[android]没什么比 instant run 更酷的东西了

发错节点了，应该发到 android 上的

https://www.youtube.com/watch?v=AefJXhCxrK8

发现效果很好，原来编译需要 30s 的项目现在 2s 就能搞定了。

现在存在的问题

Here are also some known issues that we are working on:

• Apps that are using legacy multi-dex (with minSdkVersion < 21), with a main dex file near the 65K method limit may not build. This would require reworking the app to make room in the main dex list by reducing the number of classes required in the main dex file.

• We have tested Instant Run on many devices, but it ’ s impossible to try it on every single device model. Please let us know if Instant Run doesn ’ t work on your device.
  We have seen some intermittent issues where the IDE loses connection with the app which will trigger a full rebuild.

• We have not yet tested this feature with 3rd party Gradle plugins, especially those that have not been updated to use the new transforms API. If you run into issues, please let us know.

• Data-binding is broken in this build; we will restore this shortly.

对我来说唯一不在生产项目上用的理由就是 data-binding 了，不过估计很快就能修复了。