• ConstraintLayout: version 1.0.0-alpha2
  • Fixed guidelines crash on device
  • Fixed typo in attribute name (leftToLeft)
  • Changed orientation attribute namespace from app to android to fix a conflict with GridLayout
  • ConstraintLayout now works properly inside ScrollView
  • ConstraintLayout now works properly inside RecyclerView
  • Percentage positioning of guidelines is now parsed as an integer instead of a dimension
  • Better behavior for match_parent on the device. The behavior is now the same as 0dp (the widget stretches according to its constraints)
• Layout Editor
  • Fixed bug which sometimes turned fonts blue in other editors (.xml, .java)
  • Fewer generated XML attributes
  • Better behavior for match_parent in the editor
  • Fixed widgets resizing during drag
  • Improved guidelines representation in the editor
  • Improved auto conversion to ConstraintLayout
  • Improved edition of nested layouts
  • Various bug fixes and improvements in the editor
• Fixed bug preventing the IDE from starting on some Linux distributions (in particular where /bin/sh is not bash)
• Export Signed APK wizard was exporting to the wrong folder (issue 210520)
• Fixed bug in welcome screen which meant some users couldn't create new projects
• Fixed embedded JDK handling
• Fixed a bug bugs in the native/hybrid debugger
• Disabled a couple of Groovy inspections that reported incorrect errors in build.gradle files
• Fixed an instant run bug which for some users resulted in every run turning into a full build
• Fixed a couple of crashes in lint (in the new Gradle plugin, 2.2 alpha 2)

• A bunch of improvements to the accessibility support

下载地址：https://sites.google.com/a/android.com/tools/download/studio/builds/2-2-preview-2