新手求助！extjs4 chart的问题
在学习extjs的chart,用他给的demo都没问题。尝试
数据是这样的格式的[{"speed1" : "71","num" : "10"}]
甚至点击点的时候，都可以读出speed1来。
但是为什么显示不正常呢？
代码如下：
Ext.require('Ext.chart.*');Ext.require(['Ext.Window', 'Ext.fx.target.Sprite', 'Ext.layout.container.Fit', 'Ext.window.MessageBox']);Ext.onReady(function () { window.store1 = Ext.create('Ext.data.JsonStore', { fields : ['speed1', 'num'], data : [{ "speed1" : "71", "num" : "10" }, { "speed1" : "63", "num" : "11" }, { "speed1" : "77", "num" : "12" }, { "speed1" : "85", "num" : "13" }, { "speed1" : "79", "num" : "14" } ] }); var chart = Ext.create('Ext.chart.Chart', { xtype: 'chart', style: 'background:#fff', animate: true, store: store1, shadow: true, theme: 'Category1', legend: { position: 'right' }, axes: [{ type: 'Numeric', minimum: 0, position: 'left', fields: ['speed1'], title: 'Number of Hits', // minorTickSteps: 1, grid: { odd: { opacity: 1, fill: '#ddd', stroke: '#bbb', 'stroke-width': 0.5 } } }, { type: 'Category', position: 'bottom', fields: ['num'], title: 'Month of the Year' }], series: [{ type: 'line', highlight: { size: 20, radius: 7 }, tips: { trackMouse: true, width: 80, height: 40, renderer: function(storeItem, item) { this.setTitle(storeItem.get('num')); this.update(storeItem.get('speed1')); } }, axis: 'left', // smooth: true,//平滑线条 fill: true,//填充面积 xField: ['num'], yField: ['speed1'], markerConfig: { type: 'circle',//cross是叉叉，这个是圆圈 size: 4, radius: 4, 'stroke-width': 0 } }] }); var win = Ext.create('Ext.Window', { width: 800, height: 600, minHeight: 400, minWidth: 550, hidden: false, maximizable: true, title: 'Line Chart', renderTo: Ext.getBody(), layout: 'fit', tbar: [{ text: 'Save Chart', handler: function() { Ext.MessageBox.confirm('Confirm Download', 'Would you like to download the chart as an image?', function(choice){ if(choice == 'yes'){ chart.save({ type: 'image/png' }); } }); } }], items: chart });});