paper-year-list.html
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<link rel="import" href="../iron-flex-layout/iron-flex-layout.html">
<link rel="import" href="../iron-list/iron-list.html">
<link rel="import" href="../iron-resizable-behavior/iron-resizable-behavior.html">
<link rel="import" href="../paper-ripple/paper-ripple.html">
<link rel="import" href="../paper-styles/default-theme.html">
<link rel="import" href="../polymer/polymer.html">
<dom-module id="paper-year-list">
<template>
<style>
:host {
display: block;
box-sizing: border-box;
height: 100%;
@apply(--paper-font-common-base);
/* for iron-list to fit */
position: relative;
}
.year {
cursor: pointer;
height: var(--paper-year-list-item-height, 44px);
line-height: var(--paper-year-list-item-height, 44px);
text-align: center;
vertical-align: middle;
}
.selected {
color: var(--default-primary-color);
font-size: 24px;
}
iron-list {
@apply(--layout-fit);
}
</style>
<iron-list id="yearList" items="[[_years]]">
<template>
<div class$="year{{_addSelectedClass(selected)}}" on-tap="_tappedYearHandler">
[[item.year]]
</div>
</template>
</iron-list>
</template>
<script>
Polymer({
is: 'paper-year-list',
properties: {
date: {
type: Date,
notify: true,
observer: '_dateChange'
},
/**
* Maximum allowed year.
*/
max: {
type: Number,
value: 2100,
observer: '_maxChange'
},
/**
* Minimum allowed year.
*/
min: {
type: Number,
value: 1900,
observer: '_minChange'
},
/**
* The selected year, sync with the year of the given date
* or null if year isn't within range.
*/
selected: {
type: Number,
notify: true,
observer: '_selectedChange'
},
/**
* The allowed years array.
*/
_years: {
type: Array,
computed: '_computeYears(min, max)',
readOnly: true,
value: function() {
return Date.now().getFullYear;
}
}
},
ready: function() {
// hack for iron-list not to scroll to the first visible index on resize
this.$.yearList._resizeHandler = function() {
this.debounce('resize', function() {
this._render();
if (this._itemsRendered && this._physicalItems && this._isVisible) {
this._resetAverage();
this.updateViewportBoundaries();
}
});
}.bind(this.$.yearList);
},
/**
* Scroll in the years list to center the selected year.
*/
centerSelected: function() {
if (this.selected !== null) {
var selectedYearIdx = this.selected - this.min;
this.$.yearList.scrollToIndex(selectedYearIdx);
this.async(function() {
var selectedPos = selectedYearIdx * this._physicalAverage + 1;
if (selectedPos !== this.scrollTop) {
this._update();
this.scrollTop = selectedPos;
}
if (this.scrollHeight - this.offsetHeight !== this.scrollTop) {
this.scrollTop += (this._physicalAverage - this.offsetHeight) / 2;
}
}.bind(this.$.yearList));
}
},
/**
* Return the selected class if needed.
*/
_addSelectedClass: function(selected) {
if (selected) {
return ' selected';
}
},
/**
* Compute the years array passed to the iron-list.
*/
_computeYears: function(min, max) {
if (typeof min !== 'number' || typeof max !== 'number') {
return;
}
var years = [];
for (;min <= max; min++) {
years.push({year: min});
}
return years;
},
/**
* Set 'selected' attribute to the new date's year if it is within range, else set it to null.
*/
_dateChange: function(date) {
var newYear = date.getFullYear();
this.selected = this._withinRange(newYear) ? newYear : null;
},
_maxChange: function(max) {
if (typeof max !== 'number') {
this.max = 2100;
}
},
_minChange: function(min) {
if (typeof min !== 'number') {
this.min = 1900;
}
},
/**
* If selected is null, clear iron-list selection,
* else select it in iron-list and synchronize 'date' attribute.
*/
_selectedChange: function(selected) {
if (selected === null) {
this.$.yearList.clearSelection();
return;
}
if (selected !== this.date.getFullYear()) {
// set the year using a new Date instance for notifying to work
this.date = new Date(this.date.setFullYear(selected));
}
this._selectYearInList(selected);
},
/**
* Select the given year in the years list.
*/
_selectYearInList: function(year) {
var yearIdx = year - this.min;
this.$.yearList.selectItem(yearIdx);
},
/**
* Update 'selected' attribute and select in iron-list
* from a tapped item's event in the years list.
*/
_tappedYearHandler: function(e) {
var yearItem = e.model.__data__.item;
var year = yearItem.year;
if (this.selected !== year) {
this.$.yearList.selectItem(yearItem);
this.selected = year;
}
},
/**
* Return true if year is between min and max.
*/
_withinRange: function(year) {
return !(this.min && year < this.min || this.max && year > this.max );
},
behaviors: [
Polymer.IronResizableBehavior
]
});
</script>
</dom-module>