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2021.8 第九届全国大学生光电竞赛

2021.8 第九届全国大学生光电竞赛

作者: AdRainty | 来源:发表于2021-08-24 10:39 被阅读0次

    一、竞赛要求

    图片.png
    图片.png

    二、赛题分析

    已经改成线上赛了，不需要测定标准值了

    按照要求设计部分需要全程在手机上实现，光源普通光不超过20W，激光不超过10W，经过测试透射光很小几乎不存在，因此考虑用到漫反射手机摄像头获取光照强度，为了避免外界光的影响，还需要设计暗室环境

    三、手机app界面设计

    app流程如下


    图片.png

    3.1 首页面设计

    由于要求手机界面产生学校和队伍名称，考虑采用开头动画的方式，设计一个可以进行跳过的动画来展示队伍信息

    package com.example.appsrc;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;

import java.util.Timer;
import java.util.TimerTask;

public class Welcome extends AppCompatActivity implements View.OnClickListener {

    private int recLen = 15;//跳过倒计时提示15秒
    private TextView tv;
    Timer timer = new Timer();  //定义一个计时器
    private Handler handler;
    private Runnable runnable;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getSupportActionBar().hide();
        //定义全屏参数
        int flag = WindowManager.LayoutParams.FLAG_FULLSCREEN;
        //设置当前窗体为全屏显示
        getWindow().setFlags(flag, flag);
        setContentView(R.layout.fragment_main);
        initView();
        timer.schedule(task, 1000, 1000);//等待时间一秒，停顿时间一秒
        /**
         * 正常情况下不点击跳过
         */
        handler = new Handler();
        handler.postDelayed(runnable = new Runnable() {
            @Override
            public void run() {
                //从闪屏界面跳转到首界面
                Intent intent = new Intent(Welcome.this, Category.class);
                startActivity(intent);
                finish();
            }
        }, 15000);//延迟15S后发送handler信息

    }

    private void initView() {
        tv = findViewById(R.id.skip);//跳过
        tv.setOnClickListener(this);//跳过监听
    }

    TimerTask task = new TimerTask() {
        @Override
        public void run() {
            runOnUiThread(new Runnable() { // UI thread
                @Override
                public void run() {
                    recLen--;
                    tv.setText("跳过 " + recLen);
                    if (recLen < 0) {
                        timer.cancel();
                        tv.setVisibility(View.GONE);//倒计时到0隐藏字体
                    }
                }
            });
        }
    };

    /**
     * 点击跳过
     */
    @Override
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.skip:
                //从闪屏界面跳转到首界面
                Intent intent = new Intent(Welcome.this, Category.class);
                startActivity(intent);
                finish();
                if (runnable != null) {
                    handler.removeCallbacks(runnable);
                }
                break;
            default:
                break;
        }
    }
}

    xml代码如下

    <?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@color/lightSteelBlue"
    xmlns:custom="http://schemas.android.com/apk/res-auto">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="40sp"
        android:textColor="@color/dimGray"
        android:text="@string/welcome"
        android:gravity="center"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="150sp"
        />

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/la"
        android:layout_gravity="right"
        android:layout_marginTop="40dp"
        />

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/la3"
        android:layout_marginTop="280dp"
        />

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/la2"
        android:layout_gravity="center_horizontal|bottom"
        android:layout_marginBottom="120dp"
        android:layout_marginLeft="155dp"
        />

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/logo"/>

    <Button
        android:id="@+id/skip"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|right"
        android:background="@drawable/botton_style"
        android:layout_marginBottom="20dp"
        android:layout_marginRight="20dp"
        android:padding="20dp"
        android:text="@string/skip"
        android:textSize="17sp" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="#66666666"
        android:text="@string/team"
        android:gravity="center"
        android:layout_gravity="center"
        android:padding="20dp"
        android:textColor="@android:color/white"
        android:textSize="18sp" />


</FrameLayout>

    3.2 选择苹果

    由于要求测定不同种类的苹果，因此增加一个界面，选择两种不同的苹果，传输不同的Buddle，分别对应两种不同的函数。
    代码如下：

    package com.example.appsrc;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class Category extends Activity {
    private Button chooseRed, chooseYel;

