CODEWITHSUNDEEP
javaswingjoptionpane
mustangDC
mustangDC

Reputation: 967

JOptionPane window opens in background

I am developing a swing application, just a little query about JOptionPane.showMessageDialog() which is bugging me:

The question is: while implementing null as the first argument i get the message at the background of current parent frame whereas if i write this as the first argument the window comes over the parent frame. Why is this happenning?

Upvotes: 2

Views: 1451

Answers (2)

user1803551
user1803551

Reputation: 13427

In the method

showMessageDialog(Component parentComponent, Object message)

the first argument sets the parent of the dialog:

parentComponent

Defines the Component that is to be the parent of this dialog box. It is used in two ways: the Frame that contains it is used as the Frame parent for the dialog box, and its screen coordinates are used in the placement of the dialog box. In general, the dialog box is placed just below the component. This parameter may be null, in which case a default Frame is used as the parent, and the dialog will be centered on the screen (depending on the L&F).

I assume that the method appears inside a JFrame class, in which case passing this as the argument will set the parent component as that frame.

Upvotes: 1

Callum McKinnon-Snell
Callum McKinnon-Snell

Reputation: 57

The java keyword this is used (in this case) to refer to the current class - so you're referring to your parent window. See this link, It's pretty handy:

http://javapapers.com/core-java/explain-the-java-this-keyword/

Upvotes: 0

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