GWT vertical layout

I need a vertical layout, which would fill browser's viewport top to bottom, with on overflow (scrollbars). I need to layout widgets on the top, and on the bottom, and have one widget in the center which would stretch to fill the remaining space.

There seems to be DockLayoutPanel for this purpose, the problem with it is that it forces me to specify widget sizes, and I don't know the sizes of the top/bottom widgets before the browser does it's layouting job, which is tricky (buggy) to tra开发者_如何学Cck. I cannot find the right moment when to measure my widgets, and I don't want to do this kind of layouting code anyway.

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What about the body's onload event?

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onAttach is event fired by every widget when it is been added to its parent once any widget as been added then you can get the offset height and width.

extend panel class for top, central and bottom then when all these panels has been added to parent try to get width and height..