Currently, I'm having experience that, a piece of code, which makes use of Google Drive API is running fine without introducing ProGuard.

目前，我的经验是，一段利用Google Drive API的代码在没有引入ProGuard的情况下运行得很好。

However, after introducing ProGuard, I'm getting the following run-time error.

然而，在引入ProGuard之后，我得到了以下运行时错误。

    at java.lang.Thread.run(Thread.java:856)
Caused by: java.lang.NullPointerException
    at com.google.api.client.util.Types.getActualParameterAtPosition(Types.java:329)
    at com.google.api.client.util.Types.getIterableParameter(Types.java:309)
    at com.google.api.client.json.JsonParser.parseValue(JsonParser.java:546)
    at com.google.api.client.json.JsonParser.parse(JsonParser.java:350)
    at com.google.api.client.json.JsonParser.parseValue(JsonParser.java:586)
    at com.google.api.client.json.JsonParser.parse(JsonParser.java:289)
    at com.google.api.client.json.JsonObjectParser.parseAndClose(JsonObjectParser.java:76)
    at com.google.api.client.json.JsonObjectParser.parseAndClose(JsonObjectParser.java:71)
    at com.google.api.client.http.HttpResponse.parseAs(HttpResponse.java:491)
    at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.execute(AbstractGoogleClientRequest.java:456)
    at com.jstock.c.b.a(CloudFile.java:136)

Note, the crash happens at my code (which is com.jstock.c.b.a if I retrace using mapping.txt)

请注意，崩溃发生在我的代码（如果使用mapping.txt进行回溯，则为com.jstock.c.b.a）

// request is Files.List
FileList files = request.execute();

In my proguard, I thought having the following 2 key instructions, able to prevent the crash from happen : I tell ProGuard never touch on jackson and Google libraries.

在我的ProGuard中，我认为有以下两个关键说明，能够防止崩溃的发生：我告诉ProGuard永远不要接触杰克逊和谷歌的库。

-keep class org.codehaus.** { *; }
-keep class com.google.** { *; }
-keep interface org.codehaus.** { *; }
-keep interface com.google.** { *; }

But that doesn't work. NPE still happen at Types.java

但这并不管用。NPE仍在Types.java中发生

Note that, I had another try is that, I thought obfuscate process causes NPE happens. Hence, I try to disable it using -dontobfuscate. But this time, I will not able to generate APK file, and getting a popular error message : Conversion to Dalvik format failed with error 1

请注意，我有另一个尝试是，我认为混淆过程导致NPE发生。因此，我尝试使用-dontobfuscate禁用它。但这一次，我将无法生成APK文件，并收到一条常见的错误消息：转换为Dalvik格式失败，错误为1

Here is the proguard configuration which causes NPE at Google Drive API.

以下是在Google Drive API上导致NPE的proGuard配置。

-optimizationpasses 1
-dontusemixedcaseclassnames
-dontskipnonpubliclibraryclasses
-dontpreverify
-verbose
-optimizations !code/simplification/arithmetic,!field/*,!class/merging/*

# Comment out the following line, will cause popular "Conversion to Dalvik format failed with error 1"
##-dontobfuscate

-dontwarn sun.misc.Unsafe
-dontwarn com.google.common.collect.MinMaxPriorityQueue
-dontwarn javax.swing.**
-dontwarn java.awt.**
-dontwarn org.jasypt.encryption.pbe.**
-dontwarn java.beans.**
-dontwarn org.joda.time.**
-dontwarn com.google.android.gms.**
-dontwarn org.w3c.dom.bootstrap.**
-dontwarn com.ibm.icu.text.**
-dontwarn demo.**

# Hold onto the mapping.text file, it can be used to unobfuscate stack traces in the developer console using the retrace tool
-printmapping mapping.txt

# Keep line numbers so they appear in the stack trace of the develeper console 
-keepattributes *Annotation*,EnclosingMethod,SourceFile,LineNumberTable

-keep public class * extends android.app.Activity
-keep public class * extends android.app.Application
-keep public class * extends android.app.Service
-keep public class * extends android.content.BroadcastReceiver
-keep public class * extends android.content.ContentProvider
-keep public class * extends android.app.backup.BackupAgentHelper
-keep public class * extends android.preference.Preference
-keep public class com.android.vending.licensing.ILicensingService

-keep class android.support.v4.app.** { *; }
-keep interface android.support.v4.app.** { *; }
-keep class com.actionbarsherlock.** { *; }
-keep interface com.actionbarsherlock.** { *; }

