Difference between revisions of "Language - Swift"

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<metadesc>Communicate over USB with sensors, controllers and relays with Phidgets! Our Swift library supports iOS using Xcode.</metadesc>
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[[Category:Language]]
== Quick Downloads ==
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__NOTOC__
  
Already know what you're doing? Here you go:
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We provide support for the Swift language on macOS. We also provide instructions on how to get your project started in Xcode for use in macOS and iOS applications. Select your operating system below, and follow the instructions to get your project running with Phidgets.
  
=== Documentation ===
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Once you have set up your development environment to run with Phidgets, we recommend you follow our guide on [[Phidget Programming Basics]]. The guide will showcase the fundamentals of programming with Phidgets.
  
*{{Phidget22API}} (select C from the drop-down menu)
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==Choose Your Development Environment:==
  
=== Example Code ===
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{{Language_-_Swift_Dev_Environment_Table}}
  
*{{SampleCode|Swift|Swift Examples}}
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== Quick Downloads ==
  
=== Libraries ===
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If you already know what you're doing and just need the files, you can find them all below.
  
{{MacQuickDownloads}}
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=== Documentation ===
{{iOSQuickDownloads}}
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== Getting Started with Swift ==
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*{{Phidget22API}} (select Swift from the drop-down menu)
Welcome to using Phidgets with Swift! By using Swift, you will have access to the complete {{Phidget22API}}, including events. We also provide example code in Swift for multiple Phidget classes.
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== iOS ==
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=== Example Code ===
{{IOS_Languages}}
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===Xcode===
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====Use Our Examples====
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One of the best ways to start programming with Phidgets is to use our example code as a guide. In order to run the examples for iOS you will need to download [https://developer.apple.com/xcode/ Xcode] from the Mac App Store.
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*{{SampleCode|Swift|Swift Examples}}
  
