Den ultimative vejledning: Byg en Bluetooth Swift-app med hardware på 20 minutter

I en tidligere vejledning lærte du, hvordan du tilføjer Bluetooth til en Particle Xenon-applikation. På den måde kunne du styre den indbyggede RGB LED fra en testapp som nRF Connect eller Light Blue Explorer.

I dette indlæg vil vi tage det et skridt videre. Vi udvikler en Swift-app til at styre en Particle Mesh RGB-led. Hvis alt går godt, skal du have en fungerende app på cirka 20 minutter!

Lad os komme igang.

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Download PDF-versionen her.

Kom i gang

  • Installer Xcode. Du kan downloade det fra App Store her.
  • Du skal også bruge et Apple-login. Jeg bruger min iCloud-e-mail. Du kan oprette en ny konto inden for Xcode, hvis du ikke har en endnu.
  • Installer RGB-eksempelkoden på et Particle Mesh-kort.

Opret projektet

Når alt er installeret, lad os komme til de sjove ting!

Åbn Xcode og gå til File → New Project.

Xcode nyt projekt

Vælg Single View App.

Ny projektinfo

Opdater derefter projektnavnet, så det passer dig. Jeg har også ændret min organisations-id til com.jaredwolff. Rediger det, som du finder passende!

Vælg en placering for at gemme den.

Find derefter din Info.plist.

Info.plist i Xcocde

Opdater info.plistved at tilføjePrivacy - Bluetooth Peripheral Usage Description

Beskrivelsen jeg endte med at bruge var App uses Bluetooth to connect to the Particle Xenon RGB Example

Dette giver dig mulighed for at bruge Bluetooth i din app, hvis du nogensinde vil frigive den.

Lad os nu få alt minimalt funktionelt!

Minimalt funktionel

Nyt sektionsbillede

Dernæst får vi en minimalt funktionel app til at oprette forbindelse og gøre en opdagelse af tjenester. Det meste af handlingen vil ske i ViewController.swift.

Giver mulighed for første import CoreBluetooth

 import CoreBluetooth 

Dette giver os mulighed for at kontrollere Bluetooth Low Energy-funktionaliteten i iOS. Lad os så tilføje både CBPeripheralDelegateog og CBCentralManagerDelegatetil ViewControllerklassen.

 class ViewController: UIViewController, CBPeripheralDelegate, CBCentralManagerDelegate { 

Lad os nu oprette lokale private variabler til at gemme den faktiske centrale manager og perifere enhed. Vi sætter dem op yderligere et øjeblik.

 // Properties private var centralManager: CBCentralManager! private var peripheral: CBPeripheral! 

viewDidLoadLad os starte din funktion i din funktioncentralManager

 centralManager = CBCentralManager(delegate: self, queue: nil) 

Indstilling delegate: selfer vigtig. Ellers ændres centralstaten aldrig ved opstart.

Før vi kommer videre, skal vi oprette en separat fil og kalde den ParticlePeripheral.swift. Det kan placeres hvor som helst, men jeg placerede det i en separat 'gruppe' kaldet modeller til senere.

Indvendigt opretter vi nogle offentlige variabler, der indeholder UUID'erne til vores spånplade. De skal se velkendte ud!

 import UIKit import CoreBluetooth class ParticlePeripheral: NSObject { /// MARK: - Particle LED services and charcteristics Identifiers public static let particleLEDServiceUUID = CBUUID.init(string: "b4250400-fb4b-4746-b2b0-93f0e61122c6") public static let redLEDCharacteristicUUID = CBUUID.init(string: "b4250401-fb4b-4746-b2b0-93f0e61122c6") public static let greenLEDCharacteristicUUID = CBUUID.init(string: "b4250402-fb4b-4746-b2b0-93f0e61122c6") public static let blueLEDCharacteristicUUID = CBUUID.init(string: "b4250403-fb4b-4746-b2b0-93f0e61122c6") } 

Tilbage i ViewController.swiftlad os sammensætte Bluetooth-bitene.

Bluetooth-bits

Flowdiagram for Bluetooth Swift i iOS

Alt, hvad Bluetooth har at gøre, er begivenhedsbaseret. Vi definerer flere funktioner, der håndterer disse begivenheder. Her er de vigtige:

centralManagerDidUpdateStateopdateres, når Bluetooth Peripheral er slået til eller fra. Det aktiveres, når en app først starter, så du kender Bluetooth-tilstanden. Vi begynder også at scanne her.

