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| 1 <!-- | 1 <!-- |
| 2 @license | 2 @license |
| 3 Copyright (c) 2015 The Polymer Project Authors. All rights reserved. | 3 Copyright (c) 2015 The Polymer Project Authors. All rights reserved. |
| 4 This code may only be used under the BSD style license found at http://polymer.g
ithub.io/LICENSE.txt | 4 This code may only be used under the BSD style license found at http://polymer.g
ithub.io/LICENSE.txt |
| 5 The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt | 5 The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt |
| 6 The complete set of contributors may be found at http://polymer.github.io/CONTRI
BUTORS.txt | 6 The complete set of contributors may be found at http://polymer.github.io/CONTRI
BUTORS.txt |
| 7 Code distributed by Google as part of the polymer project is also | 7 Code distributed by Google as part of the polymer project is also |
| 8 subject to an additional IP rights grant found at http://polymer.github.io/PATEN
TS.txt | 8 subject to an additional IP rights grant found at http://polymer.github.io/PATEN
TS.txt |
| 9 --><html><head><link rel="import" href="../polymer/polymer.html"> | 9 --><html><head><link rel="import" href="../polymer/polymer.html"> |
| 10 <link rel="import" href="../iron-resizable-behavior/iron-resizable-behavior.html
"> | 10 <link rel="import" href="../iron-resizable-behavior/iron-resizable-behavior.html
"> |
| 11 <link rel="import" href="../iron-a11y-keys-behavior/iron-a11y-keys-behavior.html
"> |
| 12 <link rel="import" href="../iron-scroll-target-behavior/iron-scroll-target-behav
ior.html"> |
| 11 | 13 |
| 12 <!-- | 14 <!-- |
| 13 | 15 |
| 14 `iron-list` displays a virtual, 'infinite' list. The template inside | 16 `iron-list` displays a virtual, 'infinite' list. The template inside |
| 15 the iron-list element represents the DOM to create for each list item. | 17 the iron-list element represents the DOM to create for each list item. |
| 16 The `items` property specifies an array of list item data. | 18 The `items` property specifies an array of list item data. |
| 17 | 19 |
| 18 For performance reasons, not every item in the list is rendered at once; | 20 For performance reasons, not every item in the list is rendered at once; |
| 19 instead a small subset of actual template elements *(enough to fill the viewport
)* | 21 instead a small subset of actual template elements *(enough to fill the viewport
)* |
| 20 are rendered and reused as the user scrolls. As such, it is important that all | 22 are rendered and reused as the user scrolls. As such, it is important that all |
| 21 state of the list template be bound to the model driving it, since the view may | 23 state of the list template be bound to the model driving it, since the view may |
| 22 be reused with a new model at any time. Particularly, any state that may change | 24 be reused with a new model at any time. Particularly, any state that may change |
| 23 as the result of a user interaction with the list item must be bound to the mode
l | 25 as the result of a user interaction with the list item must be bound to the mode
l |
| 24 to avoid view state inconsistency. | 26 to avoid view state inconsistency. |
| 25 | 27 |
| 26 __Important:__ `iron-list` must either be explicitly sized, or delegate scrollin
g to an | 28 __Important:__ `iron-list` must either be explicitly sized, or delegate scrollin
g to an |
| 27 explicitly sized parent. By "explicitly sized", we mean it either has an explici
t | 29 explicitly sized parent. By "explicitly sized", we mean it either has an explici
t |
| 28 CSS `height` property set via a class or inline style, or else is sized by other | 30 CSS `height` property set via a class or inline style, or else is sized by other |
| 29 layout means (e.g. the `flex` or `fit` classes). | 31 layout means (e.g. the `flex` or `fit` classes). |
| 30 | 32 |
| 31 ### Template model | 33 ### Template model |
| 32 | 34 |
| 33 List item templates should bind to template models of the following structure: | 35 List item templates should bind to template models of the following structure: |
| 34 | 36 |
| 35 { | 37 ```js |
| 36 index: 0, // data index for this item | 38 { |
| 37 item: { // user data corresponding to items[index] | 39 index: 0, // index in the item array |
