4

hidden を使用しようとしていますが、<iron-list>レンダリングが更新されない理由を理解する必要があります。

これは関連する問題です: https://github.com/PolymerElements/iron-list/issues/263

これはコードです: http://jsbin.com/vagumebupe/9/edit?html,console,output

<!doctype html>
<head>
  
  <meta charset="utf-8">

  <base href="https://polygit.org/polymer+:master/components/">

  <script src="webcomponentsjs/webcomponents-lite.min.js"></script>
  
  <link href="polymer/polymer.html" rel="import">

  <link rel="import" href="iron-flex-layout/iron-flex-layout.html">
  <link rel="import" href="iron-ajax/iron-ajax.html">
  <link rel="import" href="paper-icon-button/paper-icon-button.html">
  <link rel="import" href="iron-icon/iron-icon.html">
  <link rel="import" href="iron-icons/iron-icons.html">
  <link rel="import" href="paper-styles/color.html">
  <link rel="import" href="paper-styles/typography.html">
  <link rel="import" href="app-layout/app-toolbar/app-toolbar.html">
  <link rel="import" href="paper-menu/paper-menu.html">
  <link rel="import" href="paper-item/paper-item.html">
  <link rel="import" href="paper-badge/paper-badge.html">
  <link rel="import" href="iron-list/iron-list.html">
  
  <style is="custom-style">
  body {
    @apply(--layout-fullbleed);
  }
</style>

</head>

<body unresolved>

  <x-app></x-app>
  
<dom-module id="x-app">
  <style>
      :host {
        @apply(--layout-fit);
        @apply(--layout-vertical);
        @apply(--paper-font-common-base);
        font-family: sans-serif;
      }
      app-toolbar {
        background: var(--paper-pink-500);
        box-shadow: 0 2px 5px 0 rgba(0, 0, 0, 0.3);
        color: white;
        z-index: 1;
        color: white;
        --paper-toolbar-title: {
          font-size: 16px;
          line-height: 16px;
          font-weight: bold;
          margin-left: 0;
        };
      }
      app-toolbar paper-icon-button {
        --paper-icon-button-ink-color: white;
      }
      #itemsList,
      #selectedItemsList {
        @apply(--layout-flex);
      }
      .item {
        @apply(--layout-horizontal);
        cursor: pointer;
        padding: 16px 22px;
        border-bottom: 1px solid #DDD;
      }
      .item:focus,
      .item.selected:focus {
        outline: 0;
        background-color: #ddd;
      }
      .item.selected .star {
        color: var(--paper-blue-600);
      }
      .item.selected {
        background-color: var(--google-grey-300);
        border-bottom: 1px solid #ccc;
      }
      .avatar {
        height: 40px;
        width: 40px;
        border-radius: 20px;
        box-sizing: border-box;
        background-color: #ddd;
      }
      .pad {
        @apply(--layout-flex);
        @apply(--layout-vertical);
        padding: 0 16px;
      }
      .primary {
        font-size: 16px;
      }
      .secondary {
        font-size: 14px;
      }
      .dim {
        color: gray;
      }
      .star {
        width: 24px;
        height: 24px;
      }
      paper-badge {
        -webkit-transition: all 0.1s;
        transition: all 0.1s;
        opacity: 1;
        margin-top: 5px;
      }
      paper-badge[label="0"] {
        opacity: 0;
      }
      #starredView {
        width: 200px;
        border-left: 1px solid #ddd;
      }
      paper-item {
        white-space: nowrap;
        cursor: pointer;
        position: relative;
      }
      paper-item:hover::after {
        content: "-";
        width: 16px;
        height: 16px;
        display: block;
        border-radius: 50% 50%;
        background-color: var(--google-red-300);
        margin-left: 10px;
        line-height: 16px;
        text-align: center;
        color: white;
        font-weight: bold;
        text-decoration: none;
        position: absolute;
        right: 15px;
        top: calc(50% - 8px);
      }
      .noSelection {
        color: #999;
        margin-left: 10px;
        line-height: 50px;
      }
      .twoColumns {
        @apply(--layout-flex);
        @apply(--layout-horizontal);
        overflow: hidden;
      }
      #starredView {
        @apply(--layout-vertical);
      }
    </style>
    <template>
      <app-toolbar>
        <div title>Selection using iron-list</div>
        <div>
          <paper-icon-button icon="icons:more-horiz" alt="hidden" on-tap="_toggleHidden"></paper-icon-button>
          <paper-icon-button icon="icons:add" alt="add" on-tap="_changeContactList"></paper-icon-button>
          <paper-badge label$="[[selectedItems.length]]"></paper-badge>
          
