This example demonstrates how to use multiple NodeList features to build a simple game.
The HTML
<div class='gallery'>
<ul class="duck-row">
<li></li> <!-- each of these will be a duck -->
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
</ul>
<div class="water">
<img class="shadow" src="../assets/node/images/water-shadow.png"/>
<img src="../assets/node/images/water.png"/>
</div>
</div>
<button id="button-reset" class="yui3-button">Reset</button>
Ducks remaining: <span class="ducks-remain">10</span>
<input type="checkbox" id="show-attitude"/><label for="show-attitude">Show attitude</label>
YUI Instance
The use statement doesn't include node because it's loaded as a requirement of transition.
YUI().use('transition', 'button', function(Y){
// code goes here
});
Setting Vars
The variable ducks is used for easily manipulating all the ducks at once.
We'll display various duck comments from the array squawkTextArr on a rotating basis.
var ducks = Y.all('.duck-row li'),
ducksRemaining = 10, // value for UI display
squawkTextIndex = 0, // index in the squawkTextArr to use next
squawkTextArr = [ // duck comments
'#@&~*Q!',
'Hey!?',
'911 on U!',
"U fly's down",
'duck pile!',
'Ricochets kill!',
'how sporting.',
"shoe's untied"
];
Initializing the Ducks
Repetitive markup is added with the .append() method to all the ducks in the NodeList.
This keeps the original markup simple and clear.
// append the same content for each duck <li>
ducks.append('<img src="../assets/node/images/duck.png"/><div class="squawk"><div class="text">#@&~*Q!</div><div class="small-squawk-bubble"></div></div>');
All the ducks in the NodeList are given the set-up class with the .addClass() method.
This class is found on any duck that has the state of being set up, as opposed to being knocked down.
// give them all the set-up state class
ducks.addClass('set-up');
This state could be a Boolean property, but it's handy as a class,
because a NodeList can be made containing the squawks of all "set up" ducks in this way,
squawks = Y.all('.duck-row .set-up .squawk');
as we'll see in the makeDucksSquawk function.
Making the Ducks Swim
This uses transition to make the ducks swim right to left
// this makes the ducks move from right to left.
// When the duck on the far left disappears from view,
// it's added to the far right end of the row.
var makeDucksSwim = function () {
var frontDuck;
// move the duck row to the left one duck space over 2 seconds
Y.one('.duck-row').transition({
easing: 'linear',
left: '-119px',
duration: 2
}, function () { // when the row finishes its right to left transition...
// remove the first duck on the left
// which has trasitioned out of view
frontDuck = Y.one('.duck-row li').remove();
// append the removed first duck onto the right end
Y.one('.duck-row').appendChild(frontDuck);
// set the position for the next makeDucksSwim()
Y.one('.duck-row').setStyle('left', '10px');
// if there are ducks remaining, make them swim again
if (ducksRemaining > 0) {
makeDucksSwim();
}
});
}
makeDucksSwim(); // this initializes the ducks swimming
Click Event Handler
// handles a click on a duck
var duckClick = function(e) {
var squawks;
// remove the squawk belonging to the duck that was clicked
e.currentTarget.one('.squawk').setStyles({'top': '-400px', 'opacity': '1'});
// makes the ducks appear to lay back when clicked
e.target.transition({
duration: 0.2,
height: '3px',
width: '133px'
});
// the clicked duck will no longer have the 'set-up' class/state
e.currentTarget.removeClass('set-up');
makeDucksSquawk(); // makes the ducks squawk
updateDucksRemaining(); // update the number of ducks still set up
};
Squawking Ducks
// this makes the duck's squawks show and hide and get various text
var makeDucksSquawk = function(){
squawks = Y.all('.duck-row .set-up .squawk'); // a NodeList of the squawks of set-up ducks
if (Y.one('#show-attitude')._node.checked) { // only have ducks squawk if the checkbox is checked
// fill voice bubbles with next text string
Y.all('.duck-row .set-up .squawk .text').setContent(squawkTextArr[squawkTextIndex]);
// increment the index to get the next squawk text
