下面具體說(shuō)一說(shuō)怎么樣讓SDK2.3下的proguard.cfg文件起作用，先來(lái)看看proguard.cfg的內容：
-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 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 *;}從腳本中可以看到，混淆中保留了繼承自Activity、Service、Application、BroadcastReceiver、ContentProvider等基本組件以及com.android.vending.licensing.ILicensingService，并保留了所有的Native變量名及類(lèi)名，所有類(lèi)中部分以設定了固定參數格式的構造函數，枚舉等等。(詳細信息請參考<proguard_path>/examples中的例子及注釋。)
讓proguard.cfg起作用的做法很簡(jiǎn)單，就是在eclipse自動(dòng)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文件應該如下：
# 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-9proguard.config=proguard.cfg
大功告成，正常的編譯簽名后就可以防止代碼被反編譯了。反編譯經(jīng)過(guò)代碼混淆的apk得到的代碼應該類(lèi)似于下面的效果，是很難看懂的：
如果您使用的是2.3之前的SDK版本也沒(méi)關(guān)系，把上面的proguard.cfg文件復制一份放到項目中，然后進(jìn)行相同的操作即可。
