MyCamera

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# MyCamera
最近发现不同手机，调用系统相机效果不太好,，所以学习Android 的相机原理，自定义了一个Android相机。看了这篇博客，相信大家都会写一个自己的相机。对比了一下小猿搜题、学霸君、作业帮、阿凡题这四款app的拍照功能，个人感觉小猿搜题的体验要好一些，因为从主界面进入拍照界面，连个界面没有一个旋转的过渡，而学霸君就有一个过渡，有一丝丝的影响体验。也就是说学霸君的拍照界面是横屏的，在activity的onCreate方法里面调用了setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE)来设置全屏，而切换界面的时候又从竖屏切换为横屏，就会有个过渡的效果，影响了体验。

项目地址：https://github.com/Terrybthvi/MyCamera

这个项目仿照小猿搜题app，首先我们将相机布局最低层是显示摄像头获取到的图像，上层是网格线，聚焦图标等。

效果图如下所示：

1、绘制网格参考线

绘制网格参考线就是绘制拍照时屏幕中的竖线和直线，代码如下所示：

2、自定义相机代码

这里我们要创建一个SurfaceView，将摄像头获取到的图像放到SurfsaceView中显示。主要方法如下：

1、继承SurfaceView，定义变量，初始化类。

2、实现三个方法对sufarceView监听。

surfaceCreated();
surfaceChanged();
surfaceDestroyed();

