Jdecoux at 16:49, 13 September 2018

2018-09-13T16:49:41Z

← Older revision		Revision as of 16:49, 13 September 2018
Line 1:		Line 1:
	{{WriteCode_Intro\|Swift\|Swift}}		{{WriteCode_Intro\|Swift\|Swift}}

	=== Step One: ~~Initialize~~ and ~~Open~~ ===		=== Step One: Create and Address===
	You will need to ~~declare~~ your Phidget object in your code. For example, we can ~~declare~~ a digital input object like this:		You will need to create your Phidget object in your code. For example, we can create a digital input object like this:
	<syntaxhighlight lang="swift">		<syntaxhighlight lang=swift>
	let ch = DigitalInput()		let ch = DigitalInput()
	</syntaxhighlight>		</syntaxhighlight>

			Next, we can address which Phidget we want to connect to by setting parameters such as ''DeviceSerialNumber''.

	~~Next, the Phidget object needs to be opened:~~		<syntaxhighlight lang=swift>
	<syntaxhighlight lang="swift">		ch.setDeviceSerialNumber(496911);
	ch.~~open~~()
	</syntaxhighlight>		</syntaxhighlight>

			Although we are not including it on this page, you should handle the return codes of all Phidget functions. Here is an example of the previous code with error handling:
	Although we are not including it on this page, you ~~need to include error handling for~~ all Phidget functions. Here is an example of the previous code with error handling:		<syntaxhighlight lang=swift>
	<syntaxhighlight lang="swift">
	do{		do{
	try ch.open		try ch.open
Line 23:		Line 22:
	</syntaxhighlight>		</syntaxhighlight>

	=== Step Two: Wait for Attachment ~~(Plugging In) of the Phidget~~ ===		=== Step Two: Open and Wait for Attachment===
	~~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~~:
	<syntaxhighlight lang="swift">		After we have specified which Phidget to connect to, we can open the Phidget object like this:
			<syntaxhighlight lang=swift>
	ch.open(timeout: 5000)		ch.open(timeout: 5000)
	</syntaxhighlight>		</syntaxhighlight>
	~~Waiting for attachment will block indefinitely until a connection is made, or until the timeout value is exceeded.~~

			To use a Phidget, it must be plugged in (attached). We can handle this by calling '''open(''timeout'')''', which will block indefinitely until a connection is made, or until the timeout value is exceeded. Simply calling '''open()''' does not guarantee you can use the Phidget immediately.

			Alternately, you could verify the device is attached by using event driven programming and tracking the attach events.

			To use events to handle attachments, we have to modify our code slightly:
			<syntaxhighlight lang=swift>
			PhidgetDigitalInputHandle ch;
			PhidgetDigitalInput_create(&ch);

	~~To use events, we have to modify our code slightly:~~
	~~<syntaxhighlight lang="swift">~~
	ch.attach.addHandler(attach_handler)		ch.attach.addHandler(attach_handler)
	Phidget_open(ch)		Phidget_open(ch)
	</syntaxhighlight>		</syntaxhighlight>

	Next, we have to declare the function that will be called when an attach event is fired - in this case the function ''~~attach_handler~~'' will be called.		Next, we have to declare the function that will be called when an attach event is fired - in this case the function ''onAttachHandler'' will be called:
			<syntaxhighlight lang=swift>
	<syntaxhighlight lang="swift">
	func attach_handler(sender: Phidget){		func attach_handler(sender: Phidget){
	let attachedDevice = sender as! DigitalInput		let attachedDevice = sender as! DigitalInput
Line 45:		Line 49:
	}		}
	</syntaxhighlight>		</syntaxhighlight>

			We recommend using this attach handler to set any initialization parameters for the channel such as DataInterval and ChangeTrigger from within the AttachHandler, so the parameters are set as soon as the device becomes available.

	=== Step Three: Do Things with the Phidget ===		=== Step Three: Do Things with the Phidget ===
	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:		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:
			<syntaxhighlight lang=swift>
	<syntaxhighlight lang="swift">
	ch.attach.addHandler(attach_handler)		ch.attach.addHandler(attach_handler)
	ch.stateChange.addhandler(stateChange_handler)		ch.stateChange.addhandler(stateChange_handler)
Line 55:		Line 60:
	</syntaxhighlight>		</syntaxhighlight>

	This code will connect a function ~~and~~ an event. In this case, the ''~~stateChange_handler~~'' function will be called when there has been a change to the ~~devices~~ input. Next, we need to create the ''~~stateChange_handler~~'' function:		This code will connect a function to an event. In this case, the ''onStateChangeHandler'' function will be called when there has been a change to the channel's input. Next, we need to create the ''onStateChangeHandler'' function:
	<syntaxhighlight lang="swift">		<syntaxhighlight lang=swift>
	func stateChange_handler(sender: DigitalInput, state: Bool){		func stateChange_handler(sender: DigitalInput, state: Bool){
	if(state){		if(state){
Line 67:		Line 72:
	</syntaxhighlight>		</syntaxhighlight>

			If you are using multiple Phidgets in your program, check out our page on [[Using Multiple Phidgets]] for information on how to properly address them and use them in events.

