JNI开发--C调用java的方法

• java文件
  • MyInterface

    public interface MyInterface {
    
        public void ShowMsg(String msg);
    
    }
    

    　　

  • SumDemo

    public class SumDemo {
    
        static {
            System.loadLibrary("native-lib");
        }
      
    
        public native void CallRet(MyInterface myInterface);
    }
    

    　　
  • Activity

    package com.safeluck.facedetect.mycamera;
    
    import android.annotation.SuppressLint;
    import android.app.Activity;
    import android.app.ProgressDialog;
    import android.content.ContentUris;
    import android.content.Context;
    import android.content.Intent;
    import android.database.Cursor;
    import android.graphics.Bitmap;
    import android.graphics.BitmapFactory;
    import android.graphics.Canvas;
    import android.graphics.Color;
    import android.graphics.Paint;
    import android.graphics.PointF;
    import android.graphics.drawable.BitmapDrawable;
    import android.graphics.drawable.Drawable;
    import android.media.FaceDetector;
    import android.net.Uri;
    import android.os.AsyncTask;
    import android.os.Build;
    import android.os.Bundle;
    import android.provider.DocumentsContract;
    import android.provider.MediaStore;
    import android.support.annotation.Nullable;
    import android.util.Log;
    import android.view.View;
    import android.widget.ImageView;
    import android.widget.Toast;
    
    import com.google.gson.Gson;
    import com.safeluck.facedetect.mycamera.cpp.CustomInterface;
    import com.safeluck.facedetect.mycamera.cpp.MyInterface;
    import com.safeluck.facedetect.mycamera.cpp.SumDemo;
    
    import butterknife.BindView;
    import butterknife.ButterKnife;
    import butterknife.OnClick;
    
    /**
     * aaa
     * Created by lzw on 2018/5/25. 13:17:31
     * 邮箱：[email protected]
     * All Rights Saved! Chongqing AnYun Tech co. LTD
     */
    public class SecondActivity extends Activity implements MyInterface {
        private static final int REQUECT_CODE_SEL_PIC = 120;
        private static final int MAX_FACES = 4;
        private Bitmap bm;
        @BindView(R.id.iv) ImageView image;
        private boolean hasDetected = false; //标记是否检测到人脸
        private ProgressDialog progressDialog;
        private Paint paint;
        private int i = 0;
    
    
    
        @Override
        protected void onCreate(@Nullable Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.second_layout);
            ButterKnife.bind(this);
            progressDialog = new ProgressDialog(this);
            progressDialog.setTitle("提示");
            progressDialog.setMessage("正在检测，请稍等");
    
            initPaint();
        }
    
        private void initPaint() {
            paint = new Paint();
            paint.setAntiAlias(true);
            paint.setColor(Color.BLUE);
            paint.setStrokeWidth(2);
            //设置画出的是空心方框而不是实心
            paint.setStyle(Paint.Style.STROKE);
        }
    
    
    
    
        @OnClick({R.id.btn_select,R.id.btn_detect})
        public void clickDDemo(View view) {
            switch (view.getId()) {
                case R.id.btn_detect:
    
                    detectFace();
                    getIpWhere("123.145.106.87");
                    break;
                case R.id.btn_select:
    //                selectPicture();
                    if (i<3){
                        image.setImageLevel(i++);
                    }else{
                        i=0;
                    }
                    SumDemo sumDemo = new SumDemo();
    
                    sumDemo.CallRet(this);
    
    //                Toast.makeText(this, SumDemo.helloFromJni(),Toast.LENGTH_SHORT).show();
                    break;
                default:
                    break;
            }
        }
    
    
    
        private void detectFace() {
            if (bm == null) {
                Toast.makeText(this, R.string.pls_select, Toast.LENGTH_SHORT).show();
                return;
            }
            if (hasDetected) {
                Toast.makeText(this, R.string.has_detected, Toast.LENGTH_SHORT).show();
                return;
            }
    
            new futureTask().execute();
    
        }
    
        @Override
        public void ShowMsg(String msg) {
            Log.i(TAG,"收到回调："+msg);
        }
    
    
        class futureTask extends AsyncTask<Void, Void, FaceDetector.Face[]> {
    
    
            @Override
            protected FaceDetector.Face[] doInBackground(Void... voids) {
                FaceDetector faceDetector = new FaceDetector(bm.getWidth(), bm.getHeight(), MAX_FACES);
                FaceDetector.Face[] faces = new FaceDetector.Face[MAX_FACES];
                faceDetector.findFaces(bm, faces);
                if (faces.length > 0) {
                    return faces;
                }else{
                    return null;
                }
            }
    
            @Override
            protected void onPreExecute() {
                super.onPreExecute();
                progressDialog.show();
            }
    
            @Override
            protected void onPostExecute(FaceDetector.Face[] faces) {
                super.onPostExecute(faces);
                progressDialog.dismiss();
                if (faces == null){
                    Toast.makeText(SecondActivity.this, R.string.sorry,Toast.LENGTH_SHORT).show();
                }else{
                    drawFacesArea(faces);
                }
            }
        }
    
        private void drawFacesArea(FaceDetector.Face[] faces) {
            Canvas canvas = new Canvas(bm);
            float  eyesDistance = 0f;
            for (int i=0; i<faces.length; i++){
                FaceDetector.Face face = faces[i];
                if (face != null){
                    PointF pointF = new PointF();
                    face.getMidPoint(pointF);
                    eyesDistance = face.eyesDistance();
                    canvas.drawRect(pointF.x - eyesDistance,pointF.y-eyesDistance,
                            pointF.x+eyesDistance,pointF.y+eyesDistance,paint);
                }
            }
        }
    
    
    
    
    
    
    
    
    
        private static final String TAG = "SecondActivity";
    }
    

    　　

  • cpp文件

    #include <string>
    #include "mydemo.h"
    using namespace std;
    
    int sum(int32_t a, int32_t b){
        string c = "123";
        int cc =atoi(c.c_str())+90;
        LOGD("cc=%d",cc);
        return  a+b;
    }
    
    JNIEXPORT void JNICALL
    Java_com_safeluck_facedetect_mycamera_cpp_SumDemo_CallRet(JNIEnv *env, jobject instance,
                                                              jobject myInterface){
        jclass  jclass1 = env->GetObjectClass(myInterface);
    
    
        jmethodID  jmethodID1 = env->GetMethodID(jclass1,"ShowMsg","(Ljava/lang/String;)V");
    
        const char * msg= "Hello ,Kitty";
        jstring  jstring1=env->NewStringUTF(msg);
        env->CallVoidMethod(myInterface,jmethodID1,jstring1);
        env->DeleteLocalRef(jstring1);
    }
    

    　　

  • h文件

    #ifndef AAA_MYDEMO_H
    #define AAA_MYDEMO_H
    
    #include <jni.h>
    #include <string.h>
    #include <android/log.h>
    #include <stdlib.h>
    #include <stdio.h>
    #define LOG_TAG "System.out"
    #define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, __VA_ARGS__)
    #define LOGI(...) __android_log_print(ANDROID_LOG_INFO, LOG_TAG, __VA_ARGS__)
    
    
    int sum(int32_t a, int32_t b);
    #endif //AAA_MYDEMO_H
    extern "C"
    JNIEXPORT void JNICALL
    Java_com_safeluck_facedetect_mycamera_cpp_SumDemo_CallRet(JNIEnv *env, jobject instance,
                                                              jobject myInterface) ;
    

    　　

    • attention
    •