Question

我有一个纯粹原生的Android NDK应用，需要检索以下值： android.os.Build.MODEL

不幸的是我找不到如何解决这个问题的好例子？

Answer 1

这些值很容易通过<sys/system_properties.h>中定义的接口在本机代码中获得，该接口自第一个NDK发布以来就已存在。您只需要知道Java端使用的字符串标识符。幸运的是，使用开源操作系统，我们可以轻松找到它们。以下是检索模型名称的工作示例。

#include <sys/system_properties.h>

//
// Public codes are defined in http://developer.android.com/reference/java/lang/System.html#getProperty(java.lang.String).
// Codes below are defined in https://android.googlesource.com/platform/frameworks/base/+/refs/heads/master/core/java/android/os/Build.java.
// Items with * are intended for display to the end user.
//

#define ANDROID_OS_BUILD_VERSION_RELEASE     "ro.build.version.release"          // * The user-visible version string. E.g., "1.0" or "3.4b5".
#define ANDROID_OS_BUILD_VERSION_INCREMENTAL "ro.build.version.incremental"      // The internal value used by the underlying source control to represent this build.
#define ANDROID_OS_BUILD_VERSION_CODENAME    "ro.build.version.codename"         // The current development codename, or the string "REL" if this is a release build.
#define ANDROID_OS_BUILD_VERSION_SDK         "ro.build.version.sdk"              // The user-visible SDK version of the framework.

#define ANDROID_OS_BUILD_MODEL               "ro.product.model"                  // * The end-user-visible name for the end product..
#define ANDROID_OS_BUILD_MANUFACTURER        "ro.product.manufacturer"           // The manufacturer of the product/hardware.
#define ANDROID_OS_BUILD_BOARD               "ro.product.board"                  // The name of the underlying board, like "goldfish".
#define ANDROID_OS_BUILD_BRAND               "ro.product.brand"                  // The brand (e.g., carrier) the software is customized for, if any.
#define ANDROID_OS_BUILD_DEVICE              "ro.product.device"                 // The name of the industrial design.
#define ANDROID_OS_BUILD_PRODUCT             "ro.product.name"                   // The name of the overall product.
#define ANDROID_OS_BUILD_HARDWARE            "ro.hardware"                       // The name of the hardware (from the kernel command line or /proc).
#define ANDROID_OS_BUILD_CPU_ABI             "ro.product.cpu.abi"                // The name of the instruction set (CPU type + ABI convention) of native code.
#define ANDROID_OS_BUILD_CPU_ABI2            "ro.product.cpu.abi2"               // The name of the second instruction set (CPU type + ABI convention) of native code.

#define ANDROID_OS_BUILD_DISPLAY             "ro.build.display.id"               // * A build ID string meant for displaying to the user.
#define ANDROID_OS_BUILD_HOST                "ro.build.host"
#define ANDROID_OS_BUILD_USER                "ro.build.user"
#define ANDROID_OS_BUILD_ID                  "ro.build.id"                       // Either a changelist number, or a label like "M4-rc20".
#define ANDROID_OS_BUILD_TYPE                "ro.build.type"                     // The type of build, like "user" or "eng".
#define ANDROID_OS_BUILD_TAGS                "ro.build.tags"                     // Comma-separated tags describing the build, like "unsigned,debug".

#define ANDROID_OS_BUILD_FINGERPRINT         "ro.build.fingerprint"              // A string that uniquely identifies this build. 'BRAND/PRODUCT/DEVICE:RELEASE/ID/VERSION.INCREMENTAL:TYPE/TAGS'.


char model_id[PROP_VALUE_MAX]; // PROP_VALUE_MAX from <sys/system_properties.h>.
int len;
len = __system_property_get(ANDROID_OS_BUILD_MODEL, model_id); // On return, len will equal (int)strlen(model_id).

Answer 2

NDK并不是要取代基于Java的API，而是要补充它。要获得Build，你必须在C / C ++中找到它的私有实现，或者通过JNI从Java提供信息。

伪代码：

android_main(struct *android_app){
    JNIEnv *env = android_app->activity->env;
    jclass build_class = FindClass(env, "android.os.Build");
    jfieldID brand_id = GetStaticFieldID(env, build_class, "BRAND", "Ljava/lang/String;");
    jstring brand_obj = (jstring)GetStaticObjectField(env, brand_id);
}

Answer 3

我不认为你不能这样做。您可以始终在VM中启动，并在检索您要访问的值后通过JNI跳转到本机。

通过纯粹的原生Android应用程序检索android.os.Build ....系统属性

3 个答案: