SurfaceView Example

OverlayView.java

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

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

public class OverlayView extends SurfaceView implements Callback {

	SurfaceHolder mHolder;
	Camera mCamera;

	public OverlayView(Context context) {
		super(context);

		// Install a SurfaceHolder.Callback so we get notified when the
		// underlying surface is created and destroyed.
		mHolder = getHolder();
		mHolder.addCallback(this);
		mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
		
	}

	public void surfaceCreated(SurfaceHolder holder) {
		// The Surface has been created, acquire the camera and tell it where
		// to draw.
		mCamera = Camera.open();
		mCamera.setDisplayOrientation(90);
		try {
			mCamera.setPreviewDisplay(holder);
		} catch (IOException e) {
			mCamera.release();
			mCamera = null;
		}
	}

	public void surfaceDestroyed(SurfaceHolder holder) {
		// Surface will be destroyed when we return, so stop the preview.
		// Because the CameraDevice object is not a shared resource, it's very
		// important to release it when the activity is paused.
		mCamera.stopPreview();
		mCamera.release();
		mCamera = null;
	}

	private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
        final double ASPECT_TOLERANCE = 0.1;
        double targetRatio = (double) w / h;
        if (sizes == null) return null;

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

        int targetHeight = h;

        // Try to find an size match aspect ratio and size
        for (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 (Size size : sizes) {
                if (Math.abs(size.height - targetHeight) < minDiff) {
                    optimalSize = size;
                    minDiff = Math.abs(size.height - targetHeight);
                }
            }
        }
        return optimalSize;
    }

	public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
		// Now that the size is known, set up the camera parameters and begin
		// the preview.
		Camera.Parameters parameters = mCamera.getParameters();

        List<Size> sizes = parameters.getSupportedPreviewSizes();
		Size optimalSize = getOptimalPreviewSize(sizes, w, h);
		Log.d("DEBUG", optimalSize.width + "," + optimalSize.height);
		parameters.setPreviewSize(optimalSize.width, optimalSize.height);
		
		mCamera.setParameters(parameters);
		mCamera.startPreview();

	}
}