    @Override
    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.catelog_ele);
        chooseRed = (Button) findViewById(R.id.chooseRed);
        chooseYel = (Button) findViewById(R.id.chooseYellow);
        setListeners();

    }

    private void setListeners(){
        chooseRed.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(Category.this, MainActivity.class);
                String s = "Red";
                intent.putExtra("data",s);
                startActivity(intent);
            }
        });
        chooseYel.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(Category.this, MainActivity.class);
                String s = "Yellow";
                intent.putExtra("data",s);
                startActivity(intent);
            }
        });
    }
}

    3.3 拍照并读取数据

    拍照算法比较常见，获取图片的亮度值采用Camara相机回调自带的NV21数组


    图片.png

    其中Y代表的是每个像素点的亮度值，亮度值转化公式如下


    图片.png

    其中我们获取的图片经过裁剪成一个圆形，代码如下

    package com.example.appsrc;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.content.res.TypedArray;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.drawable.NinePatchDrawable;
import android.util.Log;
import android.widget.ImageView;

public class RoundImageView extends androidx.appcompat.widget.AppCompatImageView {

    private static final String TAG = "RoundImageView";
    private static final boolean DEBUG = true;
    private int mBorderThickness = 0;
    private Context mContext;
    private int defaultColor = 0xFFFFFFFF;
    // 如果只有其中一个有值，则只画一个圆形边框
    private int mBorderOutsideColor = 0;
    private int mBorderInsideColor = 0;
    // 控件默认长、宽
    private int defaultWidth = 0;
    private int defaultHeight = 0;
    //控件画圆的宽高。
    private int requestWH = 0;

    public RoundImageView(Context context) {
        this(context, null);
    }

    public RoundImageView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public RoundImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        mContext = context;
        setCustomAttributes(attrs);
    }

    /**
     * 获得自定义控件属性值
     *
     * @param attrs
     */
    private void setCustomAttributes(AttributeSet attrs) {
        TypedArray a = mContext.obtainStyledAttributes(attrs,
                R.styleable.RoundImageView);
        mBorderThickness = a.getDimensionPixelSize(
                R.styleable.RoundImageView_border_thickness, 0);
        mBorderOutsideColor = a
                .getColor(R.styleable.RoundImageView_border_outside_color,
                        defaultColor);
        mBorderInsideColor = a.getColor(
                R.styleable.RoundImageView_border_inside_color, defaultColor);
        a.recycle();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        Drawable drawable = getDrawable();
        if (drawable == null) {
            return;
        }

        if (getWidth() == 0 || getHeight() == 0) {
            return;
        }
        this.measure(0, 0);
        if (drawable.getClass() == NinePatchDrawable.class) {
            return;
        }
        Bitmap b = ((BitmapDrawable) drawable).getBitmap();
        Bitmap bitmap = b.copy(Bitmap.Config.ARGB_8888, true);

        int radius = getRadius(canvas);

        Bitmap roundBitmap = getCroppedRoundBitmap(bitmap, radius);
        canvas.drawBitmap(roundBitmap, requestWH / 2 - radius, requestWH
                / 2 - radius, null);
    }

    /**
     * 获取画园的半径，并且绘制圆的外边框
     *
     * @param canvas
     * @return
     */
    private int getRadius(Canvas canvas) {
        if (defaultWidth == 0) {
            defaultWidth = getWidth();

        }
        if (defaultHeight == 0) {
            defaultHeight = getHeight();
        }
        requestWH = defaultHeight > defaultWidth ? defaultWidth : defaultHeight;

        int radius = 0;
        if (mBorderInsideColor != defaultColor
                && mBorderOutsideColor != defaultColor) {// 定义画两个边框，分别为外圆边框和内圆边框
            radius = requestWH / 2 - 2 * mBorderThickness;
            // 画内圆
            drawCircleBorder(canvas, radius + mBorderThickness / 2,
                    mBorderInsideColor);
            // 画外圆
            drawCircleBorder(canvas, radius + mBorderThickness
                    + mBorderThickness / 2, mBorderOutsideColor);
        } else if (mBorderInsideColor != defaultColor
                && mBorderOutsideColor == defaultColor) {// 定义画一个边框
            radius = requestWH / 2 - mBorderThickness;
            drawCircleBorder(canvas, radius + mBorderThickness / 2,
                    mBorderInsideColor);
        } else if (mBorderInsideColor == defaultColor
                && mBorderOutsideColor != defaultColor) {// 定义画一个边框
            radius = (defaultWidth < defaultHeight ? defaultWidth
                    : defaultHeight) / 2 - mBorderThickness;
            drawCircleBorder(canvas, radius + mBorderThickness / 2,
                    mBorderOutsideColor);
        } else {// 没有边框
            radius = requestWH / 2;
        }
        return radius;
    }

