android studio之OpenCV(native)使用

参考博文：http://blog.csdn.net/sbsujjbcy/article/details/49520791

• 拷贝OpenCV SDK下的native到工程的根目录下，如下图：

• 在main下创建jni目录，如图所示：

• jni下创建android.mk和application.mk,编辑文件，内容如下：

android.mk

# Copyright (C) 2009 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.#LOCAL_PATH := $(call my-dir)include $(CLEAR_VARS)OpenCV_INSTALL_MODULES := onOpenCV_CAMERA_MODULES := offOPENCV_LIB_TYPE := SHAREDifeq ("$(wildcard $(OPENCV_MK_PATH))","")include ../../../../native/jni/OpenCV.mkelseinclude $(OPENCV_MK_PATH)endifLOCAL_MODULE    := OpenCVLOCAL_SRC_FILES := IDCardRecognizeUtil.cpp\ com_hodi_hodi_opencv_OpenCVHelper.cpp*[注意：所有要调用的C++/C类都要在这添加才可以使用]*LOCAL_LDLIBS +=  -lm -llogLOCAL_LDLIBS += -landroid*【注意：landroid 可以调试打印出android的log信息，否则不行】*include $(BUILD_SHARED_LIBRARY)

application.mk

APP_STL := gnustl_staticAPP_CPPFLAGS := -frtti -fexceptionsAPP_ABI := all【App_ABI:声明针对哪些cpu架构的.so】

• 修改app/build.gradle,内容如下：

apply plugin: 'com.android.application'android {    compileSdkVersion 24    buildToolsVersion "23.0.3"    defaultConfig {        applicationId "com.hodi.hodi_opencv"        minSdkVersion 15        targetSdkVersion 24        versionCode 1        versionName "1.0"        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"    }    buildTypes {        release {            minifyEnabled false            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'        }    }    sourceSets.main.jni.srcDirs = []    //禁止自带的ndk功能    *【添加这行jni目录由蓝色变位黄色】*    sourceSets.main.jniLibs.srcDirs = ['src/main/libs','src/main/jniLibs']    //重定向so目录为src/main/libs，原来为src/main/jniLibs    clean.dependsOn 'ndkClean'}task ndkBuild(type:Exec, group:'ndk') {    Properties properties = new Properties()    properties.load(project.rootProject.file('local.properties').newDataInputStream())    def ndkDir = properties.getProperty('ndk.dir')    if (org.apache.tools.ant.taskdefs.condition.Os.isFamily(org.apache.tools.ant.taskdefs.condition.Os.FAMILY_WINDOWS)) {        commandLine "$ndkDir/ndk-build.cmd", '-C', file('src/main/jni').absolutePath    } else {        commandLine "$ndkDir/ndk-build", '-C', file('src/main/jni').absolutePath    }}tasks.withType(JavaCompile) {        compileTask -> compileTask.dependsOn ndkBuild    }task ndkClean(type:Exec, group:'ndk'){    Properties properties = new Properties()    properties.load(project.rootProject.file('local.properties').newDataInputStream())    def ndkDir = properties.getProperty('ndk.dir')    if (org.apache.tools.ant.taskdefs.condition.Os.isFamily(org.apache.tools.ant.taskdefs.condition.Os.FAMILY_WINDOWS)) {        commandLine "$ndkDir/ndk-build.cmd",'clean', '-C', file('src/main/jni').absolutePath    } else {        commandLine "$ndkDir/ndk-build",'clean', '-C', file('src/main/jni').absolutePath    }}

• 创建一个native类，内容如下：

public class OpenCVHelper {    static {        System.loadLibrary("OpenCV");    }    public static native int[] gray(int[] buf, int w, int h);    public static native int[] imageToGray(String path);}

• **再terminal ，输入javah -d jni -classpath [class路劲]
  com.hodi.hodi_opencv.OpenCVHelper生成.h**

/* DO NOT EDIT THIS FILE - it is machine generated */#include <jni.h>/* Header for class com_hodi_hodi_opencv_OpenCVHelper */#ifndef _Included_com_hodi_hodi_opencv_OpenCVHelper#define _Included_com_hodi_hodi_opencv_OpenCVHelper#ifdef __cplusplusextern "C" {#endif/* * Class:     com_hodi_hodi_opencv_OpenCVHelper * Method:    recognizeIDCard * Signature: (Ljava/lang/String;Ljava/lang/String;)Z */JNIEXPORT jstring JNICALL Java_com_hodi_hodi_1opencv_OpenCVHelper_recognizeIDCard  (JNIEnv *, jclass, jobject,jstring, jstring);#ifdef __cplusplus}#endif#endif

