Added a listener for changes in input fields. Also in the Form. Fixes #4.

README.md

@@ -64,5 +64,6 @@ Add your issue here on GitHub. Feel free to get in touch if you have any questio
 
 - v0.2 (2018-01-10)
   - Added `Styles` variable with default colors for primitives.
+	- Completed some missing InputField functions.
 - v0.1 (2018-01-06)
   - First Release

checkbox.go

@@ -52,6 +52,11 @@ func (c *Checkbox) SetChecked(checked bool) *Checkbox {
 	return c
 }
 
+// IsChecked returns whether or not the box is checked.
+func (c *Checkbox) IsChecked() bool {
+	return c.checked
+}
+
 // SetLabel sets the text to be displayed before the input area.
 func (c *Checkbox) SetLabel(label string) *Checkbox {
 	c.label = label

demos/form/main.go

@@ -9,8 +9,8 @@ func main() {
 	app := tview.NewApplication()
 	form := tview.NewForm().
 		AddDropDown("Title", []string{"Mr.", "Ms.", "Mrs.", "Dr.", "Prof."}, 0, nil).
-		AddInputField("First name", "", 20, nil).
-		AddInputField("Last name", "", 20, nil).
+		AddInputField("First name", "", 20, nil, nil).
+		AddInputField("Last name", "", 20, nil, nil).
 		AddCheckbox("Age 18+", false, nil).
 		AddButton("Save", nil).
 		AddButton("Quit", func() {

demos/presentation/form.go

@@ -12,8 +12,8 @@ const form = `[green]package[white] main
 
 [green]func[white] [yellow]main[white]() {
     form := tview.[yellow]NewForm[white]().
-        [yellow]AddInputField[white]([red]"First name:"[white], [red]""[white], [red]20[white], nil).
-        [yellow]AddInputField[white]([red]"Last name:"[white], [red]""[white], [red]20[white], nil).
+        [yellow]AddInputField[white]([red]"First name:"[white], [red]""[white], [red]20[white], nil, nil).
+        [yellow]AddInputField[white]([red]"Last name:"[white], [red]""[white], [red]20[white], nil, nil).
         [yellow]AddDropDown[white]([red]"Role:"[white], [][green]string[white]{
             [red]"Engineer"[white],
             [red]"Manager"[white],
@@ -30,8 +30,8 @@ const form = `[green]package[white] main
 // Form demonstrates forms.
 func Form(nextSlide func()) (title string, content tview.Primitive) {
 	f := tview.NewForm().
-		AddInputField("First name:", "", 20, nil).
-		AddInputField("Last name:", "", 20, nil).
+		AddInputField("First name:", "", 20, nil, nil).
+		AddInputField("Last name:", "", 20, nil, nil).
 		AddDropDown("Role:", []string{"Engineer", "Manager", "Administration"}, 0, nil).
 		AddCheckbox("On vacation:", false, nil).
 		AddButton("Save", nextSlide).

dropdown.go

@@ -81,6 +81,16 @@ func (d *DropDown) SetCurrentOption(index int) *DropDown {
 	return d
 }
 
+// GetCurrentOption returns the index of the currently selected option as well
+// as its text. If no option was selected, -1 and an empty string is returned.
+func (d *DropDown) GetCurrentOption() (int, string) {
+	var text string
+	if d.currentOption >= 0 && d.currentOption < len(d.options) {
+		text = d.options[d.currentOption].Text
+	}
+	return d.currentOption, text
+}
+
 // SetLabel sets the text to be displayed before the input area.
 func (d *DropDown) SetLabel(label string) *DropDown {
 	d.label = label

form.go

@@ -129,9 +129,10 @@ func (f *Form) SetButtonTextColor(color tcell.Color) *Form {
 
 // AddInputField adds an input field to the form. It has a label, an optional
 // initial value, a field length (a value of 0 extends it as far as possible),
-// and an optional accept function to validate the item's value (set to nil to
-// accept any text).
-func (f *Form) AddInputField(label, value string, fieldLength int, accept func(textToCheck string, lastChar rune) bool) *Form {
+// an optional accept function to validate the item's value (set to nil to
+// accept any text), and an (optional) callback function which is invoked when
+// the input field's text has changed.
+func (f *Form) AddInputField(label, value string, fieldLength int, accept func(textToCheck string, lastChar rune) bool, changed func(text string)) *Form {
 	f.items = append(f.items, NewInputField().
 		SetLabel(label).
 		SetText(value).
@@ -169,6 +170,13 @@ func (f *Form) AddButton(label string, selected func()) *Form {
 	return f
 }
 
+// GetElement returns the form element at the given position, starting with
+// index 0. Elements are referenced in the order they were added. Buttons are
+// not included.
+func (f *Form) GetElement(index int) Primitive {
+	return f.items[index]
+}
+
 // SetCancelFunc sets a handler which is called when the user hits the Escape
 // key.
 func (f *Form) SetCancelFunc(callback func()) *Form {

inputfield.go

@@ -36,6 +36,9 @@ type InputField struct {
 	// An optional function which may reject the last character that was entered.
 	accept func(text string, ch rune) bool
 
+	// An optional function which is called when the input has changed.
+	changed func(text string)
+
 	// An optional function which is called when the user indicated that they
 	// are done entering text. The key which was pressed is provided (tab,
 	// shift-tab, enter, or escape).
@@ -55,6 +58,9 @@ func NewInputField() *InputField {
 // SetText sets the current text of the input field.
 func (i *InputField) SetText(text string) *InputField {
 	i.text = text
+	if i.changed != nil {
+		i.changed(text)
+	}
 	return i
 }
 
@@ -119,6 +125,13 @@ func (i *InputField) SetAcceptanceFunc(handler func(textToCheck string, lastChar
 	return i
 }
 
+// SetChangedFunc sets a handler which is called whenever the text of the input
+// field has changed. It receives the current text (after the change).
+func (i *InputField) SetChangedFunc(handler func(text string)) *InputField {
+	i.changed = handler
+	return i
+}
+
 // SetDoneFunc sets a handler which is called when the user is done entering
 // text. The callback function is provided with the key that was pressed, which
 // is one of the following:
@@ -202,6 +215,14 @@ func (i *InputField) setCursor(screen tcell.Screen) {
 // InputHandler returns the handler for this primitive.
 func (i *InputField) InputHandler() func(event *tcell.EventKey, setFocus func(p Primitive)) {
 	return func(event *tcell.EventKey, setFocus func(p Primitive)) {
+		// Trigger changed events.
+		currentText := i.text
+		defer func() {
+			if i.text != currentText && i.changed != nil {
+				i.changed(i.text)
+			}
+		}()
+
 		// Process key event.
 		switch key := event.Key(); key {
 		case tcell.KeyRune: // Regular character.