Add a float to string converter binding (two-way)

binding/float.go

@@ -36,6 +36,9 @@ func (f *floatBind) Get() float64 {
 }
 
 func (f *floatBind) Set(val float64) {
+	if *f.val == val {
+		return
+	}
 	*f.val = val
 
 	f.trigger(f)

binding/string.go

@@ -0,0 +1,7 @@
+package binding
+
+type String interface {
+	DataItem
+	Get() string
+	Set(string)
+}

binding/tostring.go

@@ -0,0 +1,44 @@
+package binding
+
+import (
+	"fmt"
+	"strconv"
+
+	"fyne.io/fyne"
+)
+
+type floatToString struct {
+	base
+
+	from Float
+}
+
+func FloatToString(f Float) String {
+	str := &floatToString{from: f}
+	f.AddListener(str)
+	return str
+}
+
+func (f *floatToString) Get() string {
+	val := f.from.Get()
+
+	return fmt.Sprintf("%0.2f", val) // TODO format string
+}
+
+func (f *floatToString) Set(val string) {
+	fVal, err := strconv.ParseFloat(val, 0)
+	if err != nil {
+		fyne.LogError("Float parse error", err)
+		return
+	}
+	if fVal == f.from.Get() {
+		return
+	}
+	f.from.Set(fVal)
+
+	f.trigger(f)
+}
+
+func (f *floatToString) DataChanged(_ DataItem) {
+	f.trigger(f)
+}

binding/tostring_test.go

@@ -0,0 +1,19 @@
+package binding
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFloatToString(t *testing.T) {
+	f := NewFloat()
+	s := FloatToString(f)
+	assert.Equal(t, "0.00", s.Get())
+
+	f.Set(0.3)
+	assert.Equal(t, "0.30", s.Get())
+
+	s.Set("5.00")
+	assert.Equal(t, 5.0, f.Get())
+}

widget/entry.go

@@ -7,6 +7,7 @@ import (
 	"unicode"
 
 	"fyne.io/fyne"
+	"fyne.io/fyne/binding"
 	"fyne.io/fyne/canvas"
 	"fyne.io/fyne/driver/desktop"
 	"fyne.io/fyne/driver/mobile"
@@ -77,6 +78,22 @@ func NewEntry() *Entry {
 	return e
 }
 
+// NewEntryWithData returns an Entry widget connected to the specified data source.
+func NewEntryWithData(data binding.String) *Entry {
+	entry := NewEntry()
+	entry.Text = data.Get()
+
+	data.AddListener(binding.NewDataItemListener(func(binding.DataItem) {
+		entry.Text = data.Get()
+		entry.Refresh()
+	}))
+	entry.OnChanged = func(s string) {
+		data.Set(s)
+	}
+
+	return entry
+}
+
 // NewMultiLineEntry creates a new entry that allows multiple lines
 func NewMultiLineEntry() *Entry {
 	e := &Entry{MultiLine: true}

widget/label.go

@@ -4,6 +4,7 @@ import (
 	"image/color"
 
 	"fyne.io/fyne"
+	"fyne.io/fyne/binding"
 	"fyne.io/fyne/theme"
 )
 
@@ -22,6 +23,18 @@ func NewLabel(text string) *Label {
 	return NewLabelWithStyle(text, fyne.TextAlignLeading, fyne.TextStyle{})
 }
 
+// NewLabelWithData returns an Label widget connected to the specified data source.
+func NewLabelWithData(data binding.String) *Label {
+	label := NewLabel(data.Get())
+
+	data.AddListener(binding.NewDataItemListener(func(binding.DataItem) {
+		label.Text = data.Get()
+		label.Refresh()
+	}))
+
+	return label
+}
+
 // NewLabelWithStyle creates a new label widget with the set text content
 func NewLabelWithStyle(text string, alignment fyne.TextAlign, style fyne.TextStyle) *Label {
 	l := &Label{