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.
You can download the sample stack from this url: https://tinyurl.com/y8lyj2x4
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
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 the environment is "mobile" then 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" # make the native text input field visible mobileControlSet "testinput", "visible", true # focus on the native text input field mobileControlDo "testinput", "focus", true # make sure the selected option menu options are applied to the native text input updateFieldProps end if end inputCreate on inputDelete if the environment is "mobile" then # delete the native text input mobileControlDelete "testinput" end if end inputDelete on inputFocus # set the focus to the native text input mobileControlDo "testinput", "focus" end inputFocus 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 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 if the platform is "android" then // Show the options // On other platforms the options are shown automatically local tTarget, tOptions put the long name of the target into tTarget put the cOptions of tTarget into tOptions mobilePick tOptions put the result into tResult if tResult is not "cancel" then set the label of tTarget to line tResult of tOptions end if end if updateFieldProps end if end mouseUp
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
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
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.