391 lines
10 KiB
Go
391 lines
10 KiB
Go
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package widget
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import (
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"errors"
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"reflect"
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"fyne.io/fyne/v2"
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"fyne.io/fyne/v2/canvas"
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"fyne.io/fyne/v2/internal/cache"
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"fyne.io/fyne/v2/layout"
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"fyne.io/fyne/v2/theme"
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)
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// errFormItemInitialState defines the error if the initial validation for a FormItem result
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// in an error
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var errFormItemInitialState = errors.New("widget.FormItem initial state error")
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// FormItem provides the details for a row in a form
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type FormItem struct {
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Text string
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Widget fyne.CanvasObject
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// Since: 2.0
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HintText string
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validationError error
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invalid bool
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helperOutput *canvas.Text
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}
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// NewFormItem creates a new form item with the specified label text and input widget
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func NewFormItem(text string, widget fyne.CanvasObject) *FormItem {
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return &FormItem{Text: text, Widget: widget}
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}
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var _ fyne.Validatable = (*Form)(nil)
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// Form widget is two column grid where each row has a label and a widget (usually an input).
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// The last row of the grid will contain the appropriate form control buttons if any should be shown.
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// Setting OnSubmit will set the submit button to be visible and call back the function when tapped.
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// Setting OnCancel will do the same for a cancel button.
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// If you change OnSubmit/OnCancel after the form is created and rendered, you need to call
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// Refresh() to update the form with the correct buttons.
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// Setting OnSubmit/OnCancel to nil will remove the buttons.
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type Form struct {
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BaseWidget
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Items []*FormItem
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OnSubmit func() `json:"-"`
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OnCancel func() `json:"-"`
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SubmitText string
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CancelText string
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itemGrid *fyne.Container
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buttonBox *fyne.Container
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cancelButton *Button
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submitButton *Button
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disabled bool
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onValidationChanged func(error)
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validationError error
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}
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// Append adds a new row to the form, using the text as a label next to the specified Widget
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func (f *Form) Append(text string, widget fyne.CanvasObject) {
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item := &FormItem{Text: text, Widget: widget}
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f.AppendItem(item)
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}
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// AppendItem adds the specified row to the end of the Form
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func (f *Form) AppendItem(item *FormItem) {
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f.ExtendBaseWidget(f) // could be called before render
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f.Items = append(f.Items, item)
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if f.itemGrid != nil {
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f.itemGrid.Add(f.createLabel(item.Text))
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f.itemGrid.Add(f.createInput(item))
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f.setUpValidation(item.Widget, len(f.Items)-1)
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}
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f.Refresh()
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}
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// MinSize returns the size that this widget should not shrink below
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func (f *Form) MinSize() fyne.Size {
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f.ExtendBaseWidget(f)
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return f.BaseWidget.MinSize()
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}
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// Refresh updates the widget state when requested.
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func (f *Form) Refresh() {
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f.ExtendBaseWidget(f)
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cache.Renderer(f.super()) // we are about to make changes to renderer created content... not great!
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f.ensureRenderItems()
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f.updateButtons()
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f.updateLabels()
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f.BaseWidget.Refresh()
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canvas.Refresh(f.super()) // refresh ourselves for BG color - the above updates the content
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}
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// Enable enables submitting this form.
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//
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// Since: 2.1
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func (f *Form) Enable() {
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f.disabled = false
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f.cancelButton.Enable()
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f.checkValidation(nil) // as the form may be invalid
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}
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// Disable disables submitting this form.
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//
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// Since: 2.1
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func (f *Form) Disable() {
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f.disabled = true
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f.submitButton.Disable()
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f.cancelButton.Disable()
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}
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// Disabled returns whether submitting the form is disabled.
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// Note that, if the form fails validation, the submit button may be
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// disabled even if this method returns true.
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//
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// Since: 2.1
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func (f *Form) Disabled() bool {
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return f.disabled
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}
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// SetOnValidationChanged is intended for parent widgets or containers to hook into the validation.
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// The function might be overwritten by a parent that cares about child validation (e.g. widget.Form)
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func (f *Form) SetOnValidationChanged(callback func(error)) {
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f.onValidationChanged = callback
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}
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// Validate validates the entire form and returns the first error that is encountered.