# https://sourceforge.net/p/proguard/discussion/182456/thread/e4d73acf
-keep class org.codehaus.** { *; }
-keep class com.google.** { *; }
-keep interface org.codehaus.** { *; }
-keep interface com.google.** { *; }

-assumenosideeffects class android.util.Log {
  public static int d(...);
  public static int i(...);
  public static int e(...);
  public static int v(...);  
}

-keepclasseswithmembernames class * {
    native <methods>;
}

-keepclasseswithmembers class * {
    public <init>(android.content.Context, android.util.AttributeSet);
}

-keepclasseswithmembers class * {
    public <init>(android.content.Context, android.util.AttributeSet, int);
}

-keepclassmembers class * extends android.app.Activity {
   public void *(android.view.View);
}

-keepclassmembers enum * {
    public static **[] values();
    public static ** valueOf(java.lang.String);
}

-keep class * implements android.os.Parcelable {
  public static final android.os.Parcelable$Creator *;
}

-assumenosideeffects class android.util.Log {
    public static *** d(...);
    public static *** v(...);
    public static *** i(...);
}

-keepclasseswithmembers class com.google.common.base.internal.Finalizer{
    <methods>;
}

Is there anything else I can try?

还有什么我可以试一试的吗？

I'm not sure it might be caused by the combination of the libraries. (Although things run pretty well without introducing ProGuard)

我不确定这可能是由图书馆的组合造成的。(尽管在没有引入ProGuard的情况下，事情运行得很好)

If I look at the NPE crash location (Types.getActualParameterAtPosition(Types.java:329))

如果我看一看核反应堆坠毁地点(Types.getActualParameterAtPosition(Types.java:329))

private static Type getActualParameterAtPosition(Type type, Class<?> superClass, int position) {
    ParameterizedType parameterizedType = Types.getSuperParameterizedType(type, superClass);
    Type valueType = parameterizedType.getActualTypeArguments()[position];
    // this is normally a type variable, except in the case where the class of iterableType is
    // superClass, e.g. Iterable<String>
    if (valueType instanceof TypeVariable<?>) {
      Type resolve = Types.resolveTypeVariable(Arrays.asList(type), (TypeVariable<?>) valueType);
      if (resolve != null) {
        return resolve;
      }
    }
    return valueType;
}

I suspect Types.getSuperParameterizedType returning null. So, I further look into Types.getSuperParameterizedType.

我怀疑Types.getSuperParamizedType返回空值。因此，我进一步研究了Types.getSuperPareterizedType。

public static ParameterizedType getSuperParameterizedType(Type type, Class<?> superClass) {
    if (type instanceof Class<?> || type instanceof ParameterizedType) {
    outer: while (type != null && type != Object.class) {
     Class<?> rawType;
     if (type instanceof Class<?>) {
       // type is a class
       rawType = (Class<?>) type;
     } else {
       // current is a parameterized type
       ParameterizedType parameterizedType = (ParameterizedType) type;
       rawType = getRawClass(parameterizedType);
       // check if found Collection
       if (rawType == superClass) {
         // return the actual collection parameter
         return parameterizedType;
       }
       if (superClass.isInterface()) {
         for (Type interfaceType : rawType.getGenericInterfaces()) {
           // interface type is class or parameterized type
           Class<?> interfaceClass =
               interfaceType instanceof Class<?> ? (Class<?>) interfaceType : getRawClass(
                   (ParameterizedType) interfaceType);
           if (superClass.isAssignableFrom(interfaceClass)) {
             type = interfaceType;
             continue outer;
           }
         }
       }
     }
     // move on to the super class
     type = rawType.getGenericSuperclass();
    }
    }
    return null;
}

What is the possible root cause that may cause getSuperParameterizedType returning null, after processed by ProGuard?

可能的根本原因是什么导致在ProGuard处理后，getSuperPareterizedType返回NULL？

优秀答案推荐

A combination of the following has worked for me:

以下几点对我来说很管用：

-keep class com.google.** { *;}
-keep interface com.google.** { *;}
-dontwarn com.google.**

-dontwarn sun.misc.Unsafe
-dontwarn com.google.common.collect.MinMaxPriorityQueue
-keepattributes *Annotation*,Signature
-keep class * extends com.google.api.client.json.GenericJson {
*;
}
-keep class com.google.api.services.drive.** {
*;
}

This provided a working proguard compatible solution for a recent Google Drive project.