3、获取相机实例

4、设置相机监听

5、增加自动聚焦 和点击屏幕聚焦

6、拍照以及设置图片格式

3、为相机添加聚焦功能

4、Activity调用相机

actiity中注册了SensorEventListener，也就是使用传感器监听用户手机的移动，如果有一定距离的移动，则自动聚焦，这样体验好一点。
```
package com.example.terry.mycamera;

import android.animation.AnimatorSet;
import android.animation.ObjectAnimator;
import android.annotation.TargetApi;
import android.app.Activity;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.content.res.Configuration;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.text.format.DateFormat;
import android.util.Log;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.view.animation.LinearInterpolator;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.TextView;

import com.example.terry.mycamera.Crop.CropImageView;
import com.example.terry.mycamera.Crop.CropperImage;
import com.example.terry.mycamera.camare.CameraPreview;
import com.example.terry.mycamera.camare.FocusView;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;

/**
 * @Class: TakePhotoActivity
 * @Description: 拍照界面
 * @author: leiqi(http://blog.csdn.net/u013132758)
 * @Date: 2016/3/15
 */
public class TakePhotoActivity extends Activity implements CameraPreview.OnCameraStatusListener,
        SensorEventListener {
    private static final String TAG = "TakePhoteActivity";
    public static final Uri IMAGE_URI = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
    public static final String PATH = Environment.getExternalStorageDirectory()
            .toString() + "/AndroidMedia/";
    CameraPreview mCameraPreview;
    CropImageView mCropImageView;
    RelativeLayout mTakePhotoLayout;
    LinearLayout mCropperLayout;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // 设置横屏
//        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
        // 设置全屏
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.activity_take_photo);
        // Initialize components of the app
        mCropImageView = (CropImageView) findViewById(R.id.CropImageView);
        mCameraPreview = (CameraPreview) findViewById(R.id.cameraPreview);
        FocusView focusView = (FocusView) findViewById(R.id.view_focus);
        mTakePhotoLayout = (RelativeLayout) findViewById(R.id.take_photo_layout);
        mCropperLayout = (LinearLayout) findViewById(R.id.cropper_layout);

mCameraPreview.setFocusView(focusView);
        mCameraPreview.setOnCameraStatusListener(this);
        mCropImageView.setGuidelines(2);

mSensorManager = (SensorManager) getSystemService(Context.
                SENSOR_SERVICE);
        mAccel = mSensorManager.getDefaultSensor(Sensor.
                TYPE_ACCELEROMETER);

}

boolean isRotated = false;

@TargetApi(Build.VERSION_CODES.HONEYCOMB)
    @Override
    protected void onResume() {
        super.onResume();
        if(!isRotated) {
            TextView hint_tv = (TextView) findViewById(R.id.hint);
            ObjectAnimator animator = ObjectAnimator.ofFloat(hint_tv, "rotation", 0f, 90f);
            animator.setStartDelay(800);
            animator.setDuration(1000);
            animator.setInterpolator(new LinearInterpolator());
            animator.start();
            View view =  findViewById(R.id.crop_hint);
            AnimatorSet animSet = new AnimatorSet();
            ObjectAnimator animator1 = ObjectAnimator.ofFloat(view, "rotation", 0f, 90f);
            ObjectAnimator moveIn = ObjectAnimator.ofFloat(view, "translationX", 0f, -50f);
            animSet.play(animator1).before(moveIn);
            animSet.setDuration(10);
            animSet.start();
            isRotated = true;
        }
        mSensorManager.registerListener(this, mAccel, SensorManager.SENSOR_DELAY_UI);
    }

@Override
    protected void onPause() {
        super.onPause();
        mSensorManager.unregisterListener(this);
    }

@Override
    public void onConfigurationChanged(Configuration newConfig) {
        Log.e(TAG, "onConfigurationChanged");
        super.onConfigurationChanged(newConfig);
    }

public void takePhoto(View view) {
        if(mCameraPreview != null) {
            mCameraPreview.takePicture();
        }
    }

public void openlight(View view)
    {
        if (mCameraPreview != null)
        {
            mCameraPreview.openLight();
            view.setVisibility(View.GONE);
            View v = findViewById(R.id.nolight);
            v.setVisibility(View.VISIBLE);
        }
    }
public void offlight(View v)
{
    if (mCameraPreview != null)
    {
        mCameraPreview.offLight();
        v.setVisibility(View.GONE);
        View view = findViewById(R.id.light);
        view.setVisibility(View.VISIBLE);
    }
}
    public void close(View view) {
        finish();
    }

/**
     * 关闭截图界面
     * @param view
     */
    public void closeCropper(View view) {
        showTakePhotoLayout();
    }

/**
     * 开始截图，并保存图片
     * @param view
     */
    public void startCropper(View view) {
        //获取截图并旋转90度
        CropperImage cropperImage = mCropImageView.getCroppedImage();
        Log.e(TAG, cropperImage.getX() + "," + cropperImage.getY());
        Log.e(TAG, cropperImage.getWidth() + "," + cropperImage.getHeight());
        Bitmap bitmap = Utils.rotate(cropperImage.getBitmap(), -90);
//        Bitmap bitmap = mCropImageView.getCroppedImage();
        // 系统时间
        long dateTaken = System.currentTimeMillis();
        // 图像名称
        String filename = DateFormat.format("yyyy-MM-dd kk.mm.ss", dateTaken)
                .toString() + ".jpg";
        Uri uri = insertImage(getContentResolver(), filename, dateTaken, PATH,
                filename, bitmap, null);
        cropperImage.getBitmap().recycle();
        cropperImage.setBitmap(null);
        Intent intent = new Intent(this, PreviewActivity.class);
        intent.setData(uri);
        intent.putExtra("path", PATH + filename);
        intent.putExtra("width", bitmap.getWidth());
        intent.putExtra("height", bitmap.getHeight());
        intent.putExtra("cropperImage", cropperImage);
        startActivity(intent);
        bitmap.recycle();
        finish();
        super.overridePendingTransition(R.anim.fade_in,
                R.anim.fade_out);
//        doAnimation(cropperImage);
    }

/**
     * 拍照成功后回调
     * 存储图片并显示截图界面
     * @param data
     */
    @Override
    public void onCameraStopped(byte[] data) {
        Log.i("TAG", "==onCameraStopped==");
        // 创建图像
        Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
        // 系统时间
        long dateTaken = System.currentTimeMillis();
        // 图像名称
        String filename = DateFormat.format("yyyy-MM-dd kk.mm.ss", dateTaken)
                .toString() + ".jpg";
        // 存储图像（PATH目录）
        Uri source = insertImage(getContentResolver(), filename, dateTaken, PATH,
                filename, bitmap, data);
        //准备截图
        try {
            mCropImageView.setImageBitmap(MediaStore.Images.Media.getBitmap(this.getContentResolver(), source));
//            mCropImageView.rotateImage(90);
        } catch (IOException e) {
            Log.e(TAG, e.getMessage());
        }
        showCropperLayout();
    }

/**
     * 存储图像并将信息添加入媒体数据库
