From 04bbd47f665a788fb078ef35ea239ec3618f551a Mon Sep 17 00:00:00 2001
From: anoshenko <anoshenko@gmail.com>
Date: Thu, 4 Nov 2021 14:59:25 +0300
Subject: [PATCH] Added FilePicker

---
 appLog.go              |  11 +-
 app_scripts.js         |  44 +++++
 demo/filePickerDemo.go |  39 ++++
 demo/main.go           |   1 +
 demo/splitViewDemo.go  |  26 ---
 filePicker.go          | 414 +++++++++++++++++++++++++++++++++++++++++
 mediaPlayer.go         |   2 +-
 mouseEvents.go         |   4 +-
 pointerEvents.go       |   2 +-
 propertySet.go         |   1 +
 utils.go               |   6 +-
 viewByID.go            |  86 +++++++--
 viewFactory.go         |   1 +
 viewUtils.go           |  22 +--
 14 files changed, 595 insertions(+), 64 deletions(-)
 create mode 100644 demo/filePickerDemo.go
 delete mode 100644 demo/splitViewDemo.go
 create mode 100644 filePicker.go

diff --git a/appLog.go b/appLog.go
index 7fe48a7..60919bd 100644
--- a/appLog.go
+++ b/appLog.go
@@ -45,8 +45,11 @@ func DebugLogF(format string, a ...interface{}) {
 	}
 }
 
+var lastError = ""
+
 // ErrorLog print the text to the error log
 func ErrorLog(text string) {
+	lastError = text
 	if errorLogFunc != nil {
 		errorLogFunc(text)
 		errorStack()
@@ -55,12 +58,18 @@ func ErrorLog(text string) {
 
 // ErrorLogF print the text to the error log
 func ErrorLogF(format string, a ...interface{}) {
+	lastError = fmt.Sprintf(format, a...)
 	if errorLogFunc != nil {
-		errorLogFunc(fmt.Sprintf(format, a...))
+		errorLogFunc(lastError)
 		errorStack()
 	}
 }
 
+// LastError returns the last error text
+func LastError() string {
+	return lastError
+}
+
 func errorStack() {
 	if errorLogFunc != nil {
 		skip := 2
diff --git a/app_scripts.js b/app_scripts.js
index 096ff97..e0c0762 100644
--- a/app_scripts.js
+++ b/app_scripts.js
@@ -989,6 +989,50 @@ function setInputValue(elementId, text) {
 	}
 }
 
