开发人员指南中的Google Glass LiveCard示例代码是否有错误？

Question

I was going through the GDK docs on LiveCards (high frequency) and I came across this line of code:

mLiveCard.getSurfaceHolder().addCallback(new RenderThread());

RenderThread is a Class that extends Thread and does not implement any SurfaceHolder.Callback . In the other hand, in the same sample code they define LiveCardRenderer which implements DirectRenderingCallback which in turn extends SurfaceHolder.Callback . Shouldn't LiveCardRenderer be used instead of RenderThread ?

Answer 1

Thanks for catching that. You're right, it should be new LiveCardRenderer() . The documentation has now been fixed.

Answer 2

This does look a lot like a mistake, as you rightly say, instead of new RenderThread() , you should have new LiveCardRenderer() .

If you take a look and any of the sample apps in the GDK, for example the compass app you can see they have something like

mRenderer = new CompassRenderer(this, mOrientationManager, mLandmarks);
mLiveCard.setDirectRenderingEnabled(true).getSurfaceHolder().addCallback(mRenderer);

Where CompassRenderer extends SurfaceHolder.Callback as you would expect and the code is similar in principle to that given for LiveCardRenderer .

I hope that helps.