Android / iOS API access to Bluetooth heart-rate monitors

I'm looking to write some Android or iOS applications to access a Bluetooth heart-rate monitor. There are currently some apps available like Android's "Heart Rate Monitor" that connect to heart-rate monitors like the Zephyr HxM, so 开发者_如何学GoI know it can be done.

What is the programming API like? If I write an app, would it be able to connect to any heart-rate device? Or would I have to follow some application-layer protocol from the device manufacturer and read and process Bluetooth packets?

Many of the bluetooth enabled Heart-rate monitors supports the SPP profile and you can use the Android Bluetooth SPP socket APIs to access the device. The Android chat example is a good application to modify to start with.