Den centralManagerdidDiscoverbegivenhed opstår, når du modtager resultatet af scanningen. Vi bruger dette til at starte en forbindelse.

Den centralManagerdidConnectbegivenhed brande, når enheden er tilsluttet. Vi starter enhedens opdagelse her. Bemærk: Enhedsopdagelse er den måde, vi bestemmer, hvilke tjenester og egenskaber der er tilgængelige. Dette er en god måde at bekræfte, hvilken type enhed vi har forbindelse til.

Den peripheraldidDiscoverServicesbegivenhed først, når alle de tjenester, er blevet opdaget. Bemærk, at vi er skiftet fra centralManagertil peripheralnu, hvor vi er forbundet. Vi starter den karakteristiske opdagelse her. Vi bruger RGB-tjenesten UUID som mål.

Den peripheraldidDiscoverCharacteristicsForbegivenhed vil give alle de karakteristika, der bruger den medfølgende tjeneste UUID. Dette er det sidste trin i kæden for at foretage en fuldstændig enhedsopdagelse. Det er behåret, men det skal kun gøres en gang i forbindelsesfasen!

Defining all the Bluetooth functions.

Now that we know what the functions events that get triggered. We'll define them in the logical order that they happen during a connection cycle.

First, we'll define centralManagerDidUpdateState to start scanning for a device with our Particle RGB LED Service. If Bluetooth is not enabled, it will not do anything.

 // If we're powered on, start scanning func centralManagerDidUpdateState(_ central: CBCentralManager) { print("Central state update") if central.state != .poweredOn { print("Central is not powered on") } else { print("Central scanning for", ParticlePeripheral.particleLEDServiceUUID); centralManager.scanForPeripherals(withServices: [ParticlePeripheral.particleLEDServiceUUID], options: [CBCentralManagerScanOptionAllowDuplicatesKey : true]) } } 

Defining the centralManagerdidDiscover is our next step in the process. We know we've found a device if this event has occurred.

 // Handles the result of the scan func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber) { // We've found it so stop scan self.centralManager.stopScan() // Copy the peripheral instance self.peripheral = peripheral self.peripheral.delegate = self // Connect! self.centralManager.connect(self.peripheral, options: nil) } 

So, we stop scanning using self.centralManager.stopScan(). We set the peripheral so it persists through the app. Then we connect to that device using self.centralManager.connect

Once connected, we need to double check if we're working with the right device.

 // The handler if we do connect succesfully func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral) { if peripheral == self.peripheral { print("Connected to your Particle Board") peripheral.discoverServices([ParticlePeripheral.particleLEDServiceUUID]) } } 

By comparing the two peripherals we'll know its the device we found earlier. We'll kick off a services discovery using peripheral.discoverService. We can use ParticlePeripheral.particleLEDServiceUUID as a parameter. That way we don't pick up any services we don't care about.

Once we finish the discovering services, we'll get a didDiscoverServices event. We iterate through all the "available" services. (Though there will only be one!)

 // Handles discovery event func peripheral(_ peripheral: CBPeripheral, didDiscoverServices error: Error?) { if let services = peripheral.services { for service in services { if service.uuid == ParticlePeripheral.particleLEDServiceUUID { print("LED service found") //Now kick off discovery of characteristics peripheral.discoverCharacteristics([ParticlePeripheral.redLEDCharacteristicUUID, ParticlePeripheral.greenLEDCharacteristicUUID, ParticlePeripheral.blueLEDCharacteristicUUID], for: service) return } } } } 

By this point this is the third time we're checking to make sure we have the correct service. This becomes more handy later when there are many characteristics and many services.

We call peripheral.discoverCharacteristics with an array of UUIDs for the characteristics we're looking for. They're all the UUIDs that we defined in ParticlePeripheral.swift.

Finally, we handle the didDiscoverCharacteriscsFor event. We iterate through all the available characteristics. As we iterate we compare with the ones we're looking for.

 // Handling discovery of characteristics func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) { if let characteristics = service.characteristics { for characteristic in characteristics { if characteristic.uuid == ParticlePeripheral.redLEDCharacteristicUUID { print("Red LED characteristic found") } else if characteristic.uuid == ParticlePeripheral.greenLEDCharacteristicUUID { print("Green LED characteristic found") } else if characteristic.uuid == ParticlePeripheral.blueLEDCharacteristicUUID { print("Blue LED characteristic found"); } } } } 

At this point we're ready to do a full device discovery of our Particle Mesh device. In the next section we'll test what we have to make sure things are working ok.

