Why does assembleDebug takes much longer then project build and how to optimize it?

Question

I've been dealing with gradle build time in Android Studio recently. I've managed to decrease the build time from about 3 mins to 10 seconds by removing some dependencies, but here's the thing:

When I rebuild project it takes about 10 seconds:

15:13:43 Executing tasks: [clean, :app:generateDebugSources, :app:generateDebugAndroidTestSources, :app:compileDebugSources, :app:compileDebugAndroidTestSources]
15:13:54 Gradle build finished in 11s 596ms

However when I launch the app, it takes a lot longer, about a minute:

15:15:09 Executing tasks: [:app:assembleDebug]
15:15:58 Gradle build finished in 49s 676ms

What is the cause of such big difference? Is this still because of the large amount of gradle dependencies or something else? Can I reduce the build time somehow?

score 22 · Accepted Answer · edited Oct 29 '20 at 11:57

22

Why:

Recently I enabled multidex in my app because I had over 65k methods. Dexing is what was taking a lot of time to complete.

How to speed up build:

Go to Settings (Ctrl + alt + s) -> Build, Execution, Deployment -> Compiler

Enabling compiling modules in parallel and adding --offline in compiler has decreased my execution time to about 15 seconds.

edited Oct 29 '20 at 11:57

MendelG

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answered Mar 05 '16 at 10:43

Oleg Filimonov

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This was amazing, my execution time decreased about 7 minutes. Thank you very much. – Rahmat Waisi May 06 '18 at 08:35
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How to do that in Visual Studio Code? – rubStackOverflow Jul 27 '19 at 23:16
Is there a command-line option for the first one, i.e for a parallel build? – Phani Rithvij Oct 31 '19 at 13:57
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This worked great for a few minutes, then it kept complaining this gradle version is not available for caching for offline use. I had to finally leave it alone – Phani Rithvij Oct 31 '19 at 18:26

Why does assembleDebug takes much longer then project build and how to optimize it?

1 Answers1

Why:

How to speed up build:

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