Android Asset Packaging Tool 2.0 (AAPT2) release notes

Version 2.16

aapt2 link ...

  • Versioning of XML files is more intelligent, using a small set of rules to degrade specific newer attributes to backwards compatible versions of them. Ex: android:paddingHorizontal degrades to android:paddingLeft and android:paddingRight.

Version 2.15

aapt2 compile ...

  • Add --no-crunch option to avoid processing PNGs during the compile phase. Note that this shouldn't be used as a performance optimization, as once the PNG is processed, its result is cached for incremental linking. This should only be used if the developer has specially pre-processed the PNG and wants it byte-for-byte identical to the input. NOTE: 9-patches will not be processed correctly with this flag set.

Version 2.14

aapt2 link ...

  • If an app is building with a minSdkVersion < 26 and a --package-id XX where XX > 7F, aapt2 will automatically convert any 'id' resource references from the resource ID 0xPPTTEEEE to 0x7FPPEEEE.
  • This is done to workaround a bug in previous versions of the platform that would validate a resource ID by assuming it is larger than 0. In Java, a resource ID with package ID greater than 0x7F is interpreted as a negative number, causing valid feature split IDs like 0x80010000 to fail the check.
  • '@id/foo' resources are just sentinel values and do not actually need to resolve to anything. Rewriting these resource IDs to use the package ID 7F while maintaining their definitions under the original package ID is safe. Collisions against the base APK are checked to ensure these rewritten IDs to not overlap with the base.

Version 2.13

aapt2 optimize ...

  • aapt2 optimize can now split a binary APK with the same --split parameters as the link phase.

Version 2.12

aapt2 optimize ...

  • aapt2 optimize now understands map (complex) values under the type id. It ignores their contents and interprets them as a sentinel id type. This was added to support existing apps that build with their id types as map values. AAPT and AAPT2 always generate a simple value for the type ID, so it is unclear how some these apps are encoded.

Version 2.11

aapt2 link ...

  • Adds the ability to specify assets directories with the -A parameter. Assets work just like assets in the original AAPT. It is not recommended to package assets with aapt2, however, since the resulting APK is post-processed by other tools anyways. Assets do not get processed by AAPT2, just copied, so incremental building gets slower if they are included early on.

Version 2.10

aapt2 link ...

  • Add ability to specify package ID to compile with for regular apps (not shared or static libs). This package ID is limited to the range 0x7f-0xff inclusive. Specified with the --package-id flag.
  • Fixed issue with resources being stripped for locales and other configuration.
  • Fixed issue with escaping strings in XML resources.

Version 2.9

aapt2 link ...

  • Added sparse resource type encoding, which encodes resource entries that are sparse with a binary search tree representation. Only available when minSdkVersion >= API O or resource qualifier of resource types is >= v26 (or whatever API level O becomes). Enabled with --enable-sparse-encoding flag.

aapt2 optimize ...

  • Adds an optimization pass that supports:
    • stripping out any density assets that do not match the --target-densities list of densities.
    • resource deduping when the resources are dominated and identical (already happens during link phase but this covers apps built with aapt).
    • new sparse resource type encoding with the --enable-sparse-encoding flag if possible (minSdkVersion >= O or resource qualifier >= v26).

Version 2.8

aapt2 link ...

  • Adds shared library support. Build a shared library with the --shared-lib flag. Build a client of a shared library by simply including it via -I.

Version 2.7

aapt2 compile ...

  • Fixes bug where psuedolocalization auto-translated strings marked 'translateable="false"'.

Version 2.6

aapt2

  • Support legacy configVarying resource type.
  • Support <bag> tag and treat as <style> regardless of type.
  • Add <feature-group> manifest tag verification.
  • Add <meta-data> tag support to <instrumentation>.

Version 2.5

aapt2 link ...

  • Transition XML versioning: Adds a new flag --no-version-transitions to disable automatic versioning of Transition XML resources.

Version 2.4

aapt2 link ...

  • Supports <meta-data> tags in <manifest>.

Version 2.3

aapt2

  • Support new font resource type.

Version 2.2

aapt2 compile ...

aapt link ...

  • Duplicate resource filtering: removes duplicate resources in dominated configurations that are always identical when selected at runtime. This can be disabled with --no-resource-deduping.

Version 2.1

aapt2 link ...

  • Configuration Split APK support: supports splitting resources that match a set of configurations to a separate APK which can be loaded alongside the base APK on API 21+ devices. This is done using the flag --split path/to/split.apk:<config1>[,<config2>,...].
  • SDK version resource filtering: Resources with an SDK version qualifier that is unreachable at runtime due to the minimum SDK level declared by the AndroidManifest.xml are stripped.

Version 2.0

aapt2 compile ...

  • Pseudo-localization: generates pseudolocalized versions of default strings when the --pseudo-localize option is specified.
  • Legacy mode: treats some class of errors as warnings in order to be more compatible with AAPT when --legacy is specified.
  • Compile directory: treats the input file as a directory when --dir is specified. This will emit a zip of compiled files, one for each file in the directory. The directory must follow the Android resource directory structure (res/values-[qualifiers]/file.ext).

aapt2 link ...

  • Automatic attribute versioning: adds version qualifiers to resources that use attributes introduced in a later SDK level. This can be disabled with --no-auto-version.
  • Min SDK resource filtering: removes resources that can't possibly be selected at runtime due to the application's minimum supported SDK level.