    /**
     * 获取裁剪后的圆形图片
     *
     * @param radius 半径
     */
    private static Bitmap getCroppedRoundBitmap(Bitmap bmp, int radius) {
        Bitmap scaledSrcBmp;
        int diameter = radius * 2;

        // 为了防止宽高不相等，造成圆形图片变形，因此截取长方形中处于中间位置最大的正方形图片
        int bmpWidth = bmp.getWidth();
        int bmpHeight = bmp.getHeight();
        int squareWidth = 0, squareHeight = 0;
        int x = 0, y = 0;
        Bitmap squareBitmap;
        if (DEBUG) {
            Log.d(TAG, "the Bitmap w:" + bmpWidth + " the Bitmap h:" + bmpHeight);
        }

        if (bmpHeight > bmpWidth) {// 高大于宽
            squareWidth = squareHeight = bmpWidth;
            x = 0;
            y = (bmpHeight - bmpWidth) / 2;
            // 截取正方形图片
            squareBitmap = Bitmap.createBitmap(bmp, x, y, squareWidth,
                    squareHeight);
        } else if (bmpHeight < bmpWidth) {// 宽大于高
            squareWidth = squareHeight = bmpHeight;
            x = (bmpWidth - bmpHeight) / 2;
            y = 0;
            squareBitmap = Bitmap.createBitmap(bmp, x, y, squareWidth,
                    squareHeight);
        } else {
            squareBitmap = bmp;
        }

        if (squareBitmap.getWidth() != diameter
                || squareBitmap.getHeight() != diameter) {
            scaledSrcBmp = Bitmap.createScaledBitmap(squareBitmap, diameter,
                    diameter, true);

        } else {
            scaledSrcBmp = squareBitmap;
        }
        Bitmap output = Bitmap.createBitmap(scaledSrcBmp.getWidth(),
                scaledSrcBmp.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(output);

        Paint paint = new Paint();
        Rect rect = new Rect(0, 0, scaledSrcBmp.getWidth(),
                scaledSrcBmp.getHeight());

        paint.setAntiAlias(true);
        paint.setFilterBitmap(true);
        paint.setDither(true);
        canvas.drawARGB(0, 0, 0, 0);
        canvas.drawCircle(scaledSrcBmp.getWidth() / 2,
                scaledSrcBmp.getHeight() / 2, scaledSrcBmp.getWidth() / 2,
                paint);
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        canvas.drawBitmap(scaledSrcBmp, rect, rect, paint);
        bmp.recycle();
        squareBitmap.recycle();
        scaledSrcBmp.recycle();
        bmp = null;
        squareBitmap = null;
        scaledSrcBmp = null;
        return output;
    }

    /**
     * 边缘画圆
     */
    private void drawCircleBorder(Canvas canvas, int radius, int color) {
        Paint paint = new Paint();
        /* 去锯齿 */
        paint.setAntiAlias(true);
        paint.setFilterBitmap(true);
        paint.setDither(true);
        paint.setColor(color);
        /* 设置paint的　style　为STROKE：空心 */
        paint.setStyle(Paint.Style.STROKE);
        /* 设置paint的外框宽度 */
        paint.setStrokeWidth(mBorderThickness);
        canvas.drawCircle(requestWH / 2, requestWH / 2, radius, paint);
    }

    /**
     * 设置外边框的宽度
     *
     * @param borderWith
     */
    public void setBorderWith(int borderWith) {
        mBorderThickness = borderWith;
    }

    /**
     * 设置外边框的颜色
     *
     * @param outsideColor
     */
    public void setBorderOutsideColor(int outsideColor) {
        mBorderOutsideColor = outsideColor;
    }

