examples/ux/BufferView.js

   1 /*!
   2  * Ext JS Library 3.2.1
   3  * Copyright(c) 2006-2010 Ext JS, Inc.
   4  * licensing@extjs.com
   5  * http://www.extjs.com/license
   6  */
   7 Ext.ns('Ext.ux.grid');
   8
   9 /**
  10  * @class Ext.ux.grid.BufferView
  11  * @extends Ext.grid.GridView
  12  * A custom GridView which renders rows on an as-needed basis.
  13  */
  14 Ext.ux.grid.BufferView = Ext.extend(Ext.grid.GridView, {
  15         /**
  16          * @cfg {Number} rowHeight
  17          * The height of a row in the grid.
  18          */
  19         rowHeight: 19,
  20
  21         /**
  22          * @cfg {Number} borderHeight
  23          * The combined height of border-top and border-bottom of a row.
  24          */
  25         borderHeight: 2,
  26
  27         /**
  28          * @cfg {Boolean/Number} scrollDelay
  29          * The number of milliseconds before rendering rows out of the visible
  30          * viewing area. Defaults to 100. Rows will render immediately with a config
  31          * of false.
  32          */
  33         scrollDelay: 100,
  34
  35         /**
  36          * @cfg {Number} cacheSize
  37          * The number of rows to look forward and backwards from the currently viewable
  38          * area.  The cache applies only to rows that have been rendered already.
  39          */
  40         cacheSize: 20,
  41
  42         /**
  43          * @cfg {Number} cleanDelay
  44          * The number of milliseconds to buffer cleaning of extra rows not in the
  45          * cache.
  46          */
  47         cleanDelay: 500,
  48
  49         initTemplates : function(){
  50                 Ext.ux.grid.BufferView.superclass.initTemplates.call(this);
  51                 var ts = this.templates;
  52                 // empty div to act as a place holder for a row
  53                 ts.rowHolder = new Ext.Template(
  54                         '<div class="x-grid3-row {alt}" style="{tstyle}"></div>'
  55                 );
  56                 ts.rowHolder.disableFormats = true;
  57                 ts.rowHolder.compile();
  58
  59                 ts.rowBody = new Ext.Template(
  60                         '<table class="x-grid3-row-table" border="0" cellspacing="0" cellpadding="0" style="{tstyle}">',
  61                         '<tbody><tr>{cells}</tr>',
  62                         (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>' : ''),
  63                         '</tbody></table>'
  64                 );
  65                 ts.rowBody.disableFormats = true;
  66                 ts.rowBody.compile();
  67         },
  68
  69         getStyleRowHeight : function(){
  70                 return Ext.isBorderBox ? (this.rowHeight + this.borderHeight) : this.rowHeight;
  71         },
  72
  73         getCalculatedRowHeight : function(){
  74                 return this.rowHeight + this.borderHeight;
  75         },
  76
  77         getVisibleRowCount : function(){
  78                 var rh = this.getCalculatedRowHeight(),
  79                     visibleHeight = this.scroller.dom.clientHeight;
  80                 return (visibleHeight < 1) ? 0 : Math.ceil(visibleHeight / rh);
  81         },
  82
  83         getVisibleRows: function(){
  84                 var count = this.getVisibleRowCount(),
  85                     sc = this.scroller.dom.scrollTop,
  86                     start = (sc === 0 ? 0 : Math.floor(sc/this.getCalculatedRowHeight())-1);
  87                 return {
  88                         first: Math.max(start, 0),
  89                         last: Math.min(start + count + 2, this.ds.getCount()-1)
  90                 };
  91         },
  92
  93         doRender : function(cs, rs, ds, startRow, colCount, stripe, onlyBody){
  94                 var ts = this.templates,
  95             ct = ts.cell,
  96             rt = ts.row,
  97             rb = ts.rowBody,
  98             last = colCount-1,
  99                     rh = this.getStyleRowHeight(),
 100                     vr = this.getVisibleRows(),
 101                     tstyle = 'width:'+this.getTotalWidth()+';height:'+rh+'px;',
 102                     // buffers
 103                     buf = [],
 104             cb,
 105             c,
 106             p = {},
 107             rp = {tstyle: tstyle},
 108             r;
 109                 for (var j = 0, len = rs.length; j < len; j++) {
 110                         r = rs[j]; cb = [];
 111                         var rowIndex = (j+startRow),
 112                             visible = rowIndex >= vr.first && rowIndex <= vr.last;
 113                         if (visible) {
 114                                 for (var i = 0; i < colCount; i++) {
 115                                         c = cs[i];
 116                                         p.id = c.id;
 117                                         p.css = i === 0 ? 'x-grid3-cell-first ' : (i == last ? 'x-grid3-cell-last ' : '');
 118                                         p.attr = p.cellAttr = "";
 119                                         p.value = c.renderer(r.data[c.name], p, r, rowIndex, i, ds);
 120                                         p.style = c.style;
 121                                         if (p.value === undefined || p.value === "") {
 122                                                 p.value = "&#160;";