| 38 /* user item data */ | 40 selected: false, // true if the current item is selected |
| 39 } | 41 tabIndex: -1, // a dynamically generated tabIndex for focus management |
| 40 } | 42 item: {} // user data corresponding to items[index] |
| 43 } |
| 44 ``` |
| 41 | 45 |
| 42 Alternatively, you can change the property name used as data index by changing t
he | 46 Alternatively, you can change the property name used as data index by changing t
he |
| 43 `indexAs` property. The `as` property defines the name of the variable to add to
the binding | 47 `indexAs` property. The `as` property defines the name of the variable to add to
the binding |
| 44 scope for the array. | 48 scope for the array. |
| 45 | 49 |
| 46 For example, given the following `data` array: | 50 For example, given the following `data` array: |
| 47 | 51 |
| 48 ##### data.json | 52 ##### data.json |
| 49 | 53 |
| 50 ```js | 54 ```js |
| 51 [ | 55 [ |
| 52 {"name": "Bob"}, | 56 {"name": "Bob"}, |
| 53 {"name": "Tim"}, | 57 {"name": "Tim"}, |
| 54 {"name": "Mike"} | 58 {"name": "Mike"} |
| 55 ] | 59 ] |
| 56 ``` | 60 ``` |
| 57 | 61 |
| 58 The following code would render the list (note the name and checked properties a
re | 62 The following code would render the list (note the name and checked properties a
re |
| 59 bound from the model object provided to the template scope): | 63 bound from the model object provided to the template scope): |
| 60 | 64 |
| 61 ```html | 65 ```html |
| 62 <template is="dom-bind"> | 66 <template is="dom-bind"> |
| 63 <iron-ajax url="data.json" last-response="{{data}}" auto></iron-ajax> | 67 <iron-ajax url="data.json" last-response="{{data}}" auto></iron-ajax> |
| 64 <iron-list items="[[data]]" as="item"> | 68 <iron-list items="[[data]]" as="item"> |
| 65 <template> | 69 <template> |
| 66 <div> | 70 <div> |
| 67 Name: <span>[[item.name]]</span> | 71 Name: [[item.name]] |
| 68 </div> | 72 </div> |
| 69 </template> | 73 </template> |
| 70 </iron-list> | 74 </iron-list> |
| 71 </template> | 75 </template> |
| 72 ``` | 76 ``` |
| 73 | 77 |
| 78 ### Accessibility |
| 79 |
| 80 `iron-list` automatically manages the focus state for the items. It also provide
s |
| 81 a `tabIndex` property within the template scope that can be used for keyboard na
vigation. |
| 82 For example, users can press the up and down keys to move to previous and next |
| 83 items in the list: |
| 84 |
| 85 ```html |
| 86 <iron-list items="[[data]]" as="item"> |
| 87 <template> |
| 88 <div tabindex$="[[tabIndex]]"> |
| 89 Name: [[item.name]] |
| 90 </div> |
| 91 </template> |
| 92 </iron-list> |
| 93 ``` |
| 94 |
| 74 ### Styling | 95 ### Styling |
| 75 | 96 |
| 76 Use the `--iron-list-items-container` mixin to style the container of items, e.g
. | 97 You can use the `--iron-list-items-container` mixin to style the container of it
ems: |
| 77 | 98 |
| 78 ```css | 99 ```css |
| 79 iron-list { | 100 iron-list { |
| 80 --iron-list-items-container: { | 101 --iron-list-items-container: { |
| 81 margin: auto; | 102 margin: auto; |
| 82 }; | 103 }; |
| 83 } | 104 } |
| 84 ``` | 105 ``` |
| 85 | 106 |
| 86 ### Resizing | 107 ### Resizing |
| 87 | 108 |
| 88 `iron-list` lays out the items when it receives a notification via the `iron-res
ize` event. | 109 `iron-list` lays out the items when it receives a notification via the `iron-res
ize` event. |
| 89 This event is fired by any element that implements `IronResizableBehavior`. | 110 This event is fired by any element that implements `IronResizableBehavior`. |
| 90 | 111 |
| 91 By default, elements such as `iron-pages`, `paper-tabs` or `paper-dialog` will t
rigger | 112 By default, elements such as `iron-pages`, `paper-tabs` or `paper-dialog` will t
rigger |
| 92 this event automatically. If you hide the list manually (e.g. you use `display:
none`) | 113 this event automatically. If you hide the list manually (e.g. you use `display:
none`) |
| 93 you might want to implement `IronResizableBehavior` or fire this event manually
right | 114 you might want to implement `IronResizableBehavior` or fire this event manually
right |
| 94 after the list became visible again. e.g. | 115 after the list became visible again. For example: |
| 95 | 116 |
| 96 ```js | 117 ```js |