    /**
     * 设置内边框的颜色
     *
     * @param insideColor
     */
    public void setBorderInsideColor(int insideColor) {
        mBorderInsideColor = insideColor;
    }

}

    手机1：1拍照出来的像素为3472*3472，着实够大，我们亮度点不需要取那么多，最后决定取500个最亮的像素点取平均值算出总亮度，因此核心代码如下

    package com.example.appsrc;

import android.Manifest;
import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.hardware.Camera;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;

import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import androidx.core.content.FileProvider;
import androidx.core.os.EnvironmentCompat;
import androidx.appcompat.app.AppCompatActivity;

import android.os.Environment;
import android.provider.MediaStore;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import com.tbruyelle.rxpermissions2.RxPermissions;

import java.io.File;
import java.io.IOException;
import java.lang.reflect.Array;
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Date;
import java.util.List;
import java.util.Locale;

import static java.lang.Math.pow;

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "ShortcutUtils";

    // 拍照的requestCode
    private static final int CAMERA_REQUEST_CODE = 0x00000010;
    // 申请相机权限的requestCode
    private static final int PERMISSION_CAMERA_REQUEST_CODE = 0x00000012;
    private String category;
    /**
     * 用于保存拍照图片的uri
     */
    private Uri mCameraUri;
    TextView sugarView;
    private static final int CROP_PHOTO = 12;

    /**
     * 用于保存图片的文件路径，Android 10以下使用图片路径访问图片
     */
    private String mCameraImagePath;

    /**
     *  是否是Android 10以上手机
     */
    private final boolean isAndroidQ = Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.Q;

    //预览控件
    private Button takePicBtn, clearPicBtn;
    private ImageView imgView;
    private float light = 0;

    private void getPermissions() {
        RxPermissions rxPermissions = new RxPermissions(this);
        rxPermissions.request(Manifest.permission.READ_EXTERNAL_STORAGE,
                Manifest.permission.WRITE_EXTERNAL_STORAGE)
                .subscribe(granted -> {
                    if (granted) {
                        Toast.makeText(getApplicationContext(), "已经获取所需权限", Toast.LENGTH_SHORT).show();
                    } else {
                        Toast.makeText(getApplicationContext(), "未能获取所需权限", Toast.LENGTH_SHORT).show();
                    }
                });
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Intent intent=getIntent();
        category = intent.getStringExtra("data");
        setContentView(R.layout.activity_main);
        getPermissions();
        getSupportActionBar().hide();
        takePicBtn = (Button) findViewById(R.id.takePicture);
        clearPicBtn = (Button) findViewById(R.id.clearImage);
        imgView = (ImageView) findViewById(R.id.myCustom);
        sugarView = (TextView) findViewById(R.id.SugarText);

        imgView.setImageResource(R.drawable.picture);

        setListeners();
    }

    private void setListeners(){
        takePicBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                checkPermissionAndCamera();
            }
        });
        clearPicBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                clearDegree();
            }
        });
    }

    private void clearDegree(){
        light = 0;
        imgView.setImageResource(R.drawable.picture);
        sugarView.setText(R.string.currentSugar);
    }


    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        try {
            processOnActivityResult(this, requestCode, resultCode, data);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void processOnActivityResult(Context context,int requestCode, int resultCode, Intent data) throws IOException {
        switch (requestCode) {
            case CAMERA_REQUEST_CODE:
                if (resultCode == RESULT_OK) {
                    // Android 10 使用图片uri加载
                    Intent intent = new Intent("com.android.camera.action.CROP");
                    intent.setDataAndType(mCameraUri, "image/*");
                    // aspectX aspectY 是宽高的比例
                    intent.putExtra("aspectX", 1);
                    intent.putExtra("aspectY", 1);
                    // 设置裁剪图片的宽高
                    intent.putExtra("outputX", 150);
                    intent.putExtra("outputY", 150);
                    intent.putExtra("scale", true);
                    intent.putExtra("circleCrop", true);
                    // 裁剪后返回数据
                    // intent.putExtra("return-data", true);
                    File photoFile = null;
                    Uri photoUri = null;
                    if (isAndroidQ) {
                        // 适配android 10
                        photoUri = createImageUri();
                    } else {
                        try {
                            photoFile = createImageFile();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }

