最近开发工作中需要使用到AndroidID,在Unity和native code中也需要使用,java获取很方便,Unity中也不难,最难的是在native code中获取。
获取android ID需要有一个上下文实例,也就是Context实例,看下面的java获取方式:
在java中获取
Android原生代码,这个是最简单的:
- public static String GetAndroid(Context context) {
- final String androidId;
- androidId = android.provider.Settings.Secure.getString(context.getContentResolver(), android.provider.Settings.Secure.ANDROID_ID);
- return androidId;
- }
在Unity中获取
Unity获取androidID首先需要获取Unity环境中当前的activity,由activiy调用getContentResolver。
- private String GetAndroidID()
- {
- AndroidJavaClass up = new AndroidJavaClass ("com.unity3d.player.UnityPlayer");
- AndroidJavaObject currentActivity = up.GetStatic<AndroidJavaObject> ("currentActivity");
- AndroidJavaObject contentResolver = currentActivity.Call<AndroidJavaObject> ("getContentResolver");
- AndroidJavaClass secure = new AndroidJavaClass ("android.provider.Settings$Secure");
- string android_id = secure.CallStatic<string> ("getString", contentResolver, "android_id");
- return android_id;
- }
在C中获取
在C代码中只能通过JNI方式调用java来获取,代码看起来比较乱,有很多同java进行交互的部分。获取流程如下:
- 首先JVM加载native code所在动态库的时候(loadlibrary)会自动调用JNI_OnLoad,这时候会初始化一个全局的JavaJVM,一个进程只能有一个JavaJVM。
- 当前线程获取JNIEnv,调用AttachCurrentThread来获得。
- 通过JNI获取Java中的相关类,方法。获取Context(getGlobalContext)的方法研究了很长时间,网上搜了好多资料。
- 得到jstring类型的Android,转换成char *
- 最后返回。
- #include <jni.h>
- #include <assert.h>
- #include "libavutil/avassert.h"
- #define JNI_CLASS_PATH /JNI/CLASS/path
- static JavaVM* g_jvm=NULL;
- static jobject getGlobalContext(JNIEnv *env)
- {
- jclass activityThread = (*env)->FindClass(env,"android/app/ActivityThread");
- jmethodID currentActivityThread = (*env)->GetStaticMethodID(env,activityThread, "currentActivityThread", "()Landroid/app/ActivityThread;");
- jobject at = (*env)->CallStaticObjectMethod(env,activityThread, currentActivityThread);
- jmethodID getApplication = (*env)->GetMethodID(env,activityThread, "getApplication", "()Landroid/app/Application;");
- jobject context = (*env)->CallObjectMethod(env,at, getApplication);
- return context;
- }
- static jstring
- _getAndroidID(JNIEnv *env, jobject thiz)
- {
- jclass c_settings_secure = (*env)->FindClass(env, "android/provider/Settings$Secure");
- jclass c_context = (*env)->FindClass(env,"android/content/Context");
- if(c_settings_secure == NULL || c_context == NULL){
- return NULL;
- }
- //Get the getContentResolver method
- jmethodID m_get_content_resolver = (*env)->GetMethodID(env, c_context, "getContentResolver",
- "()Landroid/content/ContentResolver;");
- if(m_get_content_resolver == NULL){
- return NULL;
- }
- //Get the Settings.Secure.ANDROID_ID constant
- jfieldID f_android_id = (*env)->GetStaticFieldID(env, c_settings_secure, "ANDROID_ID", "Ljava/lang/String;");
- if(f_android_id == NULL){
- return NULL;
- }
- jstring s_android_id = (*env)->GetStaticObjectField(env, c_settings_secure, f_android_id);
- //create a ContentResolver instance context.getContentResolver()
- jobject o_content_resolver = (*env)->CallObjectMethod(env, getGlobalContext(env), m_get_content_resolver);
- if(o_content_resolver == NULL || s_android_id == NULL){
- return NULL;
- }
- //get the method getString
- jmethodID m_get_string = (*env)->GetStaticMethodID(env, c_settings_secure, "getString",
- "(Landroid/content/ContentResolver;Ljava/lang/String;)Ljava/lang/String;");
- if(m_get_string == NULL){
- return NULL;
- }
- //get the Android ID
- jstring android_id = (*env)->CallStaticObjectMethod(env, c_settings_secure,
- m_get_string,
- o_content_resolver,
- s_android_id);
- return android_id;
- }
- static char* jstringTostr( jstring jstr)
- {
- JNIEnv* env = NULL;
- if ((*g_jvm)->GetEnv(g_jvm, (void**) &env, JNI_VERSION_1_4) != JNI_OK) {
- return -1;
- }
- assert(env != NULL);
- char* pStr = NULL;
- jclass jstrObj = (*env)->FindClass(env, "java/lang/String");
- jstring encode = (*env)->NewStringUTF(env, "utf-8");
- jmethodID methodId = (*env)->GetMethodID(env, jstrObj, "getBytes", "(Ljava/lang/String;)[B");
- jbyteArray byteArray = (jbyteArray)(*env)->CallObjectMethod(env, jstr, methodId, encode);
- jsize strLen = (*env)->GetArrayLength(env, byteArray);
- jbyte *jBuf = (*env)->GetByteArrayElements(env, byteArray, JNI_FALSE);
- if (jBuf > 0)
- {
- pStr = (char*)malloc(strLen + 1);
- if (!pStr)
- {
- return NULL;
- }
- memcpy(pStr, jBuf, strLen);
- pStr[strLen] = 0;
- }
- (*env)->ReleaseByteArrayElements(env, byteArray, jBuf, 0);
- //av_log(NULL, AV_LOG_INFO, "the android is end%s\n", pStr);
- return pStr;
- }
- char * getAndroidID()
- {
- JNIEnv* env = NULL;
- if((*g_jvm)->AttachCurrentThread(g_jvm, &env, NULL) != JNI_OK)
- {
- return NULL;
- }
- jstring androidID = _getAndroidID(env,NULL);
- return jstringTostr(androidID);
- }
- JNIEXPORT jint JNI_OnLoad(JavaVM *vm, void *reserved)
- {
- JNIEnv* env = NULL;
- g_jvm = vm;
- if ((*vm)->GetEnv(vm, (void**) &env, JNI_VERSION_1_4) != JNI_OK) {
- return -1;
- }
- assert(env != NULL);
- return JNI_VERSION_1_4;
- }