title: Adding multiple subviews to a UIView
body: <p>I'm using an iOS charting software called TWRCharts, and I'm trying to add multiple charts in the same view controller. I have added UIViews using Interface Builder, and connected them using outlets in my .h file. When I try showing one chart, my main chart, it shows fine. But when I try adding more charts, they don't appear. I have tried reversing the order of chart drawing, and in this case one of the smaller charts appears, but nothing else. When I try adding multiple subviews to their respective views, nothing appears. Here are my .h and .m files.</p>
  
  <p>.h</p>
  
  <pre><code>#import &lt;UIKit/UIKit.h&gt;
  #import "TWRChart.h"
  
  @interface OverviewViewController : UIViewController
  
  - (IBAction)didTapButton:(id)sender;
  
  @property (strong, nonatomic) IBOutlet UIView *mainCircularChartUIView;
  @property (strong, nonatomic) TWRChartView *mainCircularChart;
  
  @property (strong, nonatomic) IBOutlet UIView *tapTestCircularChartUIView;
  @property (strong, nonatomic) TWRChartView *tapTestCircularChart;
  
  @property (strong, nonatomic) IBOutlet UIView *cogTestCircularChartUIView;
  @property (strong, nonatomic) TWRChartView *cogTestCircularChart;
  
  @property (strong, nonatomic) IBOutlet UIView *voiceTestCircularChartUIView;
  @property (strong, nonatomic) TWRChartView *voiceTestCircularChart;
  
  @property (strong, nonatomic) IBOutlet UIView *mentalHealthTestControllerUIView;
  @property (strong, nonatomic) TWRChartView *mentalHealthTestController;
  
  @end
  </code></pre>
  
  <p>.m (currently commenting out adding more than one subview)</p>
  
  <pre><code>- (void)viewDidLoad {
  [super viewDidLoad];
  
  /////////// Main Circular Chart View ////////////////////////
  self.mainCircularChart = [[TWRChartView alloc] initWithFrame:CGRectMake(0, 60, 300, 300)];
  self.mainCircularChart.backgroundColor = [UIColor clearColor];
  self.mainCircularChart.userInteractionEnabled = YES;
  
  // Add the chart view to the controller's view
  [self.mainCircularChartUIView addSubview:self.mainCircularChart];
  
  /////////// Sub Circular Chart Views ////////////////////////
  self.tapTestCircularChart = [[TWRChartView alloc] initWithFrame:CGRectMake(0, 0, 75, 75)];
  self.tapTestCircularChart.backgroundColor = [UIColor clearColor];
  self.tapTestCircularChart.userInteractionEnabled = YES;
  
  self.cogTestCircularChart = [[TWRChartView alloc] initWithFrame:CGRectMake(0, 0, 75, 75)];
  self.cogTestCircularChart.backgroundColor = [UIColor clearColor];
  self.cogTestCircularChart.userInteractionEnabled = YES;
  
  // Add the chart view to the controller's view
  //    [self.tapTestCircularChartUIView addSubview:self.tapTestCircularChart];
  //    [self.cogTestCircularChartUIView addSubview:self.cogTestCircularChart];
  
  [self loadMainCircularChart];
  [self loadSubCircularCharts];
  }
  
  - (void)loadSubCircularCharts {
  // Values
  NSArray *values = @[@20, @30, @15, @5];
  
  // Colors
  UIColor *color1 = [UIColor colorWithHue:0.5 saturation:0.6 brightness:0.6 alpha:1.0];
  UIColor *color2 = [UIColor colorWithHue:0.6 saturation:0.6 brightness:0.6 alpha:1.0];
  UIColor *color3 = [UIColor colorWithHue:0.7 saturation:0.6 brightness:0.6 alpha:1.0];
  UIColor *color4 = [UIColor colorWithHue:0.8 saturation:0.6 brightness:0.6 alpha:1.0];
  NSArray *colors = @[color1, color2, color3, color4];
  
  
  // Tap Test Chart ///////////////////////////////////////////
  TWRCircularChart *tapTestChart = [[TWRCircularChart alloc] initWithValues:values colors:colors type:TWRCircularChartTypeDoughnut animated:YES];
  
  [self.tapTestCircularChart loadCircularChart:tapTestChart];
  
  // Cog Test Chart ///////////////////////////////////////////
  TWRCircularChart *cogTestChart = [[TWRCircularChart alloc] initWithValues:values colors:colors type:TWRCircularChartTypeDoughnut animated:YES];
  //
  [self.tapTestCircularChart loadCircularChart:cogTestChart];
  
  }
  
  - (void)loadMainCircularChart {
  // Values
  NSArray *values = @[@20, @30, @15, @5];
  
  // Colors
  UIColor *color1 = [UIColor colorWithHue:0.5 saturation:0.6 brightness:0.6 alpha:1.0];
  UIColor *color2 = [UIColor colorWithHue:0.6 saturation:0.6 brightness:0.6 alpha:1.0];
  UIColor *color3 = [UIColor colorWithHue:0.7 saturation:0.6 brightness:0.6 alpha:1.0];
  UIColor *color4 = [UIColor colorWithHue:0.8 saturation:0.6 brightness:0.6 alpha:1.0];
  NSArray *colors = @[color1, color2, color3, color4];
  
  // Doughnut Chart
  TWRCircularChart *pieChart = [[TWRCircularChart alloc] initWithValues:values colors:colors type:TWRCircularChartTypeDoughnut animated:YES];
  
  [self.mainCircularChart loadCircularChart:pieChart];
  
  }
  </code></pre>