                        if (photoFile != null) {
                            mCameraImagePath = photoFile.getAbsolutePath();
                            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
                                //适配Android 7.0文件权限，通过FileProvider创建一个content类型的Uri
                                photoUri = FileProvider.getUriForFile(this, getPackageName() + ".fileprovider", photoFile);
                            } else {
                                photoUri = Uri.fromFile(photoFile);
                            }
                        }
                    }

                    mCameraUri = photoUri;
                    intent.putExtra(MediaStore.EXTRA_OUTPUT, mCameraUri);
                    intent.putExtra("outputFormat", Bitmap.CompressFormat.JPEG.toString());
                    // 启动intent。开始裁剪
                    // startActivityForResult(intent, CROP_PHOTO);
                    startActivityForResult(intent, CROP_PHOTO);
                } else {
                    Toast.makeText(this,"取消",Toast.LENGTH_LONG).show();
                }
                break;
            case CROP_PHOTO:
                try {
                    Bitmap bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), mCameraUri);
                    imgView.setImageBitmap(bitmap);
                    light = getBright(bitmap);
                } catch (Exception e) {
                    e.printStackTrace();
                }
                // 裁剪后返回数据
                // intent.putExtra("return-data", true);
                break;
        }
    }

    /**
     * 检查权限并拍照。
     * 调用相机前先检查权限。
     */
    private void checkPermissionAndCamera() {
        int hasCameraPermission = ContextCompat.checkSelfPermission(getApplication(),
                Manifest.permission.CAMERA);
        if (hasCameraPermission == PackageManager.PERMISSION_GRANTED) {
            //有权限，调起相机拍照。
            openCamera();
        } else {
            //没有权限，申请权限。
            ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.CAMERA},
                    PERMISSION_CAMERA_REQUEST_CODE);
        }
    }

    /**
     * 处理权限申请的回调。
     */
    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        if (requestCode == PERMISSION_CAMERA_REQUEST_CODE) {
            if (grantResults.length > 0
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                //允许权限，有调起相机拍照。
                openCamera();
            } else {
                //拒绝权限，弹出提示框。
                Toast.makeText(this,"拍照权限被拒绝",Toast.LENGTH_LONG).show();
            }
        }
    }

    /**
     * 调起相机拍照
     */
    private void openCamera() {
        Intent captureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        // 判断是否有相机
        if (captureIntent.resolveActivity(getPackageManager()) != null) {
            File photoFile = null;
            Uri photoUri = null;

            if (isAndroidQ) {
                // 适配android 10
                photoUri = createImageUri();
            } else {
                try {
                    photoFile = createImageFile();
                } catch (IOException e) {
                    e.printStackTrace();
                }

                if (photoFile != null) {
                    mCameraImagePath = photoFile.getAbsolutePath();
                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
                        //适配Android 7.0文件权限，通过FileProvider创建一个content类型的Uri
                        photoUri = FileProvider.getUriForFile(this, getPackageName() + ".fileprovider", photoFile);
                    } else {
                        photoUri = Uri.fromFile(photoFile);
                    }
                }
            }

            mCameraUri = photoUri;
            if (photoUri != null) {
                captureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoUri);
                captureIntent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
                startActivityForResult(captureIntent, CAMERA_REQUEST_CODE);
            }
        }
    }

    /**
     * 创建图片地址uri,用于保存拍照后的照片 Android 10以后使用这种方法
     *
     * @return 图片的uri
     */
    private Uri createImageUri() {
        String status = Environment.getExternalStorageState();
        // 判断是否有SD卡,优先使用SD卡存储,当没有SD卡时使用手机存储
        if (status.equals(Environment.MEDIA_MOUNTED)) {
            return getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, new ContentValues());
        } else {
            return getContentResolver().insert(MediaStore.Images.Media.INTERNAL_CONTENT_URI, new ContentValues());
        }
    }

