docs/source/BufferView.html

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   2 <head>
   3   <title>The source code</title>
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   8     <pre class="prettyprint lang-js">Ext.ns('Ext.ux.grid');
   9
  10 <div id="cls-Ext.ux.grid.BufferView"></div>/**
  11  * @class Ext.ux.grid.BufferView
  12  * @extends Ext.grid.GridView
  13  * A custom GridView which renders rows on an as-needed basis.
  14  */
  15 Ext.ux.grid.BufferView = Ext.extend(Ext.grid.GridView, {
  16         <div id="cfg-Ext.ux.grid.BufferView-rowHeight"></div>/**
  17          * @cfg {Number} rowHeight
  18          * The height of a row in the grid.
  19          */
  20         rowHeight: 19,
  21
  22         <div id="cfg-Ext.ux.grid.BufferView-borderHeight"></div>/**
  23          * @cfg {Number} borderHeight
  24          * The combined height of border-top and border-bottom of a row.
  25          */
  26         borderHeight: 2,
  27
  28         <div id="cfg-Ext.ux.grid.BufferView-scrollDelay"></div>/**
  29          * @cfg {Boolean/Number} scrollDelay
  30          * The number of milliseconds before rendering rows out of the visible
  31          * viewing area. Defaults to 100. Rows will render immediately with a config
  32          * of false.
  33          */
  34         scrollDelay: 100,
  35
  36         <div id="cfg-Ext.ux.grid.BufferView-cacheSize"></div>/**
  37          * @cfg {Number} cacheSize
  38          * The number of rows to look forward and backwards from the currently viewable
  39          * area.  The cache applies only to rows that have been rendered already.
  40          */
  41         cacheSize: 20,
  42
  43         <div id="cfg-Ext.ux.grid.BufferView-cleanDelay"></div>/**
  44          * @cfg {Number} cleanDelay
  45          * The number of milliseconds to buffer cleaning of extra rows not in the
  46          * cache.
  47          */
  48         cleanDelay: 500,
  49
  50         initTemplates : function(){
  51                 Ext.ux.grid.BufferView.superclass.initTemplates.call(this);
  52                 var ts = this.templates;
  53                 // empty div to act as a place holder for a row
  54                 ts.rowHolder = new Ext.Template(
  55                         '<div class="x-grid3-row {alt}" style="{tstyle}"></div>'
  56                 );
  57                 ts.rowHolder.disableFormats = true;
  58                 ts.rowHolder.compile();
  59
  60                 ts.rowBody = new Ext.Template(
  61                         '<table class="x-grid3-row-table" border="0" cellspacing="0" cellpadding="0" style="{tstyle}">',
  62                         '<tbody><tr>{cells}</tr>',
  63                         (this.enableRowBody ? '<tr class="x-grid3-row-body-tr" style="{bodyStyle}"><td colspan="{cols}" class="x-grid3-body-cell" tabIndex="0" hidefocus="on"><div class="x-grid3-row-body">{body}</div></td></tr>' : ''),
  64                         '</tbody></table>'
  65                 );
  66                 ts.rowBody.disableFormats = true;
  67                 ts.rowBody.compile();
  68         },
  69
  70         getStyleRowHeight : function(){
  71                 return Ext.isBorderBox ? (this.rowHeight + this.borderHeight) : this.rowHeight;
  72         },
  73
  74         getCalculatedRowHeight : function(){
  75                 return this.rowHeight + this.borderHeight;
  76         },
  77
  78         getVisibleRowCount : function(){
  79                 var rh = this.getCalculatedRowHeight();
  80                 var visibleHeight = this.scroller.dom.clientHeight;
  81                 return (visibleHeight < 1) ? 0 : Math.ceil(visibleHeight / rh);
  82         },
  83
  84         getVisibleRows: function(){
  85                 var count = this.getVisibleRowCount();
  86                 var sc = this.scroller.dom.scrollTop;
  87                 var start = (sc == 0 ? 0 : Math.floor(sc/this.getCalculatedRowHeight())-1);
  88                 return {
  89                         first: Math.max(start, 0),
  90                         last: Math.min(start + count + 2, this.ds.getCount()-1)
  91                 };
  92         },
  93
  94         doRender : function(cs, rs, ds, startRow, colCount, stripe, onlyBody){
  95                 var ts = this.templates, ct = ts.cell, rt = ts.row, rb = ts.rowBody, last = colCount-1;
  96                 var rh = this.getStyleRowHeight();
  97                 var vr = this.getVisibleRows();
  98                 var tstyle = 'width:'+this.getTotalWidth()+';height:'+rh+'px;';
  99                 // buffers
 100                 var buf = [], cb, c, p = {}, rp = {tstyle: tstyle}, r;
 101                 for (var j = 0, len = rs.length; j < len; j++) {
 102                         r = rs[j]; cb = [];
 103                         var rowIndex = (j+startRow);
 104                         var visible = rowIndex >= vr.first && rowIndex <= vr.last;
 105                         if (visible) {
 106                                 for (var i = 0; i < colCount; i++) {
 107                                         c = cs[i];
 108                                         p.id = c.id;
 109                                         p.css = i == 0 ? 'x-grid3-cell-first ' : (i == last ? 'x-grid3-cell-last ' : '');
 110                                         p.attr = p.cellAttr = "";