	If events do not suit your needs, you can also poll the device directly for data using code like this:		If events do not suit your needs, you can also poll the device directly for data using code like this:
	<syntaxhighlight lang="swift">		<syntaxhighlight lang=swift>
	var state = ch.getState()		var state = ch.getState()
	stateLabel.text = state ? "True" : "False"		stateLabel.text = state ? "True" : "False"
	</syntaxhighlight>		</syntaxhighlight>

			'''Important Note:''' There will be a period of time between the attachment of a Phidget sensor and the availability of the first data from the device. Any attempts to get this data before it is ready will result in an error code, and a specific nonsensical result. See more information on this on our page for [[Unknown Values]].

			====Enumerations====

			Some Phidget devices have functions that deal with specific predefined values called enumerations. Enumerations commonly provide readable names to a set of numbered options.

			Enumerations with Phidgets in Swift will take the form of '''Phidget22Swift.EnumerationType.enumerationName'''.

			For example, specifying a SensorType to use the 1142 for a voltage input would look like:
			<syntaxhighlight lang=swift>
			Phidget22Swift.VoltageSensorType.PN_1142
			</syntaxhighlight>
			and specifying a K-Type thermocouple for a temperature sensor would be:
			<syntaxhighlight lang=swift>
			Phidget22Swift.ThermocoupleType.K
			</syntaxhighlight>
			The Phidget error code for timing out could be specified as:
			<syntaxhighlight lang=swift>
			Phidget22Swift.ErrorCode.timeout
			</syntaxhighlight>

			You can find the Enumeration Type under the ''Enumerations'' section of the {{Phidget22API}} for your device, and the Enumeration Name in the drop-down list within.

	=== Step Four: Close ===		=== Step Four: Close ===
	At the end of your program, be sure to close your device.		At the end of your program, be sure to close your device:
	<syntaxhighlight lang="swift">		<syntaxhighlight lang=swift>
	ch.close()		ch.close()
	</syntaxhighlight>		</syntaxhighlight>

Jdecoux: Created page with "{{WriteCode_Intro|Swift|Swift}} === Step One: Initialize and Open === You will need to declare your Phidget object in your code. For example, we can declare a digital input o..."

2018-09-13T15:51:04Z

Created page with "{{WriteCode_Intro|Swift|Swift}} === Step One: Initialize and Open === You will need to declare your Phidget object in your code. For example, we can declare a digital input o..."

New page

{{WriteCode_Intro|Swift|Swift}}

=== Step One: Initialize and Open ===
You will need to declare your Phidget object in your code. For example, we can declare a digital input object like this:
<syntaxhighlight lang="swift">
let ch = DigitalInput()
</syntaxhighlight>

Next, the Phidget object needs to be opened:
<syntaxhighlight lang="swift">
ch.open()
</syntaxhighlight>

Although we are not including it on this page, you need to include error handling for all Phidget functions. Here is an example of the previous code with error handling:
<syntaxhighlight lang="swift">
do{
try ch.open
}catch let error as PhidgetError{
//handle error
}
</syntaxhighlight>

=== Step Two: Wait for Attachment (Plugging In) of the Phidget ===
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:
<syntaxhighlight lang="swift">
ch.open(timeout: 5000)
</syntaxhighlight>
Waiting for attachment will block indefinitely until a connection is made, or until the timeout value is exceeded.

To use events, we have to modify our code slightly:
<syntaxhighlight lang="swift">
ch.attach.addHandler(attach_handler)
Phidget_open(ch)
</syntaxhighlight>

Next, we have to declare the function that will be called when an attach event is fired - in this case the function ''attach_handler'' will be called.

<syntaxhighlight lang="swift">
func attach_handler(sender: Phidget){
let attachedDevice = sender as! DigitalInput
//configure device here
}
</syntaxhighlight>

=== Step Three: Do Things with the Phidget ===
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:

<syntaxhighlight lang="swift">
ch.attach.addHandler(attach_handler)
ch.stateChange.addhandler(stateChange_handler)
ch.open()
</syntaxhighlight>

This code will connect a function and an event. In this case, the ''stateChange_handler'' function will be called when there has been a change to the devices input. Next, we need to create the ''stateChange_handler'' function:
<syntaxhighlight lang="swift">
func stateChange_handler(sender: DigitalInput, state: Bool){
if(state){
//state is true
}
else{
//State is false
}
}
</syntaxhighlight>

If events do not suit your needs, you can also poll the device directly for data using code like this:
<syntaxhighlight lang="swift">
var state = ch.getState()
stateLabel.text = state ? "True" : "False"
</syntaxhighlight>

=== Step Four: Close ===
At the end of your program, be sure to close your device.
<syntaxhighlight lang="swift">
ch.close()
</syntaxhighlight>

Template:Language - Swift Write Code - Revision history

Jdecoux at 16:49, 13 September 2018

Jdecoux: Created page with "{{WriteCode_Intro|Swift|Swift}} === Step One: Initialize and Open === You will need to declare your Phidget object in your code. For example, we can declare a digital input o..."