JNIからAndroidにパッケージ名を取得する方法は？

Question

私はの署名を取得し、javaに値を返すためのコードを持っています。

get（）メソッドで次のコードの説明に従ってJNIからパッケージ名を取得し、javaクラスに渡す必要があります。

しかし、がグローバル変数をJNIに渡している間に、がクラッシュしています。

現在の実装では、_

static jstring packageNameValue; 
char* jstringTostring(JNIEnv* env, jstring jstr) 
{ 
     char* rtn = NULL; 
     jclass clsstring = (*env)->FindClass(env, "java/lang/String"); 
     jstring strencode = (*env)->NewStringUTF(env, "utf-8"); 
     jmethodID mid = (*env)->GetMethodID(env, clsstring, "getBytes", "(Ljava/lang/String;)[B"); 
     jbyteArray barr= (jbyteArray)(*env)->CallObjectMethod(env, jstr, mid, strencode); 
     jsize alen = (*env)->GetArrayLength(env, barr); 
     jbyte* ba = (*env)->GetByteArrayElements(env, barr, JNI_FALSE); 
     if (alen > 0) 
     { 
       rtn = (char*)malloc(alen + 1); 
       memcpy(rtn, ba, alen); 
       rtn[alen] = 0; 
     } 
     (*env)->ReleaseByteArrayElements(env, barr, ba, 0); 
     return rtn; 
} 

char* loadSignature(JNIEnv* env, jobject obj) 
{ 
     jclass cls = (*env)->FindClass(env, "android/content/ContextWrapper"); 
     jmethodID mid = (*env)->GetMethodID(env, cls, "getPackageManager", 
              "()Landroid/content/pm/PackageManager;"); 
     if (mid == NULL) { 
       return ""; 
     } 

     jobject pm = (*env)->CallObjectMethod(env, obj, mid); 
     if (pm == NULL) { 
       return ""; 
     } 

     mid = (*env)->GetMethodID(env, cls, "getPackageName", "()Ljava/lang/String;"); 
     if (mid == NULL) { 
       return ""; 
     } 

     jstring packageName = (jstring)(*env)->CallObjectMethod(env, obj, mid); 
     packageNameValue = packageName; 
     cls = (*env)->GetObjectClass(env, pm); 
     mid = (*env)->GetMethodID(env, cls, "getPackageInfo", "(Ljava/lang/String;I)Landroid/content/pm/PackageInfo;"); 

     jobject packageInfo = (*env)->CallObjectMethod(env, pm, mid, packageName, 0x40); //GET_SIGNATURES = 64; 

     cls = (*env)->GetObjectClass(env, packageInfo); 
     jfieldID fid = (*env)->GetFieldID(env, cls, "signatures", "[Landroid/content/pm/Signature;"); 
     jobjectArray signatures = (jobjectArray)(*env)->GetObjectField(env, packageInfo, fid); 
     jobject sign = (*env)->GetObjectArrayElement(env, signatures, 0); 

     cls = (*env)->GetObjectClass(env, sign); 
     mid = (*env)->GetMethodID(env, cls, "toCharsString", "()Ljava/lang/String;"); 
     if(mid == NULL){ 
       return ""; 
     } 

     jstring signString = (jstring)(*env)->CallObjectMethod(env, sign, mid); 
     printf("signString", signString); 
     return jstringTostring(env, signString); 
} 

char* getSignatureMd5(JNIEnv* env, jobject obj) 
{ 
     char* sign = loadSignature(env, obj); 

     MD5_CTX context = { 0 }; 
     MD5Init(&context); 
     MD5Update(&context, sign, strlen(sign)); 
     unsigned char dest[16] = { 0 }; 
     MD5Final(dest, &context); 

     int i; 
     static char destination[32]={0}; 
     for (i = 0; i < 16; i++) { 
       sprintf(destination, "%s%02x", destination, dest[i]); 
     } 
     return destination; 
} 

jstring Java_com_example_u29692_helloandroidjni_MainActivity_getToken(JNIEnv *env, jobject obj, 
                      jobject context) { 
     char* correctSign = "72eed157ba97751805fc2a3dfacea102"; 

     char* signMd5 = loadSignature(env, obj); 
     printf("value sign", signMd5); 
     jstring packageDetail = (*env)->NewGlobalRef(env, packageNameValue); 
     char* packageDetailvalue = packageDetail; 
     return (*env)->NewStringUTF(env,packageDetailvalue); 

} 

Answer 1

を次のようにあなたはネイティブ

static jstring getpkg(JNIEnv* env, jobject thiz, jobject activity) { 
jclass android_content_Context =env->GetObjectClass(activity); 
jmethodID midGetPackageName = env->GetMethodID(android_content_Context,"getPackageName", "()Ljava/lang/String;"); 
jstring packageName= (jstring)env->CallObjectMethod(activity, midGetPackageName); 
return packageName;