Now that you have Xcode installed, download the Swift example:
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===Libraries===
*{{SampleCode|Swift|Swift Example}}
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You have previously downloaded the Phidget iOS libraries on the iOS page, but here they are again, just in case:
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*[{{SERVER}}/downloads/phidget22/libraries/ios/Phidget22_iOS.zip Phidget iOS Libraries]
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Next, unpack the Swift example and navigate to ''Phidget.xcodeproj''. Open the file in Xcode:
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[[Image:Swift_open.png|link=|center]]
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{{IOS_use_our_examples}}
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====Configure Your Project====
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Whether you are  building a project from scratch, or adding Phidget functionality to an existing project, you will need to configure your development environment to properly link the Phidget libraries. To begin:
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Create a new Xcode project:
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[[Image:Cocoa_CreateProject.png |link=|center]]
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Next, select an iOS application. For this tutorial's purposes, we will use a Single View Application:
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[[Image:iOS_SingleView.png |link=|center]]
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Name the project, select Swift as the language, and choose which devices will be supported:
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[[Image:iOS_NameProject_Swift.png|link=|center]]
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Now that your project is created, you need to add references to the Phidget iOS libraries. This is covered in detail above in the [[#Use our examples |use our examples]] section.
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After you have linked the Phidget iOS libraries, simply add a reference to phidget22.h in your bridging header file:
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<syntaxhighlight lang="objc">
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#import "phidget22.h"
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</syntaxhighlight>
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Success! The project now has access to Phidgets and we are ready to begin coding.
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==Write Code==
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{{WriteCode_Intro|Swift}}
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(Use the C API as a reference when using Swift)
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=== Step One: Initialize and Open ===
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You will need to declare your Phidget object in your code. For example, we can declare a digital input object like this:
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<syntaxhighlight lang="swift">
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var ch:PhidgetDigitalInput? = nil
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</syntaxhighlight>
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Next, the Phidget object needs to be initialized and opened:
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<syntaxhighlight lang="swift">
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PhidgetDigitalInput_create(&ch)
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Phidget_open(ch)
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</syntaxhighlight>
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Although we are not including it on this page, you should include error handling for all Phidget functions. Here is an example of the previous code with error handling:
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<syntaxhighlight lang="swift">
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var res:PhidgetReturnCode = EPHIDGET_OK
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res = PhidgetDigitalInput_create(&ch)
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if(res != EPHIDGET_OK){
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  NSLog("Error")
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}
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res = Phidget_open(ch)
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if(res != EPHIDGET_OK){
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  NSLog("Error")
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}
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Phidget_open(ch)
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</syntaxhighlight>
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=== Step Two: Wait for Attachment (Plugging In) of the Phidget ===
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Simply calling open does not guarantee you can use the Phidget immediately. To use a Phidget, it must be plugged in (attached). We can handle this by using event driven programming and tracking the attach events. Alternatively, we can modify our code so we wait for an attachment:
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<syntaxhighlight lang="swift">
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PhidgetDigitalInput_create(&ch)
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Phidget_openWaitForAttachment(ch, 5000)
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</syntaxhighlight>
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Waiting for attachment will block indefinitely until a connection is made, or until the timeout value is exceeded.
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To use events, we have to modify our code slightly:
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<syntaxhighlight lang="swift">
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PhidgetDigitalInput_create(&ch)
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Phidget_setOnAttachHandler(ch, gotAttach, bridge(self))
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Phidget_open(ch)
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</syntaxhighlight>
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Next, we have to declare the function that will be called when an attach event is fired - in this case the function ''gotAttach'' will be called.
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<syntaxhighlight lang="swift">
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let gotAttach: @convention(c)(PhidgetHandle?, UnsafeMutableRawPointer?) -> () = {phid,context in
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    DispatchQueue.main.async(execute: {
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        let myObject = Unmanaged<YourViewController>.fromOpaque(context!).takeUnretainedValue()
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        myObject.onAttachHandler()
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    })
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}
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</syntaxhighlight>
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The bridge function mentioned above is described here:
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<syntaxhighlight lang="swift">
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func bridge<T : AnyObject>(_ obj : T) -> UnsafeMutableRawPointer {
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    return Unmanaged.passUnretained(obj).toOpaque()
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}
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</syntaxhighlight>
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=== Step Three: Do Things with the Phidget ===
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We recommend the use of event driven programming when working with Phidgets. In a similar way to handling an attach event as described above, we can also add an event handler for a state change event:
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<syntaxhighlight lang="swift">
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PhidgetDigitalInput_create(&ch)
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Phidget_setOnAttachHandler(ch, gotAttach, bridge(self))
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PhidgetDigitalInput_setOnStateChangeHandler(ch, gotStateChange, bridge(self))
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Phidget_open(ch)
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</syntaxhighlight>
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This code will connect a function and an event. In this case, the ''gotStateChange'' function will be called when there has been a change to the devices input. Next, we need to create the ''gotStateChange'' function:
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<syntaxhighlight lang="swift">
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let gotStateChange: @convention(c)(PhidgetDigitalInputHandle?, UnsafeMutableRawPointer?, CInt) -> () = {_,context,cState in
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    var state:Int32 = cState
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    DispatchQueue.main.async(execute: {
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        let myObject = Unmanaged<YourViewController>.fromOpaque(context!).takeUnretainedValue()
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        myObject.onStateChangeHandler(state)
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    })
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}
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</syntaxhighlight>
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Above, the onStateChangeHandler method is invoked on the main thread. Event data is stored as an Int32.
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The method onStateChangeHandler is defined as follows:
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<syntaxhighlight lang="swift">
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func onStateChangeHandler(_ state:Int32){
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    if  state == 0{
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        stateLabel.text = "False"
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    }
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    else{
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        stateLabel.text = "True"
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    }
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}
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</syntaxhighlight>
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If events do not suit your needs, you can also poll the device directly for data using code like this:
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<syntaxhighlight lang="swift">
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var state = 0
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PhidgetDigitalOutput_getState(ch, &state)
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stateLabel.text = state ? "True" : "False"
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</syntaxhighlight>
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=== Step Four: Close and Delete ===
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At the end of your program, be sure to close your device.
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<syntaxhighlight lang="swift">
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Phidget_close(ch)
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PhidgetDigitalInput_delete(&ch)
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</syntaxhighlight>
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== Further Reading ==
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[[Phidget Programming Basics]] - Here you can find the basic concepts to help you get started with making your own programs that use Phidgets.
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[[Data Interval/Change Trigger]] - Learn about these two properties that control how much data comes in from your sensors.
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[[Using Multiple Phidgets]] - It can be difficult to figure out how to use more than one Phidget in your program. This page will guide you through the steps.
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[[Polling vs. Events]] - Your program can gather data in either a polling-driven or event-driven manner. Learn the difference to determine which is best for your application.
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[[Logging, Exceptions, and Errors]] - Learn about all the tools you can use to debug your program.
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[[Phidget Network Server]] - Phidgets can be controlled and communicated with over your network- either wirelessly or over ethernet.
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{{AllQuickDownloads}}

Latest revision as of 22:16, 28 February 2019


We provide support for the Swift language on macOS. We also provide instructions on how to get your project started in Xcode for use in macOS and iOS applications. Select your operating system below, and follow the instructions to get your project running with Phidgets.

Once you have set up your development environment to run with Phidgets, we recommend you follow our guide on Phidget Programming Basics. The guide will showcase the fundamentals of programming with Phidgets.

Choose Your Development Environment:

Swift Development Environments
OS - macOS macOS

SW XCODE MAC.png SW XCODE MAC on.png

OS - iOS iOS

SW XCODE IOS.png SW XCODE IOS on.png

Quick Downloads

If you already know what you're doing and just need the files, you can find them all below.

Documentation

Example Code

Libraries