要在Android Studio中配置使用OpenCV库的C++方法,需要完成以下步骤:
1.下载OpenCV的SDK
首先,您可以从OpenCV官方网站(Releases - OpenCV )下载适用于Android的最新版本的OpenCV库,然后解压得到 OpenCV-android-sdk文件夹。
把解压得到的OpenCV-android-sdk文件夹放到D盘。
2.创建Android Native C++项目
配置开发环境NDK:打开Android Studio,点击“Tools”,转到“SDK Manager”,选择“SDK Tools”选项卡,并选中“NDK”和“CMake”进行安装。
点击File-->New-->New Project,选择最后一项的Native C++,点击next
进入配置页面,默认,点击Next
C++标准根据自身需求设置,这里我选择默认工具链,点击Finish
项目建成后的项目是这样的,我们可以在真机/模拟器上运行测试一下。
运行成功
3.Android项目中导入OpenCV工程
将OpenCV库作为本地模块导入:在Android Studio中选择File -> New -> Import Module。
然后选择上面解压得到的OpenCV-android-sdk文件夹中的sdk文件夹,把Module name改为opencv。
导入成功,出现新的工程opencv
导入成功之后,会出现报错提示你修改,只需要进去opencv工程的build.gradle里面改一下,让compileSdkVersion,minSdkVersion和targetSdkVersionp与app工程的build.gradle的一致。
然后,在这里我出现错误;
Build file 'D:\DownLoad\Android\javadata\MyApplication7\opencv\build.gradle' line: 92
A problem occurred evaluating project ':opencv'.
> Plugin with id 'kotlin-android' not found.
解决方法:
删掉:apply plugin: 'kotlin-android'
点击make project,不报错,修改好的opencv工程build.gradle如下图所示:
点击File->Project Structure->Dependencies->app->右边的+->3 Module Dependency
选择opencv,点击OK
点击make project,如果不报错,则成功了。
4.导入OpenCV的库文件
1、把OpenCV-android-sdk下的OpenCV-android-sdk/sdk/native/jni/include文件夹拷贝到你项目
src/main下面,并修改名字为opencv_include。
2、把OpenCV-android-sdk下的OpenCV-android-sdk/sdk/native/libs文件夹拷贝到你项目src/main/
下面,并修改名字为opencv_libs。
如图所示
在您的Android项目src/main/cpp目录下的的CMakeLists.txt文件中,添加对OpenCV库的引用,配置如下:
cmake_minimum_required(VERSION 3.22.1) project("myapplication") add_library( # Sets the name of the library. myapplication SHARED native-lib.cpp) #opencv set(OPENCV_LIBS_DIR ${CMAKE_SOURCE_DIR}/../opencv_include) set(OPENCV_LIBS ${CMAKE_SOURCE_DIR}/../opencv_lib) add_library(libopencv_java4 SHARED IMPORTED ) set_target_properties(libopencv_java4 PROPERTIES IMPORTED_LOCATION ${OPENCV_LIBS}/${ANDROID_ABI}/libopencv_java4.so ) #指定引入头文件目录 include_directories(${OPENCV_LIBS_DIR}) find_library( # Sets the name of the path variable. log-lib log) target_link_libraries( # Specifies the target library. myapplication libopencv_java4 jnigraphics #JNI层,添加bitmap支持 ${log-lib})
5.实现opencv高斯模糊图像处理的demo
在native-lib.cpp中调用opencv库实现图像处理的C/C++函数。
#include <jni.h> #include <string> #include <android/bitmap.h> #include <opencv2/opencv.hpp> using namespace cv; extern "C" JNIEXPORT void JNICALL Java_com_example_myapplication_MainActivity_opencv_1test(JNIEnv *env, jclass clazz, jobject bitmap) { AndroidBitmapInfo info; void *pixels; CV_Assert(AndroidBitmap_getInfo(env, bitmap, &info) >= 0); //判断图片是位图格式有RGB_565 、RGBA_8888 CV_Assert(info.format == ANDROID_BITMAP_FORMAT_RGBA_8888 || info.format == ANDROID_BITMAP_FORMAT_RGB_565); CV_Assert(AndroidBitmap_lockPixels(env, bitmap, &pixels) >= 0); CV_Assert(pixels); //将bitmap转化为Mat类 Mat image(info.height, info.width, CV_8UC4, pixels); // 高斯模糊 GaussianBlur(image, image, Size(101, 101), 0); }
布局文件:
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity" android:orientation="vertical"> <ImageView android:id="@+id/Original_image" android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1" /> <Button android:id="@+id/button" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="高斯模糊"/> <ImageView android:id="@+id/Image" android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1" /> </LinearLayout>
在您的Java代码中,使用JNI接口来调用您在native-lib.cpp中实现的C/C++函数。
public class MainActivity extends AppCompatActivity { static { System.loadLibrary("myapplication"); } private ActivityMainBinding binding; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); binding = ActivityMainBinding.inflate(getLayoutInflater()); setContentView(binding.getRoot()); Bitmap Original_bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.img); Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.img); ImageView Original_image=findViewById(R.id.Original_image); Original_image.setImageBitmap(Original_bitmap); Button button=findViewById(R.id.button); button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { opencv_test(bitmap); ImageView Image=findViewById(R.id.Image); Image.setImageBitmap(bitmap); } }); } public static native void opencv_test(Object bitmap); }
运行效果图: