Some time while build an android project will give the error like " Failed to resolve: com.android.support:appcompat-v7:23.4.0 " you can solve this error by following steps Click File in Android studio menu than goto Setting. In left of Setting menu you can find Build,Execution,Deployment -> Build Tools->Gradle Gradle Setting page find the check box offline work you can enable or disable the offline mode of android studio,if you always have internet connection better you can disable it, you want to work in work in offline you can enable it.
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