     */
    private Uri insertImage(ContentResolver cr, String name, long dateTaken,
                            String directory, String filename, Bitmap source, byte[] jpegData) {
        OutputStream outputStream = null;
        String filePath = directory + filename;
        try {
            File dir = new File(directory);
            if (!dir.exists()) {
                dir.mkdirs();
            }
            File file = new File(directory, filename);
            if (file.createNewFile()) {
                outputStream = new FileOutputStream(file);
                if (source != null) {
                    source.compress(Bitmap.CompressFormat.JPEG, 100, outputStream);
                } else {
                    outputStream.write(jpegData);
                }
            }
        } catch (FileNotFoundException e) {
            Log.e(TAG, e.getMessage());
            return null;
        } catch (IOException e) {
            Log.e(TAG, e.getMessage());
            return null;
        } finally {
            if (outputStream != null) {
                try {
                    outputStream.close();
                } catch (Throwable t) {
                }
            }
        }
        ContentValues values = new ContentValues(7);
        values.put(MediaStore.Images.Media.TITLE, name);
        values.put(MediaStore.Images.Media.DISPLAY_NAME, filename);
        values.put(MediaStore.Images.Media.DATE_TAKEN, dateTaken);
        values.put(MediaStore.Images.Media.MIME_TYPE, "image/jpeg");
        values.put(MediaStore.Images.Media.DATA, filePath);
        return cr.insert(IMAGE_URI, values);
    }

private void showTakePhotoLayout() {
        mTakePhotoLayout.setVisibility(View.VISIBLE);
        mCropperLayout.setVisibility(View.GONE);
    }

private void showCropperLayout() {
        mTakePhotoLayout.setVisibility(View.GONE);
        mCropperLayout.setVisibility(View.VISIBLE);
        mCameraPreview.start();   //继续启动摄像头
    }

private float mLastX = 0;
    private float mLastY = 0;
    private float mLastZ = 0;
    private boolean mInitialized = false;
    private SensorManager mSensorManager;
    private Sensor mAccel;
    @Override
    public void onSensorChanged(SensorEvent event) {

float x = event.values[0];
        float y = event.values[1];
        float z = event.values[2];
        if (!mInitialized){
            mLastX = x;
            mLastY = y;
            mLastZ = z;
            mInitialized = true;
        }
        float deltaX  = Math.abs(mLastX - x);
        float deltaY = Math.abs(mLastY - y);
        float deltaZ = Math.abs(mLastZ - z);

if(deltaX > 0.8 || deltaY > 0.8 || deltaZ > 0.8){
            mCameraPreview.setFocus();
        }
        mLastX = x;
        mLastY = y;
        mLastZ = z;
    }

@Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
    }
}
```
5、添加计算焦点及测光区域、拍照后图片旋转以及检测摄像头是否可用
```
public class Utils {

public static DisplayMetrics getScreenWH(Context context) {
        DisplayMetrics dMetrics = new DisplayMetrics();
        dMetrics = context.getResources().getDisplayMetrics();
        return dMetrics;
    }

/**
     * 计算焦点及测光区域
     *
     * @param focusWidth
     * @param focusHeight
     * @param areaMultiple
     * @param x
     * @param y
     * @param previewleft
     * @param previewRight
     * @param previewTop
     * @param previewBottom
     * @return Rect(left,top,right,bottom) : left、top、right、bottom是以显示区域中心为原点的坐标
     */
    public static Rect calculateTapArea(int focusWidth, int focusHeight,
                                        float areaMultiple, float x, float y, int previewleft,
                                        int previewRight, int previewTop, int previewBottom) {
        int areaWidth = (int) (focusWidth * areaMultiple);
        int areaHeight = (int) (focusHeight * areaMultiple);
        int centerX = (previewleft + previewRight) / 2;
        int centerY = (previewTop + previewBottom) / 2;
        double unitx = ((double) previewRight - (double) previewleft) / 2000;
        double unity = ((double) previewBottom - (double) previewTop) / 2000;
        int left = clamp((int) (((x - areaWidth / 2) - centerX) / unitx),
                -1000, 1000);
        int top = clamp((int) (((y - areaHeight / 2) - centerY) / unity),
                -1000, 1000);
        int right = clamp((int) (left + areaWidth / unitx), -1000, 1000);
        int bottom = clamp((int) (top + areaHeight / unity), -1000, 1000);

return new Rect(left, top, right, bottom);
    }

public static int clamp(int x, int min, int max) {
        if (x > max)
            return max;
        if (x < min)
            return min;
        return x;
    }

/**
     * 检测摄像头设备是否可用
     * Check if this device has a camera
     * @param context
     * @return
     */
    public static boolean checkCameraHardware(Context context) {
        if (context != null && context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
            // this device has a camera
            return true;
        } else {
            // no camera on this device
            return false;
        }
    }

/**
     * @param context
     * @return app_cache_path/dirName
     */
    public static String getDBDir(Context context) {
        String path = null;
        if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
            path = Environment.getExternalStorageDirectory().getAbsolutePath() +
                    File.separator + "bbk" + File.separator + "cloudteacher" + File.separator + "db";
            File externalCacheDir = context.getExternalCacheDir();
            if (externalCacheDir != null) {
                path = externalCacheDir.getPath();
            }
        }
        if (path == null) {
            File cacheDir = context.getCacheDir();
            if (cacheDir != null && cacheDir.exists()) {
                path = cacheDir.getPath();
            }
        }
        return path;
    }

/**
     * bitmap旋转
     * @param b
     * @param degrees
     * @return
     */
    public static Bitmap rotate(Bitmap b, int degrees) {
        if (degrees != 0 && b != null) {
            Matrix m = new Matrix();
            m.setRotate(degrees, (float) b.getWidth() / 2, (float) b.getHeight() / 2);
            try {
                Bitmap b2 = Bitmap.createBitmap(
                        b, 0, 0, b.getWidth(), b.getHeight(), m, true);
                if (b != b2) {
                    b.recycle();  //Android开发再次提示Bitmap操作完应该显示的释放
                    b = b2;
                }
            } catch (OutOfMemoryError ex) {
                // Android123建议大家如何出现了内存不足异常，最好return 原始的bitmap对象。.
            }
        }
        return b;
    }

public static final int getHeightInPx(Context context) {
        final int height = context.getResources().getDisplayMetrics().heightPixels;
        return height;
    }

public static final int getWidthInPx(Context context) {
        final int width = context.getResources().getDisplayMetrics().widthPixels;
        return width;
    }

}
```

MyCamera

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