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func (f *Form) Validate() error {
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for _, item := range f.Items {
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if w, ok := item.Widget.(fyne.Validatable); ok {
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if err := w.Validate(); err != nil {
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return err
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}
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}
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}
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return nil
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}
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func (f *Form) createInput(item *FormItem) fyne.CanvasObject {
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_, ok := item.Widget.(fyne.Validatable)
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if item.HintText == "" {
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if !ok {
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return item.Widget
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}
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if !f.itemWidgetHasValidator(item.Widget) { // we don't have validation
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return item.Widget
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}
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}
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text := canvas.NewText(item.HintText, theme.PlaceHolderColor())
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text.TextSize = theme.CaptionTextSize()
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item.helperOutput = text
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f.updateHelperText(item)
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textContainer := &fyne.Container{Objects: []fyne.CanvasObject{text}}
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return &fyne.Container{Layout: formItemLayout{}, Objects: []fyne.CanvasObject{item.Widget, textContainer}}
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}
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func (f *Form) itemWidgetHasValidator(w fyne.CanvasObject) bool {
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value := reflect.ValueOf(w).Elem()
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validatorField := value.FieldByName("Validator")
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if validatorField == (reflect.Value{}) {
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return false
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}
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validator, ok := validatorField.Interface().(fyne.StringValidator)
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if !ok {
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return false
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}
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return validator != nil
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}
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func (f *Form) createLabel(text string) *canvas.Text {
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return &canvas.Text{Text: text,
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Alignment: fyne.TextAlignTrailing,
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Color: theme.ForegroundColor(),
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TextSize: theme.TextSize(),
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TextStyle: fyne.TextStyle{Bold: true}}
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}
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func (f *Form) updateButtons() {
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if f.CancelText == "" {
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f.CancelText = "Cancel"
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}
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if f.SubmitText == "" {
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f.SubmitText = "Submit"
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}
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// set visibility on the buttons
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if f.OnCancel == nil {
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f.cancelButton.Hide()
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} else {
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f.cancelButton.SetText(f.CancelText)
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f.cancelButton.OnTapped = f.OnCancel
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f.cancelButton.Show()
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}
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if f.OnSubmit == nil {
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f.submitButton.Hide()
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} else {
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f.submitButton.SetText(f.SubmitText)
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f.submitButton.OnTapped = f.OnSubmit
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f.submitButton.Show()
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}
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if f.OnCancel == nil && f.OnSubmit == nil {
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f.buttonBox.Hide()
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} else {
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f.buttonBox.Show()
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}
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}
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func (f *Form) checkValidation(err error) {
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if err != nil {
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f.submitButton.Disable()
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return
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}
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for _, item := range f.Items {
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if item.invalid {
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f.submitButton.Disable()
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return
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}
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}
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if !f.disabled {
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f.submitButton.Enable()
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}
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}
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func (f *Form) ensureRenderItems() {
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done := len(f.itemGrid.Objects) / 2
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if done >= len(f.Items) {
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f.itemGrid.Objects = f.itemGrid.Objects[0 : len(f.Items)*2]
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return
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}
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adding := len(f.Items) - done
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objects := make([]fyne.CanvasObject, adding*2)
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off := 0
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for i, item := range f.Items {
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if i < done {
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continue
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}
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objects[off] = f.createLabel(item.Text)
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off++
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f.setUpValidation(item.Widget, i)
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objects[off] = f.createInput(item)
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off++
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}
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f.itemGrid.Objects = append(f.itemGrid.Objects, objects...)