+function fileSelectedEvent(element) {
+	var files = element.files;
+	if (files) {
+		var message = "fileSelected{session=" + sessionID + ",id=" + element.id + ",files=[";
+		for(var i = 0; i < files.length; i++) {
+			if (i > 0) {
+				message += ",";
+			}
+			message += "_{name=\"" + files[i].name + 
+				"\",last-modified=" + files[i].lastModified +
+				",size=" + files[i].size +
+				",mime-type=\"" + files[i].type + "\"}";
+		}
+		sendMessage(message + "]}");
+	}
+}
+
+function loadSelectedFile(elementId, index) {
+	var element = document.getElementById(elementId);
+	if (element) {
+		var files = element.files;
+		if (files && index >= 0 && index < files.length) {
+			const reader = new FileReader();
+         	reader.onload = function() { 
+				sendMessage("fileLoaded{session=" + sessionID + ",id=" + element.id + 
+					",index=" + index + 
+					",name=\"" + files[index].name + 
+					"\",last-modified=" + files[index].lastModified +
+					",size=" + files[index].size +
+					",mime-type=\"" + files[index].type + 
+					"\",data=`" + reader.result + "`}");
+			}
+         	reader.onerror = function(error) {
+				sendMessage("fileLoadingError{session=" + sessionID + ",id=" + element.id + ",index=" + index + ",error=`" + error + "`}");
+			}
+			reader.readAsDataURL(files[index]);
+		} else {
+			sendMessage("fileLoadingError{session=" + sessionID + ",id=" + element.id + ",index=" + index + ",error=`File not found`}");
+		}
+	} else {
+		sendMessage("fileLoadingError{session=" + sessionID + ",id=" + element.id + ",index=" + index + ",error=`Invalid FilePicker id`}");
+	}
+}
+
 function startResize(element, mx, my, event) {
 	var view = element.parentNode;
 	if (!view) {
diff --git a/demo/filePickerDemo.go b/demo/filePickerDemo.go
new file mode 100644
index 0000000..2f5cbf9
--- /dev/null
+++ b/demo/filePickerDemo.go
@@ -0,0 +1,39 @@
+package main
+
+import (
+	"github.com/anoshenko/rui"
+)
+
+const filePickerDemoText = `
+GridLayout {
+	width = 100%, height = 100%, cell-height = "auto, 1fr",
+	content = [
+		FilePicker {
+			id = filePicker, accept = "txt, html"
+		},
+		EditView {
+			id = selectedFileData, row = 1, type = multiline, read-only = true, wrap = true,
+		}
+	]
+}
+`
+
+func createFilePickerDemo(session rui.Session) rui.View {
+	view := rui.CreateViewFromText(session, filePickerDemoText)
+	if view == nil {
+		return nil
+	}
+
+	rui.Set(view, "filePicker", rui.FileSelectedEvent, func(picker rui.FilePicker, files []rui.FileInfo) {
+		if len(files) > 0 {
+			picker.LoadFile(files[0], func(file rui.FileInfo, data []byte) {
+				if data != nil {
+					rui.Set(view, "selectedFileData", rui.Text, string(data))
+				} else {
+					rui.Set(view, "selectedFileData", rui.Text, rui.LastError())
+				}
+			})
+		}
+	})
+	return view
+}
diff --git a/demo/main.go b/demo/main.go
index 2bfb4a9..6f0488f 100644
--- a/demo/main.go
+++ b/demo/main.go
@@ -82,6 +82,7 @@ func createDemo(session rui.Session) rui.SessionContent {
 		{"ListView", createListViewDemo, nil},
 		{"Checkbox", createCheckboxDemo, nil},
 		{"Controls", createControlsDemo, nil},
+		{"FilePicker", createFilePickerDemo, nil},
 		{"TableView", createTableViewDemo, nil},
 		{"EditView", createEditDemo, nil},
 		{"ImageView", createImageViewDemo, nil},
diff --git a/demo/splitViewDemo.go b/demo/splitViewDemo.go
deleted file mode 100644
index 54f8981..0000000
--- a/demo/splitViewDemo.go
+++ /dev/null
@@ -1,26 +0,0 @@
-package main
-
-/*
-import (
-	"github.com/anoshenko/rui"
-)
-
-const splitViewDemoText = `
-SplitView {
-	width = 100%, height = 100%, orientation = vertical, anchor = bottom, padding = 2px,
-	view1 = GridLayout { width = 100%, height = 75%, content = ["View 1"], cell-vertical-align = center, cell-horizontal-align = center,
-		border = _{ width = 1px, style = solid, color = #FF000000 }, radius = 8px,},
-	view2 = GridLayout { width = 100%, height = 25%, content = ["View 2"], cell-align = center,
-		border = _{ width = 1px, style = solid, color = #FF000000 }, radius = 8px,},
-}
-`
-
-func createSplitViewDemo(session rui.Session) rui.View {
-	view := rui.CreateViewFromText(session, splitViewDemoText)
-	if view == nil {
-		return nil
-	}
-
-	return view
-}
-*/
diff --git a/filePicker.go b/filePicker.go
new file mode 100644
index 0000000..4cbff32
--- /dev/null
+++ b/filePicker.go
@@ -0,0 +1,414 @@
+package rui
+
+import (
+	"encoding/base64"
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const (
+	// FileSelectedEvent is the constant for "file-selected-event" property tag.
+	// The "file-selected-event" is fired when user selects file(s) in the FilePicker.
+	FileSelectedEvent = "file-selected-event"
+	// Accept is the constant for "accept" property tag.
+	// The "accept" property of the FilePicker sets the list of allowed file extensions or MIME types.
+	Accept = "accept"
+	// Multiple is the constant for "multiple" property tag.
+	// The "multiple" bool property of the FilePicker sets whether multiple files can be selected
+	Multiple = "multiple"
+)
+
+// FileInfo describes a file which selected in the FilePicker view
+type FileInfo struct {
+	// Name - the file's name.
+	Name string
+	// LastModified specifying the date and time at which the file was last modified
+	LastModified time.Time
+	// Size - the size of the file in bytes.
+	Size int64
+	// MimeType - the file's MIME type.
+	MimeType string
+}
+
+// FilePicker - the control view for the files selecting
+type FilePicker interface {
+	View
+	// Files returns the list of selected files.
+	// If there are no files selected then an empty slice is returned (the result is always not nil)
+	Files() []FileInfo
+	// LoadFile loads the content of the selected file. This function is asynchronous.
+	// The "result" function will be called after loading the data.
+	LoadFile(file FileInfo, result func(FileInfo, []byte))
+}
+
+type filePickerData struct {
+	viewData
+	files                 []FileInfo
+	fileSelectedListeners []func(FilePicker, []FileInfo)
+	loader                map[int]func(FileInfo, []byte)
+}
+
+func (file *FileInfo) initBy(node DataValue) {
+	if obj := node.Object(); obj != nil {
+		file.Name, _ = obj.PropertyValue("name")
+		file.MimeType, _ = obj.PropertyValue("mime-type")
+
+		if size, ok := obj.PropertyValue("size"); ok {
+			if n, err := strconv.ParseInt(size, 10, 64); err == nil {
+				file.Size = n
+			}
+		}
+
+		if value, ok := obj.PropertyValue("last-modified"); ok {
+			if n, err := strconv.ParseInt(value, 10, 64); err == nil {
+				file.LastModified = time.UnixMilli(n)
+			}
+		}
+	}
+}
+
+// NewFilePicker create new FilePicker object and return it
+func NewFilePicker(session Session, params Params) FilePicker {
+	view := new(filePickerData)
+	view.Init(session)
+	setInitParams(view, params)
+	return view
+}
+
+func newFilePicker(session Session) View {
+	return NewFilePicker(session, nil)
+}
+
+func (picker *filePickerData) Init(session Session) {
+	picker.viewData.Init(session)
+	picker.tag = "FilePicker"
+	picker.files = []FileInfo{}
+	picker.loader = map[int]func(FileInfo, []byte){}
+	picker.fileSelectedListeners = []func(FilePicker, []FileInfo){}
+}
+
+func (picker *filePickerData) Files() []FileInfo {
+	return picker.files
+}
+
+func (picker *filePickerData) LoadFile(file FileInfo, result func(FileInfo, []byte)) {
+	if result == nil {
+		return
+	}
+
+	for i, info := range picker.files {
+		if info.Name == file.Name && info.Size == file.Size && info.LastModified == file.LastModified {
+			picker.loader[i] = result
+			picker.Session().runScript(fmt.Sprintf(`loadSelectedFile("%s", %d)`, picker.htmlID(), i))
+			return
+		}
+	}
+}
+
+func (picker *filePickerData) Remove(tag string) {
+	picker.remove(strings.ToLower(tag))
+}
+
+func (picker *filePickerData) remove(tag string) {
+	switch tag {
+	case FileSelectedEvent:
+		picker.fileSelectedListeners = []func(FilePicker, []FileInfo){}
+
+	default:
+		picker.viewData.remove(tag)
+	}
+}
+
+func (picker *filePickerData) Set(tag string, value interface{}) bool {
+	return picker.set(strings.ToLower(tag), value)
+}
+
+func (picker *filePickerData) set(tag string, value interface{}) bool {
+	if value == nil {
+		picker.remove(tag)
+		return true
+	}
+
+	switch tag {
+	case FileSelectedEvent:
+		switch value := value.(type) {
+		case func(FilePicker, []FileInfo):
+			picker.fileSelectedListeners = []func(FilePicker, []FileInfo){value}
+
+		case func([]FileInfo):
+			fn := func(view FilePicker, files []FileInfo) {
+				value(files)
+			}
+			picker.fileSelectedListeners = []func(FilePicker, []FileInfo){fn}
+
+		case []func(FilePicker, []FileInfo):
+			picker.fileSelectedListeners = value
+
+		case []func([]FileInfo):
+			listeners := make([]func(FilePicker, []FileInfo), len(value))
+			for i, val := range value {
+				if val == nil {
+					notCompatibleType(tag, val)
+					return false
+				}
+
+				listeners[i] = func(view FilePicker, files []FileInfo) {
+					val(files)
+				}
+			}
+			picker.fileSelectedListeners = listeners
+
+		case []interface{}:
+			listeners := make([]func(FilePicker, []FileInfo), len(value))
+			for i, val := range value {
+				if val == nil {
+					notCompatibleType(tag, val)
+					return false
+				}
+
+				switch val := val.(type) {
+				case func(FilePicker, []FileInfo):
+					listeners[i] = val
+
+				case func([]FileInfo):
+					listeners[i] = func(view FilePicker, files []FileInfo) {
+						val(files)
+					}
+
+				default:
+					notCompatibleType(tag, val)
+					return false
+				}
+			}
+			picker.fileSelectedListeners = listeners
+		}
+		return true
+
+	case Accept:
+		switch value := value.(type) {
+		case string:
+			value = strings.Trim(value, " \t\n")
+			if value == "" {
+				picker.remove(Accept)
+			} else {
+				picker.properties[Accept] = value
+			}
+
+		case []string:
+			buffer := allocStringBuilder()
+			defer freeStringBuilder(buffer)
+			for _, val := range value {
+				val = strings.Trim(val, " \t\n")
+				if val != "" {
+					if buffer.Len() > 0 {
+						buffer.WriteRune(',')
+					}
+					buffer.WriteString(val)
+				}
+			}
+			if buffer.Len() == 0 {
+				picker.remove(Accept)
+			} else {
+				picker.properties[Accept] = buffer.String()
+			}
+
+		default:
+			notCompatibleType(tag, value)
+			return false
+		}
+		return true
+
+	default:
+		return picker.viewData.set(tag, value)
+	}
+}
+
+func (picker *filePickerData) htmlTag() string {
+	return "input"
+}
+
+func (picker *filePickerData) acceptCSS() string {
+	accept, ok := stringProperty(picker, Accept, picker.Session())
+	if !ok {
+		accept, ok = valueFromStyle(picker, Accept)
+	}
+	if ok {
+		buffer := allocStringBuilder()
+		defer freeStringBuilder(buffer)
+		for _, value := range strings.Split(accept, ",") {
+			if value = strings.Trim(value, " \t\n"); value != "" {
+				if buffer.Len() > 0 {
+					buffer.WriteString(", ")
+				}
+				if value[0] != '.' && !strings.Contains(value, "/") {
+					buffer.WriteRune('.')
+				}
+				buffer.WriteString(value)
+			}
+		}
+		return buffer.String()
+	}
+	return ""
+}
+
+func (picker *filePickerData) htmlProperties(self View, buffer *strings.Builder) {
+	picker.viewData.htmlProperties(self, buffer)
+
+	if accept := picker.acceptCSS(); accept != "" {
+		buffer.WriteString(` accept="`)
+		buffer.WriteString(accept)
+		buffer.WriteRune('"')
+	}
+
+	buffer.WriteString(` type="file"`)
+	if multiple, ok := boolStyledProperty(picker, Multiple); ok && multiple {
+		buffer.WriteString(` multiple`)
+	}
+
+	buffer.WriteString(` oninput="fileSelectedEvent(this)"`)
+}
+
+func (picker *filePickerData) htmlDisabledProperties(self View, buffer *strings.Builder) {
+	if IsDisabled(self) {
+		buffer.WriteString(` disabled`)
+	}
+	picker.viewData.htmlDisabledProperties(self, buffer)
+}
+
+func (picker *filePickerData) handleCommand(self View, command string, data DataObject) bool {
+	switch command {
+	case "fileSelected":
+		if node := data.PropertyWithTag("files"); node != nil && node.Type() == ArrayNode {
+			count := node.ArraySize()
+			files := make([]FileInfo, count)
+			for i := 0; i < count; i++ {
+				if value := node.ArrayElement(i); value != nil {
+					files[i].initBy(value)
+				}
+			}
+			picker.files = files
+
+			for _, listener := range picker.fileSelectedListeners {
+				listener(picker, files)
+			}
+		}
+		return true
+
+	case "fileLoaded":
+		if index, ok := dataIntProperty(data, "index"); ok {
+			if result, ok := picker.loader[index]; ok {
+				var file FileInfo
+				file.initBy(data)
+
+				var fileData []byte = nil
+				if base64Data, ok := data.PropertyValue("data"); ok {
+					if index := strings.LastIndex(base64Data, ","); index >= 0 {
+						base64Data = base64Data[index+1:]
+					}
+					decode, err := base64.StdEncoding.DecodeString(base64Data)
+					if err == nil {
+						fileData = decode
+					} else {
+						ErrorLog(err.Error())
+					}
+				}
+
+				result(file, fileData)
+				delete(picker.loader, index)
+			}
+		}
+		return true
+
+	case "fileLoadingError":
+		if error, ok := data.PropertyValue("error"); ok {
+			ErrorLog(error)
+		}
+		if index, ok := dataIntProperty(data, "index"); ok {
+			if result, ok := picker.loader[index]; ok {
+				if index >= 0 && index < len(picker.files) {
+					result(picker.files[index], nil)
+				} else {
+					result(FileInfo{}, nil)
+				}
+				delete(picker.loader, index)
+			}
+		}
+		return true
+	}
+
+	return picker.viewData.handleCommand(self, command, data)
+}
+
+// GetFilePickerFiles returns the list of FilePicker selected files
+// If there are no files selected then an empty slice is returned (the result is always not nil)
+// If the second argument (subviewID) is "" then selected files of the first argument (view) is returned
+func GetFilePickerFiles(view View, subviewID string) []FileInfo {
+	if picker := FilePickerByID(view, subviewID); picker != nil {
+		return picker.Files()
+	}
+	return []FileInfo{}
+}
+
+// LoadFilePickerFile loads the content of the selected file. This function is asynchronous.
+// The "result" function will be called after loading the data.
+// If the second argument (subviewID) is "" then the file from the first argument (view) is loaded
+func LoadFilePickerFile(view View, subviewID string, file FileInfo, result func(FileInfo, []byte)) {
+	if picker := FilePickerByID(view, subviewID); picker != nil {
+		picker.LoadFile(file, result)
+	}
+}
+
+// IsMultipleFilePicker returns "true" if multiple files can be selected in the FilePicker, "false" otherwise.
+// If the second argument (subviewID) is "" then a value from the first argument (view) is returned.
+func IsMultipleFilePicker(view View, subviewID string) bool {
+	if subviewID != "" {
+		view = ViewByID(view, subviewID)
+	}
+	if view != nil {
+		if result, ok := boolStyledProperty(view, Multiple); ok {
+			return result
+		}
+	}
+	return false
+}
+
+// GetFilePickerAccept returns sets the list of allowed file extensions or MIME types.
+// If the second argument (subviewID) is "" then a value from the first argument (view) is returned.
+func GetFilePickerAccept(view View, subviewID string) []string {
+	if subviewID != "" {
+		view = ViewByID(view, subviewID)
+	}
+	if view != nil {
+		accept, ok := stringProperty(view, Accept, view.Session())
+		if !ok {
+			accept, ok = valueFromStyle(view, Accept)
+		}
+		if ok {
+			result := strings.Split(accept, ",")
+			for i := 0; i < len(result); i++ {
+				result[i] = strings.Trim(result[i], " \t\n")
+			}
+			return result
+		}
+	}
+	return []string{}
+}
+
+// GetFileSelectedListeners returns the "file-selected-event" listener list.
+// If there are no listeners then the empty list is returned.
+// If the second argument (subviewID) is "" then a value from the first argument (view) is returned.
+func GetFileSelectedListeners(view View, subviewID string) []func(FilePicker, []FileInfo) {
+	if subviewID != "" {
+		view = ViewByID(view, subviewID)
+	}
+	if view != nil {
+		if value := view.Get(FileSelectedEvent); value != nil {
+			if result, ok := value.([]func(FilePicker, []FileInfo)); ok {
+				return result
+			}
+		}
+	}
+	return []func(FilePicker, []FileInfo){}
+}
diff --git a/mediaPlayer.go b/mediaPlayer.go
index 33138c1..d851f11 100644
--- a/mediaPlayer.go
+++ b/mediaPlayer.go
@@ -844,7 +844,7 @@ func (player *mediaPlayerData) handleCommand(self View, command string, data Dat
 	case PlayerErrorEvent:
 		if value := player.getRaw(command); value != nil {
 			if listeners, ok := value.([]func(MediaPlayer, int, string)); ok {
-				code := dataIntProperty(data, "code")
+				code, _ := dataIntProperty(data, "code")
 				message, _ := data.PropertyValue("message")
 				for _, listener := range listeners {
 					listener(player, code, message)
diff --git a/mouseEvents.go b/mouseEvents.go
index acc4092..e0d6b16 100644
--- a/mouseEvents.go
+++ b/mouseEvents.go
@@ -328,8 +328,8 @@ func getTimeStamp(data DataObject) uint64 {
 func (event *MouseEvent) init(data DataObject) {
 
 	event.TimeStamp = getTimeStamp(data)
-	event.Button = dataIntProperty(data, "button")
-	event.Buttons = dataIntProperty(data, "buttons")
+	event.Button, _ = dataIntProperty(data, "button")
+	event.Buttons, _ = dataIntProperty(data, "buttons")
 	event.X = dataFloatProperty(data, "x")
 	event.Y = dataFloatProperty(data, "y")
 	event.ClientX = dataFloatProperty(data, "clientX")
diff --git a/pointerEvents.go b/pointerEvents.go
index 60a6020..b97e261 100644
--- a/pointerEvents.go
+++ b/pointerEvents.go
@@ -277,7 +277,7 @@ func pointerEventsHtml(view View, buffer *strings.Builder) {
 func (event *PointerEvent) init(data DataObject) {
 	event.MouseEvent.init(data)
 
-	event.PointerID = dataIntProperty(data, "pointerId")
+	event.PointerID, _ = dataIntProperty(data, "pointerId")
 	event.Width = dataFloatProperty(data, "width")
 	event.Height = dataFloatProperty(data, "height")
 	event.Pressure = dataFloatProperty(data, "pressure")
diff --git a/propertySet.go b/propertySet.go
index accd8b3..492f762 100644
--- a/propertySet.go
+++ b/propertySet.go
@@ -55,6 +55,7 @@ var boolProperties = []string{
 	Loop,
 	Muted,
 	AnimationPaused,
+	Multiple,
 }
 