| 97 document.querySelector('iron-list').fire('iron-resize'); | 118 document.querySelector('iron-list').fire('iron-resize'); |
| 98 ``` | 119 ``` |
| 99 | 120 |
| 100 ### When should `<iron-list>` be used? | 121 ### When should `<iron-list>` be used? |
| 101 | 122 |
| 102 `iron-list` should be used when a page has significantly more DOM nodes than the
ones | 123 `iron-list` should be used when a page has significantly more DOM nodes than the
ones |
| 103 visible on the screen. e.g. the page has 500 nodes, but only 20 are visible at t
he time. | 124 visible on the screen. e.g. the page has 500 nodes, but only 20 are visible at t
he time. |
| 104 This is why we refer to it as a `virtual` list. In this case, a `dom-repeat` wil
l still | 125 This is why we refer to it as a `virtual` list. In this case, a `dom-repeat` wil
l still |
| 105 create 500 nodes which could slow down the web app, but `iron-list` will only cr
eate 20. | 126 create 500 nodes which could slow down the web app, but `iron-list` will only cr
eate 20. |
| 106 | 127 |
| 107 However, having an `iron-list` does not mean that you can load all the data at o
nce. | 128 However, having an `iron-list` does not mean that you can load all the data at o
nce. |
| 108 Say, you have a million records in the database, you want to split the data into
pages | 129 Say, you have a million records in the database, you want to split the data into
pages |
| 109 so you can bring a page at the time. The page could contain 500 items, and iron-
list | 130 so you can bring a page at the time. The page could contain 500 items, and iron-
list |
| 110 will only render 20. | 131 will only render 20. |
| 111 | 132 |
| 112 @group Iron Element | 133 @group Iron Element |
| 113 @element iron-list | 134 @element iron-list |
| 114 @demo demo/index.html Simple list | 135 @demo demo/index.html Simple list |
| 115 @demo demo/selection.html Selection of items | 136 @demo demo/selection.html Selection of items |
| 116 @demo demo/collapse.html Collapsable items | 137 @demo demo/collapse.html Collapsable items |
| 138 @demo demo/scroll-threshold.html Scroll thesholds |
| 139 |
| 117 --> | 140 --> |
| 118 | 141 |
| 119 </head><body><dom-module id="iron-list"> | 142 </head><body><dom-module id="iron-list"> |
| 120 <template> | 143 <template> |
| 121 <style> | 144 <style> |
| 122 :host { | 145 :host { |
| 123 display: block; | 146 display: block; |
| 124 } | |
| 125 | |
| 126 :host(.has-scroller) { | |
| 127 overflow: auto; | |
| 128 } | |
| 129 | |
| 130 :host(:not(.has-scroller)) { | |
| 131 position: relative; | 147 position: relative; |
| 132 } | 148 } |
| 133 | 149 |
| 150 @media only screen and (-webkit-max-device-pixel-ratio: 1) { |
| 151 :host { |
| 152 will-change: transform; |
| 153 } |
| 154 } |
| 155 |
| 134 #items { | 156 #items { |
| 135 @apply(--iron-list-items-container); | 157 @apply(--iron-list-items-container); |
| 136 position: relative; | 158 position: relative; |
| 137 } | 159 } |
| 138 | 160 |
| 139 #items > ::content > * { | 161 #items > ::content > * { |
| 140 width: 100%; | 162 width: 100%; |
| 141 box-sizing: border-box; | 163 box-sizing: border-box; |
| 142 position: absolute; | 164 position: absolute; |
| 143 top: 0; | 165 top: 0; |
| 144 will-change: transform; | 166 will-change: transform; |
| 145 } | 167 } |
| 146 </style> | 168 </style> |
| 147 | 169 |
| 148 <array-selector id="selector" items="{{items}}" selected="{{selectedItems}}"
selected-item="{{selectedItem}}"> | 170 <array-selector id="selector" items="{{items}}" selected="{{selectedItems}}"
selected-item="{{selectedItem}}"> |
| 149 </array-selector> | 171 </array-selector> |
| 150 | 172 |
| 151 <div id="items"> | 173 <div id="items"> |
| 152 <content></content> | 174 <content></content> |
| 153 </div> | 175 </div> |
| 154 | 176 |
| 155 </template> | 177 </template> |
| 156 </dom-module> | 178 </dom-module> |
| 157 | 179 |
| 158 <script src="iron-list-extracted.js"></script></body></html> | 180 <script src="iron-list-extracted.js"></script></body></html> |
| OLD | NEW |
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Chromium Code Reviews
Issue 1681053002:
Unrestrict version of PolymerElements/iron-list and update it (Closed)
Base URL: https://chromium.googlesource.com/chromium/src.git@fix-closure