如何设置未装饰的JFrame的不透明度？

Question

I've been having trouble setting the opacity of a window that I would like to be able to fade in gradually. For now, I'm going to stick with just setting it mostly transparent and keeping it that way. I've been having trouble doing even that. The following code should remove the window decorations and make it mostly transparent. While the decorations are removed, the window still stays completely opaque.

Color transparent = new Color(((float) 1.0), ((float) 1.0), ((float) 1.0), ((float) 0.25));
colorPickerWindow.setUndecorated(true);
colorPickerWindow.setBackground(transparent);

Thanks in advance for you help!

Edit:

colorPickerWindow.setOpacity(0.5f);

gives me

 java.lang.UnsupportedOperationException: TRANSLUCENT translucency is not supported.  

Answer 1

colorPickerWindow.setOpacity(0.5f);

注意：setOpacity需要一个浮点数。

Answer 2

It seems that not all platforms supports setOpacity (according to http://docs.oracle.com/javase/tutorial/uiswing/misc/trans_shaped_windows.html ).

Perhaps this can help? http://www.rgagnon.com/javadetails/java-0265.html