camera preview覆盖图片

摘自：http://groups.google.com/group/android-developers/browse_thread/thread/0d8587b4b2139a85/6e1f453ac051f6bd?#6e1f453ac051f6bd

 

JAVA代码：

 

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.hardware.Camera;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.Window;
import android.view.ViewGroup.LayoutParams;

public class TestCameraOverlay extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        requestWindowFeature(Window.FEATURE_NO_TITLE);

        Preview mPreview = new Preview(this);
        DrawOnTop mDraw = new DrawOnTop(this);

        setContentView(mPreview);
        addContentView(mDraw, new LayoutParams
(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));

    }

 

}

class DrawOnTop extends View {

        public DrawOnTop(Context context) {
                super(context);
                // TODO Auto-generated constructor stub
        }

        @Override
        protected void onDraw(Canvas canvas) {
                // TODO Auto-generated method stub

                Paint paint = new Paint();
                paint.setStyle(Paint.Style.FILL);
                paint.setColor(Color.BLACK);
                canvas.drawText("Test Text", 10, 10, paint);

                super.onDraw(canvas);
        }

 

}

//----------------------------------------------------------------------

class Preview extends SurfaceView implements SurfaceHolder.Callback {
    SurfaceHolder mHolder;
    Camera mCamera;

    Preview(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.setPreviewDisplay(holder);
    }

    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 = null;
    }

    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();
        parameters.setPreviewSize(w, h);
        mCamera.setParameters(parameters);
        mCamera.startPreview();
    }

 

}