问题
I am developing a Java Swing-based application with different perspectives. For the "main menu" perspective I do not want the window (JFrame) to be decorated, while in other perspective I do want the window to be decorated. In other words, I need want to change the decoration attribute dynamically.
I have tried to use setUndecorated(false) and setUndecorated(true), but I seems I can only set this once, before actually showing the window.
Is there a way to achieve this?
回答1:
From the javadoc:
Disables or enables decorations for this frame. This method can only be called while the frame is not displayable.
Therefore, once the JFrame is packed and/or displayed, you can no longer change that value. If you want to change the undecorated state of a JFrame you will need to dispose() it first, then change the state and eventually make it visible again.
回答2:
After all, I had to take a different approach. The former solution did work, as I stated in my last comment. However, it was showing the default LAF window decoration, while I was using a different LAF. So the result was graphically inconsistent with the rest of the LAF. Finally, I came with the right solution, I used setUndecorate(true) for my frame. Then, when I had to change my perspective to one using decorations I simply had to use the following code
contentPane.getRootPane().setWindowDecorationStyle(JRootPane.FRAME);
And when I had to revert to the non decorate perspective, I use
contentPane.getRootPane().setWindowDecorationStyle(JRootPane.NONE);
This approach didn't need to dispose the window and show it again (which actually produced a brief but still visible hide/show of the window)
来源：https://stackoverflow.com/questions/17236324/dynamically-show-and-hide-jframe-decorations