TextureView实现相机预览拍照功能

1. TextureView简介
2. 代码实例
- - 2.1 自定义CameraTextureView控件，实现SurfaceTextureListener，封装TextureView的初始化和销毁功能
  - 2.2 Camera的处理封装到CameraManager类中
  - 2.3 创建TakePictureActivity实现拍照页面
  - 2.4 AndroidManifest.xml中添加相机权限
3. 实现过程中遇到的坑
- - 3.1 在非全屏预览页面中出现画面挤压变形
  - 3.2 拍照后得到的图片尺寸与预览时不一致

1. TextureView简介

TextureView 是一个显示数据流的UI控件。它是View的子类，可以当做普通的View控件使用，在布局、动画和变换（平移、缩放、旋转等）中非常方便，

主要用于2种场景

1.相机预览 2:视频播放

这篇文章主要讲述TextureView相机预览拍照功能的实现

2. 代码实例

2.1 自定义CameraTextureView控件，实现SurfaceTextureListener，封装TextureView的初始化和销毁功能

public class CameraTextureView extends TextureView implements TextureView.SurfaceTextureListener {
    private static final String TAG = "CameraTextureView";
    private SurfaceTexture mSurface;
    private int mWidth;
    private int mHeight;

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

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

    public CameraTextureView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        this.setSurfaceTextureListener(this);
    }

    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
    public CameraTextureView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        this.setSurfaceTextureListener(this);
    }

    @Override
    public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
        mSurface = surface;
        mWidth = width;
        mHeight = height;
        //开启相机是耗时操作，此处异步处理
        new Thread(new OpenCameraRunnable()).start();
    }

    @Override
    public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
        CameraManager.getInstance().stopCamera();
        return true;
    }

    @Override
    public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
    }

    @Override
    public void onSurfaceTextureUpdated(SurfaceTexture surface) {
    }

    public SurfaceTexture getSurfaceTexture() {
        return mSurface;
    }

    private class OpenCameraRunnable implements Runnable {

        @Override
        public void run() {
            CameraManager.getInstance().openCamera(getContext(), mSurface, mWidth, mHeight);
        }
    }
}

2.2 Camera的处理封装到CameraManager类中

public class CameraManager {
    private static CameraManager mCameraManager;
    public static final int LEFT = 0;
    public static final int TOP = 1;
    public static final int RIGHT = 2;
    public static final int BOTTOM = 3;
    private OnCameraActionCallback mOnCameraActionCallback;
    private Camera mCamera;
    private ToneGenerator mToneGenerator;
    private Context mContext;
    private byte[] mCameraData;//拍照返回的图像数据
    private boolean isPreviewing = false;
    private int mCurrentCameraFacing;//当前摄像头
    private int mDeviceOrientation = TOP;

    public static synchronized CameraManager getInstance() {
        if (mCameraManager == null) {
            mCameraManager = new CameraManager();
        }
        return mCameraManager;
    }

    /**
     * 打开Camera
     */
    public void openCamera(Context context, SurfaceTexture surface, int width, int height) {
        mContext = context;
        mCamera = Camera.open();
        mCurrentCameraFacing = 0;
        startPreview(surface, width, height);
    }

    /**
     * 使用TextureView预览Camera
     *
     * @param surface
     */
    public void startPreview(SurfaceTexture surface, int width, int height) {
        if (isPreviewing) {
            mCamera.stopPreview();
            return;
        }
        if (mCamera != null) {
            try {
                mCamera.setPreviewTexture(surface);
            } catch (IOException e) {
                e.printStackTrace();
            }
            initCamera(width, height);
        }
    }

    /**
     * 停止预览，释放Camera
     */
    public void stopCamera() {
        if (mCamera != null) {
            mCamera.setPreviewCallback(null);
            mCamera.stopPreview();
            isPreviewing = false;
            mCamera.release();
            mCamera = null;
            mContext = null;
        }
    }

   private void initCamera(int width, int height) {
        if (mCamera != null) {
            Camera.Parameters params = mCamera.getParameters();
            params.setPictureFormat(PixelFormat.JPEG);//设置拍照后存储的图片格式
            //设置PreviewSize和PictureSize
            Size pictureSize = getOptimalSize(params.getSupportedPictureSizes(), width, height);
            params.setPictureSize(pictureSize.width, pictureSize.height);
            Size previewSize = getOptimalSize(params.getSupportedPreviewSizes(), width, height);
            params.setPreviewSize(previewSize.width, previewSize.height);

            mCamera.setDisplayOrientation(90);

