Bollinger Band Width Indicator
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Topic Overview

Purpose

This topic provides a conceptual overview of the IGChartView™ control’s Bollinger Band Width indicator and provides a code example demonstrating how to add it to the chart view.

In this topic


Introduction

Bollinger Band Width indicator summary

The Bollinger Band Width indicator is a financial indicator used in conjunction with the Bollinger Bands Overlay to represent a snapshot of the Bollinger Bands’ width at a given point. The more variation there is, the wider the band. Narrowing bandwidth (lower values) indicates decreases in standard deviation and widening bandwidth (higher values) indicates increasing standard deviation in price. Like the Bollinger Band Overlay, the Bollinger Band Width indicator supports a scaling factor to match their values.

Data requirements

While the IGChartView control allows easy binding to your own data model, make sure to supply the appropriate amounts and types of data required by the series. Failing to do so causes the IGChartView to appear blank.

Required – the data model must contain numeric fields for each, high, low, and closing values in order to render data.


Adding a Bollinger Band Width Indicator to the IGChartView – Code Example

Description

The following code uses the IGOHLCSeriesDataSourceHelper to supply randomly generated data to a financial price series by first adding to the IGChartView instance, then next adding the financial indicator to the IGChartView instance as a series, and then finally adding the IGChartView as a subview of the current UIView.

Prerequisites

This code example requires the inclusion of the IGChartView framework, detail about how to add this framework can be found in the Adding the Chart Framework File topic.

Code

In C#:

List<NSObject> open = new List<NSObject>();
for (int i = 0; i < 25; i++) {
      open.Add(new NSNumber((new Random((int)DateTime.Now.Ticks).Next(100))));
}
List<NSObject> high = new List<NSObject>();
for (int i = 0; i < 25; i++) {
      high.Add(new NSNumber((new Random((int)DateTime.Now.Ticks).Next(130))));
}
List<NSObject> low = new List<NSObject>();
for (int i = 0; i < 25; i++) {
      low.Add(new NSNumber((new Random((int)DateTime.Now.Ticks).Next(100))));
}
List<NSObject> close = new List<NSObject>();
for (int i = 0; i < 25; i++) {
      close.Add(new NSNumber((new Random((int)DateTime.Now.Ticks).Next(110))));
}
List<NSObject> volume = new List<NSObject>();
for (int i = 0; i < 25; i++) {
      volume.Add(new NSNumber((new Random((int)DateTime.Now.Ticks).Next(1100000))));
}
IGOHLCSeriesDataSourceHelper source = new IGOHLCSeriesDataSourceHelper();
source.OpenValues = open.ToArray();
source.HighValues = high.ToArray();
source.LowValues = low.ToArray();
source.CloseValues = close.ToArray();
source.VolumeValues = volume.ToArray();
IGChartView infraChart = new IGChartView(this.View.Frame);
infraChart.AutoresizingMask = UIViewAutoresizing.FlexibleWidth | UIViewAutoresizing.FlexibleHeight;
IGCategoryXAxis xAxis = new IGCategoryXAxis("xAxis");
IGNumericYAxis yAxis = new IGNumericYAxis("yAxis");
infraChart.AddAxis(xAxis);
infraChart.AddAxis(yAxis);
IGFinancialPriceSeries financialPriceSeries = new IGFinancialPriceSeries("financialPriceSeries");
financialPriceSeries.XAxis = xAxis;
financialPriceSeries.YAxis = yAxis;
financialPriceSeries.DataSource = source;
financialPriceSeries.DisplayType = IGPriceDisplayType.IGPriceDisplayTypeCandlestick;
IGBollingerBandWidthIndicator  financialIndicator = new IGBollingerBandWidthIndicator("financialIndicator");
financialIndicator.XAxis = xAxis;
financialIndicator.YAxis = yAxis;
financialIndicator.DataSource = source;
financialIndicator.Thickness = 3.0f;
infraChart.AddSeries(financialPriceSeries);
infraChart.AddSeries(financialIndicator);
(this.View).AddSubview(infraChart);

In Objective-C:

    NSMutableArray *open = [[NSMutableArray alloc] init];
    for (int i = 0; i < 25; i++) {
        [open addObject:[[NSNumber alloc] initWithDouble:(arc4random() % 100)]];
    }
    
    NSMutableArray *high = [[NSMutableArray alloc] init];
    for (int i = 0; i < 25; i++) {
        [high addObject:[[NSNumber alloc] initWithDouble:(arc4random() % 100 + 30)]];
    }
    
    NSMutableArray *low = [[NSMutableArray alloc] init];
    for (int i = 0; i < 25; i++) {
        [low addObject:[[NSNumber alloc] initWithDouble:(arc4random() % 100)]];
    }
    
    NSMutableArray *close = [[NSMutableArray alloc] init];
    for (int i = 0; i < 25; i++) {
        [close addObject:[[NSNumber alloc] initWithDouble:(arc4random() % 100 + 10)]];
    }
    
    NSMutableArray *volume = [[NSMutableArray alloc] init];
    for (int i = 0; i < 25; i++)
    {
        [volume addObject:[[NSNumber alloc] initWithDouble:(arc4random() % 1000000 + 100000)]];
    }
    
    IGOHLCSeriesDataSourceHelper *source = [[IGOHLCSeriesDataSourceHelper alloc] init];
    source.openValues = open;
    source.highValues = high;
    source.lowValues = low;
    source.closeValues = close;
    source.volumeValues = volume;
    
    IGChartView *infraChart = [[IGChartView alloc] initWithFrame:self.view.frame];
    [infraChart setAutoresizingMask:UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight];
    
    IGCategoryXAxis *xAxis = [[IGCategoryXAxis alloc] initWithKey:@"xAxis"];
    IGNumericYAxis *yAxis = [[IGNumericYAxis alloc] initWithKey:@"yAxis"];
    [infraChart addAxis:xAxis];
    [infraChart addAxis:yAxis];
    
    IGFinancialPriceSeries *financialPriceSeries = [[IGFinancialPriceSeries alloc] initWithKey:@"financialPriceSeries"];
    financialPriceSeries.xAxis = xAxis;
    financialPriceSeries.yAxis = yAxis;
    financialPriceSeries.dataSource = source;
    financialPriceSeries.displayType = IGPriceDisplayTypeCandlestick;
    IGBollingerBandWidthIndicator *financialIndicator = [[IGBollingerBandWidthIndicator alloc] initWithKey:@"financialIndicator"];
    financialIndicator.xAxis = xAxis;
    financialIndicator.yAxis = yAxis;
    financialIndicator.dataSource = source;
    financialIndicator.thickness = 3.0f;
    
    [infraChart addSeries:financialPriceSeries];
    [infraChart addSeries:financialIndicator];
    [self.view addSubview:infraChart];

Related Content

Topics

The following topics provide additional information related to this topic.

Topic

Purpose

This collection of topics explains each of the individual charts supported by the IGChartView control.