squawkTextIndex = (squawkTextIndex += 1) % (squawkTextArr.length);
squawks.transition({
top: {
delay: 0.5,
value: '0px', // drop squawks into position from hidden
duration: 0 // instant position change
},
opacity: { // fade out
delay: 3.0,
duration: 0.3,
value: 0
}
}, function(e){
// after squawks are faded out,
// move them to hidden position and set opacity to 1 again
squawks.setStyles({'top': '-400px', 'opacity': '1'});
});
}
}
Reset and Ducks Remaining
// This resets all ducks, "ducks remaining" counters, and row position
// make the duck images full height
// start them swimming
var reset = function() {
Y.all('.duck-row li img').setStyle('height', '55px');
Y.all('.duck-row li').addClass('set-up');
updateDucksRemaining();
makeDucksSwim();
}
// counts the ducks remaining, and updates the UI counter display
var updateDucksRemaining = function() {
ducksRemaining = Y.all('.gallery li.set-up').size();
Y.one('.ducks-remain').setContent(ducksRemaining);
}
Prefer node.delegate() over nodelist.on()
Sometimes you need to create individual subscriptions for each Node in a NodeList, but usually it's preferable to use event delegation as shown in this example.
Listeners
// listeners
Y.one('.duck-row').delegate('click', duckClick, 'li');
Y.one('#button-reset').on('click', reset);
Complete Ducks Example Source
<style>
.gallery{
position: relative;
background: url(../assets/node/images/background.png);
width: 638px;
height: 180px;
overflow: hidden;
-moz-border-radius: 8px;
-webkit-border-radius: 8px;
-moz-box-shadow: 0 0 45px #000 inset, 3px 0 6px rgba(0,0,0,0.8);
-webkit-box-shadow: 0 0 45px #000 inset, 3px 0 6px rgba(0,0,0,0.8);
border: 4px solid #637073;
cursor: crosshair;
margin: 0.5em 0 0.8em;
}
.water{
position: absolute;
top: 114px;
left: 0;
width: 677px;
height: 50px;
}
.water img{
position: absolute;
top: 0;
left: 0;
}
.water .shadow {
left: 8px;
opacity: 0.5;
filter: alpha(opacity=30);
}
.duck-row {
position: absolute;
left: 10px;
top: 57px;
width: 1340px;
padding: 0;
margin: 0;
}
.duck-row li{
position: relative;
display: inline-block;
zoom: 1; *display: inline; /* IE < 8: fake inline-block */
width: 133px;
height: 70px;
margin: 0 -4px 0 0;
vertical-align: bottom;
}
.duck-row li img{
position: absolute;
bottom: 7px;
left: 0;
}
/* the voice bubble of the ducks */
.duck-row .squawk {
position: absolute;
top: -400px;
left: 50px;
-moz-border-radius: 4px;
-webkit-border-radius: 4px;
background-color: #ffe;
line-height: 1.2em;
border: solid 1px #cc8;
-moz-box-shadow: 2px 2px 2px rgba(0,0,0,0.2);
-webkit-box-shadow: 2px 2px 2px rgba(0,0,0,0.2);
}
.duck-row .squawk .text{
padding: 0.2em 0.2em;
text-indent: 0.2em;
overflow: hidden;
}
.small-squawk-bubble{
position: absolute;
bottom: -4px;
left: -8px;
width: 4px;
height: 4px;
border: solid 1px #cc8;
-moz-border-radius: 3px;
-webkit-border-radius: 3px;
background-color: #ffe;
font-size: 2px;
}
#button-reset{
margin-right: 2em;
}
.ducks-remain{
font-size: 150%;
}
#show-attitude{
margin-left: 8em;
}
</style>
<div class='gallery'>
<ul class="duck-row">
<li></li> <!-- each of these will be a duck -->
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
<li></li>
</ul>
<div class="water">
<img class="shadow" src="../assets/node/images/water-shadow.png"/>
<img src="../assets/node/images/water.png"/>
</div>
</div>
<button id="button-reset" class="yui3-button">Reset</button>
Ducks remaining: <span class="ducks-remain">10</span>
<input type="checkbox" id="show-attitude"/><label for="show-attitude">Show attitude</label>
<script>
YUI().use('transition', 'button', function (Y) {
var ducks = Y.all('.duck-row li'),
ducksRemaining = 10, // value for UI display
squawkTextIndex = 0, // index in the squawkTextArr to use next
squawkTextArr = [ // duck comments
'#@&~*Q!',
'Hey!?',
'911 on U!',
"U fly's down",
'duck pile!',
'Ricochets kill!',
'how sporting.',
"shoe's untied"
];
// append the same content for each duck <li>
ducks.append('<img src="../assets/node/images/duck.png"/><div class="squawk"><div class="text">#@&~*Q!</div><div class="small-squawk-bubble"></div></div>');
// give them all the set-up state class
ducks.addClass('set-up');
// this makes the ducks move from right to left.
