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一、配置环境
1、Android studio 3.1
2、Android NDK
3、Java 8.0
4、opencv-android 3.4.4https://opencv.org/releases.html（下载地址）
二、创建opencv项目
创建一个名为OpencvTest的android project
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这里需要添加 c++ 支持 关于android ndk 配置https://www.jianshu.com/p/8b67ba7ed598
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三、opencv配置
externalNativeBuild {
cmake {
cppFlags "-std=c++11 -frtti -fexceptions"
//添加支持cpu架构
abiFilters'x86','x86_64','armeabi','arm64-v8a','armeabi-v7a','mips','mips64'
}
}
}
sourceSets{
main{
//当前这个目录下的库文件会被调用并且被打包进apk中
jniLibs.srcDirs = ['D:/opencv/OpenCV-android-sdk/sdk/native/libs']
}
}
CMake讲解https://www.jianshu.com/p/6332418b12b1
CMakeLists.txt 配置
# 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.
#该变量为真时会创建完整版本的Makefile
set(CMAKE_VERBOSE_MAKEFILE on)
#定义变量ocvlibs使后面的命令可以使用定位具体的库文件
set(ocvlibs "D:/opencv/OpenCV-android-sdk/sdk/native/libs")
#调用头文件的具体路径
include_directories(D:/opencv/OpenCV-android-sdk/sdk/native/jni/include)
#增加我们的动态库
add_library(libopencv_java3 SHARED IMPORTED )
#建立链接
set_target_properties(libopencv_java3 PROPERTIES
IMPORTED_LOCATION
"${ocvlibs}/${ANDROID_ABI}/libopencv_java3.so")
add_library(# Sets the name of the library.
native-lib
# Sets the library as a shared library.
SHARED
# Provides a relative path to your source file(s).
src/main/cpp/native-lib.cpp )
# 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增加库的链接
native-lib libopencv_java3 android log
# Links the target library to the log library
# included in the NDK.
${log-lib} )
budiler project
native-lib.cpp
#include
#include
#include
#include
using namespace cv;
using namespace std;
extern "C"
JNIEXPORT jintArray JNICALL
Java_test_opencv_com_openctbitmapgay_MainActivity_BitmapToGay(JNIEnv *env, jobject instance,
jintArray p_, jint w, jint h) {
jint *cbuf;
jboolean ptfalse =false;
cbuf = env->GetIntArrayElements(p_, &ptfalse);
if(cbuf ==NULL){
return 0;
}
Mat imgData(h, w, CV_8UC4, (unsigned char*)cbuf);
// 注意，Android的Bitmap是ARGB四通道,而不是RGB三通道
cvtColor(imgData,imgData,CV_BGRA2GRAY);
cvtColor(imgData,imgData,CV_GRAY2BGRA);
int size=w * h;
jintArray result = env->NewIntArray(size);
env->SetIntArrayRegion(result, 0, size, (jint*)imgData.data);
env->ReleaseIntArrayElements(p_, cbuf, 0);
return result;
}
MianActivity.java
public class MainActivityextends AppCompatActivity {
// Used to load the 'native-lib' library on application startup.
static {
System.loadLibrary("native-lib");
}
private Bitmapbitmap;
private Buttonbtn_1;
private ImageViewimageView;
private Buttonbtn_2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn_1 = findViewById(R.id.button_1);
btn_2 = findViewById(R.id.button_2);
imageView = findViewById(R.id.image);
bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.meinv);
btn_1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
imageView.setImageResource(R.drawable.meinv);
}
});
btn_2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
int w =bitmap.getWidth();
int h =bitmap.getHeight();
int[] piexls =new int[w * h];
bitmap.getPixels(piexls, 0, w, 0, 0, w, h);
int[] resultData = BitmapToGay(piexls, w, h);
Bitmap resultImage = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
resultImage.setPixels(resultData, 0, w, 0, 0, w, h);
imageView.setImageBitmap(resultImage);
}
});
}
public native int[]BitmapToGay(int[] p, int w, int h);
}
activity_main.xml
<?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"
android:orientation="vertical"
tools:context=".MainActivity">
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="vertical">
android:id="@+id/image"
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_weight="1"
android:src="@drawable/meinv" />
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:orientation="horizontal">
android:id="@+id/button_2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="灰度图" />
android:id="@+id/button_1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="原图" />
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