android cpp - 技术栈

MainActivity

kotlin 复制代码

package com.example.moth

import android.content.Intent
import android.content.res.AssetManager
import android.graphics.Bitmap
import android.os.Bundle
import android.util.Log
import android.view.Menu
import android.view.MenuItem
import android.widget.Button
import android.widget.TextView
import android.widget.Toast
import com.google.android.material.snackbar.Snackbar
import com.google.android.material.navigation.NavigationView
import androidx.navigation.findNavController
import androidx.navigation.ui.AppBarConfiguration
import androidx.navigation.ui.navigateUp
import androidx.navigation.ui.setupActionBarWithNavController
import androidx.navigation.ui.setupWithNavController
import androidx.drawerlayout.widget.DrawerLayout
import androidx.appcompat.app.AppCompatActivity
import com.example.moth.databinding.ActivityMainBinding
import java.io.ByteArrayOutputStream
import okhttp3.MediaType
import okhttp3.MultipartBody
import retrofit2.Call
import retrofit2.Callback
import retrofit2.Response
import com.example.moth.httpInterface.RecognizeClient.recognizeService
import com.example.moth.httpInterface.PredictResponse
import com.example.moth.httpInterface.PredictResult


class MainActivity : AppCompatActivity() {

    private lateinit var appBarConfiguration: AppBarConfiguration
    private lateinit var binding: ActivityMainBinding
    private var selectedBitMap: Bitmap? = null
    private lateinit var recognizeResultTextView: TextView

    private lateinit var assetManager: AssetManager

    companion object {
        // 加载本地库
        init {
            System.loadLibrary("native-lib")
        }
    }

    // 声明静态native方法
    private external fun staticProcessImage(bitmap: Bitmap): String

    private val insectMapping = mapOf(
        "0" to "稻纵卷叶螟",
        "1" to "亚洲稻螟虫",
        "2" to "白蛾",
        "3" to "鬼脸天蛾",
        "4" to "玉米螟",
        "5" to "夜盗蛾",
        "6" to "桃蛀螟",
        "7" to "甘蓝夜蛾",
        "8" to "草地贪夜蛾",
        "9" to "斜带葡萄天蛾",
        "10" to "棉斜纹夜蛾",
        "11" to "枯叶夜蛾",
        "12" to "横线尾夜蛾"
    )

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        // 检查token
        val sharedPreferences = getSharedPreferences("AppPreferences", MODE_PRIVATE)
        val token = sharedPreferences.getString("token", null)

        if(token == null){
            val intent = Intent(this, LoginActivity::class.java)
            startActivity(intent)
            finish()
            return
        }

        assetManager = assets

        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        setSupportActionBar(binding.appBarMain.toolbar)

        binding.appBarMain.fab.setOnClickListener { view ->
            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                .setAction("Action", null)
                .setAnchorView(R.id.fab).show()
        }
        val drawerLayout: DrawerLayout = binding.drawerLayout
        val navView: NavigationView = binding.navView
        val navController = findNavController(R.id.nav_host_fragment_content_main)
        // Passing each menu ID as a set of Ids because each
        // menu should be considered as top level destinations.
        appBarConfiguration = AppBarConfiguration(
            setOf(
                R.id.nav_home, R.id.nav_gallery, R.id.nav_slideshow
            ), drawerLayout
        )
        setupActionBarWithNavController(navController, appBarConfiguration)
        navView.setupWithNavController(navController)

        recognizeResultTextView = findViewById(R.id.recognizeResult)
        val recognizeButton: Button = findViewById(R.id.recognizeButton)
        val uploadButton: Button = findViewById(R.id.recognizeOnlineButton)

        // 设置离线识别按钮的点击事件
        recognizeButton.setOnClickListener {
            selectedBitMap?.let {bitmap ->
                val inferenceResult = staticProcessImage(bitmap)
                val inferenceTop3 = inferenceResult.split(" ")
                val mappedResult = inferenceTop3.map { insectMapping[it] ?: " "}
                val returnText = "离线识别的结果是：$mappedResult"
                recognizeResultTextView.text = returnText
            } ?: run {
                recognizeResultTextView.text = "请先选择图片"
            }
        }
        // 设置上传识别按钮的点击事件
        uploadButton.setOnClickListener {
            selectedBitMap?.let {bitmap ->
                val imageStream = bitmap2ByteArray(bitmap)
                uploadImage(imageStream)
            } ?: run{
                recognizeResultTextView.text = "请先选择图片"
            }
        }

    }

    private fun bitmap2ByteArray(bitmap: Bitmap): ByteArray {
        val outputStream = ByteArrayOutputStream()
        bitmap.compress(Bitmap.CompressFormat.JPEG, 100, outputStream)
        return outputStream.toByteArray()
    }

    private fun uploadImage(byteArray: ByteArray){
        val requestBody = okhttp3.RequestBody.create(MediaType.parse("image/jpeg"), byteArray)
        val filePart = MultipartBody.Part.createFormData("image", "image.jpg", requestBody)
        recognizeService.predict(filePart).enqueue(object : Callback<PredictResponse> {
            override fun onResponse(
                call: Call<PredictResponse>,
                response: Response<PredictResponse>
            ) {
                if(response.isSuccessful && response.body()?.success == true) {
                    val result = response.body()?.predictions
                    if(result == null){
                        Toast.makeText(this@MainActivity, "上传图片成功，但未返回识别结果", Toast.LENGTH_SHORT).show()
                    }else {
                        val labels: List<String> = result.map { it.label }
                        val mappedLabels = labels.map { insectMapping[it] ?: " "}
                        val returnText = "上传识别的结果是：$mappedLabels"
                        recognizeResultTextView.text = returnText
                    }
                }else {
                    Toast.makeText(this@MainActivity, "上传图片失败", Toast.LENGTH_SHORT).show()
                }
            }

            override fun onFailure(call: Call<PredictResponse>, t: Throwable) {
                Toast.makeText(this@MainActivity, "请求失败", Toast.LENGTH_SHORT).show()
                Log.e("MainActivity", "上传图片失败: ${t.message}")
            }

        })
    }

    override fun onCreateOptionsMenu(menu: Menu): Boolean {
        // Inflate the menu; this adds items to the action bar if it is present.
        menuInflater.inflate(R.menu.main, menu)
        return true
    }

    override fun onOptionsItemSelected(item: MenuItem): Boolean {
        when(item.itemId){
            R.id.logout -> {
                val sharedPreferences = getSharedPreferences("AppPreferences", MODE_PRIVATE)
                val editor = sharedPreferences.edit()
                editor.remove("token")
                editor.apply()
                val intent = Intent(this, LoginActivity::class.java)
                startActivity(intent)
                finish()
                return true
            }
        }
        return super.onOptionsItemSelected(item)
    }

    override fun onSupportNavigateUp(): Boolean {
        val navController = findNavController(R.id.nav_host_fragment_content_main)
        return navController.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()
    }
    fun setSelectedBitMap(bitmap: Bitmap){
        selectedBitMap = bitmap
    }
}

CMakeList

bash 复制代码

project(moth)

cmake_minimum_required(VERSION 3.10.0)

# 设置Android环境
set(CMAKE_SYSTEM_NAME Android)
set(CMAKE_ANDROID_NDK $ENV{ANDROID_NDK_HOME})
set(CMAKE_ANDROID_STL_TYPE c++_static)

# 设置 ncnn 库路径
set(ncnn_DIR ${CMAKE_SOURCE_DIR}/ncnn/${ANDROID_ABI}/lib)

# 设置opencv 库路径
set(opencv_DIR ${CMAKE_SOURCE_DIR}/opencv/native)

# 查找并连接libandroid.so
find_library(android-lib android)

# 添加 ncnn 库
add_library(ncnn SHARED IMPORTED)
set_target_properties(ncnn PROPERTIES IMPORTED_LOCATION ${ncnn_DIR}/libncnn.so)

# 添加opencv 库
add_library(opencv SHARED IMPORTED)
set_target_properties(opencv PROPERTIES IMPORTED_LOCATION ${opencv_DIR}/libs/${ANDROID_ABI}/libopencv_java4.so)

include_directories(${opencv_DIR}/jni/include)

# 添加cpp源码
add_library(native-lib SHARED native-lib.cpp)

# 添加C++标准库
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

# 链接 ncnn 库
target_link_libraries(native-lib ${android-lib} ncnn opencv jnigraphics c++_shared)

native-lib.cpp

cpp 复制代码

//
// Created by Dell on 2025/2/20.
//
//
// Created by Dell on 2025/2/20.
//
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
#include <jni.h>
#include <string>
#include <android/asset_manager.h>
#include <android/asset_manager_jni.h>
#include <android/bitmap.h>
#include <opencv2/opencv.hpp>
#include "ncnn/arm64-v8a/include/ncnn/net.h"


// 中心裁切并归一化处理
cv::Mat preprocessImage(const cv::Mat& inputImage, int targetWidth, int targetHeight) {

    cv::Mat resizedImage;
    cv::resize(inputImage, resizedImage, cv::Size(targetWidth, targetHeight));

    // 将裁切后的图像转换为浮点型并归一化
    cv::Mat normalizedImage;
    resizedImage.convertTo(normalizedImage, CV_32F, 1.0 / 255.0);

    // 归一化处理
    cv::Mat channels[3];
    cv::split(normalizedImage, channels);

    // 对每个通道进行归一化
    for (int i = 0; i < 3; ++i) {
        channels[i] = (channels[i] - 0.485) / 0.229;  // 第一个通道R
        if (i == 1) {
            channels[i] = (channels[i] - 0.456) / 0.224;  // 第二个通道G
        } else if (i == 2) {
            channels[i] = (channels[i] - 0.406) / 0.225;  // 第三个通道B
        }
    }

