Крайното ръководство: Създайте Bluetooth Swift App с хардуер за 20 минути

В предишен урок научихте как да добавите Bluetooth към приложение за частици ксенон. По този начин можете да контролирате вградения RGB светодиод от тестово приложение като nRF Connect или Light Blue Explorer.

В този пост ще направим още една крачка напред. Ще разработим приложение Swift, за да контролираме RGB, водено от Particle Mesh. Ако всичко върви добре, трябва да имате работещо приложение след около 20 минути!

Да започваме.

Нямате време в момента да прочетете цялата статия?

Изтеглете PDF версията тук.

Настройка

  • Инсталирайте Xcode. Можете да го изтеглите от App store тук.
  • Ще ви трябва и вход за Apple. Използвам имейла си от iCloud. Можете да създадете нов акаунт в Xcode, ако все още нямате такъв.
  • Инсталирайте RGB примерния код на дъска с частици.

Създайте проекта

След като всичко е инсталирано, нека да стигнем до забавните неща!

Отворете Xcode и отидете на File → New Project.

Xcode Нов проект

Изберете приложение за единичен изглед.

Нова информация за проекта

След това актуализирайте Името на проекта, за да ви хареса. Промених и идентификатора на организацията си на com.jaredwolff. Модифицирайте го, както сметнете за добре!

Изберете място, за да го запазите.

След това намерете вашия Info.plist.

Info.plist в Xcocde

Актуализирайте info.plistчрез добавянеPrivacy - Bluetooth Peripheral Usage Description

Описанието, което в крайна сметка използвах, беше App uses Bluetooth to connect to the Particle Xenon RGB Example

Това ви позволява да използвате Bluetooth в приложението си, ако някога искате да го освободите.

Сега нека да получим всичко минимално функционално!

Минимално функционален

Ново изображение на раздела

След това ще получим минимално функционално приложение за свързване и откриване на услуги. Повечето от действията ще се случат в ViewController.swift.

Нека първо импортираме CoreBluetooth

 import CoreBluetooth 

Това ни позволява да контролираме функционалността Bluetooth Low Energy в iOS. Тогава нека добавим както CBPeripheralDelegateи CBCentralManagerDelegateкъм ViewControllerкласа.

 class ViewController: UIViewController, CBPeripheralDelegate, CBCentralManagerDelegate { 

Нека сега създадем локални частни променливи, за да съхраняваме действителния централен мениджър и периферни устройства. Ще ги настроим за момент.

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

Във вашата viewDidLoadфункция, нека инициирамеcentralManager

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

Настройката delegate: selfе важна. В противен случай централното състояние никога не се променя при стартиране.

Преди да стигнем по-нататък, нека създадем отделен файл и да го извикаме ParticlePeripheral.swift. Може да се постави навсякъде, но аз го поставих в отделна „група“, наречена Модели за по-късно.

Вътре ще създадем някои публични променливи, които съдържат UUID за нашата ПДЧ. Те трябва да изглеждат познати!

 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") } 

Върнете се ViewController.swiftда сглобим Bluetooth битовете.

Bluetooth битове

Диаграма на потока за Bluetooth Swift в iOS

Всичко свързано с Bluetooth се основава на събития. Ще дефинираме няколко функции, които обработват тези събития. Ето най-важните:

centralManagerDidUpdateStateактуализира при включване или изключване на Bluetooth периферни устройства. Той ще се задейства при първо стартиране на приложение, за да знаете състоянието на Bluetooth. Започваме и сканиране тук.

В centralManagerdidDiscoverсъбитието се случва, когато получите резултати за сканиране. Ще използваме това, за да стартираме връзка.

В centralManagerdidConnectслучай задейства, след като устройството е свързано. Ще започнем откриването на устройството тук. Забележка: Откриването на устройства е начинът, по който определяме какви услуги и характеристики са налични. Това е добър начин да потвърдим към какъв тип устройство сме свързани.

В peripheraldidDiscoverServicesслучай, първо веднъж на всички услуги, са били открити. Забележете, че сме преминали от centralManagerдо peripheralсега, че ние сме свързани. Ще започнем характерното откритие тук. Като цел ще използваме UUID на RGB услугата.

На peripheraldidDiscoverCharacteristicsForсъбитието ще предостави всички характеристики с помощта на предоставената услуга UUID. Това е последната стъпка от веригата за пълно откриване на устройството. Това е космат, но трябва да се направи само веднъж по време на фазата на свързване!

Дефиниране на всички Bluetooth функции.

Сега, когато знаем какви са събитията на функциите, които се задействат. Ще ги дефинираме в логическия ред, който се случва по време на цикъл на свързване.

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

Изображение на раздела за тестване

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.

Изберете тип устройство

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.

Долен прозорец в Xcode за регистрационни файлове

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.

Актуализиране на изгледа в Xcode

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

Library button in Xcode

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

Library pane in Xcode

Drag three Labels and copy three Sliders to your view.

Dragging Labels to Xcode View

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

Dragging Slider to Xcode View

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

Alignment tools in 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!

Ruler pane in Xcode

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

Show Assistant Editor button in Xcode

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

Automatic option in Assistant Editor

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

Drag slider to code

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.

Drag value changed event to code

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.

Disable slider by default

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

Set default value and max value of slider

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.

Next section test!

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!)

If you followed everything perfectly, you should be able to move the sliders. Better yet, the RGB LED on the Particle Mesh board should change color.

Final test results

Conclusion

В тази статия сте научили как да свържете вашата платка с частици и мрежа с iOS устройство през Bluetooth. Научихме как да се свързваме с всяка от наличните характеристики. Освен това, на всичкото отгоре, направете чист интерфейс, за да го направите всичко.

Както можете да си представите, можете да слезете в заешката дупка с Bluetooth на iOS. Предстои още нещо в предстоящото ми ръководство: The Ultimate Guide to Particle Mesh. Абонатите на моя списък получават достъп до съдържанието преди стартиране и отстъпка, когато излезе! Щракнете тук, за да се регистрирате.

Код

Пълният изходен код е достъпен на Github. Ако го намерите полезен, натиснете бутона със звезда. ⭐️