Develop Reference

Retrofit2 not working when enabling Proguard

I have an application which uses retrofit to fetch logo form an API.
When i don't obfuscate and shrink my code, everything works fine. But when i enable it, the API call stops working. I don't get any crash or error messages, i just don't get any values from the API.
gradle
buildTypes {
debug{
// Enables code shrinking, obfuscation, and optimization for only
// your project's release build type.
minifyEnabled true
// Enables resource shrinking, which is performed by the
// Android Gradle plugin.
shrinkResources true
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
signingConfig signingConfigs.debug
}
release {
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
signingConfig signingConfigs.release
}
}
I used it in debug just for testing purposes. If i use it in release, it has same output.
I checked the retrofit page and they advised to use the following file
proguard-rules.pro
# Uncomment this to preserve the line number information for
# debugging stack traces.
-keepattributes SourceFile,LineNumberTable
# If you keep the line number information, uncomment this to
# hide the original source file name.
-renamesourcefileattribute SourceFile
-printusage usage.txt
-keep class com.th3pl4gu3.locky_offline.core.main.** {*;}
-keep class com.th3pl4gu3.locky_offline.repository.network.** {*;}
-keep class com.th3pl4gu3.locky_offline.repository.database.** {*;}
# Retrofit does reflection on generic parameters. InnerClasses is required to use Signature and
# EnclosingMethod is required to use InnerClasses.
-keepattributes Signature, InnerClasses, EnclosingMethod
# Retrofit does reflection on method and parameter annotations.
-keepattributes RuntimeVisibleAnnotations, RuntimeVisibleParameterAnnotations
# Retain service method parameters when optimizing.
-keepclassmembers,allowshrinking,allowobfuscation interface * {
#retrofit2.http.* <methods>;
}
# Ignore annotation used for build tooling.
-dontwarn org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement
# Ignore JSR 305 annotations for embedding nullability information.
-dontwarn javax.annotation.**
# Guarded by a NoClassDefFoundError try/catch and only used when on the classpath.
-dontwarn kotlin.Unit
# Top-level functions that can only be used by Kotlin.
-dontwarn retrofit2.KotlinExtensions
-dontwarn retrofit2.KotlinExtensions$*
# With R8 full mode, it sees no subtypes of Retrofit interfaces since they are created with a Proxy
# and replaces all potential values with null. Explicitly keeping the interfaces prevents this.
-if interface * { #retrofit2.http.* <methods>; }
-keep,allowobfuscation interface <1>
The API call still doesn't work. I tried many posts on stackoverflow but nothing works for me. Can someone help me by proposing a solution or an alternative to this ?
Thank you

Have you tried to put #SerializedName to Object field?
public class YourJsonClass{
#SerializedName("username")
String username;
}

Use progaurd rules from the official retrofit site
https://github.com/square/retrofit/blob/master/retrofit/src/main/resources/META-INF/proguard/retrofit2.pro
Sometimes issue seems to be from retrofit but it is not. It’s a GSON and ProGuard problem. To fix it you just have to add a -keep class configuration in your proguard rules of the package where your Pojo class is stored For example my API response and request classes are stored like this (package name may differ according to your app):
-keep class com.sample.myapp.model.request. { ; }
-keep class com.sample.myapp.model.model.response.* { ; }*

