Android - JNI靜態(static)載入OpenCV

Android - JNI靜態(static)載入OpenCV
JNI靜態(static)載入OpenCV

本文地址: http://blog.csdn.net/caroline_wendy

步驟:

1. 準備OpenCV-Android庫

複製OpenCV的sdk至工作資料夾.

下載OpenCV的最新android-sdk: OpenCV-2.4.9-android-sdk;

把其中的sdk檔案夾, 複製到工作目錄; sdk檔案夾裡包含native, java, etc. 三個檔案夾.

2. 載入OpenCV-Android庫

匯入(import)工作目錄的java檔案夾, 設定為當前項目的庫.

[項目名]右鍵點擊->Android->Add Library->選擇添加的庫. 即可. 不需要選擇Is Library.

3. 建立 JniClient類.

包含需要使用的方法(method), 可以多個.<喎?http://www.bkjia.com/kf/ware/vc/" target="_blank" class="keylink">vcD48cD48L3A+PHByZSBjbGFzcz0="brush:java;">/** * */package com.example.hellomyjni;/** * @author Administrator * */public class JniClient {static public native String sayName();static public native int[] grayImage(int[] pixels, int w, int h);}
使用命令列, 產生標頭檔.

進入專案檔夾, 產生JNI的標頭檔, 使用命令:

"javah -classpath bin/classes -d jni com.example.hellomyjni.JniClient"

或javah -classpath D:/eclipse-android/android-sdk/platforms/android-17/android.jar;bin/classes -d jni com.example.mycamera.CartoonifierView

包含Android庫.

命令解析:

javah 產生標頭檔;

-classpath 使用類的位置(bin/classes), 都是.class檔案;

-d jni 需要產生JNI的類(com.example.hellomyjni.JniClient), 包括[package].[classname].

其餘參考: http://blog.csdn.net/caroline_wendy/article/details/39032551

4. 修改JNI設定檔

需要在jni檔案夾內建立Application.mk, 主要負責C++標準的使用(APP_STL), 和需要編譯的庫.

APP_STL := gnustl_staticAPP_CPPFLAGS := -frtti -fexceptionsAPP_ABI := armeabi-v7a

修改 Android.mk, 不需要使用OPENCV_LIB_TYPE:=STATIC

LOCAL_PATH := $(call my-dir)include $(CLEAR_VARS)#OPENCV_LIB_TYPE:=STATICOPENCV_INSTALL_MODULES:=oninclude C:/Users/Administrator/android-workspace/opencv-sdk/native/jni/OpenCV.mkLOCAL_MODULE    := HelloMyJniLOCAL_SRC_FILES := HelloMyJni.cppLOCAL_LDLIBS +=  -llog -ldl#LOCAL_C_INCLUDES += ./LOCAL_SRC_FILES += ./sayname.cppinclude $(BUILD_SHARED_LIBRARY)

5. JNI函數

#include #include using namespace cv;#include "com_example_hellomyjni_JniClient.h"#include "sayname.h"JNIEXPORT jstring JNICALL Java_com_example_hellomyjni_JniClient_sayName  (JNIEnv *env, jclass) {string str = sayname();return env->NewStringUTF(str.c_str());}JNIEXPORT jintArray JNICALL Java_com_example_hellomyjni_JniClient_grayImage  (JNIEnv *env, jclass, jintArray buf, jint w, jint h ) {jint *cbuf;cbuf = env->GetIntArrayElements(buf, false);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++) {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);env->SetIntArrayRegion(result, 0, size, cbuf);env->ReleaseIntArrayElements(buf, cbuf, 0);return result;}

在項目中添加 OpenCV標頭檔的檢查, 可以避免檔案報錯.

6. 修改MainActivity

調用JNI的函數.

package com.example.hellomyjni;import org.opencv.android.OpenCVLoader;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Bitmap.Config;import android.os.Bundle;import android.view.Menu;import android.view.MenuItem;import android.widget.ImageView;import android.widget.TextView;public class MainActivity extends Activity{private ImageView iv;private Bitmap bmp;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);TextView tv = (TextView) findViewById(R.id.text_view);tv.setText(JniClient.sayName()); //recall JNIiv = (ImageView) findViewById(R.id.image_view);bmp = BitmapFactory.decodeResource(getResources(), R.drawable.shoes);int w = bmp.getWidth();int h = bmp.getHeight();int[] pixels = new int[w * h];bmp.getPixels(pixels, 0, w, 0, 0, w, h);int[] resultInt = JniClient.grayImage(pixels, w, h); //recall JNIBitmap resultImg = Bitmap.createBitmap(w, h, Config.ARGB_8888);resultImg.setPixels(resultInt, 0, w, 0, 0, w, h);iv.setImageBitmap(resultImg);}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.main, menu);return true;}@Overridepublic boolean onOptionsItemSelected(MenuItem item) {// Handle action bar item clicks here. The action bar will// automatically handle clicks on the Home/Up button, so long// as you specify a parent activity in AndroidManifest.xml.int id = item.getItemId();if (id == R.id.action_settings) {return true;}return super.onOptionsItemSelected(item);}static {if (!OpenCVLoader.initDebug()) {    } else {        System.loadLibrary("HelloMyJni");    }}}

7. 輸出