Question

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，显示相机预览而不执行任何操作。但是我希望在实时摄像头上获得图像叠加。请帮帮我......

Answer 1

如果你仍然被卡住，我会给你一个提示。在布局定义中，您可以以视图所在的方式或相互重叠的方式定义框架布局或相对布局。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

如何在相机预览上获得图像叠加

1 个答案: