Android – Usage of mipmap launcher icons before Android 4.2

Gradle cache is located at

• On Windows: %USERPROFILE%\.gradle\caches
• On Mac / UNIX: ~/.gradle/caches/

You can browse to these directory and manually delete it or run

rm -r $HOME/.gradle/caches/

on UNIX system. Run this command will also force to download dependencies.

UPDATE

Clear the Android build cache of current project

NOTE: Android Studio's File > Invalidate Caches / Restart doesn't clear the Android build cache, so you'll have to clean it separately.

On Windows:

gradlew cleanBuildCache

On Mac or UNIX:

./gradlew cleanBuildCache

UPDATE 2

This article Put your Android Studio on a diet gives more details on Android Studio caches

There are two distinct uses of mipmaps:

1. For launcher icons when building density specific APKs. Some developers build separate APKs for every density, to keep the APK size down. However some launchers (shipped with some devices, or available on the Play Store) use larger icon sizes than the standard 48dp. Launchers use getDrawableForDensity and scale down if needed, rather than up, so the icons are high quality. For example on an hdpi tablet the launcher might load the xhdpi icon. By placing your launcher icon in the mipmap-xhdpi directory, it will not be stripped the way a drawable-xhdpi directory is when building an APK for hdpi devices. If you're building a single APK for all devices, then this doesn't really matter as the launcher can access the drawable resources for the desired density.

2. The actual mipmap API from 4.3. I haven't used this and am not familiar with it. It's not used by the Android Open Source Project launchers and I'm not aware of any other launcher using.