How do you keep track of your UI elements in Titanium? Say you have a window with a TableView that has some Switches (on/off) in it and you'd like to reference the changed switch onchange with a generic event listener. There's the property event.source, but you still don't really know what field of a form was just toggled, you just have a reference to the element. Is there a way to give the element an ID, as you would with a radiobutton in JavaScript?
Up to now, registered each form UI element in a dictionary, and saved all the values at once, looping through the dictionary and getting each object value. But now I'd like to do this onchange, and I can't find any other way to do it than create a specific callback function for each element (which I'd really rather not).
just assign and id to the element... all of these other solution CAN work, but they seem to be over kill for what you are asking for.
// create switch with id
var switcher0 = Ti.Ui.createSwitch({id:"switch1"});
then inside your event listener
myform.addEventListener('click', function(e){
var obj = e.source;
if ( obj.id == "switch1" ) {
// do some magic!!
}
});
A simple solution is to use a framework that helps you keep track of all your elements, which speeds up development quite a bit, as the project and app grows. I've built a framework of my own called Adamantium.js, which lets you use a syntax like jQuery to deal with your elements, based on ID and type selectors. In a coming release, it will also support for something like classes, that can be arbitrarily added or removed from an element, tracking of master/slave relationships and basic filter methods, to help you narrow your query. Most methods are chainable, so building apps with rich interaction is quick and simple.
A quick demo:
// Type selector, selects all switches
$(':Switch')
// Bind a callback to the change event on all switches
// This callback is also inherited by all new switch elements
$(':Switch').bind('change', function (e) {
alert(e.type + ' fired on ' + e.source.id + ', value = ' + e.value);
});
// Select by ID and trigger an event
$('#MyCustomSwitch').trigger('change', {
foo: 'bar'
});
Then there's a lot of other cool methods in the framework, that are all designed to speed up development and modeled after the familiar ways of jQuery, more about that in the original blog post.
I completely understand not wanting to write a listener to each one because that is very time consuming. I had the same problem that you did and solved it like so.
var switches = [];
function createSwitch(i) {
switches[i] = Ti.UI.createSwitch();
switches[i].addEventListener('change', function(e) {
Ti.API.info('switch '+i+' = '+e.value);
});
return switches[i];
}
for(i=0;i<rows.length;i++) {
row = Ti.UI.createTableViewRow();
row.add(createSwitch(i));
}
However keep in mind that this solution may not fit your needs as it did mine. For me it was good because each time I created a switch it added a listener to it dynamically then I could simply get the e.source.parent of the switch to interact with whatever I needed.
module Id just for the hold it's ID. When we have use id the call any another space just use . and use easily.
Try This
var but1 = Ti.Ui.createButton({title : 'Button', id:"1"});
window.addEventListener('click', function(e){
var obj = e.source;
if ( obj.id == "1" ) {
// do some magic!!
}
});
window.add(but1);
I, think this is supported for you.
how do you create your tableview and your switcher? usually i would define a eventListener function while creating the switcher.
// first switch
var switcher0 = Ti.Ui.createSwitch();
switch0.addEventListener('change',function(e){});
myTableViewRow.add(switch0);
myTableView.add(myTableViewRow);
// second switch
var switch1 = ..
so no generic event listener is needed.
Related
I am looking to make the enter key behave exactly like the tab key on a form.
I am stuck on the fireEvent section.
var inputs = $$('input, textarea');
$each(inputs,function(el,i) {
el.addEvent('keypress',function(e) {
if(e.key == 'enter') {
e.stop();
el.fireEvent('keypress','tab');
}
});
});
How do I fire a keypress event with a specified key? Any help would be greatly appreciated.
this will work but it relies on dom order and not tabindex
var inputs = $$('input,textarea');
inputs.each(function(el,i){
el.addEvent('keypress',function(e) {
if(e.key == 'enter'){
e.stop();
var next = inputs[i+1];
if (next){
next.focus();
}
else {
// inputs[0].focus(); or form.submit() etc.
}
}
});
});
additionally, textarea enter capture? why, it's multiline... anyway, to do it at keyboard level, look at Syn. https://github.com/bitovi/syn
the above will fail with hidden elements (you can filter) and disabled elements etc. you get the idea, though - focus(). not sure what it will do on input[type=radio|checkbox|range] etc.
p.s. your code won't work because .fireEvent() will only call the bound event handler, not actually create the event for you.
Take a look at the class keyboard (MooTools More).
It can fire individual events for keys and provides methodology to disable and enable the listeners assigned to a Keyboard instance.