// When the duck on the far left disappears from view,
// it's added to the far right end of the row.
var makeDucksSwim = function () {
var frontDuck;
// move the duck row to the left one duck space over 2 seconds
Y.one('.duck-row').transition({
easing: 'linear',
left: '-119px',
duration: 2
}, function () { // when the row finishes its right to left transition...
// remove the first duck on the left
// which has trasitioned out of view
frontDuck = Y.one('.duck-row li').remove();
// append the removed first duck onto the right end
Y.one('.duck-row').appendChild(frontDuck);
// set the position for the next makeDucksSwim()
Y.one('.duck-row').setStyle('left', '10px');
// if there are ducks remaining, make them swim again
if (ducksRemaining > 0) {
makeDucksSwim();
}
});
}
makeDucksSwim(); // this initializes the ducks swimming
// handles a click on a duck
var duckClick = function(e) {
var squawks;
// remove the squawk belonging to the duck that was clicked
e.currentTarget.one('.squawk').setStyles({'top': '-400px', 'opacity': '1'});
// makes the ducks appear to lay back when clicked
e.target.transition({
duration: 0.2,
height: '3px',
width: '133px'
});
// the clicked duck will no longer have the 'set-up' class/state
e.currentTarget.removeClass('set-up');
makeDucksSquawk();
updateDucksRemaining(); // update the number of ducks still set up
};
// this makes the duck's squawks show and hide and get various text
var makeDucksSquawk = function(){
squawks = Y.all('.duck-row .set-up .squawk'); // a NodeList of the squawks of set-up ducks
if (Y.one('#show-attitude')._node.checked) { // only have ducks squawk if the checkbox is checked
// fill voice bubbles with next text string
Y.all('.duck-row .set-up .squawk .text').setContent(squawkTextArr[squawkTextIndex]);
// increment the index to get the next squawk text
squawkTextIndex = (squawkTextIndex += 1) % (squawkTextArr.length);
squawks.transition({
top: {
delay: 0.5,
value: '0px', // drop squawks into position from hidden
duration: 0 // instant position change
},
opacity: { // fade out
delay: 3.0,
duration: 0.3,
value: 0
}
}, function(e){
// after squawks are faded out,
// move them to hidden position and set opacity to 1 again
squawks.setStyles({'top': '-400px', 'opacity': '1'});
});
}
}
// This resets all ducks, "ducks remaining" counters, and row position
// make the duck images full height
// start them swimming
var reset = function() {
Y.all('.duck-row li img').setStyle('height', '55px');
Y.all('.duck-row li').addClass('set-up');
updateDucksRemaining();
makeDucksSwim();
}
// counts the ducks remaining, and updates the UI counter display
var updateDucksRemaining = function() {
ducksRemaining = Y.all('.gallery li.set-up').size();
Y.one('.ducks-remain').setContent(ducksRemaining);
}
// listeners
Y.one('.duck-row').delegate('click', duckClick, 'li');
Y.one('#button-reset').on('click', reset);
});
</script>