apk文件防止反编译

转：http://blog.csdn.net/sunboy_2050/article/details/6727640

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：

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• -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 <methods>;  
• }  
•   
• -keepclasseswithmembernames class * {  
•     public <init>(android.content.Context, android.util.AttributeSet);  
• }  
•   
• -keepclasseswithmembernames class * {  
•     public <init>(android.content.Context, android.util.AttributeSet, int);  
• }  
•   
• -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 <methods>;}-keepclasseswithmembernames class * {    public <init>(android.content.Context, android.util.AttributeSet);}-keepclasseswithmembernames class * {    public <init>(android.content.Context, android.util.AttributeSet, int);}-keepclassmembers enum * {    public static **[] values();    public static ** valueOf(java.lang.String);}-keep class * implements android.os.Parcelable {  public static final android.os.Parcelable$Creator *;} 

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<proguard_path>/examples中的例子及注释。)

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：

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• # 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  
• 
  proguardproguard.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：