Folks at XDA Developers received a tip from a fellow member, 500 Internal Server Error which proves that Android P will arrive with support for using your phone as a keyboard or mouse. This feature might come handy while giving presentations or making a makeshift keyboard for your HTPC.
This is possible due to Bluetooth Profiles, commonly known as A2DP(Advanced Audio Distribution Profile), HFP(Hands-Free Profile). Android P might bring the HID aka Human Interface Device profile, thus allowing input devices to work. This patch was first seen in 2014 when a user from the Qualcomm CodeAurora forums submitted it. This patch was committed back in December of 2016 but remained disabled. The tipster has shown two commits that prove the enabling of the Bluetooth HID profile. Till now, Android does not natively support HID profile in its Bluetooth stack, but on rooted devices, you can use apps that patch the framework and allow you to use your smartphone as an input device.
This sounds pretty cool if you just need a makeshift keyboard for your Smart TV or HTPC. Some may like it, some may not. There’s no beating the pleasure of typing on an actual keyboard and touch screens will never be able to reach that point. But this opens up doors for other advancements in the use of your smartphone. Android P will probably come with the HID profile enabled by default, thus allowing app developers to develop apps using the functionality.