Edit

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Functions

Edit*	edit_create (void)
Edit*	edit_multiline (void)
void	edit_OnFilter (...)
void	edit_OnChange (...)
void	edit_OnFocus (...)
void	edit_text (...)
void	edit_font (...)
void	edit_align (...)
void	edit_passmode (...)
void	edit_editable (...)
void	edit_autoselect (...)
void	edit_select (...)
void	edit_tooltip (...)
void	edit_color (...)
void	edit_color_focus (...)
void	edit_bgcolor (...)
void	edit_bgcolor_focus (...)
void	edit_phtext (...)
void	edit_phcolor (...)
void	edit_phstyle (...)
void	edit_vpadding (...)
const char_t*	edit_get_text (...)
real32_t	edit_get_height (...)
void	edit_copy (...)
void	edit_cut (...)
void	edit_paste (...)

1. Filter texts
2. Text selection
3. Clipboard operations

EditBox are small text boxes with editing capabilities. Like the Label they are of uniform format: The typeface and colors will affect the entire text (Figure 1). They are usually used to edit fields in forms, normally restricted to a single line, although they can also be extended to several of them. To edit texts with multiple attributes use TextView. In Hello Edit and UpDown! you have an example of use.

Use edit_create to create an edit box.
Use edit_multiline to create a multi-line editing box.
Use edit_passmode to hide the text of the control.
Use edit_phtext to set a placeholder.

Window where several edit boxes appear, as a form. — Figure 1: Edition boxes on different platforms.

1. Filter texts

Use edit_OnChange to validate the final text.
Use edit_OnFilter to detect and correct each user keystroke.

Depending on the value we are editing, it may be necessary to validate the entered text. We can do this when finishing editing or while we are writing. For the first case we will use the edit_OnChange (Listing 1) event that will call the handler just before the control loses keyboard focus (Figure 2). If the text is invalid, the handler must return FALSE, thus preventing the focus from changing to the next control, remaining in the editbox and forcing the user to correct it.

static void i_OnChange(App *app, Event *e)
{
    const EvText *p = event_params(e, EvText);
    if (is_valid_text(data, p->text) == FALSE)
    {
        // Force the focus remain in editbox
        bool_t *r = event_result(e, bool_t);
        *r = FALSE;
    }
}
...
edit_OnChange(edit, listener(NULL, i_OnChange, void));

Shows changing keyboard focus between two edit boxes. — Figure 2: The *OnChange* event is called just before the control loses focus.

For example, in Hello Edit and UpDown! activating the Field validations check will show a modal window within the OnChange event allowing you to validate or reject text (Figure 3).

Displays a form where the user is asked if the data is valid. — Figure 3: Validation of text fields using modal windows.

It will not be possible to move keyboard focus to another control while the text is invalid.

In case we want to implement more elaborate filters that correct the text while it is being written, we will use the edit_OnFilter event. We will receive, through the EvText structure, a copy of the current text, the position of the cursor (caret) and the number of characters added or deleted. From here, the filter will be able to validate the text, setting the apply field of EvTextFilter to FALSE. If the new characters are not appropriate, we will return the new text and cursor position in the text and cpos fields of EvTextFilter, putting apply to TRUE. For example, in (Listing 2) we have a simple filter that only allows numeric characters (Figure 4).

Displays the event after pressing a key in an edit box. — Figure 4: The *OnFilter* event is called after each key press.

Listing 2: Filter that only allows numeric characters.

static void OnFilter(void *noused, Event *e)
{
    const EvText *params = event_params(e, EvText);
    EvTextFilter *result = event_result(e, EvTextFilter);
    uint32_t i = 0, j = 0;
    while (params->text[i] != '\0')
    {
        if (params->text[i] >= '0' && params->text[i] <= '9')
        {
            result->text[j] = params->text[i];
            j += 1;
        }

        i += 1;
    }

    result->text[j] = '\0';
    result->apply = TRUE;
}
...
edit_OnFilter(edit, listener(NULL, i_OnFilter, void));

2. Text selection

Use edit_select to select text.
Use edit_autoselect to automatically select all text whenever the control receives keyboard focus.

It is possible through code to change the text selection and the position of the cursor (caret), using this logic.

Edit box with selected text. — Figure 5: Text selection (2, 6).

If start == -1 and end == 0, all text is deselected, leaving the caret in its current position.
If start == -1 and end == -1, all text is deselected, moving the caret to the end of the text.
If start == 0 and end == -1 all the text is selected, moving the caret to the end of the text.
If start > 0 and end == -1 is selected until the end, moving the caret to the end of the text.
If start == end the caret is moved to the position, deselecting all text.

3. Clipboard operations

Being native components, the Edit controls support typical clipboard operations: Copy, Paste, Cut, etc, as well as their keyboard shortcuts. However, it can be useful to access these operations from the program code, allowing, for example, the text selected in the control to be copied to the clipboard.

Use edit_copy to copy the selected text to the clipboard.
Use edit_cut to cut the selected text, copying it to the clipboard.
Use edit_paste to paste the clipboard text at the caret position.

edit_create ()

Create a text edit control.

