Dynamic menus

Sorry for the delay in responding, for some reason I'm not getting notification of replies to my posts.

addItem(name as Lang.String or Lang.Symbol, identifier as Lang.Symbol) as Void

The identifier, which the doco indicates must be a Symbol, is returned in the delegate's onMenuItem callback is not required to be a symbol as indicated in the doco. 

Just pass it a number that you dynamically allocate from the web call (which probably returns a JSON).

But don't forget that the number of items is limited to 16 entries.

Here's what I do in one of my apps. I do my own "menu" (really just a list).  Works with touch/button/button-touch devices.  Highlight a day, press select, and it does to a full details page

It is weird. The issue is that the value passed to onMenuItem() is always a Lang.Symbol regardless of what is passed into the addItem() call. The type is completely lost. Interestingly enough, the symbol it can successfully be used in comparisons using the equals operator (as opposed to the equals() method) to find the matching object...

using Toybox.Application as App;
using Toybox.Lang as Lang;
using Toybox.System as Sys;
using Toybox.WatchUi as Ui;

class XMenu extends Ui.Menu
{
function initialize() {
Menu.initialize();
}
}

class XMenuInputDelegate extends Ui.MenuInputDelegate
{
hidden var _M_callback;

function initialize(callback) {
MenuInputDelegate.initialize();
_M_callback = callback;
}

function onMenuItem(item) {
return _M_callback.invoke(item);
}
}

var _symbol = :symbol;
var _number = 1;
var _long = 37000l;
var _float = 8.0;
var _double = 10.0d;
var _string = "abc";
var _array = [ 1, "2" ];
var _dict = { 1 => "2" };

class XBehaviorDelegate extends Ui.BehaviorDelegate
{
function initialize() {
BehaviorDelegate.initialize();
}

function onMenu() {
var menu = new XMenu();

menu.addItem("Symbol", _symbol);
menu.addItem("Number", _number);
menu.addItem("Long", _long);
menu.addItem("Float", _float);
menu.addItem("Double", _double);
menu.addItem("String", _string);
menu.addItem("Array", _array);
menu.addItem("Dictionary", _dict);

var delegate = new XMenuInputDelegate(self.method(:onMenuItem));

Ui.pushView(menu, delegate, Ui.SLIDE_UP);

return true;
}

function onMenuItem(item) {

if (item instanceof Lang.Symbol) {
Sys.print(item);
}
else if (item instanceof Lang.Number) {
Sys.print(Lang.format("Number: $1$", [ item ]));
}
else if (item instanceof Lang.Long) {
Sys.print(Lang.format("Long: $1$", [ item ]));
}
else if (item instanceof Lang.Float) {
Sys.print(Lang.format("Float: $1$", [ item ]));
}
else if (item instanceof Lang.Double) {
Sys.print(Lang.format("Double: $1$", [ item ]));
}
else if (item instanceof Lang.String) {
Sys.print(Lang.format("String: $1$", [ item ]));
}
else if (item instanceof Lang.String) {
Sys.print(Lang.format("String: $1$", [ item ]));
}
else if (item instanceof Lang.Array) {
Sys.print(Lang.format("Array: $1$", [ item ]));
}
else if (item instanceof Lang.Dictionary) {
Sys.print(Lang.format("Dictionary: $1$", [ item ]));
}
else {
Sys.print(Lang.format("Unknown: $1$", [ item ]));
}

if (_symbol.equals(item)) {
Sys.println(" match for symbol");
}
else if (_number.equals(item)) {
Sys.println(" _number.equals(item)");
}
else if (_number == item) {
Sys.println(" _number == item");
}
else if (_long.equals(item)) {
Sys.println(" _long.equals(item)");
}
else if (_long == item) {
Sys.println(" _long == item");
}
else if (_float.equals(item)) {
Sys.println(" _float.equals(item)");
}
else if (_float == item) {
Sys.println(" _float == item");
}
else if (_double.equals(item)) {
Sys.println(" _double.equals(item)");
}
else if (_double == item) {
Sys.println(" _double == item");
}
else if (_string.equals(item)) {
Sys.println(" _string.equals(item)");
}
else if (_string == item) {
Sys.println(" _string == item");
}
else if (_array.equals(item)) {
Sys.println(" _array.equals(item)");
}
else if (_array == item) {
Sys.println(" _array == item");
}
else if (_dict.equals(item)) {
Sys.println(" _dict.equals(item)");
}
else if (_dict == item) {
Sys.println(" _dict == item");
}
else {
Sys.println(" unknown value");
}
}
}

class XView extends Ui.View
{
function initialize() {
View.initialize();
}
}

class XApp extends App.AppBase
{
function initialize() {
AppBase.initialize();
}

function getInitialView() {
return [ new XView(), new XBehaviorDelegate() ];
}
}


If I run that testcase and select each menu item in order, I see the following output...

Device Version 0.1.0
Device id 1 name "A garmin device"
Shell Version 0.1.0
symbol (8389891) match for symbol
symbol (1) _number == item
symbol (16) _long == item
symbol (1090519040) _float == item
symbol (17) _double == item
symbol (15) _string == item
symbol (18) _array == item
symbol (20) _dict == item
Complete
Connection Finished
Closing shell and port


If you have a situation like the initial post and you make a dynamic menu, it gets weird.

using Toybox.Application as App;
using Toybox.Lang as Lang;
using Toybox.System as Sys;
using Toybox.WatchUi as Ui;

class XMenu extends Ui.Menu
{
function initialize() {
Menu.initialize();
}
}

class XMenuInputDelegate extends Ui.MenuInputDelegate
{
hidden var _M_callback;

function initialize(callback) {
MenuInputDelegate.initialize();
_M_callback = callback;
}

function onMenuItem(item) {
return _M_callback.invoke(item);
}
}

var _array = [
{ "name" => "A", "lat" => 1.0, "lon" => 1.0 },
{ "name" => "B", "lat" => 2.0, "lon" => 2.0 },
{ "name" => "C", "lat" => 3.0, "lon" => 3.0 }
];

class XBehaviorDelegate extends Ui.BehaviorDelegate
{
function initialize() {
BehaviorDelegate.initialize();
}

function onMenu() {
var menu = new XMenu();

for (var i = 0; i < _array.size(); ++i) {
menu.addItem(_array["name"], _array);
}

var delegate = new XMenuInputDelegate(self.method(:onMenuItem));

Ui.pushView(menu, delegate, Ui.SLIDE_UP);

return true;
}

function onMenuItem(item) {
Sys.println(item["name"]);
}
}

class XView extends Ui.View
{
function initialize() {
View.initialize();
}
}

class XApp extends App.AppBase
{
function initialize() {
AppBase.initialize();
}

function getInitialView() {
return [ new XView(), new XBehaviorDelegate() ];
}
}
[/code]

The problem is that you can't treat item as if it were a Lang.Dictionary (the type of the object passed in) inside onMenuItem(), because the type has been lost. You can work around this by searching the original array for the matching item (using the equals operator), and when you find a match you can access the item from the original array...

function onMenuItem(item) {
// Sys.println(item["name"]); // UnexpectedTypeException: Expected Object/Array/Dictionary, given Symbol

// this works...
for (var i = 0; i < _array.size(); ++i) {
if (_array== item) {
Sys.println(_array["name"]);
}
}
}
[/code]

This is just as ugly as my original suggestion (using a lookup table of symbols) because the data has to be shared between the view and the delegate.

As you've pointed out, you can pass a Lang.Number as the second parameter to addItem(), but that still has the same problem... you need to do the same lookup trick to avoid the UnexpectedTypeException you get from passing a Lang.Symbol to the array index operator.


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