added switch to show on demo the introduced new feature for multiple selection on pie chart

@@ -25,12 +25,13 @@
 @property (weak, nonatomic) IBOutlet UIButton *changeValueButton;
 
 @property (weak, nonatomic) IBOutlet UISwitch *leftSwitch;
+@property (weak, nonatomic) IBOutlet UISwitch *centerSwitch;
 @property (weak, nonatomic) IBOutlet UISwitch *rightSwitch;
 @property (weak, nonatomic) IBOutlet UILabel *leftLabel;
 @property (weak, nonatomic) IBOutlet UILabel *rightLabel;
 
 - (IBAction)rightSwitchChanged:(id)sender;
 - (IBAction)leftSwitchChanged:(id)sender;
-
+- (IBAction)rightSwitchChanged:(id)sender;
 
 @end

@@ -344,6 +344,15 @@
     }
 }
 
+- (IBAction)centerSwitchChanged:(id)sender
+{
+    if (self.pieChart)
+    {
+        [self.pieChart setEnableMultipleSelection:self.centerSwitch.on];
+        [self.pieChart strokeChart];
+    }
+}
+
 - (IBAction)leftSwitchChanged:(id)sender {
     if ([self.title isEqualToString:@"Pie Chart"]){
         UISwitch *showRelative = (UISwitch*) sender;