如何在Core-Plot iphone中动态更改BarChart的值？ [英] How can i change the values to BarChart dynamically in Core-Plot iphone?

问题描述

我正在使用Core-Plot库在iPhone中绘制条形图。我正在使用 CPTTestApp-iPhone 进行培训。在我的项目中，酒吧看起来非常好，看起来像样品项目。但是，我不需要给出值来绘制酒吧。然后，在我的实际项目中，我需要动态地改变条形值。我该怎么办？请帮我找出解决方案。提前致谢。下面的示例数据源代码

I am using Core-Plot library to draw bar chart in iPhone. I am using CPTTestApp-iPhone to my training. In my project the bar appear very good thats looks like from the sample project. But, i dont where i need to give the values to draw the bars. Then, in my actual project i need to change the bar values dynamically. How can i do this? Please help me to find out the solution. Thanks in advance. Below the sample datasource code,

#pragma mark -
#pragma mark Plot Data Source Methods

-(NSUInteger)numberOfRecordsForPlot:(CPTPlot *)plot 
{
    return 10;
}

-(NSNumber *)numberForPlot:(CPTPlot *)plot field:(NSUInteger)fieldEnum recordIndex:(NSUInteger)index 
{
    NSDecimalNumber *num = nil;
    if ( [plot isKindOfClass:[CPTBarPlot class]] ) 
    {
        switch ( fieldEnum ) 
        {
            case CPTBarPlotFieldBarLocation:
                num = (NSDecimalNumber *)[NSDecimalNumber numberWithUnsignedInteger:index];
                break;
            case CPTBarPlotFieldBarTip:
                num = (NSDecimalNumber *)[NSDecimalNumber numberWithUnsignedInteger:(index+1)*(index+1)];
                if ( [plot.identifier isEqual:@"Bar Plot 2"] ) 
                    num = [num decimalNumberBySubtracting:[NSDecimalNumber decimalNumberWithString:@"10"]];//10
                break;
        }
    }

    return num;
}

-(CPTFill *) barFillForBarPlot:(CPTBarPlot *)barPlot recordIndex:(NSNumber *)index; 
{
    return nil;
}

如何在coreplot iPhone中增加条长度？谢谢。

How to increment the bar length in coreplot iPhone? Thanks.

推荐答案

核心绘图将在首次显示时从数据源请求其数据。您可以强制以多种方式加载新数据：

A Core Plot plot will request its data from the datasource when it is first displayed. You can force it to load new data in several ways:

1. 调用 -reloadData 在图表上重新加载所有的图。


2. 在图上调用 -reloadData ，以重新加载所有图形的所有数据。 / li>
   
3. 在图上调用 -reloadDataInIndexRange：，以重新加载一系列数据索引，而不更改数据点的总数。


4. 调用 -insertDataAtIndex：numberOfRecords：在给定的索引中插入新数据。更高指数的任何数据将被移动以腾出空间。

1. Call -reloadData on the graph to reload all plots.
2. Call -reloadData on the plot to reload all of the data for only that plot.
3. Call -reloadDataInIndexRange: on the plot to reload a range of data indices without changing the total number of data points.
4. Call -insertDataAtIndex:numberOfRecords: to insert new data at the given index. Any data at higher indices will be moved to make room. Only the new data will be requested from the datasource.

您还可以从图形中删除数据，而无需使用 -deleteDataInIndexRange：方法。

You can also remove data from the plot without reloading anything by using the -deleteDataInIndexRange: method.

顾名思义， -numberOfRecordsForPlot：方法告诉绘图将绘制多少数据点。将调用 -numberForPlot：field：recordIndex：方法来加载实际的数据值。它被称为字段（位置和提示）和数据索引的每个组合。

As the name implies, the -numberOfRecordsForPlot: method tells the plot how many data points will be plotted. The -numberForPlot:field:recordIndex: method will be called to load the actual data values. It gets called for each combination of field (location and tip) and data index.

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