Java Method Call Expected

Question

This is a java program with two buttons used to change an integer value and display it. However in IntelliJIDEA the two lines with

increase.addActionListene         


        

Answer 1

incListener and declListener are classes, not methods.

Try

increase.addActionListener(new incListener());

btw, rename your classes names to make them start with an uppercase

Answer 2

It's sad but I had to Google this same error... I was staring at a method that returned a class. I left off the new operator.

return <class>(<parameters>) vs return new <class>(<parameters>)

Answer 3

Whenever a string object is created using new operator a new object is created which is what your program is looking for. The following link is useful in learning about the difference between a string and a new string. What is the difference between "text" and new String("text")?

Answer 4

substitute the lines with

increase.addActionListener( new incListener());
decrease.addActionListener( new decListener());

Answer 5

It's simple: use new incListener() instead of incListener(). The later is trying to call a method named incListener, the former creates an object from the class incListener, which is what we want.

Answer 6

Make these changes:

 public Main() {
    contentPane = new JPanel();
    setContentPane(contentPane);
    setModal(true);

    increase = new JButton("inc");
    decrease = new JButton("dec");
    contentPane.add(increase);
    contentPane.add(decrease);
    increase.addActionListener(new incListener());
    decrease.addActionListener(new decListener());

    number = 50;
    label = new JLabel(number+"");
    contentPane.add(label);
}