Copy intellij-java-google-style.xml into the directory $HOME/Library/Preferences/IdeaIC14/codestyles/.

Export at home:
File > Export Settings > Select which settings you want to export

Import anywhere else:
File > Import Settings > Browse to the exported file

To change formatter options go to File | Settings | Code Style | Java

To reformat your code manually, press Ctrl + Alt + L (or using the menu Code | Reformat code...). To reformat the whole source code of your module, just select the module folder first.

More information about reformating source code can be found on the IntelliJ Web Help

You can download the development repo from Android source. The development/ide/intellij folder includes code style, templates...

I've done quite a lot of researches, but in the end, I haven't reached a very satisfying answer: probably it's just a code style for IntelliJ.

The first thing I did was trying to compare the IntelliJ style with something else, but I always found some differences.

It doesn't follow Google's style because they don't fully qualify import, in fact, IntelliJ will try to unify imports by putting *, like writing import foo.*; instead of import foo.Bar;.

It doesn't follow Oracle's guidelines either since the switch statement is formatted in a different way:

switch (condition) {
    case IDEA:
        statements;
        break;
case ORACLE:
    statements;
    break;
}

At this point, I've started looking for something else, but found even less. In fact, IntelliJ doesn't tell about the code style used in their software anywhere. Instead, they just explain how to change it.

Moreover, there are plugins for every possible code style! If one of them was the actual style in IDEA a plugin shouldn't be needed...

To make things worse, even for Kotlin, a language created by IntelliJ, they differentiate between "Kotlin Coding Conventions" and "IntelliJ IDEA default code style".

What I think is that they made a code style that works for most languages supported by their IDEs with little differences, and this is what Android Studio ended up using by default.

Try selecting the radio button "Whole Project" instead of the individual file under Code>Reformat

Additionally, you could right click the folder in the tree and choose Reformat from there.

There is a good description of code style rules here.

If you want to enforce this rules without remembering all of them, and you are using eclipse then you can use formatting rules provided by Android team: android-formatting.xml. Just import it into eclipse using Preferences->Java->Code Style->Formatter, click Import.

If any package is having more than N numbers of import of the same package in Android studio, it automatically converts it to * imports for that package (default are 5 for Top-level Symbols and 3 for Java Statics and Enum Members).

So, for example if you're having some N number of imports from package java.util, it gets converted to java.util.*.

Where to find that setting to change it?

1. Open Settings from File-> Settings in Android Studio (ctrl+alt+s).

2. Go to Editor -> Code Style -> Java/Kotlin and open imports tab then change that N number to any of your suitable case.

There are other options available as well.

Go to File -> Settings.

Then in dialog, Editor -> Code Style -> Java -> Wrapping and Braces tab, then you can adjust braces placement

Remember to "Apply" your changes.