android 调用JNI SO动态库的方法
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2022-06-24 10:10:20
总结一下:android 调用jni 分为静态调用与动态调用(不论动态还是静态前提都是ndk环境已经配置好的前提下)一、静态主要就是将c(.c)或者c++(cpp)的源文件直接加到项目中进行调用,然后...
总结一下:
android 调用jni 分为静态调用与动态调用(不论动态还是静态前提都是ndk环境已经配置好的前提下)
一、静态主要就是将c(.c)或者c++(cpp)的源文件直接加到项目中进行调用,
然后在cmakelists.txt中进行配置。
二、动态调用
1、动态调用使用已经编译好的动态库.so文件
2、android调用ndk类
生成后的so文件
public class serialport { p */ public static native int getsover(string ar); static { system.loadlibrary("serialport");//初始化so库(注意这里添加是需要去掉lib与.so) } }
3、.c文件添加
/* * copyright 2009-2011 cedric priscal * * 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 <jni.h> #include <termios.h> #include <unistd.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <string.h> #include "m1900_drv.h" #include "serialport.h" #include "include/tinyalsa/audio_i2s.h" #include "include/tinyalsa/asoundlib.h" #include "android/log.h" #include "newland_linux_so.h" static const char *tag = "serial_port"; #define logi(fmt, args...) __android_log_print(android_log_info, tag, fmt, ##args) #define logd(fmt, args...) __android_log_print(android_log_debug, tag, fmt, ##args) #define loge(fmt, args...) __android_log_print(android_log_error, tag, fmt, ##args) //测试 java_(固定)_com_littt_util_serialport(android包名原来的.更改为_,string ar 传入的字符串参数,jnienv *env, jclass固定写法) jniexport jint jnicall java_com_littt_util_serialport_getsover(jnienv *env, jclass clazz, jstring ar) { // todo: implement getsover() return 9;//返回一个9的值 }
4、.h头文件中声明
/* do not edit this file - it is machine generated */ #include <jni.h> /* header for class android_serialport_api_serialport */ #ifndef _included_android_serialport_api_serialport #define _included_android_serialport_api_serialport #ifdef __cplusplus extern "c" { #endif jniexport jint jnicall java_com_littt_util_serialport_getsover(jnienv *env, jclass clazz,jstring v); #ifdef __cplusplus } #endif #endif
5、头文件与c文件写好了,就需要在cmake 中添加.c与.h都需要添加
# for more information about using cmake with android studio, read the # documentation: https://d.android.com/studio/projects/add-native-code.html # sets the minimum version of cmake required to build the native library. cmake_minimum_required(version 3.4.1) # creates and names a library, sets it as either static # or shared, and provides the relative paths to its source code. # you can define multiple libraries, and cmake builds them for you. # gradle automatically packages shared libraries with your apk. add_library( # sets the name of the library. serialport # sets the library as a shared library. shared # provides a relative path to your source file(s). m1900_drv.c m1900_drv.h audio_i2s.c linux_so.cpp mixer.c include/tinyalsa/asoundlib.h include/tinyalsa/audio_i2s.h ) # searches for a specified prebuilt library and stores the path as a # variable. because cmake includes system libraries in the search path by # default, you only need to specify the name of the public ndk library # you want to add. cmake verifies that the library exists before # completing its build. find_library( # sets the name of the path variable. log-lib # specifies the name of the ndk library that # you want cmake to locate. log) # specifies libraries cmake should link to your target library. you # can link multiple libraries, such as libraries you define in this # build script, prebuilt third-party libraries, or system libraries. target_link_libraries( # specifies the target library. serialport # links the target library to the log library # included in the ndk. ${log-lib}) set(cmake_c_flags_release "${cmake_c_flags_release} -s") set(cmake_cxx_flags_release "${cmake_cxx_flags_release} -s")
6、在build.gradle同样需要配置
plugins { id 'com.android.application' } android { compilesdkversion 28 buildtoolsversion "28.0.3" defaultconfig { applicationid "com.littt.interphone" minsdkversion 17 targetsdkversion 28 versioncode 1 versionname "1.0" testinstrumentationrunner "androidx.test.runner.androidjunitrunner" // cmake externalnativebuild { cmake { cppflags "" abifilters 'armeabi-v7a', 'arm64-v8a', 'x86', 'x86_64' } } } externalnativebuild { cmake { path "src/main/cpp/cmakelists.txt" version "3.10.2" } } buildtypes { release { minifyenabled false proguardfiles getdefaultproguardfile('proguard-android-optimize.txt'), 'proguard-rules.pro' } } sourcesets { main { jnilibs.srcdirs = ['libs'] } } compileoptions { sourcecompatibility javaversion.version_1_8 targetcompatibility javaversion.version_1_8 } ndkversion '22.1.7171670' } dependencies { // implementation 'androidx.appcompat:appcompat:1.2.0' // implementation 'com.google.android.material:material:1.2.1' }
7、如果静态调用可以成功,那么就可以生成动态so库文件
点击图中锤子会进行编译。完成后可以打开如下路径查看
红框中生成后 so文件
7.1、生成的.so文件(工程文件夹模式)目录为app/build/intermediates/ndk/lib,将其复制到另一个工程的app/lib目录下。
7.2、要使用上述的.so文件 ,必须将工程的包名改为生成.so文件时的包名,要不然 编译能通过,但是app不能正常运行。logcat会提示找不到所调用函数的实现。
7.3、将so文件复制到需要的路径下。
7.4、在gradle.properties中最后加一行:android.usedeprecatedndk=true。
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