Ext.ns('Ext.ux.grid');

/** * @class Ext.ux.grid.BufferView * @extends Ext.grid.GridView * A custom GridView which renders rows on an as-needed basis. */ Ext.ux.grid.BufferView = Ext.extend(Ext.grid.GridView, {
/** * @cfg {Number} rowHeight * The height of a row in the grid. */ rowHeight: 19,
/** * @cfg {Number} borderHeight * The combined height of border-top and border-bottom of a row. */ borderHeight: 2,
/** * @cfg {Boolean/Number} scrollDelay * The number of milliseconds before rendering rows out of the visible * viewing area. Defaults to 100. Rows will render immediately with a config * of false. */ scrollDelay: 100,
/** * @cfg {Number} cacheSize * The number of rows to look forward and backwards from the currently viewable * area. The cache applies only to rows that have been rendered already. */ cacheSize: 20,
/** * @cfg {Number} cleanDelay * The number of milliseconds to buffer cleaning of extra rows not in the * cache. */ cleanDelay: 500, initTemplates : function(){ Ext.ux.grid.BufferView.superclass.initTemplates.call(this); var ts = this.templates; // empty div to act as a place holder for a row ts.rowHolder = new Ext.Template( '
' ); ts.rowHolder.disableFormats = true; ts.rowHolder.compile(); ts.rowBody = new Ext.Template( '', '{cells}', (this.enableRowBody ? '' : ''), '
{body}
' ); ts.rowBody.disableFormats = true; ts.rowBody.compile(); }, getStyleRowHeight : function(){ return Ext.isBorderBox ? (this.rowHeight + this.borderHeight) : this.rowHeight; }, getCalculatedRowHeight : function(){ return this.rowHeight + this.borderHeight; }, getVisibleRowCount : function(){ var rh = this.getCalculatedRowHeight(); var visibleHeight = this.scroller.dom.clientHeight; return (visibleHeight < 1) ? 0 : Math.ceil(visibleHeight / rh); }, getVisibleRows: function(){ var count = this.getVisibleRowCount(); var sc = this.scroller.dom.scrollTop; var start = (sc == 0 ? 0 : Math.floor(sc/this.getCalculatedRowHeight())-1); return { first: Math.max(start, 0), last: Math.min(start + count + 2, this.ds.getCount()-1) }; }, doRender : function(cs, rs, ds, startRow, colCount, stripe, onlyBody){ var ts = this.templates, ct = ts.cell, rt = ts.row, rb = ts.rowBody, last = colCount-1; var rh = this.getStyleRowHeight(); var vr = this.getVisibleRows(); var tstyle = 'width:'+this.getTotalWidth()+';height:'+rh+'px;'; // buffers var buf = [], cb, c, p = {}, rp = {tstyle: tstyle}, r; for (var j = 0, len = rs.length; j < len; j++) { r = rs[j]; cb = []; var rowIndex = (j+startRow); var visible = rowIndex >= vr.first && rowIndex <= vr.last; if (visible) { for (var i = 0; i < colCount; i++) { c = cs[i]; p.id = c.id; p.css = i == 0 ? 'x-grid3-cell-first ' : (i == last ? 'x-grid3-cell-last ' : ''); p.attr = p.cellAttr = ""; p.value = c.renderer(r.data[c.name], p, r, rowIndex, i, ds); p.style = c.style; if (p.value == undefined || p.value === "") { p.value = " "; } if (r.dirty && typeof r.modified[c.name] !== 'undefined') { p.css += ' x-grid3-dirty-cell'; } cb[cb.length] = ct.apply(p); } } var alt = []; if(stripe && ((rowIndex+1) % 2 == 0)){ alt[0] = "x-grid3-row-alt"; } if(r.dirty){ alt[1] = " x-grid3-dirty-row"; } rp.cols = colCount; if(this.getRowClass){ alt[2] = this.getRowClass(r, rowIndex, rp, ds); } rp.alt = alt.join(" "); rp.cells = cb.join(""); buf[buf.length] = !visible ? ts.rowHolder.apply(rp) : (onlyBody ? rb.apply(rp) : rt.apply(rp)); } return buf.join(""); }, isRowRendered: function(index){ var row = this.getRow(index); return row && row.childNodes.length > 0; }, syncScroll: function(){ Ext.ux.grid.BufferView.superclass.syncScroll.apply(this, arguments); this.update(); }, // a (optionally) buffered method to update contents of gridview update: function(){ if (this.scrollDelay) { if (!this.renderTask) { this.renderTask = new Ext.util.DelayedTask(this.doUpdate, this); } this.renderTask.delay(this.scrollDelay); }else{ this.doUpdate(); } }, doUpdate: function(){ if (this.getVisibleRowCount() > 0) { var g = this.grid, cm = g.colModel, ds = g.store; var cs = this.getColumnData(); var vr = this.getVisibleRows(); for (var i = vr.first; i <= vr.last; i++) { // if row is NOT rendered and is visible, render it if(!this.isRowRendered(i)){ var html = this.doRender(cs, [ds.getAt(i)], ds, i, cm.getColumnCount(), g.stripeRows, true); this.getRow(i).innerHTML = html; } } this.clean(); } }, // a buffered method to clean rows clean : function(){ if(!this.cleanTask){ this.cleanTask = new Ext.util.DelayedTask(this.doClean, this); } this.cleanTask.delay(this.cleanDelay); }, doClean: function(){ if (this.getVisibleRowCount() > 0) { var vr = this.getVisibleRows(); vr.first -= this.cacheSize; vr.last += this.cacheSize; var i = 0, rows = this.getRows(); // if first is less than 0, all rows have been rendered // so lets clean the end... if(vr.first <= 0){ i = vr.last + 1; } for(var len = this.ds.getCount(); i < len; i++){ // if current row is outside of first and last and // has content, update the innerHTML to nothing if ((i < vr.first || i > vr.last) && rows[i].innerHTML) { rows[i].innerHTML = ''; } } } }, layout: function(){ Ext.ux.grid.BufferView.superclass.layout.call(this); this.update(); } });