问题:

I have a TextField in which there is some text but I want to change that text on some event but I am getting the NullPointerException.

I am using setText() method but still its not working. I am calling that function from other class .

Any Help?

Thanks in advance.

回答1:

At beginning of the controller's class definition:

@FXML private TextField txtDescription;

Within the initialize method, add:

txtDescription = new TextField();

Within a method that acts on that text field, something like:

txtDescription.setText("This is my new text.");

Make sure that you have a TextField definition in your .fxml file with the following:

 fx:id="myCoolTextField"

If you don't have that, init the text field in your display() method with the following:

myCoolTextField = new TextField();

You may also override the special initialize() method. This method is being called every time your scene updated.

@FXML
public void initialize() {
    myCoolTextField.setText("Here is my updated text.");
}