Android NDK几点回调方式

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一、NDK中获取android设备ID的方式

Java代码如下（获取设备ANDROID_ID）：

final String androidId = Secure.getString(context.getContentResolver(), Secure.ANDROID_ID);

对应的c代码（相当蛋疼），注意如果是C++，需要把所有的(*env)->替换成env->，同时去掉第一个参数env

char *
get_android_id(JNIEnv *env, jobject mContext, jobject actObj)
{
char *szDevId = NULL; if (!mContext) {
return szDevId;
} jclass resCls = (*env)->FindClass(env, "android/content/Context");
jmethodID getMethod = (*env)->GetMethodID(env, resCls, "getContentResolver", "()Landroid/content/ContentResolver;");
jobject resolver = (*env)->CallObjectMethod(env, actObj, getMethod);
if (resolver == NULL) {
LOGE("Invalid resolver!");
} jclass cls_context = (*env)->FindClass(env, "android/provider/Settings$Secure");
if (cls_context == NULL) {
LOGE("Invalid cls_context!");
} jmethodID getStringMethod = (*env)->GetStaticMethodID(env, cls_context, "getString", "(Landroid/content/ContentResolver;Ljava/lang/String;)Ljava/lang/String;");
if (getStringMethod == NULL) {
LOGE("Invalid getStringMethod!");
} jfieldID ANDROID_ID = (*env)->GetStaticFieldID(env, cls_context,
"ANDROID_ID", "Ljava/lang/String;");
jstring str = (jstring)((*env)->GetStaticObjectField(env, cls_context, ANDROID_ID)); jstring jId = (jstring)((*env)->CallStaticObjectMethod(env, cls_context, getStringMethod, resolver, str));
szDevId = (char *)((*env)->GetStringUTFChars(env, jId, )); return szDevId;
}

如果是手机，还可以通过TelephoneManager.getDeviceId()方式来获取：

Java代码：

final String deviceId = ((TelephonyManager) context.getSystemService( Context.TELEPHONY_SERVICE )).getDeviceId();

对应的C代码：

char *
get_telepone_id(JNIEnv *env, jobject mContext, jobject actObj) {
char *szDevId = NULL; if(mContext == ){
return szDevId;
} jclass cls_context = (*env)->FindClass(env, "android/content/Context"); jmethodID getSystemService = (*env)->GetMethodID(env, cls_context, "getSystemService",
"(Ljava/lang/String;)Ljava/lang/Object;"); if(!getSystemService){
return szDevId;
} jfieldID TELEPHONY_SERVICE = (*env)->GetStaticFieldID(env, cls_context,
"TELEPHONY_SERVICE", "Ljava/lang/String;");
if(!TELEPHONY_SERVICE){
return szDevId;
} jstring str = (jstring)(*env)->GetStaticObjectField(env, cls_context, TELEPHONY_SERVICE);
jclass cls_tm = (*env)->FindClass(env, "android/telephony/TelephonyManager");
if(!cls_tm){
return szDevId;
} jobject telephonymanager = (*env)->CallObjectMethod(env, actObj, getSystemService, str);
if(!telephonymanager){
return szDevId;
} jmethodID getDeviceId = (*env)->GetMethodID(env, cls_tm, "getDeviceId", "()Ljava/lang/String;");
if(!getDeviceId){
return szDevId;
}
jstring deviceid = (jstring)(*env)->CallObjectMethod(env, telephonymanager, getDeviceId); szDevId = (char *)(*env)->GetStringUTFChars(env, deviceid, ); (*env)->DeleteLocalRef(env, cls_tm);
(*env)->DeleteLocalRef(env, cls_context);
(*env)->DeleteLocalRef(env, telephonymanager); return szDevId;
}

二、通过NDK获取证书签名

Java代码：

PackageInfo pis;
try {
pis = mContext.getPackageManager().getPackageInfo(packageName, PackageManager.GET_SIGNATURES); //获取包信息
Signature sigs = pis.signatures[0]; //获取签名
int hash = sigs.hashCode(); //获取签名的哈希码
} catch(Exception e) {
//TODO:log here.
}

对应的C代码：

int
get_apk_signature(JNIEnv *env, jobject obj) { jclass cls = (*env)->FindClass(env, "android/content/ContextWrapper");
//this.getPackageManager();
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 -;
} //this.getPackageName();
mid = (*env)->GetMethodID(env, cls, "getPackageName", "()Ljava/lang/String;");
if (mid == NULL) {
return -;
} jstring packageName = (jstring)(*env)->CallObjectMethod(env, obj, mid); // packageManager->getPackageInfo(packageName, GET_SIGNATURES);
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 sig = (*env)->GetObjectArrayElement(env, signatures, ); cls = (*env)->GetObjectClass(env, sig);
mid = (*env)->GetMethodID(env, cls, "hashCode", "()I");
int sig_value = (int)(*env)->CallIntMethod(env, sig, mid);
return sig_value;
}