Android Studio suddenly cannot resolve symbols

Question

Android Studio 0.4.2 was working fine and today I opened it and almost everything was red and the auto-completion had stopped working. I look at the imports and AS seems to

Answer 1

Android Studio 1.3

1. Open Module Settings
2. Click on your module under Modules menu
3. In the properties tab, set the Source Compatibility and Target Compatibility to your java version.

I did nothing else and it worked for me.