        </div>
      </app-toolbar>

        <!-- Main List for the items -->
        <iron-list id="itemsList" items="[[data]]" selected-items="{{selectedItems}}" selection-enabled multi-selection hidden="{{hidden}}">
          <template>
            <div>
              <div tabindex$="[[tabIndex]]" aria-label$="Select/Deselect [[item.name]]" class$="[[_computedClass(selected)]]">
                <img class="avatar" src="[[item.image]]">
                <div class="pad">
                  <div class="primary">
                    [[item.name]]
                  </div>
                  <div class="secondary dim">[[item.shortText]]</div>
                </div>
                <iron-icon icon$="[[iconForItem(selected)]]" class="star"></iron-icon>
              </div>
              <div class="border"></div>
            </div>
          </template>
        </iron-list>
    </template>
  <script>
    
    addEventListener('WebComponentsReady', function() {
      
      Polymer({
        is: "x-app",
        behaviors: [
          Polymer.IronResizableBehavior
        ],
        listeners: {
          'iron-resize': '_onIronResize'
        },
        properties: {
          hidden: {
            type: Object,
            notify: true,
            value: false
          },
          selectedItems: {
            type: Object
          },
          data: {
            type: Object,
            notify: true,
            value : [
                      {
                        "name": "Liz Grimes",
                        "image": "https://s3.amazonaws.com/uifaces/faces/twitter/enda/73.jpg",
                        "shortText": "est ad reprehenderit occaecat consequat"
                      },
                      {
                        "name": "Frazier Lara",
                        "image": "https://s3.amazonaws.com/uifaces/faces/twitter/guillogo/73.jpg",
                        "shortText": "consectetur culpa adipisicing voluptate enim"
                      }
                    ]
          }
        },
        iconForItem: function(isSelected) {
          return isSelected ? 'star' : 'star-border';
        },
        _computedClass: function(isSelected) {
          var classes = 'item';
          if (isSelected) {
            classes += ' selected';
          }
          return classes;
        },
        _unselect: function(e) {
          this.$.itemsList.deselectItem(e.model.item);
        },
        _changeContactList: function() {
          this.data = [
            {
              "name": "Shelley Molina",
              "image": "https://s3.amazonaws.com/uifaces/faces/twitter/smalonso/73.jpg",
              "shortText": "laboris do velit ipsum non"
            }
          ];
          console.log('Replace data !')
        },
        _toggleHidden: function(){
          this.hidden = !this.hidden;
          console.log('Hidden : ' + this.hidden)
        },
        _onIronResize: function() {
           console.log('Resize');
        }

      });
      
    });
    
  </script>
</dom-module>
  
</body>

4

1 に答える 1

5

リストのiron-listサイズが変更されたとき、またはそのitemsプロパティが変更されたときに、 は項目をレンダリングします。最適化として、リストが表示されていない場合は_render() 終了します。(アイテムの複雑さ、特にモバイル デバイスによっては、リスト アイテムのレンダリングに比較的コストがかかる可能性があるため、リストが非表示のときにレンダリングを無視すると、CPU サイクルが節約されます。)

リストを再表示すると、の(またはこの場合は を実装する)iron-resizeの物理的な寸法が変更されていないため、イベントはトリガーされず、リストは更新されません。iron-listx-appIronResizableBehavior

ドキュメントからのアドバイスに従ってください(強調は私のものです):

サイズ変更

iron-listiron-resizeイベント経由で通知を受け取ると、アイテムをレイアウトします。このイベントは、 を実装するすべての要素によって発生しますIronResizableBehavior

