SurfaceView 和 TextureView 预览came

SurfaceView 和 TextureView 预览camera数据得方式非常相似

在SurfaceView中就是在surface创建得回调开启摄像头 并将摄像头数据送到holder 中
在TextureView中就是在surfaceTexture可用得回调中开启摄像头 并将摄像头得数据送到surface中

SurfaceView预览代码：

import android.hardware.Camera;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Display;
import android.view.Surface;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.Window;
import android.view.WindowManager;

import com.lemniscate.audio_and_video_demo.R;

import java.io.IOException;
import java.util.List;

public class SurfaceViewCameraActivity extends AppCompatActivity implements SurfaceHolder.Callback {

    private SurfaceView sv;
    private SurfaceHolder holder;
    private Camera mCamera;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_surface_view_camera);

        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

        sv = findViewById(R.id.sv);
        holder = sv.getHolder();
        holder.addCallback(this);
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        mCamera = getCamera();
        if (mCamera != null) {
            try {
                mCamera.setPreviewDisplay(holder);//预览数据送到holder
                mCamera.startPreview();
                mCamera.setPreviewCallback(new Camera.PreviewCallback() {
                    @Override
                    public void onPreviewFrame(byte[] data, Camera camera) {
                          //得到的预览数据
                    }
                });

            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        //这里变化的时候转换方向 等
        refreshCamera();
        int displayOrientation = getDisplayOrientation();
        mCamera.setDisplayOrientation(displayOrientation);
        Camera.Parameters params = mCamera.getParameters();
        Camera.Size optimalPreviewSize = getOptimalPreviewSize(mCamera.getParameters().getSupportedPreviewSizes(), width, height);
        params.setPictureSize(optimalPreviewSize.width, optimalPreviewSize.height);
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        holder.removeCallback(this);
        mCamera.setPreviewCallback(null);
        mCamera.stopPreview();
        mCamera.release();
        mCamera = null;
    }

//获取最佳的分辨率 而且是16：9的
    private Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {
        final double ASPECT_TOLERANCE = 0.75;
        double targetRatio = (double) w / h;
        if (sizes == null)
            return null;

        Camera.Size optimalSize = null;
        double minDiff = Double.MAX_VALUE;

        int targetHeight = h;

        // Try to find an size match aspect ratio and size
        for (Camera.Size size : sizes) {
            double ratio = (double) size.width / size.height;
            if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE)
                continue;
            if (Math.abs(size.height - targetHeight) < minDiff) {
                optimalSize = size;
                minDiff = Math.abs(size.height - targetHeight);
            }
        }

        // Cannot find the one match the aspect ratio, ignore the requirement
        if (optimalSize == null) {
            minDiff = Double.MAX_VALUE;
            for (Camera.Size size : sizes) {
                if (Math.abs(size.height - targetHeight) < minDiff) {
                    optimalSize = size;
                    minDiff = Math.abs(size.height - targetHeight);
                }
            }
        }
        return optimalSize;
    }
    //这里是一小段算法算出摄像头转多少都和屏幕方向一致
    private int getDisplayOrientation() {
        WindowManager windowManager = getWindowManager();
        Display defaultDisplay = windowManager.getDefaultDisplay();
        int orientation = defaultDisplay.getOrientation();
        int degress = 0;
        switch (orientation) {
            case Surface.ROTATION_0:
                degress = 0;
                break;
            case Surface.ROTATION_90:
                degress = 90;
                break;
            case Surface.ROTATION_180:
                degress = 180;
                break;
            case Surface.ROTATION_270:
                degress = 270;
                break;
        }
        Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
        android.hardware.Camera.getCameraInfo(Camera.CameraInfo.CAMERA_FACING_BACK, cameraInfo);
        int result = (cameraInfo.orientation - degress + 360) % 360;
        return result;
    }

    private void refreshCamera() {
        if (holder.getSurface() == null) {
            //preview surface does not exist
            return;
        }
        mCamera.stopPreview();

        try {
            mCamera.setPreviewDisplay(holder);
            mCamera.startPreview();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private Camera getCamera() {
        return Camera.open();
    }
}

TextureView的代码

import android.graphics.SurfaceTexture;
import android.hardware.Camera;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Display;
import android.view.Surface;
import android.view.TextureView;
import android.view.WindowManager;

import com.lemniscate.audio_and_video_demo.R;

import java.io.IOException;
import java.util.List;

public class TextureViewCameraActivity extends AppCompatActivity {

    private TextureView textureView;

    private SurfaceTexture surfaceTexture;
    private Camera camera;

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

        textureView = findViewById(R.id.textureView);
        textureView.setSurfaceTextureListener(new MySurfaceTextureViewListener());
    }

    private class MySurfaceTextureViewListener implements TextureView.SurfaceTextureListener {

        @Override
        public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
            surfaceTexture = surface;
            initCamera();
        }

        @Override
        public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
            int displayOrientation = getDisplayOrientation();
            camera.setDisplayOrientation(displayOrientation);
            List<Camera.Size> supportedPreviewSizes = camera.getParameters().getSupportedPreviewSizes();
            Camera.Size optimalPreviewSize = getOptimalPreviewSize(supportedPreviewSizes, width, height);
            camera.getParameters().setPictureSize(optimalPreviewSize.width, optimalPreviewSize.height);
        }

        @Override
        public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
            surface.release();
            camera.setPreviewCallback(null);
            camera.stopPreview();
            camera.release();
            camera = null;
            return false;
        }

        @Override
        public void onSurfaceTextureUpdated(SurfaceTexture surface) {

        }
    }

    这里删除掉一些上面有的重复方法