Testing our minimal example

Afsnit billede om test

Before we get started, if you run into trouble I've put some troubleshooting steps in the footnotes.

To test, you'll have to have an iPhone with Bluetooth Low Energy. Most modern iPhones have it. The last iPhone not to have it I believe was either the iPhone 4 or 3Gs. (so you're likely good)

First, plug it into your computer.

Go to the top by the play and stop buttons. Select your target device. In my case I chose my phone (Jared's iPhone). You can also use an iPad.

Vælg enhedstype

Then you can hit Command + R or hit that Play button to load the app to your phone.

Make sure you have your log tab open. Enable it by clicking the bottom pane button in the top right corner.

Nederste rude i Xcode til logfiler

Make sure you have a mesh device setup and running the example code. You can go to this post to get it. Remember your Particle Mesh board needs to be running device OS 1.3.0 or greater for Bluetooth to work!

Once both the firmware and app is loaded, let's check the log output.

It should look something like this:

View loaded Central state update Central scanning for B4250400-FB4B-4746-B2B0-93F0E61122C6 Connected to your Particle Board LED service found Red LED characteristic found Green LED characteristic found Blue LED characteristic found 

This means that your Phone has connected, found the LED service! The characteristics also being discovered is important here. Without those we wouldn't be able to send data to the mesh device.

Next step is to create some sliders so we can update the RGB values on the fly.

Slide to the left. Slide to the right.

Next we're going to add some elements to our Main.storyboard. Open Main.storyboard and click on the View underneath View Controller.

Opdaterer visning i Xcode

Then click on the Library button. (It looks like the old art Apple used for the home button)

Bibliotek-knap i Xcode

You'll get a pop-up with all the choices that you can insert into your app.

Biblioteksrude i Xcode

Drag three Labels and copy three Sliders to your view.

Træk etiketter til Xcode-visning

You can double click on the labels and rename them as you go.

Træk skyderen til Xcode-visning

If you click and hold, some handy alignment tools will popup. They'll even snap to center!

Justeringsværktøjer i Xcode

You can also select them all and move them together. We'll align them vertically and horizontally.

In order for them to stay in the middle, let's remove the autoresizing property. Click the Ruler icon on the top right. Then click each of the red bars. This will ensure that your labels and sliders stay on the screen!

Linealrude i Xcode

Next let's click the Show Assistant Editor button. (Looks like a Venn diagram)

Vis knappen Assistent Editor i Xcode

Note: make sure that ViewController.swift is open in your Assistant Editor.

Automatisk mulighed i Assistent Editor

Then underneath the /properties section, Control-click and dragthe Red Slider into your code.

Træk skyderen til kode

Repeat with all the other ones. Make sure you name them something different. Your code should look like this when you're done:

 // Properties private var centralManager: CBCentralManager! private var peripheral: CBPeripheral! // Sliders @IBOutlet weak var redSlider: UISlider! @IBOutlet weak var greenSlider: UISlider! @IBOutlet weak var blueSlider: UISlider! 

This allow us to access the value of the sliders.

Next, let's attach the Value Changed event to each of the sliders. Right click on the Red Slider in the folder view.

Træk værdi ændret begivenhed til kode

It should give you some options for events. Click and drag the Value Changed event to your code. Make sure you name it something that makes sense. I used RedSliderChanged for the Red Slider.

Repeat two more times. Your code should look like this at the end of this step:

 @IBAction func RedSliderChanged(_ sender: Any) { } @IBAction func GreenSliderChanged(_ sender: Any) { } @IBAction func BlueSliderChanged(_ sender: Any) { } 

I've also selected each of the sliders to and un-checked Enabled. That way you can't move them. We'll enable them later on in code.

Deaktiver skyderen som standard

Also, this is a great time to change the maximum value to 255. Also set the default value from 0.5 to 0.

Indstil standardværdi og maksimumværdi for skyderen

Back at the top of the file. Let's create some local variables for each of the characteristics. We'll use these so we can write the slider variables to the Particle Mesh board.

 // Characteristics private var redChar: CBCharacteristic? private var greenChar: CBCharacteristic? private var blueChar: CBCharacteristic? 

Now, let's tie everything together!

In the didDiscoverCharacteristicsFor callback function. Let's assign those characteristics. For example

 if characteristic.uuid == ParticlePeripheral.redLEDCharacteristicUUID { print("Red LED characteristic found") redChar = characteristic 

As we find each characteristic, we can also enable each of the sliders in the same spot.

