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ConstraintLayout alpha 8 is now available

posted Sep 13, 2016, 11:07 AM by Nicolas Roard   [ updated Sep 13, 2016, 11:14 AM ]
We've just released ConstraintLayout alpha 8, available in the SDK Manager (under the "Support Repository" section)

Note: due to API change, you might have to restart Android Studio 2.2 after upgrading to alpha 8 for layout preview to work.

This build has many changes from alpha 7:
  • Left-to-right bug fix (layout params were cached, preventing you to change them at runtime)
  • Performance improvements on first layout
  • New visibility behavior when dealing with View.GONE widgets -- now, gone widgets are completely removed (their connections margins are set to zero, their size is zero). But we added new attributes (app:layout_goneMarginTop/Bottom/Left/Right/Start/End) to specify different margin values for widgets connected to a GONE widget. This let you better adapt a layout when a widget is marked as gone, as you can apply different margin values depending if the widget you connect to is gone or not.
  • Ratio support was extended to work when both dimensions are set to MATCH_CONSTRAINT (0dp). This deal with the case when one dimension is constrained and you want to define the other dimension as a ratio.
  • New Programming API via a ConstraintSet class that let you create a set of constraints at runtime and apply it to a ConstraintLayout -- no need to manually set up LayoutParams.
  • And finally, documentation! you will be able to find it here:
As always, please try it, we want your feedback!