The CommonsBlog


Secondary Display Support: Presentation and Errata

Yesterday, at the Samsung Developer Conference, I delivered a presentation on supporting secondary displays from your Android app, so you can push custom content to a TV, projector, or monitor. I have uploaded the slides to this presentation… but I have a couple of errata to report.

First, the way I referenced SlimPort in the slides was inappropriate. I had forgotten about SlimPort when I was working on the presentation originally, as few devices support SlimPort. When I remembered it, I basically went to the first slide where I mentioned MHL and added SlimPort to the same bullet… not noticing that the bullet I was adding it to was defining the MHL abbreviation (“Mobile High-Definition Link”). While SlimPort serves a similar role as does MHL, SlimPort is not MHL, and I apologize for creating a slide that suggested it.

Second, I implied, in the slides and my delivery, that the way to connect MHL devices to displays involves an MHL->HDMI cable or adapter. While this works, it turns out that there are some TVs and monitors that offer native MHL ports, so a direct MHL->MHL cable can work with those. Examples include the Dell P2314T monitor and the LG 50LN5400 TV. More displays are expected to include native MHL ports as time progresses, and you can monitor the MHL site for a list of displays offering MHL support. Note, though, that not all of these displays may be sold in your area.

Finally, I indicated that the simulated secondary displays worked with hardware but not the x86 emulator. It turns out that the latest x86 4.2 emulator image does support simulated secondary displays, via the Developer Options portion of Settings. Alas, the 4.3 x86 emulator image suffers from the same problems as I had seen previously with the 4.2 image, where the overlay appears but is black, rather than showing a mirror of the primary display or the Presentation that you are trying to show.

Many thanks to Michael Bergen (MHL) and Eric Mantion (Intel) for helping me with these errors.


Need a speaker at your Android development meetup? Mark Murphy is available, in person in the Boston/Pittsburgh/DC triangle, or by remote anywhere in the world! Contact Mark for details!