 111                                         p.value = c.renderer(r.data[c.name], p, r, rowIndex, i, ds);
 112                                         p.style = c.style;
 113                                         if (p.value == undefined || p.value === "") {
 114                                                 p.value = "&#160;";
 115                                         }
 116                                         if (r.dirty && typeof r.modified[c.name] !== 'undefined') {
 117                                                 p.css += ' x-grid3-dirty-cell';
 118                                         }
 119                                         cb[cb.length] = ct.apply(p);
 120                                 }
 121                         }
 122                         var alt = [];
 123                         if(stripe && ((rowIndex+1) % 2 == 0)){
 124                             alt[0] = "x-grid3-row-alt";
 125                         }
 126                         if(r.dirty){
 127                             alt[1] = " x-grid3-dirty-row";
 128                         }
 129                         rp.cols = colCount;
 130                         if(this.getRowClass){
 131                             alt[2] = this.getRowClass(r, rowIndex, rp, ds);
 132                         }
 133                         rp.alt = alt.join(" ");
 134                         rp.cells = cb.join("");
 135                         buf[buf.length] =  !visible ? ts.rowHolder.apply(rp) : (onlyBody ? rb.apply(rp) : rt.apply(rp));
 136                 }
 137                 return buf.join("");
 138         },
 139
 140         isRowRendered: function(index){
 141                 var row = this.getRow(index);
 142                 return row && row.childNodes.length > 0;
 143         },
 144
 145         syncScroll: function(){
 146                 Ext.ux.grid.BufferView.superclass.syncScroll.apply(this, arguments);
 147                 this.update();
 148         },
 149
 150         // a (optionally) buffered method to update contents of gridview
 151         update: function(){
 152                 if (this.scrollDelay) {
 153                         if (!this.renderTask) {
 154                                 this.renderTask = new Ext.util.DelayedTask(this.doUpdate, this);
 155                         }
 156                         this.renderTask.delay(this.scrollDelay);
 157                 }else{
 158                         this.doUpdate();
 159                 }
 160         },
 161
 162     onRemove : function(ds, record, index, isUpdate){
 163         Ext.ux.grid.BufferView.superclass.onRemove.apply(this, arguments);
 164         if(isUpdate !== true){
 165             this.update();
 166         }
 167     },
 168
 169         doUpdate: function(){
 170                 if (this.getVisibleRowCount() > 0) {
 171                         var g = this.grid, cm = g.colModel, ds = g.store;
 172                         var cs = this.getColumnData();
 173
 174                         var vr = this.getVisibleRows();
 175                         for (var i = vr.first; i <= vr.last; i++) {
 176                                 // if row is NOT rendered and is visible, render it
 177                                 if(!this.isRowRendered(i)){
 178                                         var html = this.doRender(cs, [ds.getAt(i)], ds, i, cm.getColumnCount(), g.stripeRows, true);
 179                                         this.getRow(i).innerHTML = html;
 180                                 }
 181                         }
 182                         this.clean();
 183                 }
 184         },
 185
 186         // a buffered method to clean rows
 187         clean : function(){
 188                 if(!this.cleanTask){
 189                         this.cleanTask = new Ext.util.DelayedTask(this.doClean, this);
 190                 }
 191                 this.cleanTask.delay(this.cleanDelay);
 192         },
 193
 194         doClean: function(){
 195                 if (this.getVisibleRowCount() > 0) {
 196                         var vr = this.getVisibleRows();
 197                         vr.first -= this.cacheSize;
 198                         vr.last += this.cacheSize;
 199
 200                         var i = 0, rows = this.getRows();
 201                         // if first is less than 0, all rows have been rendered
 202                         // so lets clean the end...
 203                         if(vr.first <= 0){
 204                                 i = vr.last + 1;
 205                         }
 206                         for(var len = this.ds.getCount(); i < len; i++){
 207                                 // if current row is outside of first and last and
 208                                 // has content, update the innerHTML to nothing
 209                                 if ((i < vr.first || i > vr.last) && rows[i].innerHTML) {
 210                                         rows[i].innerHTML = '';
 211                                 }
 212                         }
 213                 }
 214         },
 215
 216         layout: function(){
 217                 Ext.ux.grid.BufferView.superclass.layout.call(this);
 218                 this.update();
 219         }
 220 });
 221 </pre>
 222 </body>
 223 </html>