NDK开发第二章hello-libs-引用第三方库文件

1、CmakeList.txt编写

#
# Copyright (C) The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

cmake_minimum_required(VERSION 3.4.1)

# configure import libs,设置目录
set(distribution_DIR ${CMAKE_CURRENT_SOURCE_DIR}/../../../../distribution)

add_library(lib_gmath STATIC IMPORTED)
set_target_properties(lib_gmath PROPERTIES IMPORTED_LOCATION
    ${distribution_DIR}/gmath/lib/${ANDROID_ABI}/libgmath.a)

# shared lib will also be tucked into APK and sent to target
# refer to app/build.gradle, jniLibs section for that purpose.
# ${ANDROID_ABI} is handy for our purpose here. Probably this ${ANDROID_ABI} is
# the most valuable thing of this sample, the rest are pretty much normal cmake
add_library(lib_gperf SHARED IMPORTED)
set_target_properties(lib_gperf PROPERTIES IMPORTED_LOCATION
    ${distribution_DIR}/gperf/lib/${ANDROID_ABI}/libgperf.so)

# build application's shared lib
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++11")

add_library(hello-libs SHARED
            hello-libs.cpp)
##include 第三方库 .h文件
target_include_directories(hello-libs PRIVATE
                           ${distribution_DIR}/gmath/include
                           ${distribution_DIR}/gperf/include)
## 后续有用到 android 库中log,
target_link_libraries(hello-libs
                      android
                      lib_gmath
                      lib_gperf
                      log)

2、hellp-libs.cpp

/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */
#include <cstring>
#include <jni.h>
#include <cinttypes>//此头文件原作为  存在于 C 标准库。定义了__VA_ARGS__
//引用android log所以可以打印
#include <android/log.h>
#include <gmath.h>//引用第三方库 .a文件,静态文件
#include <gperf.h>//引用第三方文件so，动态文件
#include <string>

//此处不用这个话的会报错，强制换行的意思
#define LOGI(...) \
  ((void)__android_log_print(ANDROID_LOG_INFO, "hello-libs::", __VA_ARGS__))//将可变参数传给宏
//    auto test = ANDROID_LOG_INFO;
//    auto test2 = __VA_ARGS__


/* This is a trivial JNI example where we use a native method
 * to return a new VM String. See the corresponding Java source
 * file located at:
 *
 *   app/src/main/java/com/example/hellolibs/MainActivity.java
 */
extern "C" JNIEXPORT jstring JNICALL
Java_com_example_hellolibs_MainActivity_stringFromJNI(JNIEnv *env, jobject thiz) {
    // Just for simplicity, we do this right away; correct way would do it in
    // another thread...
    auto ticks = GetTicks();

    for (auto exp = 0; exp< 32; ++exp) {
        volatile unsigned val = gpower(exp);
        (void) val;  // to silence compiler warning
    }
    ticks = GetTicks() - ticks;
    LOGI("calculation time: %" PRIu64, ticks);
    return env->NewStringUTF("Hello from JNI LIBS!");
}

遇到的错误

Error:Failed to notify build listener.

解决办法修改gradle版本为4.6 插件版本为3.2.1

Failed to notify build listener. 的一些处理经历 - a260724032的博客
https://blog.youkuaiyun.com/a260724032/article/details/89978494