 123                                         }
 124                                         if (r.dirty && typeof r.modified[c.name] !== 'undefined') {
 125                                                 p.css += ' x-grid3-dirty-cell';
 126                                         }
 127                                         cb[cb.length] = ct.apply(p);
 128                                 }
 129                         }
 130                         var alt = [];
 131                         if(stripe && ((rowIndex+1) % 2 === 0)){
 132                             alt[0] = "x-grid3-row-alt";
 133                         }
 134                         if(r.dirty){
 135                             alt[1] = " x-grid3-dirty-row";
 136                         }
 137                         rp.cols = colCount;
 138                         if(this.getRowClass){
 139                             alt[2] = this.getRowClass(r, rowIndex, rp, ds);
 140                         }
 141                         rp.alt = alt.join(" ");
 142                         rp.cells = cb.join("");
 143                         buf[buf.length] =  !visible ? ts.rowHolder.apply(rp) : (onlyBody ? rb.apply(rp) : rt.apply(rp));
 144                 }
 145                 return buf.join("");
 146         },
 147
 148         isRowRendered: function(index){
 149                 var row = this.getRow(index);
 150                 return row && row.childNodes.length > 0;
 151         },
 152
 153         syncScroll: function(){
 154                 Ext.ux.grid.BufferView.superclass.syncScroll.apply(this, arguments);
 155                 this.update();
 156         },
 157
 158         // a (optionally) buffered method to update contents of gridview
 159         update: function(){
 160                 if (this.scrollDelay) {
 161                         if (!this.renderTask) {
 162                                 this.renderTask = new Ext.util.DelayedTask(this.doUpdate, this);
 163                         }
 164                         this.renderTask.delay(this.scrollDelay);
 165                 }else{
 166                         this.doUpdate();
 167                 }
 168         },
 169
 170     onRemove : function(ds, record, index, isUpdate){
 171         Ext.ux.grid.BufferView.superclass.onRemove.apply(this, arguments);
 172         if(isUpdate !== true){
 173             this.update();
 174         }
 175     },
 176
 177         doUpdate: function(){
 178                 if (this.getVisibleRowCount() > 0) {
 179                         var g = this.grid,
 180                 cm = g.colModel,
 181                 ds = g.store,
 182                 cs = this.getColumnData(),
 183                         vr = this.getVisibleRows(),
 184                 row;
 185                         for (var i = vr.first; i <= vr.last; i++) {
 186                                 // if row is NOT rendered and is visible, render it
 187                                 if(!this.isRowRendered(i) && (row = this.getRow(i))){
 188                                         var html = this.doRender(cs, [ds.getAt(i)], ds, i, cm.getColumnCount(), g.stripeRows, true);
 189                                         row.innerHTML = html;
 190                                 }
 191                         }
 192                         this.clean();
 193                 }
 194         },
 195
 196         // a buffered method to clean rows
 197         clean : function(){
 198                 if(!this.cleanTask){
 199                         this.cleanTask = new Ext.util.DelayedTask(this.doClean, this);
 200                 }
 201                 this.cleanTask.delay(this.cleanDelay);
 202         },
 203
 204         doClean: function(){
 205                 if (this.getVisibleRowCount() > 0) {
 206                         var vr = this.getVisibleRows();
 207                         vr.first -= this.cacheSize;
 208                         vr.last += this.cacheSize;
 209
 210                         var i = 0, rows = this.getRows();
 211                         // if first is less than 0, all rows have been rendered
 212                         // so lets clean the end...
 213                         if(vr.first <= 0){
 214                                 i = vr.last + 1;
 215                         }
 216                         for(var len = this.ds.getCount(); i < len; i++){
 217                                 // if current row is outside of first and last and
 218                                 // has content, update the innerHTML to nothing
 219                                 if ((i < vr.first || i > vr.last) && rows[i].innerHTML) {
 220                                         rows[i].innerHTML = '';
 221                                 }
 222                         }
 223                 }
 224         },
 225
 226     removeTask: function(name){
 227         var task = this[name];
 228         if(task && task.cancel){
 229             task.cancel();
 230             this[name] = null;
 231         }
 232     },
 233
 234     destroy : function(){
 235         this.removeTask('cleanTask');
 236         this.removeTask('renderTask');
 237         Ext.ux.grid.BufferView.superclass.destroy.call(this);
 238     },
 239
 240         layout: function(){
 241                 Ext.ux.grid.BufferView.superclass.layout.call(this);
 242                 this.update();
 243         }
 244 });