CODEWITHSUNDEEP
javaswingawt
Sam
Sam

Reputation: 1229

JCheckbox is not showing text in label when being selected

I have a JCheckbox and when clicking the checkbox I want to setText within a label.

So far I have the variables declared and the settings within the frame for the checkbox and the label: 

JCheckBox chckbxIncludeExt;
        JLabel lblNewLabel_1;


JCheckBox chckbxIncludeExt = new JCheckBox("Include ext");
chckbxIncludeExt.setForeground(UIManager.getColor("Button.background"));
chckbxIncludeExt.setBackground(UIManager.getColor("Button.darkShadow"));
chckbxIncludeExt.setBounds(0, 264, 113, 25);
panel.add(chckbxIncludeExt);

JLabel lblNewLabel_1 = new JLabel("");
        lblNewLabel_1.setBounds(12, 311, 230, 16);
        panel.add(lblNewLabel_1);

I have created a class and added an item listener to the checkbox: 

CheckboxStatus checkboxd = new CheckboxStatus();
        chckbxIncludeExt.addItemListener(checkboxd);

This is the class I have created:

private class CheckboxStatus implements ItemListener{
        public void itemStateChanged(ItemEvent event){

            if (chckbxIncludeExt.isSelected()){
                lblNewLabel_1.setText("You have selected the checkbox");
            }



        }
    }

This is giving me an error that shows: 

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at com.example.android.apis.appwidget.VFSTool$CheckboxStatus.itemStateChanged(VFSTool.java:199)
    at javax.swing.AbstractButton.fireItemStateChanged(Unknown Source)

The error is on line 199 where the label sets the text in line 199. When I check the box it shows this and does not show the text.

Upvotes: 0

Views: 648

Answers (1)

kiheru
kiheru

Reputation: 6618

You are shadowing the fields:

JCheckBox chckbxIncludeExt;
...
// and later:
JCheckBox chckbxIncludeExt = new JCheckBox("Include ext");

Change the later to just:

chckbxIncludeExt = new JCheckBox("Include ext");

You have the same problem with lblNewLabel_1

Upvotes: 3

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