Replacing NativeActivity-based renderer with SurfaceView

[Andreas Falkenhahn]

I'm moving away from NativeActivity because I want to do more things on the Java side and less things in C. However, I still want to keep the renderer in C. That's why I'm using an Activity which has a SurfaceView as its content.

When I used NativeActivity, ANativeWindow_getFormat() returned RGBX_8888 which was just fine. With my new renderer based on SurfaceView, however, my surfaceChanged() callback always receives RGB_565 as the pixel format which looks really ugly because it only has 65536 colors and gradients look pretty cheap in 16 bits.

So I tried to add the following code to my onCreate() before calling setContentView():

getWindow().setFormat(PixelFormat.RGBX_8888);

This indeed solves the problem on my Nexus 5X device running Android 8 but on my Nexus 9 tablet running Android 6 it doesn't work and I still get 16-bit surfaces. What is confusing me, however, is the fact that when using NativeActivity on my Nexus 9 tablet running Android 6 I actually *get* RGBX_8888 surfaces! So this is definitely *not* a hardware/system limitation on Nexus 9/Android 6. It works for NativeActivity, but not for my SurfaceView.

This leads me to the following question: What magic does NativeActivity do in order to get RGBX_8888 surfaces on Nexus 9/Android 6? In other words, what do I have to do in order to get RGBX_8888 in my non-NativeActivity app as well?

I've already peeked into the Android sources but I don't see anything. To make the confusion complete, NativeActivity.java explicitly sets the pixel format to RGB_565 in onCreate() but I definitely get RGBX_8888 surfaces with NativeActivity! So where do these come from and how do I request them in a non-NativeActivity app?

Thanks for listening!
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Best regards,
Andreas Falkenhahn mailto:***@falkenhahn.com