Android NFC tag and NFC data format的关系

There are 4 standard NFC tag types: Type 1, Type 2, Type 3, Type 4 They differ in how you access data on them, and on the communication frame work you use to talk to them. (This gets into the mechanics of how data is exchanged) Mifare is a proprietary standard made by NXP Mifare Ultralite is a type 2 tag

The tags differ in the maximum amount of data you can store on them, and the maximum amount of data that can be exchanged per command (Type 2 tags can read 16 bytes at a time, and can write 4 bytes at a time)

NDEF is a way of formatting data on the tags. Mifare and the 4 tag types can all be formatted to store data in a NDEF format.

Android recognizes these tag types when you use the NDEF class for accessing and filtering tags it scans.

Not all Nfc tags (even the standard ones and Mifare) will be set up for Ndef, or will hold Ndef formatted data. But Android automates this process, so you don't have to worry about what type of tag you have, only if it can store Ndef data on it.

Mifare, as a proprietary standard, is not guaranteed to have it's own class in Android, so you may have to write your own stack for accessing it on a phone.