GWT checking if textbox is empty

问题:

Im working on a school project and i'm trying to check in GWT if a textbox i create is empty or not. I have done the exact same thing on another project and there it worked fine. i have searched for the answer here and on google but couldn't find any answer.

voornaamTB = new TextBox();
voornaamTB.setText(null);

ok.addClickHandler(new ClickHandler() {
        public void onClick(ClickEvent event) {
            if (voornaamTB != null) {
                System.out.println("not empty");
            } else {
                System.out.println("empty");
            }
        }
    });

回答1:

Something like:

if(!voornaamTB.getText().isEmpty()) { ...

will work. You're currently testing to see whether the TextBox itself is null, which it isn't as you initialized it on the first line.

You probably don't need the setText(null) after immediately creating it.

回答2:

Your object is not empty, so you can get only not empty. try this

voornaamTB = new TextBox();
voornaamTB.setText(null);

ok.addClickHandler(new ClickHandler() {
        public void onClick(ClickEvent event) {
            if (voornaamTB.getText() != null) {
                System.out.println("not empty");
            } else {
                System.out.println("empty");
            }
        }
    });