Android app crashes in Release but not in Debug NullPointerException

I recently changed 2 lines of code as a workaround due to changes to the data being returned from an API I'm using. Now the app is crashing when using the release apk and aab. However, when I'm using the app through the Android Emulator on API 27 and connecting an API 27 device to my computer running the debug apk, the app works flawlessly.
I'm really stumped on this problem, and do not understand the error messages at all.
FATAL EXCEPTION: main
Process: com.guy.aqi, PID: 8328
java.lang.NullPointerException: throw with null exception
at com.guy.aqi.n.a(Unknown Source:3)
at com.guy.aqi.m.b(CurrentAirQualityFragment.java:8)
at com.guy.aqi.m.b(CurrentAirQualityFragment.java:6)
at com.guy.aqi.d.a(Unknown Source:4)
at b.a.a.a.m.c(StringRequest.java:4)
at b.a.a.a.m.a(StringRequest.java:1)
at b.a.a.h$a.run(ExecutorDelivery.java:4)
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
My API stopped sending the "main pollutant" String, so I changed this line:
textViewMainPollutantUS.setText("U.S. Main Pollutant: " decodePollutant(mainPollutantUS));
to
textViewMainPollutantUS.setText("");
and this line:
textViewMainPollutantCN.setText("China Main Pollutant: " decodePollutant(mainPollutantCN));
to
textViewMainPollutantCN.setText("");
I expected changing these lines would fix the issue. But now the issue seems to be fixed in debug version of the app, but not the release version.
proguard-rules.pro
# Add project specific ProGuard rules here.
# You can control the set of applied configuration files using the
# proguardFiles setting in build.gradle.
#
# For more details, see
# http://developer.android.com/guide/developing/tools/proguard.html
# If your project uses WebView with JS, uncomment the following
# and specify the fully qualified class name to the JavaScript interface
# class:
#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
# public *;
#}
# Uncomment this to preserve the line number information for
# debugging stack traces.
#-keepattributes SourceFile,LineNumberTable
# If you keep the line number information, uncomment this to
# hide the original source file name.
#-renamesourcefileattribute SourceFile
# JSR 305 annotations are for embedding nullability information.
-dontwarn javax.annotation.**
# A resource is loaded with a relative path so the package of this class must be preserved.
-keepnames class okhttp3.internal.publicsuffix.PublicSuffixDatabase
# Animal Sniffer compileOnly dependency to ensure APIs are compatible with older versions of Java.
-dontwarn org.codehaus.mojo.animal_sniffer.*
# OkHttp platform used only on JVM and when Conscrypt dependency is available.
-dontwarn okhttp3.internal.platform.ConscryptPlatform
# Prevent Proguard from inlining methods that are intentionally extracted to ensure locals have a
# constrained liveness scope by the GC. This is needed to avoid keeping previous request references
# alive for an indeterminate amount of time. See also https://github.com/google/volley/issues/114
-keepclassmembers,allowshrinking,allowobfuscation class com.android.volley.NetworkDispatcher {
void processRequest();
}
-keepclassmembers,allowshrinking,allowobfuscation class com.android.volley.CacheDispatcher {
void processRequest();
}
##---------------Begin: proguard configuration for Gson ----------
# Gson uses generic type information stored in a class file when working with fields. Proguard
# removes such information by default, so configure it to keep all of it.
-keepattributes Signature
# For using GSON #Expose annotation
-keepattributes *Annotation*
# Gson specific classes
-dontwarn sun.misc.**
#-keep class com.google.gson.stream.** { *; }
# Application classes that will be serialized/deserialized over Gson
-keep class com.google.gson.examples.android.model.** { *; }
# Prevent proguard from stripping interface information from TypeAdapterFactory,
# JsonSerializer, JsonDeserializer instances (so they can be used in #JsonAdapter)
-keep class * implements com.google.gson.TypeAdapterFactory
-keep class * implements com.google.gson.JsonSerializer
-keep class * implements com.google.gson.JsonDeserializer
##---------------End: proguard configuration for Gson ----------
-keep class com.crashlytics.** { *; }
-keepattributes SourceFile,LineNumberTable

For me, adding lines (you may have other name for package where you put your POJO files):
-keep class [mypackagename].model.** { *; }
-keep class [mypackagename].datamodel.** { *; }
to proguard.rules worked perfectly, then options:
android
{
...
buildTypes {
release {
minifyEnabled true
shrinkResources true
}
}
}
are set in build.gradle (Module: app)

Edit:-
Replace this
minifyEnabled true
to
minifyEnabled false

Why is Proguard not obfuscating my code?

