass().getResource("StartController.fxml"));
rootPane.getChildren().setAll(startPage);
}
My question is: can I somehow call the makeFadeIn method from the first class so I don't have to write it in my second class? I guess I need to inherit it in some way but I'm not sure how. I tried declaring it public instead of private but that did not help much.
You could move this functionality to a base class:
public class BaseController {
#FXML
private AnchorPane rootPane;
protected AnchorPane getRootPage() {
return rootPane;
}
protected void makeFadeIn() {
FadeTransition fadeTransition = new FadeTransition();
fadeTransition.setDuration(Duration.millis(1000));
fadeTransition.setNode(rootPane);
fadeTransition.setFromValue(0);
fadeTransition.setToValue(1);
fadeTransition.play();
}
}
And then have the other controllers extend it:
public class StartController extends BaseController {
#FXML
private void loadSecondPage(ActionEvent event) throws IOException {
AnchorPane startPage =
FXMLLoader.load(getClass().getResource("SecondController.fxml"));
getRootPane().getChildren().setAll(startPage);
makeFadeIn();
}
}
public class SecondController extends BaseController {
#FXML
private void loadFirstPage(ActionEvent event) throws IOException {
AnchorPane startPage =
FXMLLoader.load(getClass().getResource("StartController.fxml"));
getRootPane().getChildren().setAll(startPage);
}
}
I am creating an application where I'm combining FXML and regular javaFX to create an application. I'm, however, experiencing problems writing EventHandlers for a Stage-subclass called AddItemWindow that generates custom windows.
The application shows a list of items (keys and weapons) in an inventory. The user can add items, and needs to press a button to add the item of his choice (Add Key or Add Weapon).
A new window then pops up, where the user has to input the relevant data. It will generate a GridPane with the TextFields where the user can input the data. This will be a custom GridPane, depending on the ItemType. It will then load the FXML and add the GridPane.
With the below code, I am getting LoadExceptions for my SetOnAction-code for the buttons cancelling the window or confirming the new item.
Would any-one know where I'm making an error?
/* StartUp Class*/
package main;
//imports from javafx and java
import domain.DomainController;
import gui.OverviewWindow;
public class StartUpGUI extends Application {
#Override
public void start(Stage primaryStage) {
Parent root = new OverviewWindow(new DomainController());
Scene scene = new Scene(root);
primaryStage.setTitle("Weapons and Keys");
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String... args) {
Application.launch(StartUpGUI.class, args);
}
}
/* OverviewWindow, subclass of BorderPane */
package gui;
//imports from javafx and java
import domain.DomainController;
import domain.ItemType;
public class OverviewWindow extends BorderPane{
#FXML
private Button btnAddWeapon;
#FXML
private Button btnAddKey;
#FXML
private TextArea txaOverview;
private DomainController dc;
this.dc = dc;
FXMLLoader loader = new FXMLLoader(getClass().getResource("OverviewWindow.fxml"));
loader.setRoot(this);
loader.setController(this);
try{
loader.load();
txaOverview.setText(dc.showOverview()); // showOverview returns a String containing a toString of all items in the inventory
}
catch (IOException ex){
throw new RuntimeException(ex);
}
}
#FXML
public void btnAddWeaponOnAction(ActionEvent event){
try{
add(ItemType.WEAPON); // ItemType is an Enum where all the properties of the items are defined; for Weapon: name, weight, level, power, used(boolean)
}
catch (Exception e){
throw e;
}
}
#FXML
public void btnAddKeyOnAction(ActionEvent event){
try{
add(ItemType.SLEUTEL); // ItemType is an Enum where all the properties of the items are defined; for Key: name, weight, level, door
