Is it possible to connect iOS and android device u

问题:

I have to make an application to pair an iOS and Android device (iPhone 5, iPad 3, Galaxy S3, Nexus 7 they all use Bluetooth 4.0) and then send data to each other.

• Is this amount of data limited ? Can we send something like a photo or a PDF?

I've already done the pairing and sending data between 2 iOS devices using CoreBluetooth and the sample code from Apple BTLE_Transfer

Of what i understood, a Peripheral (Server) can Advertise to a Central (Client). This central is scanning around itself, and then try to find the Server by looking for the UUID of the service advertised.

When i make a Server on Android, it is waiting for a connection (listening), i know the UUID and the mac address of my Server. But when i scan with my iPhone (scanning for the same UUID of course), i can't find the server.

• So is there a possibility for the android server to advertise like the Peripheral on iOS?
• Or maybe a possibility for my iPhone client to connect using the mac address of the server?

回答1:

Q: Is this amount of data limited ? Can we send something like a photo or a PDF?

Bluetooth Low Energy was not optimised for sending large amounts of data, nor is it optimised for streaming. It is more suitable for sending small chunks of data periodically (e.g. temperature readings, time, etc). Please have a look at this answer to understand how BLE transfer is different from classic Bluetooth. That being said, you can still send large amounts of data over BLE, and the amount of data is unlimited. However, this might end up being unreliable and relatively slow.

Q: So is there a possibility for the android server to advertise like the Peripheral on iOS?

Being a server/client is a completely different thing from being a peripheral/central:-

Peripheral/central dictates how the connection is made. A central device should initiate the connection. A peripheral device should advertise and wait for a connection request.

Client/Server dictates how the data is distributed. The Gatt Server holds the data. The Gatt Client can read, write or be notified (getting a continuous stream of readings) of this data. In most cases, the server is also the peripheral, but this is not mandatory.

So to answer your question, yes, the server can advertise like the peripheral on iOS. However, for Android, this feature is not yet available and will be part of the next version (Android L) release. Please see this answer for more information.

Q: Or maybe a possibility for my iPhone client to connect using the mac address of the server?

As far as I know, in coreBluetooth you would need the UUID, not the MAC Address, of a peripheral device to connect to it. You do not need to know the services being advertised from the peripheral device. Your best bet would be to scan for peripheral devices, and then connect to the one with the UUID and/or the advertising data that u know belong to your peripheral.

I hope this helps.

回答2:

I'm not sure. Bluetooth LE isn't good idea to transfer large files. In one request phone you have only 18 bytes.

Nexus 7 bluetooth chip has some defect - not work correctly.

Try free application for IPhone - Light Blue.

so...

First question: yes.

Second: Yes but it's not good idea. MAc address in Iphone is alternating every 10 minutes and all turn on/off bluetooth.

回答3:

In general, sending large files is best done using an internet connection (over the cloud), there are many frameworks that can cut down the overhead for you.

However, the main question is still how to discover to which device you would want to send the data.

There could be multiple ways of doing that on your own such as using BLE or even sound.

To be honest, its a lot of work so if your app is end-user driven, i would suggest using a framework that can do cross platform discovery for you such as: http://p2pkit.io or google nearby.

Disclaimer: i work for Uepaa developing p2pkit for iOS and Android