How to fix NullPointerException in javafx-8


Question

JavaFX produces NullPointerexception while it's setting text to text field. This code produces this exception:

public void invalidate() {
    model.getLock().lock();
    try {
        memoryDisplayTextField.setText(model.getMemory() != 0 ? "M" : "");
        mainDisplayTextField.setText(model.getDisplayText());
    } finally {
        model.getLock().unlock();
    }
}

Stacktrace is below:

java.lang.NullPointerException
at com.sun.javafx.text.TextLayout.layout(TextLayout.java:1365)
at com.sun.javafx.text.TextLayout.ensureLayout(TextLayout.java:174)
at com.sun.javafx.text.TextLayout.getBounds(TextLayout.java:197)
at javafx.scene.text.Text.getLogicalBounds(Text.java:387)
at javafx.scene.text.Text.impl_computeGeomBounds(Text.java:1182)
at javafx.scene.Node.updateGeomBounds(Node.java:3322)
at javafx.scene.Node.getGeomBounds(Node.java:3275)
at javafx.scene.Node.getLocalBounds(Node.java:3257)
at javafx.scene.Node.updateTxBounds(Node.java:3335)
at javafx.scene.Node.getTransformedBounds(Node.java:3175)
at javafx.scene.Node.updateBounds(Node.java:504)
at javafx.scene.Parent.updateBounds(Parent.java:1643)
at javafx.scene.Parent.updateBounds(Parent.java:1643)
at javafx.scene.Parent.updateBounds(Parent.java:1643)
at javafx.scene.Parent.updateBounds(Parent.java:1643)
at javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:2268)
at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:352)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:511)
at com.sun.javafx.tk.quantum.QuantumToolkit$12.run(QuantumToolkit.java:379)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(Unknown Source)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$300(Unknown Source)
at com.sun.glass.ui.win.WinApplication$3$1.run(Unknown Source)
at java.lang.Thread.run(Thread.java:722)

Is there any workaround? Or I should wait until the release?

Thanks.

1
2
12/21/2014 9:13:52 PM

Accepted Answer

As I understand, problem was caused by calling setText methods out of JavaFX Application Thread, so wrapping it by Platform.runLater() solves this problem.

 public void invalidate() {
    Platform.runLater(() -> {
        model.getLock().lock();
        try {
            memoryDisplayTextField.setText(model.getMemory() != 0 ? "M" : "");
            mainDisplayTextField.setText(model.getDisplayText());
        } finally {
            model.getLock().unlock();
        }
    });
}

PS Thanks to jewelsea for help.

5
3/24/2013 1:16:44 AM

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