}
catch (Exception e){
throw e;
}
}
private void add(ItemType itemType){
Stage stage = new Stage();
stage.setTitle(itemType== VoorwerpSoort.WEAPON ? "Add Weapon" : "Add Key");
AddItem addItem = new AddItem(dc,itemType,this);
addItem.setOnHiding(new EventHandler<WindowEvent>(){
#Override
public void handle(WindowEvent e){
txaOverview.setText(dc.showOverview()); // when we close the AddItemWindow, we will update the item overview by having the domain controller get this data from the repository
}
});
addItem.show();
}
}
/* AddItemWindow, a subclass of Stage*/
package gui;
// import relevant javafx and java classes
import domain.DomainController;
import domain.ItemType;
public class AddItemWindow extends Stage {
#FXML
private BorderPane addRoot;
#FXML
private Button btnOK;
#FXML
private Button btnCancel;
private DomainController dc;
private ItemType itemType;
private Parent parent;
private TextField[] txfAttributes;
public AddItemWindow(DomainController dc, ItemType itemType, OverviewWindow overviewWindow){
this.dc = dc;
this.itemType = itemType;
this.parent = overviewWindow;
this.setScene(buildGUI(dc,itemType,overviewWindow));
}
private Scene buildGUI(DomeinController dc, VoorwerpSoort vwps, OverzichtSchermController ovsController){
Parent root = new BorderPane();
GridPane properties = new GridPane();
properties.setPadding(new Insets(10));
properties.setHgap(10);
properties.setVgap(10);
ColumnConstraints col1 = new ColumnConstraints();
col1.setHalignment(HPos.RIGHT);
ColumnConstraints col2 = new ColumnConstraints();
properties.getColumnConstraints().addAll(col1, col2);
String[] attributes = itemType.attributeNames();
txfAttributes = new TextField[attributes.length];
for(int i = 0; i<attributes.length; i++){
properties.add(new Label(attributes[i]),0,i);
properties.add(txfAttributes[i] = new TextField(),1,i);
}
((BorderPane) root).setCenter(properties);
FXMLLoader loader = new FXMLLoader(getClass().getResource("AddItemWindow.fxml"));
loader.setRoot(root);
loader.setController(root);
try{
loader.load();
return new Scene(root);
}
catch(IOException e){
throw new RuntimeException(e);
}
}
// NOT WORKING
#FXML
public void btnOKOnAction(){
addItem();
}
// NOT WORKING
#FXML
public void btnCancelOnAction(ActionEvent event){
hide();
}
private void voorwerpToevoegen(){ // we're calling the domaincontroller to add the new item to the repository
switch (itemType)
{
// for the item, add an item by getting the value of each TextField, which are the
// parameters for a constructor of the new item
case WEAPON:
dc.addWeapon(txfAttributes[0].getText(),
Double.parseDouble(txfAttributes[1].getText()),
Integer.parseInt(txfAttributes[2].getText()),
Integer.parseInt(txfAttributes[3].getText()),
Boolean.parseBoolean(txfAttributes[4].getText()));
break;
case KEY:
dc.addKey(txfAttributes[0].getText(),
Double.parseDouble(txfAttributes[1].getText()),
Integer.parseInt(txfAttributes[2].getText()),
Integer.parseInt(txfAttributes[3].getText()));
break;
}
hide();
}
}
At the top you have #FXML private Button btnOK; which is good.
To specify the button's action in Java code, you can use this Java 8 syntax in your buildGUI() method (see JavaFX 8 Event Handling Examples):
btnOK.setOnAction((event) -> addItem());
If you're not using Java 8, see UI Control Sample.
You don't need the methods annotated with #FXML.
This question already has answers here:
Javafx PropertyValueFactory not populating Tableview
(2 answers)
Closed 8 years ago.
I have following basic code in JavaFx. If I want to change the name of PropertyValueFactory("id") to let's say "rid" it does not fill my table anymore. Even if I change the SimpleLongProperty object to rid too. Do you know where the "id" is referencing / pointing to?
public class Main_Controller implements Initializable{
public class Item {
public SimpleLongProperty id = new SimpleLongProperty();
public Long getId() {
return id.get();
}
}
// The table and columns
#FXML TableView<Item> itemTbl;
#FXML TableColumn itemIdCol;
#FXML Button add_Button;
// The table's data
ObservableList<Item> data;
#Override
public void initialize(URL url, ResourceBundle rb) {
// Set up the table data
itemIdCol.setCellValueFactory(
new PropertyValueFactory<Item,Long>("id")
);
data = FXCollections.observableArrayList();
itemTbl.setItems(data);
}
static long nextId = 1;
#FXML
private void handleButtonAction(ActionEvent event) {
Item item = new Item();
item.id.setValue(nextId++);
data.add(item);
}
}
Code With changed PropertyValueFactory:
public class Main_Controller implements Initializable{
public class Item {
public SimpleLongProperty rid = new SimpleLongProperty();
public Long getId() {
return rid.get();
}
}
// The table and columns
#FXML TableView<Item> itemTbl;
#FXML TableColumn itemIdCol;
#FXML Button add_Button;
// The table's data
ObservableList<Item> data;
#Override
public void initialize(URL url, ResourceBundle rb) {
// Set up the table data
itemIdCol.setCellValueFactory(
new PropertyValueFactory<Item,Long>("rid")
);
data = FXCollections.observableArrayList();
itemTbl.setItems(data);
}
static long nextId = 1;
#FXML
private void handleButtonAction(ActionEvent event) {
Item item = new Item();
item.rid.setValue(nextId++);
data.add(item);
}
}
You need a method in your Item class called
public Long getRid(){return rid.get();}
or
public SimpleLongProperty ridProperty(){return rid;}
Note, it's not the name of the variable, which would normally be private, but the name of the getter that matters.
Javadoc link
I have a BorderPane, onto which I placed a MenuBar. At the center of the BorderPane I display differnt AnchorPanes depending on the MenuItem selected. So far so good.
Now, how do I make sure that the Menus change behavior in response to the item selected in the child AnchorPane? So for example if the user selects "Edit", there will be a different action depending on whether the item currently higlighted is a user account, a file etc.
So far I made something along these lines:
The BorderPane controller:
public class MenuTest implements Initializable{
#FXML
private BorderPane borderPaneMain;
#FXML
private AnchorPane anchorPaneMain;
#FXML
private Menu menuEdit;
#FXML
private MenuItem itemEdit;
static String menuMode;
static String entityName;
public MenuTest(){
menuMode ="";
entityName = "";
}
#Override
public void initialize(URL arg0, ResourceBundle arg1) {
AnchorPane anchor;
try {
anchor = (AnchorPane) new FXMLLoader().load(getClass().getResource("views/MainView.fxml"));
borderPaneMain.setCenter(anchor);
} catch (IOException e) {
e.printStackTrace();
}
}
protected static void setMenuMode(String menuMd, String entityNm){
entityName = entityNm;
menuMode = menuMd;
}
#FXML
private void onEditClick(){
if(entityName.equals(AnchorTest.FILE)){
//Launches correct edit view
new FXMLLoader().load(getClass().getResource("views/EditFile.fxml"));
//Passes the name of the entity so that the controller can retrieve its data
FileEditController.setFile(entityName);
}else if(entityName.equals(AnchorTest.PERSON)){
new FXMLLoader().load(getClass().getResource("views/EditPerson.fxml"));
PersonEditController.setFile(entityName);
}
}
}
The child AnchorPane controller:
public class AnchorTest implements Initializable{
public static final String PERSON = "PERSON";
public static final String FILE = "FILE";
ObservableList<String> peopleList;
ObservableList<String> fileList;
#FXML
private ListView<String> listPeople;
#FXML
private ListView<String> listFiles;
#Override
public void initialize(URL location, ResourceBundle resources) {
peopleList = FXCollections.observableArrayList("Frank","Matin","Anne");
fileList = FXCollections.observableArrayList("hello.txt","holiday.jpg","cv.doc");
listPeople.setItems(peopleList);
listFiles.setItems(fileList);
}
#FXML
private void personSelected(){
MenuTest.setMenuMode(this.PERSON, listPeople.getSelectionModel().getSelectedItem());
}
#FXML
private void fileSelected(){
MenuTest.setMenuMode(this.FILE, listFiles.getSelectionModel().getSelectedItem());
}
}
However I'm not sure that it's the best solution, especially considering the if/elseif statement will need to be altered whenever I add a new element type and its corresponding edit options. So is there any way that I can do this better?
I think if your application has only a few (2-4) different types of "things" that are represented by a AnchorPane, then your approach is totally fine. An alternative to your approach is the state pattern. In that case, your currently selected "item type" would be your state.