这为最近的一个Google Drive项目提供了一个有效的前卫兼容解决方案。

Cannot take all credit for this solution though, originally found at this link here

不过，我不能完全归功于此解决方案，最初可在此处的链接中找到

Proper combination is :

适当的组合为：

-keepattributes Signature,RuntimeVisibleAnnotations,AnnotationDefault

-保留属性签名、运行可见注释、注释默认

There's proguard configuration prepared by Google for project google-api-java-client

这是Google为Google-API-Java-Client项目准备的前卫配置

https://github.com/google/google-api-java-client/blob/57fe35766cbba0a0d5a9a296be81468d730a29f8/google-api-client-assembly/proguard-google-api-client.txt

Https://github.com/google/google-api-java-client/blob/57fe35766cbba0a0d5a9a296be81468d730a29f8/google-api-client-assembly/proguard-google-api-client.txt

First -keeping a class does not mean to not touch it. It means do not change its name, and use it as a basis for determining if other classes are not referenced & can be deleted.

第一，上课并不意味着不去碰它。这意味着不要更改其名称，并将其用作确定其他类是否未被引用或可以删除的基础。

Optimization still occurs, which is likely your problem. Next step I would do is try with:
-dontoptimize

优化仍然会发生，这很可能是您的问题。我要做的下一步是尝试：-不要优化

This should cause your other optimizations to be ignored.

这将导致您的其他优化被忽略。

BTW, not sure what version of SDK you are using. Am using 15, 20 is latest, and a proguard-project.txt file is create with the project. The optimization options it uses is:

顺便说一句，不确定您使用的是什么版本的SDK。我使用的是15，20是最新的，并且使用该项目创建了一个proGuard-project t.txt文件。它使用的优化选项是：

-optimizations !code/simplification/arithmetic,!code/simplification/cast,!field/*,!class/merging/*

If turning off optimization gets it running, maybe turning off all the optimizations (that's what ! does) the SDK does, will allow you to do optimization as well.

如果关闭优化使其运行，可能会关闭所有优化(就是这样！做)SDK做，也会让你做优化。

There have been few update to GooglePlayServices lately. I don't like the new API. I had the same problems.

最近GooglePlayServices的更新很少。我不喜欢新的API。我也有同样的问题。

I couldn't compile signed app with proguard. Proguard template from Google didn't work for me.

我无法用ProGuard编译签名的应用程序。谷歌的ProGuard模板对我不起作用。

I add these four lines to my proguard config and it is working:

我将以下四行添加到我的proGuard配置中，它正在工作：

-dontwarn com.google.android.gms.**
-keep interface com.google.** { *; }
-keep class * extends com.google.api.client.json.GenericJson {*;}
-keep class com.google.api.services.drive.** {*;}

This is strange. Previous version of google-api-services-drive-v2 compiled without any problems.

这太奇怪了。以前版本的google-api-services-Drive-v2编译时没有任何问题。

I'm using the latest version at the moment: google-api-services-drive-v2-rev47-1.12.0-beta.jar

我目前使用的是最新版本：google-api-services-drive-v2-rev47-1.12.0-beta.jar

The method Types.getSuperParameterizedType relies on information about generics. Generics are erased in Java. The compiler only adds them as annotation attributes, the JVM ignores them, and ProGuard discards them unless you tell it not to. So this might help:

方法Types.getSuperParamizedType依赖于有关泛型的信息。泛型在Java中被删除了。编译器只将它们作为注释属性添加，JVM会忽略它们，ProGuard会丢弃它们，除非您告诉它不要这样做。因此，这可能会有所帮助：

-keepattributes *Annotation*

This worked for me.

这对我很管用。

-keepattributes Signature,RuntimeVisibleAnnotations,AnnotationDefault
-keepclassmembers class * {
  @com.google.api.client.util.Key <fields>;
}
-dontwarn com.google.api.client.extensions.android.**
-dontwarn com.google.api.client.googleapis.extensions.android.**
-dontwarn com.google.android.gms.**
-dontnote java.nio.file.Files, java.nio.file.Path
-dontnote **.ILicensingService
-dontnote sun.misc.Unsafe
-dontwarn sun.misc.Unsafe
-keep class * extends com.google.api.client.json.** { *; }
-keep class * extends com.google.api.client.util.** { *; }
-keep class com.google.api.services.drive.** { *; }

does your code use any thing that implement Serializable? All of those need to be excluded too.

您的代码是否使用任何实现Serializable的东西？所有这些都需要被排除在外。