Merge pull request #1985 from fpabl0/fix/1965

Guarantee widget.Form tracks all entry validation changes, fixes #1965

widget/form.go

@@ -1,13 +1,19 @@
 package widget
 
 import (
+	"errors"
+
 	"fyne.io/fyne/v2"
 	"fyne.io/fyne/v2/canvas"
 	"fyne.io/fyne/v2/internal/cache"
 	"fyne.io/fyne/v2/layout"
 	"fyne.io/fyne/v2/theme"
 )
 
+// errFormItemInitialState defines the error if the initial validation for a FormItem result
+// in an error
+var errFormItemInitialState = errors.New("widget.FormItem initial state error")
+
 // FormItem provides the details for a row in a form
 type FormItem struct {
 	Text   string
@@ -155,10 +161,14 @@ func (f *Form) checkValidation(err error) {
 func (f *Form) setUpValidation(widget fyne.CanvasObject, i int) {
 	if w, ok := widget.(fyne.Validatable); ok {
 		f.Items[i].invalid = w.Validate() != nil
-		if e, ok := w.(*Entry); ok && e.Validator != nil {
-			e.SetValidationError(nil) // clear initial state, will appear when we type
+		if e, ok := w.(*Entry); ok && e.Validator != nil && f.Items[i].invalid {
+			// set initial state error to guarantee next error (if triggers) is always different
+			e.SetValidationError(errFormItemInitialState)
 		}
 		w.SetOnValidationChanged(func(err error) {
+			if err == errFormItemInitialState {
+				return
+			}
 			f.Items[i].validationError = err
 			f.Items[i].invalid = err != nil
 			f.checkValidation(err)

widget/form_test.go

@@ -1,6 +1,7 @@
 package widget
 
 import (
+	"errors"
 	"testing"
 
 	"fyne.io/fyne/v2"
@@ -188,3 +189,46 @@ func TestForm_Validation(t *testing.T) {
 
 	test.AssertImageMatches(t, "form/validation_valid.png", w.Canvas().Capture())
 }
+
+func TestForm_EntryValidation_FirstTypeValid(t *testing.T) {
+	app := test.NewApp()
+	defer test.NewApp()
+	app.Settings().SetTheme(theme.LightTheme())
+
+	notEmptyValidator := func(s string) error {
+		if s == "" {
+			return errors.New("can't be empty")
+		}
+		return nil
+	}
+
+	entry1 := &Entry{Validator: notEmptyValidator, Text: ""}
+	entry2 := &Entry{Validator: notEmptyValidator, Text: ""}
+	items := []*FormItem{
+		{Text: "First", Widget: entry1},
+		{Text: "Second", Widget: entry2},
+	}
+
+	form := &Form{Items: items, OnSubmit: func() {}, OnCancel: func() {}}
+	w := test.NewWindow(form)
+	defer w.Close()
+
+	assert.Equal(t, errFormItemInitialState, entry1.validationError)
+	assert.Equal(t, errFormItemInitialState, entry2.validationError)
+
+	test.AssertImageMatches(t, "form/validation_entry_first_type_initial.png", w.Canvas().Capture())
+
+	test.Type(entry1, "H")
+	test.Type(entry2, "L")
+	entry1.focused = false
+	entry1.Refresh()
+	w = test.NewWindow(form)
+
+	test.AssertImageMatches(t, "form/validation_entry_first_type_valid.png", w.Canvas().Capture())
+
+	entry1.SetText("")
+	entry2.SetText("")
+	w = test.NewWindow(form)
+
+	test.AssertImageMatches(t, "form/validation_entry_first_type_invalid.png", w.Canvas().Capture())
+}