 var intProperties = []string{
diff --git a/utils.go b/utils.go
index 4a10ec3..8fad6c3 100644
--- a/utils.go
+++ b/utils.go
@@ -52,13 +52,13 @@ func GetLocalIP() string {
 	return "localhost"
 }
 
-func dataIntProperty(data DataObject, tag string) int {
+func dataIntProperty(data DataObject, tag string) (int, bool) {
 	if value, ok := data.PropertyValue(tag); ok {
 		if n, err := strconv.Atoi(value); err == nil {
-			return n
+			return n, true
 		}
 	}
-	return 0
+	return 0, false
 }
 
 func dataBoolProperty(data DataObject, tag string) bool {
diff --git a/viewByID.go b/viewByID.go
index 074bf1e..91a2927 100644
--- a/viewByID.go
+++ b/viewByID.go
@@ -36,7 +36,7 @@ func viewByID(rootView ParanetView, id string) View {
 }
 
 // ViewsContainerByID return a ViewsContainer with id equal to the argument of the function or
-//   nil if there is no such View or View is not ViewsContainer
+// nil if there is no such View or View is not ViewsContainer
 func ViewsContainerByID(rootView View, id string) ViewsContainer {
 	if view := ViewByID(rootView, id); view != nil {
 		if list, ok := view.(ViewsContainer); ok {
@@ -48,7 +48,7 @@ func ViewsContainerByID(rootView View, id string) ViewsContainer {
 }
 
 // ListLayoutByID return a ListLayout with id equal to the argument of the function or
-//   nil if there is no such View or View is not ListLayout
+// nil if there is no such View or View is not ListLayout
 func ListLayoutByID(rootView View, id string) ListLayout {
 	if view := ViewByID(rootView, id); view != nil {
 		if list, ok := view.(ListLayout); ok {
@@ -60,7 +60,7 @@ func ListLayoutByID(rootView View, id string) ListLayout {
 }
 
 // StackLayoutByID return a StackLayout with id equal to the argument of the function or
-//   nil if there is no such View or View is not StackLayout
+// nil if there is no such View or View is not StackLayout
 func StackLayoutByID(rootView View, id string) StackLayout {
 	if view := ViewByID(rootView, id); view != nil {
 		if list, ok := view.(StackLayout); ok {
@@ -72,7 +72,7 @@ func StackLayoutByID(rootView View, id string) StackLayout {
 }
 
 // GridLayoutByID return a GridLayout with id equal to the argument of the function or
-//   nil if there is no such View or View is not GridLayout
+// nil if there is no such View or View is not GridLayout
 func GridLayoutByID(rootView View, id string) GridLayout {
 	if view := ViewByID(rootView, id); view != nil {
 		if list, ok := view.(GridLayout); ok {
@@ -84,7 +84,7 @@ func GridLayoutByID(rootView View, id string) GridLayout {
 }
 
 // ColumnLayoutByID return a ColumnLayout with id equal to the argument of the function or
-//   nil if there is no such View or View is not ColumnLayout
+// nil if there is no such View or View is not ColumnLayout
 func ColumnLayoutByID(rootView View, id string) ColumnLayout {
 	if view := ViewByID(rootView, id); view != nil {
 		if list, ok := view.(ColumnLayout); ok {
@@ -96,7 +96,7 @@ func ColumnLayoutByID(rootView View, id string) ColumnLayout {
 }
 
 // DetailsViewByID return a ColumnLayout with id equal to the argument of the function or
-//   nil if there is no such View or View is not DetailsView
+// nil if there is no such View or View is not DetailsView
 func DetailsViewByID(rootView View, id string) DetailsView {
 	if view := ViewByID(rootView, id); view != nil {
 		if details, ok := view.(DetailsView); ok {
@@ -108,7 +108,7 @@ func DetailsViewByID(rootView View, id string) DetailsView {
 }
 
 // DropDownListByID return a DropDownListView with id equal to the argument of the function or
-//   nil if there is no such View or View is not DropDownListView
+// nil if there is no such View or View is not DropDownListView
 func DropDownListByID(rootView View, id string) DropDownList {
 	if view := ViewByID(rootView, id); view != nil {
 		if list, ok := view.(DropDownList); ok {
@@ -120,7 +120,7 @@ func DropDownListByID(rootView View, id string) DropDownList {
 }
 
 // TabsLayoutByID return a TabsLayout with id equal to the argument of the function or
-//   nil if there is no such View or View is not TabsLayout
+// nil if there is no such View or View is not TabsLayout
 func TabsLayoutByID(rootView View, id string) TabsLayout {
 	if view := ViewByID(rootView, id); view != nil {
 		if list, ok := view.(TabsLayout); ok {
@@ -132,7 +132,7 @@ func TabsLayoutByID(rootView View, id string) TabsLayout {
 }
 
 // ListViewByID return a ListView with id equal to the argument of the function or
-//   nil if there is no such View or View is not ListView
+// nil if there is no such View or View is not ListView
 func ListViewByID(rootView View, id string) ListView {
 	if view := ViewByID(rootView, id); view != nil {
 		if list, ok := view.(ListView); ok {
@@ -144,7 +144,7 @@ func ListViewByID(rootView View, id string) ListView {
 }
 
 // TextViewByID return a TextView with id equal to the argument of the function or
-//   nil if there is no such View or View is not TextView
+// nil if there is no such View or View is not TextView
 func TextViewByID(rootView View, id string) TextView {
 	if view := ViewByID(rootView, id); view != nil {
 		if text, ok := view.(TextView); ok {
@@ -156,7 +156,7 @@ func TextViewByID(rootView View, id string) TextView {
 }
 
 // ButtonByID return a Button with id equal to the argument of the function or
-//   nil if there is no such View or View is not Button
+// nil if there is no such View or View is not Button
 func ButtonByID(rootView View, id string) Button {
 	if view := ViewByID(rootView, id); view != nil {
 		if button, ok := view.(Button); ok {
@@ -168,7 +168,7 @@ func ButtonByID(rootView View, id string) Button {
 }
 
 // CheckboxByID return a Checkbox with id equal to the argument of the function or
-//   nil if there is no such View or View is not Checkbox
+// nil if there is no such View or View is not Checkbox
 func CheckboxByID(rootView View, id string) Checkbox {
 	if view := ViewByID(rootView, id); view != nil {
 		if checkbox, ok := view.(Checkbox); ok {
@@ -180,7 +180,7 @@ func CheckboxByID(rootView View, id string) Checkbox {
 }
 
