I have a simple program that draws the preview of the Camera
into a SurfaceView
. What I'm trying to do is using the onPreviewFrame
method, which is invoked each time a new frame is drawn into the SurfaceView
, in order to execute the invalidate
method which is supposed to invoke the onDraw
method. In fact, the onDraw
method is being invoked, but nothing there is being printed (I guess the camera preview is overwriting the text I'm trying to draw).
This is a simplify version of the SurfaceView
subclass I have:
public class Superficie extends SurfaceView implements SurfaceHolder.Callback {
SurfaceHolder mHolder;
public Camera camera;
Superficie(Context context) {
super(context);
mHolder = getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void surfaceCreated(final SurfaceHolder holder) {
camera = Camera.open();
try {
camera.setPreviewDisplay(holder);
camera.setPreviewCallback(new PreviewCallback() {
public void onPreviewFrame(byte[] data, Camera arg1) {
invalidar();
}
});
} catch (IOException e) {}
}
public void invalidar(){
invalidate();
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
Camera.Parameters parameters = camera.getParameters();
parameters.setPreviewSize(w, h);
camera.setParameters(parameters);
camera.startPreview();
}
@Override
public void draw(Canvas canvas) {
super.draw(canvas);
// nothing gets drawn :(
Paint p = new Paint(Color.RED);
canvas.drawText("PREVIEW", canvas.getWidth() / 2,
canvas.getHeight() / 2, p);
}
}
SurfaceView
probably does not work like a regular View
in this regard.
Instead, do the following:
SurfaceView
inside of a
FrameLayout
or RelativeLayout
in
your layout XML file, since both of
those allow stacking of widgets on
the Z-axisView
classFrameLayout
or
RelativeLayout
, but have it appear
after the SurfaceView
This will cause your custom View
class to appear to float above the SurfaceView
.
See here for a sample project that layers popup panels above a SurfaceView
used for video playback.