Android BLE Made Easy
An easy to use, kotlin friendly BLE library for Android.
Installing
- Step 1. Add the JitPack repository to your project gradle file
allprojects {
repositories {
...
maven { url 'https://jitpack.io' }
}
}-
Step 1.1 Only if you have the file settings.gradle at your project root folder
- Add the JitPack repository to your project settings.gradle file
dependencyResolutionManagement { repositories { ... maven { url 'https://jitpack.io' } } }- Add the JitPack repository to your project gradle file
buildscript { repositories { ... maven { url 'https://jitpack.io' } } } -
Step 2. Add the implementation dependency to your app gradle file
dependencies {
...
implementation 'com.github.LeandroSQ:android-ble-made-easy:1.5.2'
...
}-
Step 3. Gradle sync
-
Step 4. Add these permissions to your manifest.xml file
<uses-permission
android:name="android.permission.BLUETOOTH"
android:maxSdkVersion="30" />
<uses-permission
android:name="android.permission.BLUETOOTH_ADMIN"
android:maxSdkVersion="30" />
<!-- These 2 bellow, only if you are targeting Android 12+ -->
<uses-permission android:name="android.permission.BLUETOOTH_CONNECT"
tools:targetApi="s" />
<uses-permission
android:name="android.permission.BLUETOOTH_SCAN"
android:usesPermissionFlags="neverForLocation"
tools:targetApi="s" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<!-- These 2 bellow, only if you are targeting Android 10+ -->
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_BACKGROUND_LOCATION" />
<uses-feature android:name="android.hardware.bluetooth_le" android:required="true"/>
<uses-feature android:name="android.hardware.bluetooth" android:required="true"/>And you are ready to go!
Core features
Lifecycle
The library accepts being used both in an Activity and a Fragment!
val ble = BLE(activity = this)
// or
val ble = BLE(fragment = this)Automatic handle permissions
The library requests the permissions for you.
Asynchronous:
ble.verifyPermissionsAsync(
rationaleRequestCallback = { next ->
// Include your code to show an Alert or UI explaining why the permissions are required
// Calling the function bellow if the user agrees to give the permissions
next()
},
callback = { granted ->
if (granted) {
// Continue your code....
} else {
// Include your code to show an Alert or UI indicating that the permissions are required
}
}
)Coroutines:
GlobalScope.launch {
val granted = ble.verifyPermissions(
rationaleRequestCallback = { next ->
// Include your code to show an Alert or UI explaining why the permissions are required
// Calling the function bellow if the user agrees to give the permissions
next()
}
)
if (granted) {
// Continue your code....
} else {
// Include your code to show an Alert or UI indicating that the permissions are required
}
}Automatic turn on the Bluetooth adapter
The library requests the Bluetooth hardware to be activated whenever it is off.
Asynchronous:
ble.verifyBluetoothAdapterStateAsync { active ->
if (active) {
// Continue your code...
} else {
// Include your code to show an Alert or UI indicating that the Bluetooth adapter is required to be on in order to your project work
}
}Coroutines:
GlobalScope.launch {
if (ble.verifyBluetoothAdapterState()) {
// Continue your code...
} else {
// Include your code to show an Alert or UI indicating that the Bluetooth adapter is required to be on in order to your project work
}
}Automatic turn on Location services
The library requests Location services to be activated whenever it is off.
Asynchronous:
ble.verifyLocationStateAsync{ active ->
if (active) {
// Continue your code...
} else {
// Include your code to show an Alert or UI indicating that Location is required to be on in order to your project work
}
}Coroutines:
GlobalScope.launch {
if (ble.verifyLocationState()) {
// Continue your code...
} else {
// Include your code to show an Alert or UI indicating that Location is required to be on in order to your project work
}
}Asynchronous and Coroutines
You can both use the library with callbacks and with coroutines suspended functions The callback functions having the 'async' suffix. And requiring a HOF callback as a parameter .
Handling the bluetooth connections with graceful connection shutdown, in another words, waits for current running operations (Read and Write) to be finished before closing the connection
JetPack Contracts Ready!
The library uses the new JetPack contracts API to automatically handle permissions and adapter activation for you.
Compatible with older API levels
Theoretically compatible all the way down to API 18, but made targeting API 21+.
Well documented!