 // Unmask red slider redSlider.isEnabled = true 

In the end your didDiscoverCharacteristicsFor should look like:

 // Handling discovery of characteristics func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) { if let characteristics = service.characteristics { for characteristic in characteristics { if characteristic.uuid == ParticlePeripheral.redLEDCharacteristicUUID { print("Red LED characteristic found") redChar = characteristic redSlider.isEnabled = true } else if characteristic.uuid == ParticlePeripheral.greenLEDCharacteristicUUID { print("Green LED characteristic found") greenChar = characteristic greenSlider.isEnabled = true } else if characteristic.uuid == ParticlePeripheral.blueLEDCharacteristicUUID { print("Blue LED characteristic found"); blueChar = characteristic blueSlider.isEnabled = true } } } } 

Now, let's update the RedSliderChangedGreenSliderChanged and BlueSliderChanged functions. What we want to do here is update the characteristic associated with the Changed function. I created a separate function called writeLEDValueToChar. We'll pass in the characteristic and the data.

 private func writeLEDValueToChar( withCharacteristic characteristic: CBCharacteristic, withValue value: Data) { // Check if it has the write property if characteristic.properties.contains(.writeWithoutResponse) && peripheral != nil { peripheral.writeValue(value, for: characteristic, type: .withoutResponse) } } 

Now add a call to writeLEDValueToChar to each of the Changed functions. You will have to cast the value to a Uint8. (The Particle Mesh device expects an unsigned 8-bit number.)

 @IBAction func RedSliderChanged(_ sender: Any) { print("red:",redSlider.value); let slider:UInt8 = UInt8(redSlider.value) writeLEDValueToChar( withCharacteristic: redChar!, withValue: Data([slider])) } 

Repeat this for GreenSliderChanged and BlueSliderChanged. Make sure you changed red to green and blue for each!

Finally, to keep things clean, i've also added a function that handles Bluetooth disconnects.

 func centralManager(_ central: CBCentralManager, didDisconnectPeripheral peripheral: CBPeripheral, error: Error?) { 

Inside, we should reset the state of the sliders to 0 and disable them.

 if peripheral == self.peripheral { print("Disconnected") redSlider.isEnabled = false greenSlider.isEnabled = false blueSlider.isEnabled = false redSlider.value = 0 greenSlider.value = 0 blueSlider.value = 0 

It's a good idea to reset self.peripheral to nil that way we're not ever trying to write to a phantom device.

 self.peripheral = nil 

Finally, because we've disconnected, start scanning again!

 // Start scanning again print("Central scanning for", ParticlePeripheral.particleLEDServiceUUID); centralManager.scanForPeripherals(withServices: [ParticlePeripheral.particleLEDServiceUUID], options: [CBCentralManagerScanOptionAllowDuplicatesKey : true]) } 

Alright! We just about ready to test. Let's move on to the next (and final) step.

Test the sliders.

Test i næste afsnit!

The hard work is done. Now it's time to play!

The easiest way to test everything is to click the Play button in the top left or the Command + R keyboard shortcut. Xcode will load the app to your phone. You should see a white screen proceeded by a screen with your sliders!

The sliders should stay greyed out until connected to your Particle Mesh board. You can check your log output if the connection has been established.

View loaded Central state update Central scanning for B4250400-FB4B-4746-B2B0-93F0E61122C6 Connected to your Particle Board LED service found Red LED characteristic found Green LED characteristic found Blue LED characteristic found 

(Look familiar? We're connected!)

Hvis du fulgte alt perfekt, skulle du være i stand til at flytte skyderne. Endnu bedre, RGB-LED på partikelnetkortet skal ændre farve.

Endelige testresultater

Konklusion

I denne artikel har du lært, hvordan du forbinder dit Particle Mesh-kort og iOS-enhed via Bluetooth. Vi har lært, hvordan man opretter forbindelse til hver af de tilgængelige egenskaber. Plus, oven på det hele, lav en ren grænseflade for at gøre det hele.

Som du kan forestille dig, kan du gå ned i kaninhullet med Bluetooth på iOS. Der kommer mere i min kommende guide: The Ultimate Guide to Particle Mesh. Abonnenter på min liste får adgang til pre-launch indhold og en rabat, når det kommer ud! Klik her for at blive tilmeldt.

Kode

Den fulde kildekode er tilgængelig på Github. Hvis du finder det nyttigt, skal du trykke på stjerneknappen. ⭐️