友盟SDK 混淆 问题

集成友盟的意见反馈和统计SDK，混淆后出现如下问题：

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.shenzy.boke/com.umeng.fb.ConversationActivity}: java.lang.IllegalArgumentException: ResClass is not initialized. Please make sure you have added neccessary resources. Also make sure you have com.shenzy.boke.R$* configured in obfuscation. field=umeng_fb_activity_conversation

说明resource找不到的问题。究其原因，由于SDK需要引用导入工程的资源文件，通过了反射机制得到资源引用文件R.java，但是在开发者通过proguard等混淆/优化工具处理apk时，proguard可能会将R.java删除。

详见其官网FAQ：http://dev.umeng.com/analytics/reference/faq

这里涉及到的一个问题是 jar包里面通过反射机制获取资源文件。

做jar，jar代码获取资源不能直接引用 R.xx.name,

有两种方法：

1.通过方法: int android.content.res.Resources.getIdentifier(String name, String defType, String defPackage)

2.通过反射

第一种方法比较常见，主要看第二种方法：

publicclass ResoureExchange {
privatestaticfinal String TAG = ResoureExchange.class.getName();
privatestatic ResoureExchange self;

private Context mContext;

privatestatic Class<?> CDrawable = null;

privatestatic Class<?> CLayout = null;

privatestatic Class<?> CId = null;

privatestatic Class<?> CAnim = null;

privatestatic Class<?> CStyle = null;

privatestatic Class<?> CString = null;

privatestatic Class<?> CArray = null;

publicstatic ResoureExchange getInstance(Context context){
if(self == null){
 self = new ResoureExchange(context);
 }
return self;
 }

private ResoureExchange(Context context){
this.mContext = context.getApplicationContext();
try{
 CDrawable = Class.forName(this.mContext.getPackageName() + ".R$drawable");
 CLayout = Class.forName(this.mContext.getPackageName() + ".R$layout");
 CId = Class.forName(this.mContext.getPackageName() + ".R$id");
 CAnim = Class.forName(this.mContext.getPackageName() + ".R$anim");
 CStyle = Class.forName(this.mContext.getPackageName() + ".R$style");
 CString = Class.forName(this.mContext.getPackageName() + ".R$string");
 CArray = Class.forName(this.mContext.getPackageName() + ".R$array");

 }catch(ClassNotFoundException e){
 Log.i(TAG,e.getMessage());
 }
 }

publicint getDrawableId(String resName){
return getResId(CDrawable,resName);
 }

publicint getLayoutId(String resName){
return getResId(CLayout,resName);
 }

publicint getIdId(String resName){
return getResId(CId,resName);
 }

publicint getAnimId(String resName){
return getResId(CAnim,resName);
 }

publicint getStyleId(String resName){
return getResId(CStyle,resName);
 }

publicint getStringId(String resName){
return getResId(CString,resName);
 }

publicint getArrayId(String resName){
return getResId(CArray,resName);
 }

privateint getResId(Class<?> resClass,String resName){
if(resClass == null){
 Log.i(TAG,"getRes(null," + resName + ")");
thrownew IllegalArgumentException("ResClass is not initialized. Please make sure you have added neccessary resources. Also make sure you have " + this.mContext.getPackageName() + ".R$* configured in obfuscation. field=" + resName);
 }

try {
 Field field = resClass.getField(resName);
return field.getInt(resName);
 } catch (Exception e) {
 Log.i(TAG, "getRes(" + resClass.getName() + ", " + resName + ")");
 Log.i(TAG, "Error getting resource. Make sure you have copied all resources (res/) from SDK to your project. ");

 Log.i(TAG, e.getMessage());
 }

return -1;
 }
}