Proguard errors while generating signed APK

Question

I have minifyEnabled set to true in my build.gradle file. I get a lot of errors while generating a signed APK for my app:

Warning:com.dropbox.core.http.OkHttp3Requestor$AsyncCallback: can't find superclass or interface okhttp3.Callback
Warning:com.dropbox.core.http.OkHttp3Requestor$PipedRequestBody: can't find superclass or interface okhttp3.RequestBody
Warning:com.dropbox.core.http.OkHttpRequestor$AsyncCallback: can't find superclass or interface com.squareup.okhttp.Callback
Warning:com.dropbox.core.http.OkHttpRequestor$PipedRequestBody: can't find superclass or interface com.squareup.okhttp.RequestBody
Warning:com.dropbox.core.DbxStandardSessionStore: can't find referenced class javax.servlet.http.HttpSession
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.URLFetchServiceFactory
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPMethod
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.URLFetchService
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPMethod
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPRequest
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPHeader
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPRequest
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.FetchOptions$Builder
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.FetchOptions
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPResponse
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPHeader
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPResponse
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.FetchOptions
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.URLFetchService
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPRequest
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPHeader
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.URLFetchServiceFactory
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPMethod
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.URLFetchService
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.FetchOptions$Builder
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.FetchOptions
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPResponse
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.URLFetchService
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.FetchOptions
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.URLFetchService
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.FetchOptions
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.URLFetchService
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.FetchOptions
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.URLFetchService
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPRequest
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPResponse
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPRequest
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPMethod
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPRequest
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPMethod
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPRequest
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPMethod
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPRequest
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.FetchOptions
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPResponse
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPHeader
Warning:com.dropbox.core.http.GoogleAppEngineRequestor: can't find referenced class com.google.appengine.api.urlfetch.HTTPResponse
Warning:com.dropbox.core.http.GoogleAppEngineRequestor$FetchServiceUploader: can't find referenced class com.google.appengine.api.urlfetch.HTTPRequest
Warning:com.dropbox.core.http.GoogleAppEngineRequestor$FetchServiceUploader: can't find referenced class com.google.appengine.api.urlfetch.URLFetchService
Warning:com.dropbox.core.http.GoogleAppEngineRequestor$FetchServiceUploader: can't find referenced class com.google.appengine.api.urlfetch.HTTPRequest
Warning:com.dropbox.core.http.GoogleAppEngineRequestor$FetchServiceUploader: can't find referenced class com.google.appengine.api.urlfetch.URLFetchService
Warning:com.dropbox.core.http.GoogleAppEngineRequestor$FetchServiceUploader: can't find referenced class com.google.appengine.api.urlfetch.HTTPRequest
Warning:com.dropbox.core.http.GoogleAppEngineRequestor$FetchServiceUploader: can't find referenced class com.google.appengine.api.urlfetch.URLFetchService
Warning:com.dropbox.core.http.GoogleAppEngineRequestor$FetchServiceUploader: can't find referenced class com.google.appengine.api.urlfetch.HTTPRequest
Warning:com.dropbox.core.http.GoogleAppEngineRequestor$FetchServiceUploader: can't find referenced class com.google.appengine.api.urlfetch.URLFetchService
Warning:com.dropbox.core.http.GoogleAppEngineRequestor$FetchServiceUploader: can't find referenced class com.google.appengine.api.urlfetch.HTTPRequest
Warning:com.dropbox.core.http.GoogleAppEngineRequestor$FetchServiceUploader: can't find referenced class com.google.appengine.api.urlfetch.HTTPResponse
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.OkHttpClient$Builder
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.OkHttpClient
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.Dispatcher
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.Request$Builder
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.OkHttpClient
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.Call
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.Response
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.ResponseBody
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.Request$Builder
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.Headers
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.OkHttpClient
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.Dispatcher
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.Request
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.Call
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.Response
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.ResponseBody
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.Headers
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.OkHttpClient
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.Request$Builder
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.Response
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.Request$Builder
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.Response
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.Request$Builder
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.Headers
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.OkHttpClient
Warning:com.dropbox.core.http.OkHttp3Requestor: can't find referenced class okhttp3.Headers
Warning:com.dropbox.core.http.OkHttp3Requestor$AsyncCallback: can't find referenced class okhttp3.Callback
Warning:com.dropbox.core.http.OkHttp3Requestor$AsyncCallback: can't find referenced class okhttp3.Response
Warning:com.dropbox.core.http.OkHttp3Requestor$AsyncCallback: can't find referenced class okhttp3.Call
Warning:com.dropbox.core.http.OkHttp3Requestor$AsyncCallback: can't find referenced class okhttp3.Response
Warning:com.dropbox.core.http.OkHttp3Requestor$AsyncCallback: can't find referenced class okhttp3.Call
Warning:com.dropbox.core.http.OkHttp3Requestor$AsyncCallback: can't find referenced class okhttp3.Response
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.Request$Builder
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.OkHttpClient
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.Call
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.Request$Builder
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.RequestBody
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.Call
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.Response
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.ResponseBody
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.Request$Builder
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.Response
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.OkHttpClient
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.Call
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.RequestBody
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.Response
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.ResponseBody
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.Request
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.Request$Builder
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.RequestBody
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.Call
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.Request$Builder
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.RequestBody
Warning:com.dropbox.core.http.OkHttp3Requestor$BufferedUploader: can't find referenced class okhttp3.Response
Warning:com.dropbox.core.http.OkHttp3Requestor$PipedRequestBody: can't find referenced class okhttp3.RequestBody
Warning:com.dropbox.core.http.OkHttp3Requestor$PipedRequestBody: can't find referenced class okhttp3.MediaType
Warning:com.dropbox.core.http.OkHttp3Requestor$PipedRequestBody: can't find referenced class okio.BufferedSink
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.OkHttpClient
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.Dispatcher
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.OkHttpClient
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.Request$Builder
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.OkHttpClient
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.Call
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.Response
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.ResponseBody
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.Request$Builder
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.Headers
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.OkHttpClient
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.Dispatcher
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.Request
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.Call
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.Response
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.ResponseBody
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.Headers
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.OkHttpClient
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.Request$Builder
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.Response
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.Request$Builder
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.Response
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.Request$Builder
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.Headers
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.OkHttpClient
Warning:com.dropbox.core.http.OkHttpRequestor: can't find referenced class com.squareup.okhttp.Headers
Warning:com.dropbox.core.http.OkHttpRequestor$AsyncCallback: can't find referenced class com.squareup.okhttp.Callback
Warning:com.dropbox.core.http.OkHttpRequestor$AsyncCallback: can't find referenced class com.squareup.okhttp.Response
Warning:com.dropbox.core.http.OkHttpRequestor$AsyncCallback: can't find referenced class com.squareup.okhttp.Request
Warning:com.dropbox.core.http.OkHttpRequestor$AsyncCallback: can't find referenced class com.squareup.okhttp.Response
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.Request$Builder
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.OkHttpClient
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.Call
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.Request$Builder
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.RequestBody
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.Call
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.Response
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.ResponseBody
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.Request$Builder
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.Response
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.OkHttpClient
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.Call
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.RequestBody
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.Response
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.ResponseBody
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.Request
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.Request$Builder
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.RequestBody
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.Call
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.Request$Builder
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.RequestBody
Warning:com.dropbox.core.http.OkHttpRequestor$BufferedUploader: can't find referenced class com.squareup.okhttp.Response
Warning:com.dropbox.core.http.OkHttpRequestor$PipedRequestBody: can't find referenced class com.squareup.okhttp.RequestBody
Warning:com.dropbox.core.http.OkHttpRequestor$PipedRequestBody: can't find referenced class com.squareup.okhttp.MediaType
Warning:com.dropbox.core.http.OkHttpRequestor$PipedRequestBody: can't find referenced class okio.BufferedSink
Warning:com.dropbox.core.http.OkHttpUtil$PipedStream: can't find referenced class okio.Okio
Warning:com.dropbox.core.http.OkHttpUtil$PipedStream: can't find referenced class okio.BufferedSink
Warning:com.dropbox.core.http.OkHttpUtil$PipedStream: can't find referenced class okio.Okio
Warning:com.dropbox.core.http.OkHttpUtil$PipedStream: can't find referenced class okio.BufferedSink
Warning:com.google.common.cache.Striped64: can't find referenced class sun.misc.Unsafe
Warning:com.google.common.cache.Striped64$1: can't find referenced class sun.misc.Unsafe
Warning:com.google.common.cache.Striped64$Cell: can't find referenced class sun.misc.Unsafe
Warning:com.google.common.primitives.UnsignedBytes$LexicographicalComparatorHolder$UnsafeComparator: can't find referenced class sun.misc.Unsafe
Warning:com.google.common.primitives.UnsignedBytes$LexicographicalComparatorHolder$UnsafeComparator$1: can't find referenced class sun.misc.Unsafe
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.OkHttpClient
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Cache
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.OkHttpClient
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.CacheControl
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.CacheControl$Builder
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Request$Builder
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.OkHttpClient
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Call
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Response
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.ResponseBody
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Response
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.ResponseBody
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.OkHttpClient
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Cache
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.CacheControl
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.CacheControl$Builder
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Request$Builder
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Response
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Cache
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.CacheControl
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Request
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Call
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Response
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.ResponseBody
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.OkHttpClient
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.CacheControl$Builder
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.CacheControl
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Request$Builder
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Response
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.ResponseBody
Warning:com.squareup.picasso.OkHttpDownloader: can't find referenced class com.squareup.okhttp.Cache
Warning:there were 355 unresolved references to classes or interfaces.
Warning:Exception while processing task java.io.IOException: Please correct the above warnings first.
Error:Execution failed for task ':app:transformClassesAndResourcesWithProguardForRelease'.
> java.io.IOException: Please correct the above warnings first.

So i added these lines in the progard-rules.pro file:

-keep com.dropbox.** {*;}
-keep com.google.common.** {*;}
-keep com.square.picasso.** {*;}

But then, i get this error:

Warning:Exception while processing task java.io.IOException: proguard.ParseException: Unexpected keyword 'com.dropbox.**' in line 18 of file '/home/AndroidProjects/Poolex/app/proguard-rules.pro'
Error:Execution failed for task ':app:transformClassesAndResourcesWithProguardForRelease'.
> java.io.IOException: proguard.ParseException: Unexpected keyword 'com.dropbox.**' in line 18 of file '/home/AndroidProjects/Poolex/app/proguard-rules.pro'

How do i solve this?

Answer 1

If you want, you can ignore all errors from proguard and try if the app works. I use this
-dontwarn **
to ignore all errors. If it doesn't work, try with:
-keep **
And if you want to do it with only one, use like
-keep class com.dropbox.**
or
-ignore com.dropbox.**

Answer 2

Add to proguard-rules.pro this:

-dontwarn okio.**
-dontwarn okhttp3.**
-dontwarn com.squareup.okhttp.**
-dontwarn com.google.appengine.**
-dontwarn javax.servlet.**
# Support classes for compatibility with older API versions
-dontwarn android.support.**
-dontnote android.support.**

Make sure in build.gradle(Module:app) you got:

proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'

within the android > buildTypes > release block.

Answer 3

Try this:

-keep class com.dropbox.** {*;}
-keep class com.google.common.** {*;}
-keep class com.square.picasso.** {*;}