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public class PreviewDemo extends Activity {
    private SurfaceView preview=null;
    private SurfaceHolder previewHolder=null;
    private Camera camera=null;
    private boolean inPreview=false;
    private boolean cameraConfigured=false;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        preview=(SurfaceView)findViewById(R.id.preview);
        previewHolder=preview.getHolder();
        previewHolder.addCallback(surfaceCallback);
        previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    @Override
    public void onResume() {
        super.onResume();

        camera=Camera.open();
        startPreview();
    }

    @Override
    public void onPause() {
        if (inPreview) {
            camera.stopPreview();
        }

        camera.release();
        camera=null;
        inPreview=false;

        super.onPause();
    }

    private Camera.Size getBestPreviewSize(int width, int height,
            Camera.Parameters parameters) {
        Camera.Size result=null;

        for (Camera.Size size : parameters.getSupportedPreviewSizes()) {
            if (size.width<=width && size.height<=height) {
                if (result==null) {
                    result=size;
                }
                else {
                    int resultArea=result.width*result.height;
                    int newArea=size.width*size.height;

                    if (newArea>resultArea) {
                        result=size;
                    }
                }
            }
        }

        return(result);
    }

    private void initPreview(int width, int height) {
        if (camera!=null && previewHolder.getSurface()!=null) {
            try {
                camera.setPreviewDisplay(previewHolder);
            }
            catch (Throwable t) {
                Log.e("PreviewDemo-surfaceCallback",
                    "Exception in setPreviewDisplay()", t);
                Toast
                    .makeText(PreviewDemo.this, t.getMessage(), Toast.LENGTH_LONG)
                    .show();
            }

            if (!cameraConfigured) {
                Camera.Parameters parameters=camera.getParameters();
                Camera.Size size=getBestPreviewSize(width, height,
                    parameters);

                if (size!=null) {
                    parameters.setPreviewSize(size.width, size.height);
                    camera.setParameters(parameters);
                    cameraConfigured=true;
                }
            }
        }
    }

    private void startPreview() {
        if (cameraConfigured && camera!=null) {
            camera.startPreview();
            inPreview=true;
        }
    }

    SurfaceHolder.Callback surfaceCallback=new SurfaceHolder.Callback() {
        public void surfaceCreated(SurfaceHolder holder) {
            // no-op -- wait until surfaceChanged()
        }

        public void surfaceChanged(SurfaceHolder holder,
                int format, int width,
                int height) {
            initPreview(width, height);
            startPreview();
        }

        public void surfaceDestroyed(SurfaceHolder holder) {
            // no-op
        }
    };
}

上面的代码工作正常，当我启动应用程序时，会显示相机预览，但没有执行任何操作。但我想在实时摄像头上获得图像叠加。请帮我.....

4

1 回答 1

1

如果你仍然卡住，我会给你一个提示。在您的布局定义中，您可以定义框架布局或相对布局，使视图彼此重叠或看起来重叠。你可以在这里看到一个例子：

http://littlesaiph.blogspot.de/2011/07/getting-images-laid-pause-over-video-in.html

于 2012-04-17T20:13:02.703 回答