デフォルトではiron-pagespaper-tabsやなどの要素paper-dialogがこのイベントを自動的にトリガーします。リストを手動で非表示にした場合 (たとえば、display: none を使用) IronResizableBehavior、リストが再び表示されるようになった直後に、このイベントを手動で実装または起動することができます。例えば:

document.querySelector('iron-list').fire('iron-resize');

...非表示を解除したら、手動でiron-resizeイベントをトリガーする必要がありiron-listます。hiddenそのために、要素のプロパティでオブザーバーを使用します。

Polymer({
  ...
  properties: {
    hidden: {
      type: Object,
      notify: true,
      value: false,
      observer: '_hiddenChanged'
    },
    ...
  },
  _hiddenChanged: function(hidden) {
    if (!hidden) {
      this.$.itemsList.fire('iron-resize');
    }
  },
});

これが実際のデモです:

<!doctype html>

<head>
  <meta name="description" content="Polymer iron-list items added while list hidden">

  <meta charset="utf-8">

  <base href="https://polygit.org/polymer+1.5.0/components/">

  <script src="webcomponentsjs/webcomponents-lite.min.js"></script>

  <link href="polymer/polymer.html" rel="import">

  <link rel="import" href="iron-flex-layout/iron-flex-layout.html">
  <link rel="import" href="iron-ajax/iron-ajax.html">
  <link rel="import" href="paper-icon-button/paper-icon-button.html">
  <link rel="import" href="iron-icon/iron-icon.html">
  <link rel="import" href="iron-icons/iron-icons.html">
  <link rel="import" href="paper-styles/color.html">
  <link rel="import" href="paper-styles/typography.html">
  <link rel="import" href="app-layout/app-toolbar/app-toolbar.html">
  <link rel="import" href="paper-menu/paper-menu.html">
  <link rel="import" href="paper-item/paper-item.html">
  <link rel="import" href="paper-badge/paper-badge.html">
  <link rel="import" href="iron-list/iron-list.html">

  <style is="custom-style">
    body {
      @apply(--layout-fullbleed);

    }
  </style>

</head>

<body unresolved>

  <x-app></x-app>

  <dom-module id="x-app">
    <style>
      :host {
        @apply(--layout-fit);

@apply(--layout-vertical);

@apply(--paper-font-common-base);

font-family: sans-serif;
      }
      app-toolbar {
        background: var(--paper-pink-500);
        box-shadow: 0 2px 5px 0 rgba(0, 0, 0, 0.3);
        color: white;
        z-index: 1;
        color: white;
        --paper-toolbar-title: {
          font-size: 16px;
          line-height: 16px;
          font-weight: bold;
          margin-left: 0;
        }
        ;
      }
      app-toolbar paper-icon-button {
        --paper-icon-button-ink-color: white;
      }
      #itemsList,
      #selectedItemsList {
        @apply(--layout-flex);

      }
      .item {
        @apply(--layout-horizontal);

cursor: pointer;
        padding: 16px 22px;
        border-bottom: 1px solid #DDD;
      }
      .item:focus,
      .item.selected:focus {
        outline: 0;
        background-color: #ddd;
      }
      .item.selected .star {
        color: var(--paper-blue-600);
      }
      .item.selected {
        background-color: var(--google-grey-300);
        border-bottom: 1px solid #ccc;
      }
      .avatar {
        height: 40px;
        width: 40px;
        border-radius: 20px;
        box-sizing: border-box;
        background-color: #ddd;
      }
      .pad {
        @apply(--layout-flex);