All the functions and variables you're gonna be using are very well documented with KotlinDOC. So you can get autocompletion information on Android Studio. But if you want to take a look without installing it... You can take a look on the dokka generated documentation
Both low level bytes and String conversion
The library gives you the option to receive and send raw Bytes if you want. But also you can let it encode and decode your strings automatically.
Automatically handles the pain of Known issues
Take for instance Issue 183108 where Lollipop devices will not work properly without a workaround to handle the connection.
Or the well-known BLE 133 error! The nightmare of everyone that already worked with BLE on Android, this library has a compilation of techniques being used to get around it
Usage
After instantiating the BLE class...
Fast scan for a specific device
If you already know the device you wanna connect to, you could use this:
Asynchronous:
ble.scanForAsync(
// You only need to supply one of these, no need for all of them!
macAddress = "00:00:00:00",
name = "ESP32",
service = "00000000-0000-0000-0000-000000000000",
onFinish = { connection ->
if (connection != null) {
// And you can continue with your code
it.write("00000000-0000-0000-0000-000000000000", "Testing")
} else {
// Show an Alert or UI with your preferred error message about the device not being available
}
},
onError = { errorCode ->
// Show an Alert or UI with your preferred error message about the error
}
)
// It is important to keep in mind that every single one of the provided arguments of the function shown above, are optionals! Therefore, you can skip the ones that you don't need.Coroutines:
GlobalScope.launch {
// You can specify filters for your device, being them 'macAddress', 'service' and 'name'
val connection = ble.scanFor(
// You only need to supply one of these, no need for all of them!
macAddress = "00:00:00:00",
name = "ESP32",
service = "00000000-0000-0000-0000-000000000000"
)
// And it will automatically connect to your device, no need to boilerplate
if (connection != null) {
// And you can continue with your code
it.write("00000000-0000-0000-0000-000000000000", "Testing")
} else {
// Show an Alert or UI with your preferred error message about the device not being available
}
}Scanning BLE devices
Asynchronous:
ble.scanAsync(
duration = 10000,
onDiscover = { device ->
// Update your UI with the newest found device, in real time
},
onFinish = { devices ->
// Continue with your code handling all the devices found
},
onError = { errorCode ->
// Show an Alert or UI with your preferred error message
}
)Coroutines:
GlobalScope.launch {
try {
// Continue with your code handling all the devices found
val devices = ble.scan(duration = 10000)
} catch (e: Exception) {
// Show an Alert or UI with your preferred error message
} catch (e: ScanFailureException) {
// Show an Alert or UI with your preferred error message
}
}Or you could use the scan method without any timeout, only stopping it manually
ble.scanAsync(
duration = 0, // Disables the timeout
onDiscover = { device ->
// Update your UI with the newest found device, in real time
},
onFinish = { devices ->
// Continue with your code handling all the devices found
},
onError = { errorCode ->
// Show an Alert or UI with your preferred error message
}
)
// Stops your scan manually
ble.stopScan()Manually connecting to a discovered device
After a successful scan, you'll have your Bluetooth device, now it is time to connect with it!
ble.connect(device)?.let { connection ->
// Continue with your code
val value = connection.read("00000000-0000-0000-0000-000000000000")
connection.write("00000000-0000-0000-0000-000000000000", "0")
connection.close()
}Observing changes
There are two ways to observe changes, the first is using the native BLE NOTIFY, which is the preferred option.
// If you want to make use of the NOTIFY functionality
ble.connect(device)?.let { connection ->
// For watching bytes
connection.observe(characteristic = "00000000-0000-0000-0000-000000000000") { value: ByteArray ->
// This will run everytime the characteristic changes it's value
}
// For watching strings
connection.observeString(characteristic = "00000000-0000-0000-0000-000000000000", charset = Charsets.UTF_8) { value: String ->
// This will run everytime the characteristic changes it's value
}
}
The second way is to manually read the characteristic in a fixed interval and compare with the last value. Which uses more battery, isn't as effective and should only be used when the characteristic doesn't provide the NOTIFY property. Fortunately the library handles both ways in a similar API.
// If you want to use NOTIFY when available and fallback to the legacy way when it isn't
ble.connect(device)?.let { connection ->
connection.observe(
characteristic = "00000000-0000-0000-0000-000000000000",
owner = viewLifeCycleOwner, // The Lifecycle Owner to attach to
interval = 1000L // The interval in ms (in this example 1 second)
) { value: ByteArray ->
// This will run everytime the characteristic changes it's value
}
}Made With <3 by Leandro Quevedo