android驱动开发流程3-JNI 方法

namespace Android2.{

/*在硬件抽象层中定义的硬件访问结构体,参考*/

struct hello_device_t* hello_device = NULL;

/*通过硬件抽象层定义的硬件访问接口设置硬件寄存器val 的值*/

static void hello_setVal(JNIEnv* env, jobject clazz, jint value) {

    int val = value;

    LOGI("Hello JNI: set value %d to device.", val);

    if(!hello_device) {

            LOGI("Hello JNI: device is not open.");

            return;

    }

    hello_device->set_val(hello_device, val);

}

/*通过硬件抽象层定义的硬件访问接口读取硬件寄存器val 的值*/

static jint hello_getVal(JNIEnv* env, jobject clazz) {

    int val = 0;

    if(!hello_device) {

        LOGI("Hello JNI: device is not open.");

        return val;

     }

    hello_device->get_val(hello_device, &val);

    LOGI("Hello JNI: get value %d from device.", val);

    return val;

 }

/*通过硬件抽象层定义的硬件模块打开接口打开硬件设备*/

static inline int hello_device_open(const hw_module_t* module, struct hello_device_t** device) {

    return module->methods->open(module, HELLO_HARDWARE_MODULE_ID, (struct hw_device_t**)device);

}

/*通过硬件模块ID 来加载指定的硬件抽象层模块并打开硬件*/

static jboolean hello_init(JNIEnv* env, jclass clazz) {

    hello_module_t* module;

    LOGI("Hello JNI: initializing......");

    if(hw_get_module(HELLO_HARDWARE_MODULE_ID, (const struct hw_module_t**)&module) == 0) {

    LOGI("Hello JNI: hello Stub found.");

    if(hello_device_open(&(module->common), &hello_device) == 0) {

        LOGI("Hello JNI: hello device is open.");

        return 0;

    }

    LOGE("Hello JNI: failed to open hello device.");

    return -1;

   }

    LOGE("Hello JNI: failed to get hello stub module.");

    return -1;

}

/*JNI 方法表*/

static const JNINativeMethod method_table[] = {

    {"init_native", "()Z", (void*)hello_init},

    {"setVal_native", "(I)V", (void*)hello_setVal},

    {"getVal_native", "()I", (void*)hello_getVal},

};

/*注册JNI 方法*/

int register_Android_server_HelloService(JNIEnv *env) {

    return jniRegisterNativeMethods(env, "com/Android/server/HelloService", method_table,NELEM(method_table));

}

};


修改onload.cpp

修改Android.mk

你可能感兴趣的:(android驱动开发流程3-JNI 方法)