@apply(--layout-vertical);

padding: 0 16px;
      }
      .primary {
        font-size: 16px;
      }
      .secondary {
        font-size: 14px;
      }
      .dim {
        color: gray;
      }
      .star {
        width: 24px;
        height: 24px;
      }
      paper-badge {
        -webkit-transition: all 0.1s;
        transition: all 0.1s;
        opacity: 1;
        margin-top: 5px;
      }
      paper-badge[label="0"] {
        opacity: 0;
      }
      #starredView {
        width: 200px;
        border-left: 1px solid #ddd;
      }
      paper-item {
        white-space: nowrap;
        cursor: pointer;
        position: relative;
      }
      paper-item:hover::after {
        content: "-";
        width: 16px;
        height: 16px;
        display: block;
        border-radius: 50% 50%;
        background-color: var(--google-red-300);
        margin-left: 10px;
        line-height: 16px;
        text-align: center;
        color: white;
        font-weight: bold;
        text-decoration: none;
        position: absolute;
        right: 15px;
        top: calc(50% - 8px);
      }
      .noSelection {
        color: #999;
        margin-left: 10px;
        line-height: 50px;
      }
      .twoColumns {
        @apply(--layout-flex);

@apply(--layout-horizontal);

overflow: hidden;
      }
      #starredView {
        @apply(--layout-vertical);

      }
    </style>
    <template>
      <app-toolbar>
        <div title>Selection using iron-list</div>
        <div>
          <paper-icon-button icon="icons:more-horiz" alt="hidden" on-tap="_toggleHidden"></paper-icon-button>
          <paper-icon-button icon="icons:add" alt="add" on-tap="_changeContactList"></paper-icon-button>
          <paper-badge label="[[selectedItems.length]]"></paper-badge>

        </div>
      </app-toolbar>

      <!-- Main List for the items -->
      <iron-list id="itemsList" items="[[data]]" selected-items="{{selectedItems}}" selection-enabled multi-selection hidden="{{hidden}}">
        <template>
          <div>
            <div tabindex$="[[tabIndex]]" aria-label$="Select/Deselect [[item.name]]" class$="[[_computedClass(selected)]]">
              <img class="avatar" src="[[item.image]]">
              <div class="pad">
                <div class="primary">
                  [[item.name]]
                </div>
                <div class="secondary dim">[[item.shortText]]</div>
              </div>
              <iron-icon icon="[[iconForItem(selected)]]" class="star"></iron-icon>
            </div>
            <div class="border"></div>
          </div>
        </template>
      </iron-list>
    </template>
    <script>
      HTMLImports.whenReady(function() {

        Polymer({
          is: "x-app",
          behaviors: [
            Polymer.IronResizableBehavior
          ],
          listeners: {
            'iron-resize': '_onIronResize'
          },
          properties: {
            hidden: {
              type: Object,
              notify: true,
              value: false,
              observer: '_hiddenChanged'
            },
            selectedItems: {
              type: Object
            },
            data: {
              type: Object,
              notify: true,
              value: [{
                "name": "Liz Grimes",
                "image": "https://s3.amazonaws.com/uifaces/faces/twitter/enda/73.jpg",
                "shortText": "est ad reprehenderit occaecat consequat"
              }, {
                "name": "Frazier Lara",
                "image": "https://s3.amazonaws.com/uifaces/faces/twitter/guillogo/73.jpg",
                "shortText": "consectetur culpa adipisicing voluptate enim"
              }]
            }
          },
          iconForItem: function(isSelected) {
            return isSelected ? 'star' : 'star-border';
          },
          _computedClass: function(isSelected) {
            var classes = 'item';
            if (isSelected) {
              classes += ' selected';
            }
            return classes;
          },
          _hiddenChanged: function(hidden) {
            if (!hidden) {
              console.log('firing iron-list.iron-resize');
              this.$.itemsList.fire('iron-resize');
            }
          },
          _unselect: function(e) {
            this.$.itemsList.deselectItem(e.model.item);
          },
          _changeContactList: function() {
            this.push('data', {
              "name": "Shelley Molina",
              "image": "https://s3.amazonaws.com/uifaces/faces/twitter/smalonso/73.jpg",
              "shortText": "laboris do velit ipsum non"
            });
            console.log('Replace data !')
          },
          _toggleHidden: function() {
            this.hidden = !this.hidden;
            console.log('Hidden : ' + this.hidden)
          },
          _onIronResize: function() {
            console.log('Resize');
          }

        });

      });
    </script>
  </dom-module>

</body>

変更された jsbin

于 2016-06-14T01:38:27.130 に答える