No response on Restart button: Runtime errors

Question

Hi all,

me again.

I'm really struggling with Java. I've painstakingly followed the video and I believe I've got the code correct with no errors showing up on my IDE.

However when I click the restart button I get the following runtime errors that mean absolutely nothing to me. I have no idea how to fix.

I bow to your superior knowledge. :)

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$MouseEventNotification.run(GlassViewEventHandler.java:380)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:294)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java:416)
    at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:415)
    at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
    at com.sun.glass.ui.View.notifyMouse(View.java:937)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
    at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1769)
    ... 48 more
Caused by: java.lang.NullPointerException
    at com.teamtreehouse.pomodoro.model.Attempt.<init>(Attempt.java:14)
    at com.teamtreehouse.pomodoro.controllers.Home.prepareAttempt(Home.java:35)
    at com.teamtreehouse.pomodoro.controllers.Home.handleRestart(Home.java:96)
    ... 58 more

home.java

package com.teamtreehouse.pomodoro.controllers;

import com.teamtreehouse.pomodoro.model.Attempt;
import com.teamtreehouse.pomodoro.model.AttemptKind;
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.scene.control.Label;
import javafx.scene.layout.VBox;
import javafx.util.Duration;

import java.lang.String;

/**
 * Created by Jonnie on 18/09/2016.
 */
public class Home {


    @FXML
    private VBox container;

    @FXML
    private Label title;
    private Attempt mCurrentAttempt;
    private StringProperty mTimerText;
    private Timeline mTimeline;

    private void prepareAttempt(AttemptKind kind){

        clearAttemptStyles();
        mCurrentAttempt = new Attempt(kind, "");
        addAttemptStyle(kind);
        title.setText(kind.getDisplayName());
        setTimerText(mCurrentAttempt.getRemainingSeconds() );
        mTimeline = new Timeline();
        mTimeline.setCycleCount(kind.getTotalSeconds());


        mTimeline.getKeyFrames().add(new KeyFrame(Duration.seconds(1), e -> {
            mCurrentAttempt.tick();
            setTimerText(mCurrentAttempt.getRemainingSeconds());
        }));
    }

    public Home() {
        mTimerText = new SimpleStringProperty();
        setTimerText("Hammer");
    }


    private void addAttemptStyle(AttemptKind kind) {
        container.getStyleClass().add(kind.toString().toLowerCase());
    }


    private void clearAttemptStyles() {
        for (AttemptKind kind : AttemptKind.values()) {
            container.getStyleClass().remove(kind.toString().toLowerCase());
        }
    }

    public void DEBUG(ActionEvent actionEvent) {
        System.out.println("Hi Mom!");
    }


    public String getTimerText() {

        return mTimerText.get();
    }

    public void setTimerText(String timerText) {
        mTimerText.setValue(timerText);
    }

    public void setTimerText(int remainingSeconds) {
        int minutes = remainingSeconds / 60;
        int seconds = remainingSeconds % 60;
        setTimerText(String.format("02d:%02d", minutes, seconds));
    }


    public void playTimer() {
        mTimeline.play();
    }

    public void pauseTimer() {
        mTimeline.pause();
    }

    public void handleRestart(ActionEvent actionEvent) {
        prepareAttempt(AttemptKind.FOCUS);
        playTimer();
    }
}

Attempt.java

   public void tick() {
        mRemainingSeconds--;
    }
}

Answer 1 · 2016-09-22T12:37:18Z

September 22, 2016 12:37pm

So I've found number of inconsitencies...

I will start listing them, and one by one we'll get to the same App that he does:

First, change the following line in home.fxml:

        <Label fx:id="time" text="25:00"/>

To

        <Label fx:id="time" text="${controller.timerText}"/>

This way you'll attach timerText to your controller, and when pressing restart time should appear

Second, change this linein Home.setTimerText, because of the typo in string formatting:

        setTimerText(String.format("02d:%02d", minutes, seconds));

        setTimerText(String.format("%02d:%02d", minutes, seconds));

When you do this, in your timer when pressing Restart should appear 05:00, not 25:00 like Craig did because you set up both of your Break and Focus times to 5 in AttemptKind:

    BREAK(5*60, "Break"),
    FOCUS(5*60, "Focus");

I also noted this error line in Attempt class:

    public void setMessage(String mMessage) {
        mMessage = mMessage;
    }

Change it to

    public void setMessage(String mMessage) {
        this.mMessage = mMessage;
    }

Otherwise, you are setting the argument to the argument itself ... You can see how intellijidea will make both lines grey, meaning something is not right.

That is it for now.

I was not able to make the clock working, like in Video, will edit the answer when ready ...

Update GitHub project if possible, so I can see later problems if any ...

[EDIT]

Please add to Home:

    public StringProperty timerTextProperty() {
        return mTimerText;
    }

That will make your clock tick. That line apparently is needed to provide relationship between controller and fxml

Answer 2 · 2016-09-22T09:37:34Z

September 22, 2016 9:37am

The problem is in your Attempt class.

Actually, constructor that is commented - works:

    /*
    public Attempt(AttemptKind kind, String message) {
        mKind = kind;
        mMessage = message;
        mRemainingSeconds = kind.getTotalSeconds();
    }*/

If you uncomment it and replace it with the wrong one, things should work.

Why the new constructor is wrong?

Because you are trying to execute mKind.getTotalSeconds() while mKind is null

   public Attempt(AttemptKind kind, String message) {
        mMessage = message;
        // mKind is null here
        mRemainingSeconds = mKind.getTotalSeconds();
        // this line should be BEFORE mKind.getTotalSeconds obviously
        mKind = kind;
    }

You also have some problems in Attempt class, please compare it with the project files:

For example two methods doing the same :

    // "dangerous" getter naming
    public int getmRemainingSeconds() {
        return mRemainingSeconds;
    }
    // correct, conventional getter naming
    public int getRemainingSeconds() {
        return mRemainingSeconds;
    }
}

It is also very common practice for getters to be write as getRemainingSeconds. It is very important later if in some frameworks getter will be inferred (If you ever get to 'Java Spring Basics' course e.g.), so it is better stick to conventional naming.

So change getmKind() as well...

Again, if you feel confused, check out the project files, they are "gold" standart :)

Answer 3 · 2017-01-12T19:51:38Z

January 12, 2017 7:51pm

Thanks for this! My timer wasn't running and it turned out that I missed the curly braces around the controller binding for the timer text in the FXML file. Once fixed everything works!

Answer 4 · 2017-02-11T14:29:04Z

February 11, 2017 2:29pm

Hello,

Can somebody exmplain what is up with the: public StringProperty timerTextProperty() { return mTimerText; }

Why is it needed? How exactly does it provide a relationship between controller and fxml?

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