 // EditViewByID return a EditView with id equal to the argument of the function or
-//   nil if there is no such View or View is not EditView
+// nil if there is no such View or View is not EditView
 func EditViewByID(rootView View, id string) EditView {
 	if view := ViewByID(rootView, id); view != nil {
 		if buttons, ok := view.(EditView); ok {
@@ -192,7 +192,7 @@ func EditViewByID(rootView View, id string) EditView {
 }
 
 // ProgressBarByID return a ProgressBar with id equal to the argument of the function or
-//   nil if there is no such View or View is not ProgressBar
+// nil if there is no such View or View is not ProgressBar
 func ProgressBarByID(rootView View, id string) ProgressBar {
 	if view := ViewByID(rootView, id); view != nil {
 		if buttons, ok := view.(ProgressBar); ok {
@@ -203,8 +203,20 @@ func ProgressBarByID(rootView View, id string) ProgressBar {
 	return nil
 }
 
+// ColorPickerByID return a ColorPicker with id equal to the argument of the function or
+// nil if there is no such View or View is not ColorPicker
+func ColorPickerByID(rootView View, id string) ColorPicker {
+	if view := ViewByID(rootView, id); view != nil {
+		if input, ok := view.(ColorPicker); ok {
+			return input
+		}
+		ErrorLog(`ColorPickerByID(_, "` + id + `"): The found View is not ColorPicker`)
+	}
+	return nil
+}
+
 // NumberPickerByID return a NumberPicker with id equal to the argument of the function or
-//   nil if there is no such View or View is not NumberPicker
+// nil if there is no such View or View is not NumberPicker
 func NumberPickerByID(rootView View, id string) NumberPicker {
 	if view := ViewByID(rootView, id); view != nil {
 		if input, ok := view.(NumberPicker); ok {
@@ -215,8 +227,44 @@ func NumberPickerByID(rootView View, id string) NumberPicker {
 	return nil
 }
 
+// TimePickerByID return a TimePicker with id equal to the argument of the function or
+// nil if there is no such View or View is not TimePicker
+func TimePickerByID(rootView View, id string) TimePicker {
+	if view := ViewByID(rootView, id); view != nil {
+		if input, ok := view.(TimePicker); ok {
+			return input
+		}
+		ErrorLog(`TimePickerByID(_, "` + id + `"): The found View is not TimePicker`)
+	}
+	return nil
+}
+
+// DatePickerByID return a DatePicker with id equal to the argument of the function or
+// nil if there is no such View or View is not DatePicker
+func DatePickerByID(rootView View, id string) DatePicker {
+	if view := ViewByID(rootView, id); view != nil {
+		if input, ok := view.(DatePicker); ok {
+			return input
+		}
+		ErrorLog(`DatePickerByID(_, "` + id + `"): The found View is not DatePicker`)
+	}
+	return nil
+}
+
+// FilePickerByID return a FilePicker with id equal to the argument of the function or
+// nil if there is no such View or View is not FilePicker
+func FilePickerByID(rootView View, id string) FilePicker {
+	if view := ViewByID(rootView, id); view != nil {
+		if input, ok := view.(FilePicker); ok {
+			return input
+		}
+		ErrorLog(`FilePickerByID(_, "` + id + `"): The found View is not FilePicker`)
+	}
+	return nil
+}
+
 // CanvasViewByID return a CanvasView with id equal to the argument of the function or
-//   nil if there is no such View or View is not CanvasView
+// nil if there is no such View or View is not CanvasView
 func CanvasViewByID(rootView View, id string) CanvasView {
 	if view := ViewByID(rootView, id); view != nil {
 		if canvas, ok := view.(CanvasView); ok {
@@ -229,7 +277,7 @@ func CanvasViewByID(rootView View, id string) CanvasView {
 
 /*
 // TableViewByID return a TableView with id equal to the argument of the function or
-//   nil if there is no such View or View is not TableView
+// nil if there is no such View or View is not TableView
 func TableViewByID(rootView View, id string) TableView {
 	if view := ViewByID(rootView, id); view != nil {
 		if canvas, ok := view.(TableView); ok {
@@ -242,7 +290,7 @@ func TableViewByID(rootView View, id string) TableView {
 */
 
 // AudioPlayerByID return a AudioPlayer with id equal to the argument of the function or
-//   nil if there is no such View or View is not AudioPlayer
+// nil if there is no such View or View is not AudioPlayer
 func AudioPlayerByID(rootView View, id string) AudioPlayer {
 	if view := ViewByID(rootView, id); view != nil {
 		if canvas, ok := view.(AudioPlayer); ok {
@@ -254,7 +302,7 @@ func AudioPlayerByID(rootView View, id string) AudioPlayer {
 }
 