    /**
     * 创建保存图片的文件
     */
    private File createImageFile() throws IOException {
        String imageName = new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.getDefault()).format(new Date());
        File storageDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
        if (!storageDir.exists()) {
            storageDir.mkdir();
        }
        File tempFile = new File(storageDir, imageName);
        if (!Environment.MEDIA_MOUNTED.equals(EnvironmentCompat.getStorageState(tempFile))) {
            return null;
        }
        return tempFile;
    }

    // 获取图片的亮度值
    public float getBright(Bitmap bm) {
        if(bm == null) return -1;
        int width = bm.getWidth();
        int height = bm.getHeight();
        float r, g, b;
        int count = 0;
        float bright = 0;
        float data[] = new float[500];
        for (int i = 0; i < width; i++) {
            for (int j = 0; j < height; j++) {
                int localTemp = bm.getPixel(i, j);
                if (localTemp == 0){
                    continue;
                }
                count++;
                r = (localTemp | 0xff00ffff) >> 16 & 0x00ff;
                g = (localTemp | 0xffff00ff) >> 8 & 0x0000ff;
                b = (localTemp | 0xffffff00) & 0x0000ff;
                bright = (float) (0.299 * r + 0.587 * g + 0.114 * b);
                Arrays.sort(data);
                if (count > 500) {
                    if (data[0] <= bright) {
                        data[0] = bright;
                    }
                }
                else {
                    data[count-1] = bright;
                }
            }
        }
        light = totalCount(data);
        float sugar = (float) (-0.2039*light+19.33987);
        if (category.equals("Yellow")){
            sugar = (float) (sugar - 2.75);
        }
        DecimalFormat decimalFormat = new DecimalFormat(".00");
        String string = decimalFormat.format(sugar);
        showSugar(string);
        return light;
    }

    /**
     * 计算数组的平均值
     *
     * @param array 数组
     * @return 返回平均值
     */
    public static float totalCount(float[] array){
        float total=0;
        for (float value : array) {
            total += value;
        }
        total = total / array.length;
        return total;
    }

    public void showSugar(String sugar){
        String string = String.format("测得糖度值为：%s Brix", sugar);
        sugarView.setText(string);
    }
}

    xml界面代码如下

    <?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@color/lightSteelBlue"
    xmlns:custom="http://schemas.android.com/apk/res-auto">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="40sp"
        android:textColor="@color/dimGray"
        android:text="@string/welcome"
        android:gravity="center"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="90sp"
        />

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/la"
        android:layout_gravity="right"
        />

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/logo"/>

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/la3"
        android:layout_marginTop="280dp"
        />

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/la2"
        android:layout_gravity="center_horizontal|bottom"
        android:layout_marginBottom="80dp"
        android:layout_marginLeft="155dp"
        />

    <Button
        android:id="@+id/takePicture"
        android:layout_width="180dp"
        android:layout_height="70dp"
        android:layout_gravity="center_horizontal|bottom"
        android:layout_marginBottom="160dp"
        android:background="@drawable/botton_style"
        android:gravity="center"
        android:text="@string/takePhoto"
        android:textSize="20sp" />

    <Button
        android:id="@+id/clearImage"
        android:layout_width="180dp"
        android:layout_height="70dp"
        android:layout_gravity="center_horizontal|bottom"
        android:background="@drawable/botton_style"
        android:layout_marginBottom="60dp"
        android:padding="20dp"
        android:text="@string/closePicture"
        android:textSize="17sp" />

    <com.example.appsrc.RoundImageView
        android:id="@+id/myCustom"
        android:layout_width="150dp"
        android:layout_height="150dp"
        android:layout_gravity="center"
        android:scaleType="centerInside"
        custom:border_inside_color="@color/ivory"
        custom:border_outside_color="@android:color/black"
        custom:border_thickness="2dp" />

    <TextView
        android:id="@+id/SugarText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="#66666666"
        android:text="@string/currentSugar"
        android:gravity="center"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="230sp"
        android:padding="20dp"
        android:textColor="@android:color/white"
        android:textSize="18sp" />

</FrameLayout>

    四、亮度值与糖度值的测试

    学校没钱买不起爱括，只能有损测量了，哎

    图片.png

    嗯 数据差不多就是这样，输入到测试公式就好了

    五、结语

    管他什么误差呢，做完就好还混了个奖是吧~~~

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