Edit*
edit_create(void);

Return

The edit.

edit_multiline ()

Create a text editing control that allows multiple lines.

Edit*
edit_multiline(void);

Return

The edit.

edit_OnFilter ()

Set a function to filter the text while editing.

void
edit_OnFilter(Edit *edit,
              Listener *listener);

edit	The edit.
listener	Callback function to be called after each key press. In EvTextFilter from event_result filtered text will be returned.

Remarks

See Filter texts and GUI Events.

edit_OnChange ()

Set a function to detect when the text has changed.

void
edit_OnChange(Edit *edit,
              Listener *listener);

edit	The edit.
listener	Callback function to be called when the control loses focus on the keyboard, indicating the end of the edition.

Remarks

See Filter texts and GUI Events.

edit_OnFocus ()

Sets a handler for keyboard focus.

void
edit_OnFocus(Edit *edit,
             Listener *listener);

edit	The edit.
listener	Callback function that will be called when keyboard focus is received or lost.

Remarks

See GUI Events.

edit_text ()

Set the edit control text.

void
edit_text(Edit *edit,
          const char_t *text);

edit	The edit.
text	UTF8 C-string terminated in null character `'\0'`.

edit_font ()

Set the font of the edit control.

void
edit_font(Edit *edit,
          const Font *font);

edit	The edit.
font	Font.

edit_align ()

Set text alignment.

void
edit_align(Edit *edit,
           const align_t align);

edit	The edit.
align	Alignment.

edit_passmode ()

Activate the password mode, which will hide the typed characters.

void
edit_passmode(Edit *edit,
              const bool_t passmode);

edit	The edit.
passmode	Enable or disable password mode.

edit_editable ()

Enable or disable editing in the control.

void
edit_editable(Edit *edit,
              const bool_t is_editable);

edit	The edit.
is_editable	`TRUE`will allow to edit the text (by default).

edit_autoselect ()

Activate or deactivate auto-selection of text.

void
edit_autoselect(Edit *edit,
                const bool_t autoselect);

edit	The edit.
autoselect	`TRUE` the control text will be fully selected when it receives focus. Default `FALSE`.

Remarks

See Text selection.

edit_select ()

Select text.

void
edit_select(Edit *edit,
            const int32_t start,
            const int32_t end);

edit	The edit.
start	Position of the initial character.
end	Position of the final character.

Remarks

See Text selection.

edit_tooltip ()

Assigns a tooltip to the edit control.

void
edit_tooltip(Edit *edit,
             const char_t *text);

edit	The edit.
text	UTF8 C-string terminated in null character `'\0'`.

edit_color ()

Set the text color.

void
edit_color(Edit *edit,
           const color_t color);

edit	The edit.
color	Text color.

Remarks

RGB values may not be fully portable. See Colors.

edit_color_focus ()

Sets the color of the text, when the control has the keyboard focus.

void
edit_color_focus(Edit *edit,
                 const color_t color);

edit	The edit.
color	Text color.

Remarks

RGB values may not be fully portable. See Colors.

edit_bgcolor ()

Set the background color.

void
edit_bgcolor(Edit *edit,
             const color_t color);

edit	The edit.
color	Background color.

Remarks

RGB values may not be fully portable. See Colors.

edit_bgcolor_focus ()

Sets the background color, when the control has keyboard focus.

void
edit_bgcolor_focus(Edit *edit,
                   const color_t color);

edit	The edit.
color	Background color.

Remarks

RGB values may not be fully portable. See Colors.

edit_phtext ()

Set an explanatory text for when the control is blank (placeholder).

void
edit_phtext(Edit *edit,
            const char_t *text);

edit	The edit.
text	UTF8 C-string terminated in null character `'\0'`.

edit_phcolor ()

Set the color of the placeholder text.

void
edit_phcolor(Edit *edit,
             const color_t color);

edit	The edit.
color	Text color.

Remarks

RGB values may not be fully portable. See Colors.

edit_phstyle ()

Set the font style for the placeholder.

void
edit_phstyle(Edit *edit,
             const uint32_t fstyle);

edit	The edit.
fstyle	Combination of values of fstyle_t.

edit_vpadding ()

Sets the inner vertical margin.

void
edit_vpadding(Edit *edit,
              const real32_t padding);

edit	The edit.
padding	If `0` there will be no margin between the text and the border of the control. If `<0` the default margin will be set.

edit_get_text ()

Get control text.

const char_t*
edit_get_text(const Edit *edit);

edit

The edit.

Return

UTF8 C-string terminated in null character '\0'.

edit_get_height ()

Gets the current height of the control.

real32_t
edit_get_height(const Edit *edit);

edit

The edit.

Return

The height of the control, which will change depending on the font size and vpadding.

edit_copy ()

Copies the selected text to the clipboard.

void
edit_copy(const Edit *edit);

edit

The edit.

Remarks

See Clipboard operations.

edit_cut ()

Cuts the selected text, copying it to the clipboard.

void
edit_cut(Edit *edit);

edit

The edit.

Remarks

See Clipboard operations.

edit_paste ()

Pastes the text from the clipboard into the caret position.

void
edit_paste(Edit *edit);

edit

The edit.

Remarks

See Clipboard operations.