 // VideoPlayerByID return a VideoPlayer with id equal to the argument of the function or
-//   nil if there is no such View or View is not VideoPlayer
+// nil if there is no such View or View is not VideoPlayer
 func VideoPlayerByID(rootView View, id string) VideoPlayer {
 	if view := ViewByID(rootView, id); view != nil {
 		if canvas, ok := view.(VideoPlayer); ok {
diff --git a/viewFactory.go b/viewFactory.go
index f30f63e..e2a25a2 100644
--- a/viewFactory.go
+++ b/viewFactory.go
@@ -24,6 +24,7 @@ var viewCreators = map[string]func(Session) View{
 	"ColorPicker":    newColorPicker,
 	"DatePicker":     newDatePicker,
 	"TimePicker":     newTimePicker,
+	"FilePicker":     newFilePicker,
 	"EditView":       newEditView,
 	"ListView":       newListView,
 	"CanvasView":     newCanvasView,
diff --git a/viewUtils.go b/viewUtils.go
index 77fa9c6..f59b84d 100644
--- a/viewUtils.go
+++ b/viewUtils.go
@@ -11,8 +11,8 @@ func Get(rootView View, viewID, tag string) interface{} {
 }
 
 // Set sets the property with name "tag" of the "rootView" subview with "viewID" id by value. Result:
-//  true - success,
-//  false - error (incompatible type or invalid format of a string value, see AppLog).
+// true - success,
+// false - error (incompatible type or invalid format of a string value, see AppLog).
 func Set(rootView View, viewID, tag string, value interface{}) bool {
 	if view := ViewByID(rootView, viewID); view != nil {
 		return view.Set(tag, value)
@@ -21,8 +21,8 @@ func Set(rootView View, viewID, tag string, value interface{}) bool {
 }
 
 // SetParams sets properties with name "tag" of the "rootView" subview. Result:
-//  true - all properties were set successful,
-//  false - error (incompatible type or invalid format of a string value, see AppLog).
+// true - all properties were set successful,
+// false - error (incompatible type or invalid format of a string value, see AppLog).
 func SetParams(rootView View, viewID string, params Params) bool {
 	view := ViewByID(rootView, viewID)
 	if view == nil {
@@ -678,8 +678,8 @@ func GetTextTransform(view View, subviewID string) int {
 }
 
 // GetWritingMode returns whether lines of text are laid out horizontally or vertically, as well as
-//   the direction in which blocks progress. Valid values are HorizontalTopToBottom (0),
-//   HorizontalBottomToTop (1), VerticalRightToLeft (2) and VerticalLeftToRight (3)
+// the direction in which blocks progress. Valid values are HorizontalTopToBottom (0),
+// HorizontalBottomToTop (1), VerticalRightToLeft (2) and VerticalLeftToRight (3)
 // If the second argument (subviewID) is "" then a value from the first argument (view) is returned.
 func GetWritingMode(view View, subviewID string) int {
 	if subviewID != "" {
@@ -697,7 +697,7 @@ func GetWritingMode(view View, subviewID string) int {
 }
 
 // GetTextDirection - returns a direction of text, table columns, and horizontal overflow.
-//   Valid values are Inherit (0), LeftToRightDirection (1), and RightToLeftDirection (2).
+// Valid values are Inherit (0), LeftToRightDirection (1), and RightToLeftDirection (2).
 // If the second argument (subviewID) is "" then a value from the first argument (view) is returned.
 func GetTextDirection(view View, subviewID string) int {
 	if subviewID != "" {
@@ -716,8 +716,8 @@ func GetTextDirection(view View, subviewID string) int {
 }
 
 // GetVerticalTextOrientation returns a orientation of the text characters in a line. It only affects text
-//   in vertical mode (when "writing-mode" is "vertical-right-to-left" or "vertical-left-to-right").
-//   Valid values are MixedTextOrientation (0), UprightTextOrientation (1), and SidewaysTextOrientation (2).
+// in vertical mode (when "writing-mode" is "vertical-right-to-left" or "vertical-left-to-right").
+// Valid values are MixedTextOrientation (0), UprightTextOrientation (1), and SidewaysTextOrientation (2).
 // If the second argument (subviewID) is "" then a value from the first argument (view) is returned.
 func GetVerticalTextOrientation(view View, subviewID string) int {
 	if subviewID != "" {
@@ -804,8 +804,8 @@ func GetPerspectiveOrigin(view View, subviewID string) (SizeUnit, SizeUnit) {
 
 // GetBackfaceVisible returns a bool property that sets whether the back face of an element is
 // visible when turned towards the user. Values:
-//   true - the back face is visible when turned towards the user (default value).
-//   false - the back face is hidden, effectively making the element invisible when turned away from the user.
+// true - the back face is visible when turned towards the user (default value).
+// false - the back face is hidden, effectively making the element invisible when turned away from the user.
 // If the second argument (subviewID) is "" then a value from the first argument (view) is returned.
 func GetBackfaceVisible(view View, subviewID string) bool {
 	if subviewID != "" {