            List<String> focusModes = params.getSupportedFocusModes();
            if (focusModes.contains(Camera.Parameters.FOCUS_MODE_CONTINUOUS_VIDEO)) {
                params.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_VIDEO);
            }
            mCamera.setParameters(params);
            mCamera.startPreview();//开启预览

            isPreviewing = true;
        }
    }

    /**
     * 拍照
     */
    public void takePicture(OnCameraActionCallback callback) {
        mOnCameraActionCallback = callback;
        if (isPreviewing && (mCamera != null)) {
            mCamera.takePicture(mShutterCallback, null, mJpegPictureCallback);
        }
    }

    /**
     * 保存照片
     */
    public String save() {
        if (mCameraData != null) {
            Bitmap bitmap = BitmapFactory.decodeByteArray(mCameraData, 0, mCameraData.length);//data是字节数据，将其解析成位图
            //保存图片到sdcard
            //设置FOCUS_MODE_CONTINUOUS_VIDEO)之后，myParam.set("rotation", 90)失效。
            //图片竟然不能旋转了，故这里要旋转下
            bitmap = BitmapUtils.rotateBitmap(bitmap, 90.0f);
            return BitmapUtils.saveBitmap(mContext, bitmap);
        }
        return null;
    }

    public void cancel() {
        //再次进入预览
        mCamera.startPreview();
        isPreviewing = true;
    }

    public interface OnCameraActionCallback {
        void onTakePictureComplete(Bitmap bitmap);
    }

    //快门按下的回调，在这里我们可以设置类似播放“咔嚓”声之类的操作。默认的就是咔嚓。
    private Camera.ShutterCallback mShutterCallback = new Camera.ShutterCallback() {

        public void onShutter() {
            // TODO Auto-generated method stub
            if (mToneGenerator == null) {
                //发出提示用户的声音
                mToneGenerator = new ToneGenerator(AudioManager.STREAM_MUSIC,
                        ToneGenerator.MAX_VOLUME);
            }
            mToneGenerator.startTone(ToneGenerator.TONE_PROP_BEEP2);
        }
    };

    //对jpeg图像数据的回调,最重要的一个回调
    private Camera.PictureCallback mJpegPictureCallback = new Camera.PictureCallback() {

        public void onPictureTaken(byte[] data, Camera camera) {
            //mCameraData = data;
            if (mOnCameraActionCallback != null) {
                Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);//data是字节数据，将其解析成位图
                if (mCurrentCameraFacing == Camera.CameraInfo.CAMERA_FACING_BACK) {
                    if (mDeviceOrientation == TOP) {
                        bitmap = BitmapUtils.rotateBitmap(bitmap, 90.0f);
                    } else if (mDeviceOrientation == RIGHT) {
                        bitmap = BitmapUtils.rotateBitmap(bitmap, 180.0f);
                    } else if (mDeviceOrientation == BOTTOM) {
                        bitmap = BitmapUtils.rotateBitmap(bitmap, 270.0f);
                    }
                } else if (mCurrentCameraFacing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
                    if (mDeviceOrientation == TOP) {
                        bitmap = BitmapUtils.rotateBitmap(bitmap, 270.0f);
                    } else if (mDeviceOrientation == RIGHT) {
                        bitmap = BitmapUtils.rotateBitmap(bitmap, 180.0f);
                    } else if (mDeviceOrientation == BOTTOM) {
                        bitmap = BitmapUtils.rotateBitmap(bitmap, 90.0f);
                    }
                }
                mOnCameraActionCallback.onTakePictureComplete(bitmap);
            }
        }
    };
}

2.3 创建TakePictureActivity实现拍照页面

public class TakePictureActivity extends AppCompatActivity implements View.OnClickListener,
        CameraManager.OnCameraActionCallback {
    private CameraTextureView mTextureView;
    private ImageView mPicture;
    private View mTakePicture;
    private View mCameraSave;

    private Bitmap mPictureBitmap;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_take_picture);

        initView();
    }

    private void initView() {
        mTextureView = findViewById(R.id.texture_view);
        mPicture = findViewById(R.id.iv_camera_picture);
        mTakePicture = findViewById(R.id.iv_take_picture);
        mCameraSave = findViewById(R.id.iv_camera_save);

        mTakePicture.setOnClickListener(this);
        mCameraSave.setOnClickListener(this);

        findViewById(R.id.iv_camera_cancel).setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.iv_take_picture:
                CameraManager.getInstance().takePicture(this);
                break;
            case R.id.iv_camera_cancel:
                CameraManager.getInstance().cancel();
                setResultState(false);
                break;
            case R.id.iv_camera_save:
                //todo 此处可以实现保存图片到相册功能
                break;
            default:
                break;
        }
    }

    private void setResultState(boolean state) {
        mTextureView.setTouchEnable(!state);
        if (state) {
            mTakePicture.setVisibility(View.GONE);
            ((View) mCameraSave.getParent()).setVisibility(View.VISIBLE);
            mTextureView.setVisibility(View.GONE);
            mPicture.setVisibility(View.VISIBLE);
        } else {
            mTakePicture.setVisibility(View.VISIBLE);
            ((View) mCameraSave.getParent()).setVisibility(View.GONE);
            mTextureView.setVisibility(View.VISIBLE);
            mPicture.setVisibility(View.GONE);
        }
    }

    @Override
    public void onTakePictureComplete(Bitmap bitmap) {
        if (mPictureBitmap != null) {
            mPictureBitmap.recycle();
        }
        mPictureBitmap = bitmap;
        mPicture.setImageBitmap(bitmap);
        setResultState(true);
    }
}

布局文件如下：

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

    <com.owner.camera.camera.CameraTextureView
        android:id="@+id/texture_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <ImageView
        android:id="@+id/iv_camera_picture"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        android:layout_marginBottom="48dp"
        android:layout_marginLeft="36dp"
        android:layout_marginRight="36dp"
        android:visibility="visible">

        <ImageView
            android:id="@+id/iv_camera_cancel"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:padding="12dp"
            android:src="@android:drawable/ic_menu_close_clear_cancel" />

        <ImageView
            android:id="@+id/iv_camera_save"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="right|center_vertical"
            android:padding="12dp"
            android:src="@android:drawable/ic_menu_save" />
    </FrameLayout>

    <ImageView
        android:id="@+id/iv_take_picture"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal|bottom"
        android:layout_marginBottom="32dp"
        android:layout_marginLeft="36dp"
        android:layout_marginRight="36dp"
        android:src="@android:drawable/ic_menu_camera" />
</FrameLayout>

2.4 AndroidManifest.xml中添加相机权限

<!-- 多媒体相关 -->
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-feature android:name="android.hardware.camera" />
    <uses-feature android:name="android.hardware.camera.autofocus" />

TakePictureActivity默认开启了硬件加速，这也是TextureView生效的前提条件

android:hardwareAccelerated="true"

至此基于TextureView的相机拍照预览功能已基本实现，可根据此Demo定制自己的相机，添加更丰富的功能。

3. 实现过程中遇到的坑

3.1 在非全屏预览页面中出现画面挤压变形

原因是UI中CameraTextureView的宽高比与相机提供的宽高比不一致，所以在设置控件宽高时一定要按照标准比例设计，Camera系统提供了多种预览尺寸（使用

getSupportedPreviewSizes()

获得），根据需要选择其一即可，你也可以在运行时根据选取的预览尺寸动态设置控件宽高

3.2 拍照后得到的图片尺寸与预览时不一致

原因与3.1相似，是因为PictureSize与PreviewSize不一致导致的，设置成一样的比例即可

总结：TextureView 与 PreViewSize 以及 PictureSize 这三者的宽高比应尽量相同，以免造成视觉上的不一致。前两者决定预览时我们所看见的效果，而 PictureSize 只最终决定生成的位图文件的大小。

TextureView实现相机预览拍照功能1. TextureView简介2. 代码实例3. 实现过程中遇到的坑

TextureView实现相机预览拍照功能

1. TextureView简介

2. 代码实例

2.1 自定义CameraTextureView控件，实现SurfaceTextureListener，封装TextureView的初始化和销毁功能

2.2 Camera的处理封装到CameraManager类中

2.3 创建TakePictureActivity实现拍照页面

2.4 AndroidManifest.xml中添加相机权限

3. 实现过程中遇到的坑

3.1 在非全屏预览页面中出现画面挤压变形

3.2 拍照后得到的图片尺寸与预览时不一致

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