proguard 缺少类型参数

Question

我尝试用 ProGuard 混淆我的 Android 应用程序代码。但在此之后，我的应用程序在运行时出现异常：

11-15 01:46:26.818: W/System.err(21810): java.lang.RuntimeException: Missing type parameter.
11-15 01:46:26.828: W/System.err(21810):    at da.<init>(Unknown Source)
11-15 01:46:26.828: W/System.err(21810):    at gc.<init>(Unknown Source)
11-15 01:46:26.828: W/System.err(21810):    at fx.f(Unknown Source)
11-15 01:46:26.828: W/System.err(21810):    at com.yourshows.activity.UnwatchedActivity.onResume(Unknown Source)

我检查了一个映射文件并发现了这一点：

com.google.gson.reflect.TypeToken -> da:

我认为我的应用程序中的行如下：

        Type mapType = new TypeToken<Map<Integer, WatchedEpisodes>>(){}.getType(); // define generic type
        jsData = gson.fromJson(r, mapType);

我无法理解我应该做什么结论？不要使用少于三个字符的变量名或者什么？

UPD：答案

Answer 1

答案是：使用这个 proguard.cfg

##---------------Begin: proguard configuration common for all Android apps ----------
-optimizationpasses 5
-dontusemixedcaseclassnames
-dontskipnonpubliclibraryclasses
-dontskipnonpubliclibraryclassmembers
-dontpreverify
-verbose
-dump class_files.txt 
-printseeds seeds.txt 
-printusage unused.txt 
-printmapping mapping.txt 
-optimizations !code/simplification/arithmetic,!field/*,!class/merging/*


-allowaccessmodification
-keepattributes *Annotation*
-renamesourcefileattribute SourceFile
-keepattributes SourceFile,LineNumberTable
-repackageclasses ''


-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
-dontnote com.android.vending.licensing.ILicensingService


# Explicitly preserve all serialization members. The Serializable interface
# is only a marker interface, so it wouldn't save them.
-keepclassmembers class * implements java.io.Serializable {
    static final long serialVersionUID;
    private static final java.io.ObjectStreamField[] serialPersistentFields;
    private void writeObject(java.io.ObjectOutputStream);
    private void readObject(java.io.ObjectInputStream);
    java.lang.Object writeReplace();
    java.lang.Object readResolve();
}


# Preserve all native method names and the names of their classes.
-keepclasseswithmembernames class * {
    native <methods>;
}


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


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


# Preserve static fields of inner classes of R classes that might be accessed
# through introspection.
-keepclassmembers class **.R$* {
  public static <fields>;
}


# Preserve the special static methods that are required in all enumeration classes.
-keepclassmembers enum * {
    public static **[] values();
    public static ** valueOf(java.lang.String);
}


-keep public class * {
    public protected *;
}


-keep class * implements android.os.Parcelable {
  public static final android.os.Parcelable$Creator *;
}
##---------------End: proguard configuration common for all Android apps ----------


##---------------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


# Gson specific classes
-keep class sun.misc.Unsafe { *; }
#-keep class com.google.gson.stream.** { *; }


# Application classes that will be serialized/deserialized over Gson
-keep class com.google.gson.examples.android.model.** { *; }


##---------------End: proguard configuration for Gson  ----------

非常感谢这个项目的所有者 --> google-gson

---

UPD：
google/gson 有针对 Android 应用程序的 proguard 配置示例。

在 github 上查看

他们建议使用此配置模板

##---------------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
-keep class sun.misc.Unsafe { *; }
#-keep class com.google.gson.stream.** { *; }

# Application classes that will be serialized/deserialized over Gson
-keep class com.google.gson.examples.android.model.** { *; }

##---------------End: proguard configuration for Gson  ----------

Answer 2

由于我一开始没有注意到问题中的链接，因此以下是线程中提到的让 GSON 与 Proguard 一起使用所需的具体行：

# 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

# Gson specific classes
-keep class sun.misc.Unsafe { *; }
#-keep class com.google.gson.stream.** { *; }

# Application classes that will be serialized/deserialized over Gson
-keep class com.google.gson.examples.android.model.** { *; }

Answer 3

这个问题可以通过使用不同的方式创建 TypeToken 实例（对于参数化类型 Map）来解决：

Type collectionType = 
  TypeToken.get(
    $Gson$Types.newParameterizedTypeWithOwner(null,
      Map.class, Integer.class, WatchedEpisodes.class)).getType();

gson 的下一个版本（我假设2.8)，将允许您更轻松地键入：

Type collectionType =
  TypeToken.getParameterized(Map.class,
                             Integer.class,
                             WatchedEpisodes.class).getType();

Answer 4

当前的答案没有解决我的问题。这是我的解决方案：

将这些行添加到您的 proguard-rules.pro 文件中：

##---------------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 PATH_TO_YOUR_MODELS_PACKAGE.models.** { *; }

# Prevent proguard from stripping interface information from TypeAdapter, TypeAdapterFactory,
# JsonSerializer, JsonDeserializer instances (so they can be used in @JsonAdapter)
-keep class * extends com.google.gson.TypeAdapter
-keep class * implements com.google.gson.TypeAdapterFactory
-keep class * implements com.google.gson.JsonSerializer
-keep class * implements com.google.gson.JsonDeserializer

# Prevent R8 from leaving Data object members always null
-keepclassmembers,allowobfuscation class * {
  @com.google.gson.annotations.SerializedName <fields>;
}

# Retain generic signatures of TypeToken and its subclasses with R8 version 3.0 and higher.
-keep,allowobfuscation,allowshrinking class com.google.gson.reflect.TypeToken
-keep,allowobfuscation,allowshrinking class * extends com.google.gson.reflect.TypeToken

##---------------End: proguard configuration for Gson  ----------

重要提示：

您应该将所有与 gson 一起使用的模型放入一个包中并将其排除使用此 proguard 规则进行 minify：

 -keep class PATH_TO_YOUR_MODELS_PACKAGE.** { *; }

根据您的包名称更改它。 例如如果您的模型位于 com.example.models 中，您应该具有以下行：

 -keep class com.example.models.** { *; }

Answer 5

导入不正确：

您可能使用的是 Guava (com.google.common.reflect.TypeToken) 中的 TypeToken 类，而不是 Gson (com.google.gson.反射.TypeToken）。确保根据您正在使用的库导入正确的类。