    // 合并通道
    cv::merge(channels, 3, normalizedImage);

    return normalizedImage;
}


extern "C"
JNIEXPORT jstring JNICALL
JNICALL
Java_com_example_moth_MainActivity_staticProcessImage(JNIEnv* env, jobject thiz, jobject bitmap) {
    // 获取 AssetManager
    jclass clazz = env->GetObjectClass(thiz);
    jfieldID assetManagerFieldID = env->GetFieldID(clazz, "assetManager", "Landroid/content/res/AssetManager;");
    jobject assetManagerObj = env->GetObjectField(thiz, assetManagerFieldID);
    AAssetManager* assetManager = AAssetManager_fromJava(env, assetManagerObj);

    // 加载 .param 文件
    AAsset* paramAsset = AAssetManager_open(assetManager, "effivit.param", AASSET_MODE_BUFFER);
    if (!paramAsset) {
        return env->NewStringUTF("Failed to open model.param");
    }

    // 读取 .param 文件内容
    size_t paramSize = AAsset_getLength(paramAsset);
    char* paramBuffer = new char[paramSize];
    AAsset_read(paramAsset, paramBuffer, paramSize);
    AAsset_close(paramAsset);

    // 加载 .bin 文件
    AAsset* binAsset = AAssetManager_open(assetManager, "effivit.bin", AASSET_MODE_BUFFER);
    if (!binAsset) {
        delete[] paramBuffer;
        return env->NewStringUTF("Failed to open model.bin");
    }

    // 读取 .bin 文件内容
    size_t binSize = AAsset_getLength(binAsset);
    char* binBuffer = new char[binSize];
    AAsset_read(binAsset, binBuffer, binSize);
    AAsset_close(binAsset);

    // 创建 ncnn 网络
    ncnn::Net net;
    int ret = net.load_param(assetManager, "effivit.param");
    if (ret != 0) {
        delete[] paramBuffer;
        delete[] binBuffer;
        return env->NewStringUTF("Failed to load model.param");
    }
    ret = net.load_model(assetManager, "effivit.bin");
    if (ret != 0) {
        delete[] paramBuffer;
        delete[] binBuffer;
        return env->NewStringUTF("Failed to load model.bin");
    }

    // 释放内存
    delete[] paramBuffer;
    delete[] binBuffer;

    // 获取 Bitmap 信息
    AndroidBitmapInfo info;
    void* pixels;
    int retBitmap;

    if ((retBitmap = AndroidBitmap_getInfo(env, bitmap, &info)) < 0) {
        return env->NewStringUTF("AndroidBitmap_getInfo() failed!");
    }

    if (info.format != ANDROID_BITMAP_FORMAT_RGBA_8888) {
        return env->NewStringUTF("Bitmap format is not RGBA_8888!");
    }

    if ((retBitmap = AndroidBitmap_lockPixels(env, bitmap, &pixels)) < 0) {
        return env->NewStringUTF("AndroidBitmap_lockPixels() failed!");
    }

    // 将 Bitmap 转换为 OpenCV Mat
    cv::Mat mat(info.height, info.width, CV_8UC4, pixels);
    cv::Mat mat3;
    cv::cvtColor(mat, mat3, cv::COLOR_RGBA2BGR);

    // 调整图像大小
    int targetWidth = 224;
    int targetHeight = 224;
    cv::Mat resizedMat;  //= preprocessImage(mat3, targetWidth, targetHeight);
    cv::resize(mat3, resizedMat, cv::Size(targetWidth, targetHeight));

    // 将 Mat 转换为 ncnn::Mat
    ncnn::Mat in = ncnn::Mat::from_pixels(resizedMat.data, ncnn::Mat::PIXEL_BGR, targetWidth, targetHeight);

    // 进行推理
    ncnn::Extractor ex = net.create_extractor();
    ex.input("input.1", in);
    ncnn::Mat out;
    ex.extract("1270", out);

    // 释放 Bitmap 像素数据
    AndroidBitmap_unlockPixels(env, bitmap);

    // 处理输出结果
    // 假设张量 out 的形状为 (1, 13)，即 1 行 13 列
    float* outputData = (float*)out.data;
    int numClasses = out.w; // 获取类别数量（13）

    // 找到概率最大的三个下标
    std::vector<std::pair<float, int>> probIndexPairs;
    for (int i = 0; i < numClasses; i++) {
        probIndexPairs.push_back(std::make_pair(outputData[i], i));
    }

    // 按概率值从大到小排序
    std::sort(probIndexPairs.begin(), probIndexPairs.end(), [](const std::pair<float, int>& a, const std::pair<float, int>& b) {
        return a.first > b.first;
    });

    // 获取概率最大的三个下标
    std::string result;
    for (int i = 0; i < 3 && i < probIndexPairs.size(); i++) {
        result += std::to_string(probIndexPairs[i].second) + " ";
    }

    // 返回结果给调用方
    return env->NewStringUTF(result.c_str());
}

stb_image.h

c 复制代码

在这里插入代码片