问题
I have set up my project's minSdkVersion as 15 and enabled Instant Run .
I have deployed the app in my device running on API 21
But the "Apply Changes" button is grayed out.When I hover over the button it says "No Active 'App' launch" although I am running the app in my device at that time .
回答1:
According to the guide, you also need to choose the debug build variant.
To start using Instant Run, you also need to change the build variant to a debug version of your app and deploy it to a target device running Android 5.0 (API level 21) or higher.
回答2:
By default, Instant Run is disable when you first install Android Studio. So you need to enable it by following this path :- File/Settings/Build, Execution, Deployment/InstantRun and checked the Enable InstantRun check box.
回答3:
click Run icon to run your project ,android the icon will be highlight.
来源：https://stackoverflow.com/questions/43976751/apply-changes-button-grayed-out-android-studio