• 创建对应.h的实现类.cpp或.c

//// Created by AA on 2016/11/18.//#include "com_hodi_hodi_opencv_OpenCVHelper.h"#include "IDCardRecognizeUtil.h"#include <string.h>#include <Android/log.h>#include <Android/asset_manager.h>#include <Android/asset_manager_jni.h>#define TAG "cn.linjk.ihouse.jni"#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG,TAG ,__VA_ARGS__)#define LOGI(...) __android_log_print(ANDROID_LOG_INFO,TAG ,__VA_ARGS__)#define LOGW(...) __android_log_print(ANDROID_LOG_WARN,TAG ,__VA_ARGS__)#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR,TAG ,__VA_ARGS__)#define LOGF(...) __android_log_print(ANDROID_LOG_FATAL,TAG ,__VA_ARGS__)////////////////////////////////////////////////////////////////////////////////extern "C" {JNIEXPORT jstring JNICALL Java_com_hodi_hodi_1opencv_OpenCVHelper_recognizeIDCard        (JNIEnv *, jclass, jobject,jstring, jstring);////////////////////////////////////////////////////////////////////////////JNIEXPORT jintArray JNICALL Java_com_hodi_hodi_1opencv_OpenCVHelper_gray(        JNIEnv *env, jclass obj, jintArray buf, int w, int h) {    jint *cbuf;    cbuf = env->GetIntArrayElements(buf, JNI_FALSE );//将JNI数组转换为基本类型数组    if (cbuf == NULL) {        return 0;    }    Mat imgData(h, w, CV_8UC4, (unsigned char *) cbuf);    uchar* ptr = imgData.ptr(0);    for(int i = 0; i < w*h; i ++){        //计算公式：Y(亮度) = 0.299*R + 0.587*G + 0.114*B        //对于一个int四字节，其彩色值存储方式为：BGRA        int grayScale = (int)(ptr[4*i+2]*0.299 + ptr[4*i+1]*0.587 + ptr[4*i+0]*0.114);        ptr[4*i+1] = grayScale;        ptr[4*i+2] = grayScale;        ptr[4*i+0] = grayScale;    }    int size = w * h;    jintArray result = env->NewIntArray(size);//生成新的数组    env->SetIntArrayRegion(result, 0, size, cbuf);//为result赋值    env->ReleaseIntArrayElements(buf, cbuf, 0);//释放内存    return result;}}

• 执行task ndkBuild,生成.so库

task ndkBuild(type:Exec, group:'ndk') {    Properties properties = new Properties()    properties.load(project.rootProject.file('local.properties').newDataInputStream())    def ndkDir = properties.getProperty('ndk.dir')    if (org.apache.tools.ant.taskdefs.condition.Os.isFamily(org.apache.tools.ant.taskdefs.condition.Os.FAMILY_WINDOWS)) {        commandLine "$ndkDir/ndk-build.cmd", '-C', file('src/main/jni').absolutePath    } else {        commandLine "$ndkDir/ndk-build", '-C', file('src/main/jni').absolutePath    }}

• 在测试类调用，调用成功即可

package com.hodi.hodi_opencv;import android.content.Intent;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.drawable.BitmapDrawable;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.Button;import android.widget.ImageView;public class MainActivity extends AppCompatActivity {    private Button btn;    private ImageView img;    private Button btn_id;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initView();    }    private void initView() {        btn= (Button) findViewById(R.id.btn);        img= (ImageView) findViewById(R.id.img);        btn_id = (Button) findViewById(R.id.bt_id_card);        btn.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                Bitmap bitmap = ((BitmapDrawable) getResources().getDrawable(                        R.drawable.im)).getBitmap();                int w = bitmap.getWidth();                int h = bitmap.getHeight();                int[] pix = new int[w * h];                bitmap.getPixels(pix, 0, w, 0, 0, w, h);                int [] resultPixes = OpenCVHelper.gray(pix,w,h);                Bitmap result = Bitmap.createBitmap(w,h, Bitmap.Config.RGB_565);                result.setPixels(resultPixes, 0, w, 0, 0,w, h);                img.setImageBitmap(result);            }        });}}