作为Android应用开发者,不得不面对一个尴尬的局面,就是自己辛辛苦苦开发的应用可以被别人很轻易的就反编译出来。
Google似乎也发现了这个问题,从SDK2.3开始我们可以看到在android-sdk-windows\tools\下面多了一个proguard文件夹
proguard是一个java代码混淆的工具,通过proguard,别人即使反编译你的apk包,也只会看到一些让人很难看懂的代码,从而达到保护代码的作用。
下面具体说一说怎么样让SDK2.3下的proguard.cfg文件起作用,先来看看android-sdk-windows\tools\lib\proguard.cfg的内容:
-optimizationpasses 5
-dontusemixedcaseclassnames
-dontskipnonpubliclibraryclasses
-dontpreverify
-verbose
-optimizations !code/simplification/arithmetic,!field/*,!class/merging/*
-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
-keepclasseswithmembernames class * {
native
}
-keepclasseswithmembernames class * {
public
}
-keepclasseswithmembernames class * {
public
}
-keepclassmembers enum * {
public static **[] values();
public static ** valueOf(java.lang.String);
}
-keep class * implements android.os.Parcelable {
public static final android.os.Parcelable$Creator *;
}
-optimizationpasses 5-dontusemixedcaseclassnames-dontskipnonpubliclibraryclasses-dontpreverify-verbose-optimizations !code/simplification/arithmetic,!field/*,!class/merging/*-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-keepclasseswithmembernames class * { native
从脚本中可以看到,混淆中保留了继承自Activity、Service、Application、BroadcastReceiver、ContentProvider等基本组件以及com.android.vending.licensing.ILicensingService,
并保留了所有的Native变量名及类名,所有类中部分以设定了固定参数格式的构造函数,枚举等等。(详细信息请参考
让proguard.cfg起作用的做法很简单,就是在eclipse自动生成的default.properties文件中加上一句“proguard.config=proguard.cfg”就可以了
完整的default.properties文件应该如下:
# This file is automatically generated by Android Tools.
# Do not modify this file -- YOUR CHANGES WILL BE ERASED!
#
# This file must be checked in Version Control Systems.
#
# To customize properties used by the Ant build system use,
# "build.properties", and override values to adapt the script to your
# project structure.
# Project target.
target=android-9
proguard.config=proguard.cfg
# This file is automatically generated by Android Tools.# Do not modify this file -- YOUR CHANGES WILL BE ERASED!## This file must be checked in Version Control Systems.## To customize properties used by the Ant build system use,# "build.properties", and override values to adapt the script to your# project structure.# Project target.target=android-9proguard.config=proguard.cfg
大功告成,正常的编译签名后就可以防止代码被反编译了。反编译经过代码混淆的apk得到的代码应该类似于下面的效果,是很难看懂的: