Preview.java (MyCamera )

Preview.java

package gclue.com.camera;

import android.content.Context;
import android.hardware.Camera;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

import java.util.List;

class Preview extends SurfaceView implements SurfaceHolder.Callback {

    private static final String TAG = "MyCamera";
    private Camera mCamera;

    Preview(Context context) {
        super(context);

        getHolder().addCallback(this);
        getHolder().setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        Log.d(TAG, "onLayout l:"+l+"t:"+t+"r:"+r+"b:"+b);
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        Log.d(TAG, "surfaceCreated");

        mCamera = Camera.open();


        try {
            mCamera.setPreviewDisplay(holder);
        } catch (Exception e){ }
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        Log.d(TAG, "surfaceChanged format:"+format+"width:"+width+"height:"+height);

        Camera.Parameters mParams = mCamera.getParameters();
        List<Camera.Size> mPreviewSize = mCamera.getParameters().getSupportedPreviewSizes();
        Camera.Size opticalSize = getOptimalPreviewSize(mPreviewSize, width, height);
        mParams.setPreviewSize(opticalSize.width, opticalSize.height);
        mCamera.setParameters(mParams);
        mCamera.startPreview();
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        Log.d(TAG, "surfaceDestroyed");
    }

    private Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {
        final double ASPECT_TOLERANCE = 0.05;
        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;
    }
}