awt eventqueue 0 nullpointerexception error

问题

Ok I'm getting this error awt eventqueue 0 nullpointerexception error. When I try to remove a JPanel.

Whats confusing me is when I remove another JPanel it works perfectly fine but this one it doesn't. The first Code below shows the JPanel that when I click on a JButton it doesn't remove the JPanel.

public class buttontime implements ActionListener { //creating actionlistener for clicking on timebutton to bring up a combobox

    public void actionPerformed(ActionEvent clickTime) {
        Price priceObject = new Price();
        priceObject.getPricepanel();
        remove(priceObject.getPricepanel());
        priceObject.getPricepanel().revalidate();

        add(timeObject.getTimePanel(), BorderLayout.EAST);
        timeObject.getTimePanel().revalidate();


    }
}

//This one gives me 0 errors.
public class buttonprice implements ActionListener { //creating actionlistener for clicking on timebutton to bring up a combobox

    public void actionPerformed(ActionEvent ClickPrice) {


        Price priceObject = new Price();
        priceObject.SelectPrice();
        remove(timeObject.getTimePanel());
        timeObject.getTimePanel().revalidate();

        add(priceObject.getPricepanel(), BorderLayout.EAST);
        priceObject.getPricepanel().revalidate();


    }
}

回答1:

remove(priceObject.getPricepanel());

If you are getting a NullPointerException only when removing this panel, priceObject.getPricepanel() must be returning null.

来源：https://stackoverflow.com/questions/15536790/awt-eventqueue-0-nullpointerexception-error