The manual has some examples how to work with this class, here's just a simple example how I implemented it in a similar situation:
var myKeyEv1 = new Keyboard({
defaultEventType: 'keydown'
});
myKeyEv1.addEvents({
'shift+h': myApp.help() // <- calls a function opening a help screen
});
Regarding the enter key in your example, you have to return false somewhere to prevent the enter-event from firing. Check out this SO post for more details.
I'm sorry to ask this question because it seems like the answer should be obvious, but I can't find it.
I am processing the "complete" event after a create action on a detail grid because I wish to refresh the grid after the insert. But I can't find a sensible way to it. Here is what I have done. I am doing it all in HTML and JavaScript. When the detail grid is initialized, I "name: it 'panegrid' suffixed by the key of the master record. Like below:
function detailInit(e) {
if (e.data.Id != '') { // Must be a Create for Lite so don't create a grid
$("<div id='panegrid" + e.data.Id + "' />").appendTo(e.detailCell).kendoGrid({
dataSource: {
And then when the create completes I find the grid like this:
complete: function (e) {
var selector = '#panegrid' + $.parseJSON(e.responseText).IGUnit_Id;
$(selector).data('kendoGrid').dataSource.read();
}
This works (IGUnit_Id is the primary key of the Master Grid), but it just doesn't seem right to have to do it this way. Surely there is some "correct way" to find the grid from within the complete event directly without playing around with selectors.
I appreciate your help and apologize for asking such a dumb question.
If you want to save a reference to a grid when you create it, simply assign a variable to it and append .data('kendoGrid') to your create expression, e.g.
var myGrid = $("<div id='panegrid" + e.data.Id + "' />").appendTo(e.detailCell).kendoGrid({
dataSource: {
// etc...
}
}).data('kendoGrid');
Then later
myGrid.dataSource.read();
Of course, you wouldn't want it to be a local variable, you would need to add it as a property of something visible from the rest of your code, but I leave that exercise up to you.
I apologize if this has been asked before but, is there a way to add an event listener/handler to a Javascript object? Preferably using JQuery.
Such as:
var foo;
$(foo).bind('change', function() {
alert("Foo has changed!");
});
I have tried this, but nothing seems to happen. Does this only work with DOM elements?
EDIT:
I need an event fired every time that the audio or video tags throw an error. Originally, I was using an interval to check whether or not the error, 'media.error', object was null, but this uses excess processing power and I would like to avoid it.
EDIT 2: Apparently I was going about it wrong, easiest way I found was to add the "onerror" property to the video/audio tag.
I agree with Cheeso that it's more important for you to state what you actually want to do, however one workaround for your specific question could be to store your variable within an object and only provide access through getter / setter, then you can do what you want in the setter. e.g.
function data() {
var foo = 0;
this.setFoo = function(newVal) {
foo = newVal;
alert(foo);
};
}
var theData = new data();
theData.setFoo(5);
Yes, that's correct. You cannot make a "variable watcher". There is no event fired for variables when they are changed.
What are you really trying to do?
You could try:
http://higginsforpresident.net/js/static/jq.pubsub.js
See
http://weblog.bocoup.com/publishsubscribe-with-jquery-custom-events
Or use a framework like backbone/underscore or knockout.js.
HTML/Elements/audio
var foo;
$(foo).bind('error', function() {
//your code here
});
I want to dynamically add some preconfigured HTML-Elements in use of a 'click'-event with mootools.
So I can make it work with my basic knowledge, although it isn´t very nifty. I coded this so far...
This is my preconfigured element, with some text, a classname and some event, cause i wanna have events already added, when it´s inserted into my container:
var label = new Element('label', {
'text': 'Label',
'class': 'label',
'events': {
'click': function(el){
alert('click');
}
}
});
Here is my function, which adds the label-Element:
function addText(){
$('fb-buildit').addEvent('click', function(){
row.adopt(label, textinput, deletebtn);
$('the-form').adopt(row.clone());
row.empty();
/*
label.clone().inject($('the-form'));
textinput.inject($('the-form'));
deletebtn.inject($('the-form'));
*/
});
}
The second part which uses inject also works, but there, my click-Event, which fires the "alert('click')" works too. The method with adopt doesn´t add any event to my label Object, when its inserted in the dom.
Can anyone help me with this. I just wanna know why adobt ignores my "events" settings and inject doesn´t.
Thanks in advance.