When I build a release build of the app Proguard runs, but on looking at the APK using APK Analyzer everything is readable with apparently no obfuscation being applied.
My intent is to apply obfuscation to the APK to make reverse engineering a little more difficult.
Gradle:
buildTypes {
release {
signingConfig signingConfigs.release
minifyEnabled true
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
Proguard is definitely running as I can see that in the Gradle console.
proguard-rules.pro:
-dontshrink
-dontoptimize
-keep class com.squareup.picasso.** { *; }
-dontwarn com.squareup.picasso.**
-keep class com.squareup.okhttp.** { *; }
-dontwarn com.squareup.okhttp.**
-keep class kotlin.reflect.** { *; }
-dontwarn kotlin.reflect.**
-keep class javax.annotation.** { *; }
-dontwarn javax.annotation.**
-keep class org.codehaus.mojo.** { *; }
-dontwarn org.codehaus.mojo.**
The Proguard docs say obfuscation runs by default. The docs also say classes specified in keep statements will not be obfuscated, but the classes in the app itself are not specified in keep statements, but are still not obfuscated.
On looking further, there is a file in the build folder called aapt_rules.txt that contains what look like keep statements for every class in the app. I don't understand why that would be.
How do I reconfigure Proguard so it obfuscates all of the code in my app (not the libraries), without shrinking or removing any classes?

by looking at line keep class com.squareup.picasso.** { *; }and -keep class com.squareup.okhttp.** { *; } ,
you are not obfuscating anything which are part of above packages or sub packages.
Progaurd will obfuscate anything which is not part of above package and sub package.
do you have class outside of these packages.

Runtime issues while using Proguard to minify

My app is completely ready to deploy and its using many libraries. I want to minify the code using Proguard and also want to remove unused classes and resources but while using proguard I am getting Runtime error
java.lang.RuntimeException: Unable to create application com.rig.onblick.App: java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.hashCode()' on a null object reference
I gone through many tutorial but its seems too complicated to write proguard configuration because I have to write many rules to make sure my app will run perfectly. I have never used proguard in this kind of big project. Can anyone tell me the minimal configuration which make sure at least my code will be minified and will not get any runtime error.
My present configuration is as below.
-dontwarn com.witt.mspapp.**
-keep class com.github.mikephil.** { *; }
-dontwarn com.github.mikephil.**
-keep class com.github.mikephil.** { *; }
-dontwarn org.apache.**
-keep class com.google.gms.** { *; }
-dontwarn com.google.gms.**
-keep class com.viewpagerindicator.** { *; }
-dontwarn com.viewpagerindicator.**
-keep class org.jivesoftware.smackx.** { *; }
-dontwarn org.jivesoftware.smackx.**
I am testing in debug env. and my gradle configuration is as below
debug {
minifyEnabled true
shrinkResources true
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}

There is nothing "minimal configuration" for proguard configuration. You will get the proguard configuration for each library on his official repo page. So whatever dependencies you have used go through these and add proguard configuration for each of that dependency.

Getting warnings and errors after enabling proguard

I enabled proguard for my release build and when I ran the project, I get these warnings and errors. Here is my buildTypes block:
buildTypes {
release {
minifyEnabled true
//shrinkResources true
signingConfig signingConfigs.myConfig
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
The build message was too long to post here so have put external link.
What is the reason for these warnings? Is there something I have done wrong? How can I fix this?

for any external library that you are using you need to add rules in your proguard.pro file.
For example in my project these are the proguard rules I added for retrofit and okhttp
# Retrofit 1.X
-keep class com.squareup.okhttp.** { *; }
-keep class retrofit.** { *; }
-keep interface com.squareup.okhttp.** { *; }
-dontwarn com.squareup.okhttp.**
-dontwarn okio.**
-dontwarn retrofit.**
-dontwarn rx.**
-keepclasseswithmembers class * {
#retrofit.http.* <methods>;
}
These rules are taken from
https://github.com/krschultz/android-proguard-snippets/blob/master/libraries/proguard-square-retrofit.pro
So you need to check similarly for each library what are the rules to be added.

Each library mentioned in the warnings has its' own proguard rules which you have to put in your proguard-rules.pro. For example you can find ButterKnife's rules at http://jakewharton.github.io/butterknife/ "Proguard" section.