How do I use Native Text Controls on Mobile

This lesson describes how to interact with the native UITextField class from within your LiveCode application.

Screen captures and sample code are provided.

Introduction

This lesson shows you how to interact with a native text control within your LiveCode application and demonstrates some of the features that are available. You should review the user guide in order to get updates on the features covered here.

Creating a Test Interface

Creating a Test Interface

The interface shown in this step provides a number of option menus that allow you to set properties that control how you interact with the native text field. You can control font size, border style, auto correction type, keyboard type, content type, text color, text align, auto capitalization, keyboard style, return key type and receive the editing, text changed and return key messages. This list is only a subset of the native text field control features that are available in LiveCode.

The option menus do not contain any LiveCode script and are processed purely on the content of their names and labels. A generic message handler probes the content of these values for each option menu and applies the value using the command mobileControlSet.

Setting up the Button Code

The stack in this lesson has three buttons: The Reset Text Changed button, the Create button and the Delete button. Each of these buttons executes a small script. These scripts are listed in this step.

The Reset Text Changed button changes label "Text Changed: true" to "Text Changed: false"

on mouseUp
   put "Text Changed: false" into field "textChanged"
end mouseUp

The Create button creates an instance of a text field.

on mouseUp
	inputCreate
end mouseUp

The Delete button deletes an instance of a text field.

on mouseUp
	inputDelete
end mouseUp

Setting up the Stack Code

The card stack contains a number of message handlers that are responsible for a number of control aspects within the application. The comments in the following message event handler scripts provide details of what each script does.

on closeCard
	# handle the close card event
	inputDelete
end closeCard

on inputCreate
	# handle the input creation event
	if "testinput" is among the lines of mobileControls() then
		# ensure that only one native text input is open
		inputDelete
	end if   
	mobileControlCreate "input", "testinput"
	# set the native text input field to the size and position of the graphic input rectangle
	mobileControlSet "testinput", "rect", the rect of graphic "InputRect"
	mobileControlSet "testinput", "visible", true
	# make sure the selected option menu options are applied to the native text input
	updateFieldProps
end inputCreate

on inputDelete
	# delete the native text input
	mobileControlDelete "testinput"
end inputDelete

on inputFocus
	# set the focus to the native text input
	mobileControlDo "testinput", "focus"
end inputFocus

on mouseUp
	# handle any mouseUp here that is not handled explicitly by a control
	if word 1 of the name of the target is "button" then
		updateFieldProps
	end if
end mouseUp

on inputBeginEditing
	# handle the inputBeingEdited message
	# this updates a label field on the interface
	put "Editing: true" into field "editing"
end inputBeginEditing

on inputEndEditing
	# handle the inputEndEdited message
	# this updates a label field on the interface
	put "Editing: false" into field "editing"
end inputEndEditing

on inputTextChanged
	# handle the inputTextChanged message
	# this updates a label field on the interface
	put "Text Changed: true" into field "textChanged"
end inputTextChanged

on inputReturnKey
	# handle the inputReturnKey message
	# this raises a dialog box, indicating that the return key was pressed
	# and focus was removed from the text field
	answer "The return key was pressed" with "Okay"
end inputReturnKey

Updating the Properties

As discussed earlier in this lesson, the option menu items do not have LiveCode associated with them. Rather, they are processed using a generic message handler that uses the name and the label of the option menus to set up the respective control that has been changed. updateFieldProps is stored on the stack script and implements this generic process.

on updateFieldProps
	local tX

	# ensure that we are handling messages from our native text input
	if "testinput" is not among the lines of mobileControls() then
		exit updateFieldProps
	end if

	# loop through each control on the card
	repeat with tX = 1 to the number of controls
		# if the control name does not start with "property" then go to the next item 
		if word 1 of the short name of control tX is not "property" then
			next repeat
		end if
		# set the native control property using the value of the current card control 
		mobileControlSet "testinput", word 2 of the short name of control tX, the label of control tX
	end repeat

end updateFieldProps

Note: Using a generic process to apply any option menu selection allows you as a developer to add or remove option menus, knowing that any further LiveCode changes are minimal or not needed at all.

Editing Example 1

Editing Example 1

Once you raise your application on the iOS device of choice, you should be presented with the following or similar display. You have to select the button Create before you can start entering text. Once text has been entered (see next example), you should see how the label content of Text Changed and Editing changes. You can reset the Text Changed label by selecting the Reset Text Changed button. Selecting the option menus and altering their content should have an immediate impact on the content that is displayed in the text field.

Editing Example 2

Editing Example 2

You can enter text by selecting the text input area. This raises the keyboard you specified under the Keyboard Style option menu. Type in the text as required and complete editing with the return key.

Using the Native Text Control

Once the native text control is created it has all the behavior of a iOS field.

You can touch and hold on the field to show a magnified view or touch and release to show editing options.

8 Comments

Daniel ROBERT

Hello, very interesting !
Is it possible to find this stack already done ?

Thank-you
Best regards
Daniel ROBERT

Hanson Schmidt-Cornelius

Hi Daniel,

I have uploaded the sample stack to this lesson.

Kind Regards,

Hanson

Matthias Rebbe

Hi,

the autoCapitalization does not work. The name for this text input property is autoCapitalizationType and not just autoCapitalization.

So to get autoCapitalization working you have to rename the btn "property autoCapitalization" to "property autoCapitalizationType"

Btw: the dictionary also lists the wrong property name.
Regards,

Matthias

Hanson Schmidt-Cornelius

Hi Matthias,

thank you very much for your comment. The test stack has been updated and the dictionary entry fixed for the next release.

Kind Regards,

Hanson

Danny

Hi

Thanks for this - very helpful, however ... I downloaded the sample stack and when I want to open it, Livecode gives an error message: "there was a problem opening the stack: file is not a stack". Is the file to download corrupted in some way?

Regards
Danny

Hanson Schmidt-Cornelius

Hi Danny,

no, the stack is not corrupted. As of release LiveCode 5.5.0, the file format is changing to accommodate some of the new features we added.

The features in the sample stack do not take advantage of the features that require the new format, so I uploaded the stack again in the format that is supported with older versions of LiveCode.

You should be able to download and run the stack now.

Kind Regards,

Hanson

MaxV

Is there a way to format just a part of the text inside.the native control input?
For example: first line bold, second line italic...

Elanor Buchanan

Hi Max

I don't believe there is, all styling applies to the whole control.

The properties you can set on native controls can be found in the Dictionary entry for the mobileControlSet command.

Kind regards

Elanor

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