public void loadPatch() {mLoaders.put("*", mContext.getClassLoader());// wildcardSet<String> patchNames;List<String> classes;for (Patch patch : mPatchs) {patchNames = patch.getPatchNames();for (String patchName : patchNames) {classes = patch.getClasses(patchName);mAndFixManager.fix(patch.getFile(),mContext.getClassLoader(), classes);}}
}

/*** fix* * @param file*            patch file* @param classLoader*            classloader of class that will be fixed* @param classes*            classes will be fixed*/
public synchronized void fix(File file, ClassLoader classLoader,List<String> classes) {//是否是支持的Android版本(在AndFixManager类初始化的时候会修改mSupport变量)if (!mSupport) {return;}//验证这个文件的签名和此应用是否一致if (!mSecurityChecker.verifyApk(file)) {// security check failreturn;}//这段代码的源码中的注释很清楚，我就不写了File optfile = new File(mOptDir, file.getName());boolean saveFingerprint = true;if (optfile.exists()) {// need to verify fingerprint when the optimize file exist,// prevent someone attack on jailbreak device with// Vulnerability-Parasyte.// btw:exaggerated android Vulnerability-Parasyte// http://secauo.com/Exaggerated-Android-Vulnerability-Parasyte.htmlif (mSecurityChecker.verifyOpt(optfile)) {saveFingerprint = false;} else if (!optfile.delete()) {return;}}//startfinal DexFile dexFile = DexFile.loadDex(file.getAbsolutePath(),optfile.getAbsolutePath(), Context.MODE_PRIVATE);if (saveFingerprint) {mSecurityChecker.saveOptSig(optfile);}ClassLoader patchClassLoader = new ClassLoader(classLoader) {@Overrideprotected Class<?> findClass(String className)throws ClassNotFoundException {Class<?> clazz = dexFile.loadClass(className, this);if (clazz == null&& className.startsWith("com.alipay.euler.andfix")) {return Class.forName(className);// annotation’s class// not found}if (clazz == null) {throw new ClassNotFoundException(className);}return clazz;}};//Enumerate the names of the classes in this DEX file.Enumeration<String> entrys = dexFile.entries();Class<?> clazz = null;while (entrys.hasMoreElements()) {String entry = entrys.nextElement();if (classes != null && !classes.contains(entry)) {continue;// skip, not need fix}clazz = dexFile.loadClass(entry, patchClassLoader);if (clazz != null) {fixClass(clazz, classLoader);}}
}

private void fixClass(Class<?> clazz, ClassLoader classLoader) {//使用反射获取这个类中所有的方法Method[] methods = clazz.getDeclaredMethods();//MethodReplace是这个库自定义的Annotation，标记哪个方法需要被替换MethodReplace methodReplace;String clz;String meth;for (Method method : methods) {//找到被MethodReplace注解的方法methodReplace = method.getAnnotation(MethodReplace.class);if (methodReplace == null)continue;clz = methodReplace.clazz();meth = methodReplace.method();if (!isEmpty(clz) && !isEmpty(meth)) {replaceMethod(classLoader, clz, meth, method);}}
}

private void replaceMethod(ClassLoader classLoader, String clz,String meth, Method method) {//对每个类创建一个不会冲突的keyString key = clz + "@" + classLoader.toString();//mFixedClass是一个Map<String, Class<?>>，并被实例化为ConcurrentHashMap<>();Class<?> clazz = mFixedClass.get(key);if (clazz == null) {// class not loadClass<?> clzz = classLoader.loadClass(clz);// initialize target class and modify access flag of class’ fields to publicclazz = AndFix.initTargetClass(clzz);}if (clazz != null) {// initialize class OKmFixedClass.put(key, clazz);//获取名为meth的方法Method src = clazz.getDeclaredMethod(meth,method.getParameterTypes());AndFix.addReplaceMethod(src, method);}
}

public static void addReplaceMethod(Method src, Method dest) {replaceMethod(src, dest);initFields(dest.getDeclaringClass());
}

/*** modify access flag of class’ fields to public* * @param clazz*            class*/
private static void initFields(Class<?> clazz) {Field[] srcFields = clazz.getDeclaredFields();for (Field srcField : srcFields) {Log.d(TAG, "modify " + clazz.getName() + "." + srcField.getName()+ " flag:");setFieldFlag(srcField);}
}