如何从其方法之外访问对象

Question

I have a problem that looks simple but I can't figure it out.

Here is a simplified version of my problem:

public void createContents() {
  Composite dataCalcComposite = new Composite(shell, SWT.NONE);
  dataCalcComposite.setBounds(0, 10, 279, 146);
}

public void repositionObjects() {
  dataCalcComposite.setLocation(50, 10)
}

This won't work because repositonObjects can't see the dataCalcComposite variable.

I know I could fix this by calling repostionObjects inside the first method and passing the variable in as a parameter but this is a very simplified version of my problem and the number of objects that need to be repositioned will be changing, so I don't think that method will work.

Also, I can't use static on the variable, my IDE says that only final will work with it.

So without being able to use static on the variable, how can I access it from another method?

Answer 1

You can move the declaration Composite dataCalcComposite; to be outside the method, so this variable will become an instance variable.

....
private Composite dataCalcComposite;

public void createContents() {
  dataCalcComposite = new Composite(shell, SWT.NONE);
  dataCalcComposite.setBounds(0, 10, 279, 146);
}

public void repositionObjects() {
  if (dataCalcComposite != null) {
      dataCalcComposite.setLocation(50, 10)
  }
}
....