(sorry for my english ^^)
you go label.clone().inject but row.adopt(label) and not row.adopt(label.clone()) -
either way. .clone() does not cloneEvents for you - you need to do that manually.
var myclone = label.clone();
myclone.cloneEvents(label);
row.adopt(label);
this is how it will work
as for why that is, events are stored in the Element storage - which is unique per element. mootools assigns a uid to each element, eg, label = 1, label.clone() -> 2, label.clone() -> 3 etc.
this goes to Storage[1] = { events: ... } and so forth. cloning an element makes for a new element.uid so events don't work unless you implicitly use .cloneEvents()
you are sometimes not doing .clone() which works because it takes the ORIGINAL element along with its storage and events.
suggestion consider looking into event delegation. you could do
formElement.addEvent("click:relay(label.myLabel)", function(e, el) {
alert("hi from "+ el.uid);
});
this means no matter how many new elements you add, as long as they are of type label and class myLabel and children of formElement, the click will always work as the event bubbles to the parent.
So I have been adding my events thusly:
element.addEvent('click', function() {
alert('foobar');
});
However, when attempting to remove said event, this syntactically identical code (with "add" switched to "remove") does not work.
element.removeEvent('click', function() {
alert('foobar');
});
I assume this is because the two functions defined are not referenced the same, so the event is not technically removed. Alright, so I redefine the event addition and removal:
element.addEvent('click', alert('foobar'));
element.removeEvent('click', alert('foobar'));
Which works great, except now when the page loads, the click event is fired even before it's clicked!
The function is removed, though, which is great......
update: when you do .addEvent('type', function(){ }) and .removeEvent('type', function(){ }), even though the functions may have the same 'signatures', they are two separte anonymous functions, assigned on the fly. function 1 is !== to function 2 - hence there is no match when MooTools tries to remove it.
to be able to remove an exact handler, o:
function handler(){ ... }
el.addEvent('click', handler);
// .. later
el.removeEvent('click', handler);
Internally, events are actually a map of keys to functions in element storage. have a look at this fiddle i did a while back for another SO question - http://www.jsfiddle.net/mVJDr/
it will check to see how many events are stacked up for a particular event type on any given element (or all events).
similarly, removeEvent looks for a match in the events storage - have a look on http://jsfiddle.net/dimitar/wLuY3/1/. hence, using named functions like Nikolaus suggested allows you to remove them easily as it provides a match.
also, you can remove events via element.removeEvents("click") for all click events.
your page now alerts because you pass on alert as the function as well as execute it with the params 'foobar'. METHOD followed by () in javascript means RUN THE METHOD PRECEDING IT IMMEDIATELY, NOT LATER. when you bind functions to events, you pass the reference (the method name) only.
to avoid using an anonymous function and to pass argument,s you can do something like:
document.id('foobar').addEvent('click', alert.bind(this, 'foo'));
as bind raps it for you, but removing this will be even more complicated.
as for event delegation, it's:
parentEl.addEvents({
"click:relay(a.linkout)": function(e, el) {
},
"mouseover:relay(li.menu)": function(e, el) {
}
});
more on that here http://mootools.net/docs/more/Element/Element.Delegation#Element:removeEvent
keep in mind it's not great / very stable. works fine for click stuff, mouseenter is not to be used delegated, just mouseover - which means IE can fire mouseout when it should not. the way i understand it, it's coming improved in mootools 2.0
edit updating to show an example of bound and unbound method within a class pattern in mootools
http://www.jsfiddle.net/wmhgw/
var foo = new Class({
message: "hi",
toElement: function() {
return this.element = new Element("a", {
href: "http://www.google.com",
text: "google",
events: {
"click": this.bar.bind(this), // bind it
"mouseenter": this.bar // unbound -> this.element becomes this
}
});
},
bar: function(event) {
event.stop();
// hi when bound to class instance (this.message will exist)
// 'undefined' otherwise.
console.log(this.message || "undefined");
}
});
document.id(new foo()).inject(document.body);
the mouseenter here will be unbound where this will refer to the default scope (i.e the element that triggered the event - the a href). when bound, you can get the element via event.target instead - the event object is always passed on to the function as a parameter.
btw, this is a slightly less familiar use of class and element relation but it serves my purposes here to illustrate binding in the context of classes.
assig the function to a variable and use the same reference to add and remove the event.
if you use an anonymous function you will get to different references
var test = function(){ alert('test: ' + this.id); }
$('element').addEvent('click', test);
...
$('element').removeEvent('click', test);
addEvent : Attaches an event listener to a DOM element.
Example -
$('myElement').addEvent('click', function(){
alert('clicked!');
});
removeEvent : Works as Element.addEvent, but instead removes the specified event listener.
Example -
var destroy = function(){ alert('Boom: ' + this.id); } // this refers to the Element.
$('myElement').addEvent('click', destroy);
//later...
$('myElement').removeEvent('click', destroy);
This means when you add an event with a eventhandler not an anonymous function if you than remove the event than it will be removed.