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}
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func (f *Form) setUpValidation(widget fyne.CanvasObject, i int) {
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updateValidation := func(err error) {
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if err == errFormItemInitialState {
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return
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}
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f.Items[i].validationError = err
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f.Items[i].invalid = err != nil
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f.setValidationError(err)
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f.checkValidation(err)
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f.updateHelperText(f.Items[i])
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}
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if w, ok := widget.(fyne.Validatable); ok {
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f.Items[i].invalid = w.Validate() != nil
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if e, ok := w.(*Entry); ok {
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e.onFocusChanged = func(bool) {
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updateValidation(e.validationError)
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}
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if e.Validator != nil && f.Items[i].invalid {
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// set initial state error to guarantee next error (if triggers) is always different
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e.SetValidationError(errFormItemInitialState)
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}
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}
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w.SetOnValidationChanged(updateValidation)
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}
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}
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func (f *Form) setValidationError(err error) {
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if err == nil && f.validationError == nil {
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return
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}
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if !errors.Is(err, f.validationError) {
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if err == nil {
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for _, item := range f.Items {
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if item.invalid {
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err = item.validationError
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break
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}
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}
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}
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f.validationError = err
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if f.onValidationChanged != nil {
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f.onValidationChanged(err)
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}
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}
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}
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func (f *Form) updateHelperText(item *FormItem) {
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if item.helperOutput == nil {
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return // testing probably, either way not rendered yet
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}
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showHintIfError := false
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if e, ok := item.Widget.(*Entry); ok && (!e.dirty || e.focused) {
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showHintIfError = true
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}
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if item.validationError == nil || showHintIfError {
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item.helperOutput.Text = item.HintText
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item.helperOutput.Color = theme.PlaceHolderColor()
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} else {
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item.helperOutput.Text = item.validationError.Error()
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item.helperOutput.Color = theme.ErrorColor()
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}
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item.helperOutput.Refresh()
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}
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func (f *Form) updateLabels() {
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for i, item := range f.Items {
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l := f.itemGrid.Objects[i*2].(*canvas.Text)
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l.TextSize = theme.TextSize()
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if dis, ok := item.Widget.(fyne.Disableable); ok {
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if dis.Disabled() {
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l.Color = theme.DisabledColor()
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} else {
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l.Color = theme.ForegroundColor()
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}
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} else {
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l.Color = theme.ForegroundColor()
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}
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l.Text = item.Text
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l.Refresh()
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f.updateHelperText(item)
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}
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}
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// CreateRenderer is a private method to Fyne which links this widget to its renderer
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func (f *Form) CreateRenderer() fyne.WidgetRenderer {
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f.ExtendBaseWidget(f)
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f.cancelButton = &Button{Icon: theme.CancelIcon(), OnTapped: f.OnCancel}
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f.submitButton = &Button{Icon: theme.ConfirmIcon(), OnTapped: f.OnSubmit, Importance: HighImportance}
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buttons := &fyne.Container{Layout: layout.NewGridLayoutWithRows(1), Objects: []fyne.CanvasObject{f.cancelButton, f.submitButton}}
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f.buttonBox = &fyne.Container{Layout: layout.NewBorderLayout(nil, nil, nil, buttons), Objects: []fyne.CanvasObject{buttons}}
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f.validationError = errFormItemInitialState // set initial state error to guarantee next error (if triggers) is always different
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f.itemGrid = &fyne.Container{Layout: layout.NewFormLayout()}
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content := &fyne.Container{Layout: layout.NewVBoxLayout(), Objects: []fyne.CanvasObject{f.itemGrid, f.buttonBox}}
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renderer := NewSimpleRenderer(content)
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f.ensureRenderItems()
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f.updateButtons()
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f.updateLabels()
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f.checkValidation(nil) // will trigger a validation check for correct intial validation status
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return renderer
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}
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// NewForm creates a new form widget with the specified rows of form items
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// and (if any of them should be shown) a form controls row at the bottom
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func NewForm(items ...*FormItem) *Form {
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form := &Form{Items: items}
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form.ExtendBaseWidget(form)
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return form
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}
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type formItemLayout struct{}
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func (f formItemLayout) Layout(objs []fyne.CanvasObject, size fyne.Size) {
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itemHeight := objs[0].MinSize().Height
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objs[0].Resize(fyne.NewSize(size.Width, itemHeight))
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objs[1].Move(fyne.NewPos(theme.InnerPadding(), itemHeight+theme.InnerPadding()/2))
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objs[1].Resize(fyne.NewSize(size.Width, objs[1].MinSize().Width))
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}
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func (f formItemLayout) MinSize(objs []fyne.CanvasObject) fyne.Size {
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|
|
min0 := objs[0].MinSize()
|
||
|
|
min1 := objs[1].MinSize()
|
||
|
|
|
||
|
|
minWidth := fyne.Max(min0.Width, min1.Width)
|
||
|
|
return fyne.NewSize(minWidth, min0.Height+min1.Height+theme.InnerPadding())
|
||
|
|
}
|