RCDropdown.h

#import <UIKit/UIKit.h>

@interface RCDropdown : UITextField

@property (nonatomic) id<UIPickerViewDelegate> pickerDelegate;
@property (nonatomic) id<UIPickerViewDataSource> pickerDataSource;

@end

RCDropdown.m

#import "RCDropdown.h"
#import "RCDropdownArrowView.h"

@implementation RCDropdown {
    UIPickerView* _pickerView;
}

-(id)initWithCoder:(NSCoder *)aDecoder {
    if(self = [super initWithCoder:aDecoder]) {
        
        // The leftView is optional, but I like a little padding.
        // You may also want to subclass this into your own UITextField
        self.leftView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 5, 20)];
        self.leftViewMode = UITextFieldViewModeAlways;
        
        self.layer.borderColor = [[UIColor colorWithRed: 0.827 green: 0.827 blue: 0.827 alpha: 1] CGColor];;
        self.layer.borderWidth= 1.0f;

        self.rightView = [RCDropdownArrowView default];
        self.rightViewMode = UITextFieldViewModeAlways;
        
        _pickerView  = [[UIPickerView alloc] initWithFrame:CGRectZero];
        _pickerView.showsSelectionIndicator = YES;
        self.inputView = _pickerView;
    }
    
    return self;
}

-(void)setTag:(NSInteger)tag {
    [super setTag:tag];
    _pickerView.tag = tag;
}

-(void)setPickerDelegate:(id<UIPickerViewDelegate>)pickerDelegate {
    _pickerView.delegate = pickerDelegate;
}

-(void)setPickerDataSource:(id<UIPickerViewDataSource>)pickerDataSource {
    _pickerView.dataSource = pickerDataSource;
}

@end

RCDropdownArrowView.h

#import <UIKit/UIKit.h>

// This view is used to draw an arrow for the rightView within the UITextField

@interface RCDropdownArrowView : UIView

+(RCDropdownArrowView*) default;

@end

RCDropdownArrowView.m

#import "RCDropdownArrowView.h"

@implementation RCDropdownArrowView

+(RCDropdownArrowView*) default {
    
    RCDropdownArrowView* view = [[RCDropdownArrowView alloc] initWithFrame:CGRectMake(0, 0, 31, 28)];
    view.backgroundColor = [UIColor whiteColor];
    return view;
    
}

- (void)drawRect:(CGRect)rect {
    
    //// Color Declarations
    UIColor* strokeColor = [UIColor colorWithRed: 0.827 green: 0.827 blue: 0.827 alpha: 1];
    
    //// Frames
    CGRect frame = self.bounds;
    
    //// Bezier Drawing
    UIBezierPath* bezierPath = [UIBezierPath bezierPath];
    [bezierPath moveToPoint: CGPointMake(CGRectGetMinX(frame) + 24.82, CGRectGetMinY(frame) + 8.08)];
    [bezierPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 25.98, CGRectGetMinY(frame) + 9.25)];
    [bezierPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 17.01, CGRectGetMinY(frame) + 18.22)];
    [bezierPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 17.01, CGRectGetMinY(frame) + 18.22)];
    [bezierPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 15.85, CGRectGetMinY(frame) + 19.38)];
    [bezierPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 15.85, CGRectGetMinY(frame) + 19.38)];
    [bezierPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 15.85, CGRectGetMinY(frame) + 19.38)];
    [bezierPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 14.68, CGRectGetMinY(frame) + 18.22)];
    [bezierPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 14.68, CGRectGetMinY(frame) + 18.22)];
    [bezierPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 5.71, CGRectGetMinY(frame) + 9.25)];
    [bezierPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 6.88, CGRectGetMinY(frame) + 8.08)];
    [bezierPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 15.85, CGRectGetMinY(frame) + 17.05)];
    [bezierPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 24.82, CGRectGetMinY(frame) + 8.08)];
    [bezierPath closePath];
    bezierPath.miterLimit = 4;
    
    bezierPath.usesEvenOddFillRule = YES;
    
    [strokeColor setFill];
    [bezierPath fill];
    
    
    //// Bezier 2 Drawing
    UIBezierPath* bezier2Path = [UIBezierPath bezierPath];
    [bezier2Path moveToPoint: CGPointMake(CGRectGetMinX(frame) + 0.5, CGRectGetMinY(frame) + 28)];
    [bezier2Path addCurveToPoint: CGPointMake(CGRectGetMinX(frame) + 0.5, CGRectGetMinY(frame)) controlPoint1: CGPointMake(CGRectGetMinX(frame) + 0.5, CGRectGetMinY(frame)) controlPoint2: CGPointMake(CGRectGetMinX(frame) + 0.5, CGRectGetMinY(frame))];
    [strokeColor setStroke];
    bezier2Path.lineWidth = 1;
    [bezier2Path stroke];
    
    
    //// Bezier 3 Drawing
    UIBezierPath* bezier3Path = [UIBezierPath bezierPath];
    [bezier3Path moveToPoint: CGPointMake(CGRectGetMinX(frame) + 31, CGRectGetMinY(frame) + 28)];
    [bezier3Path addCurveToPoint: CGPointMake(CGRectGetMinX(frame) + 31, CGRectGetMinY(frame)) controlPoint1: CGPointMake(CGRectGetMinX(frame) + 31, CGRectGetMinY(frame)) controlPoint2: CGPointMake(CGRectGetMinX(frame) + 31, CGRectGetMinY(frame))];
    [strokeColor setStroke];
    bezier3Path.lineWidth = 1;
    [bezier3Path stroke];
    
}

RCRegisterViewController.m

#import "RCRegisterViewController.h"

@interface RCRegisterViewController () {
    NSArray* _titleSelectionData;
}

- (void)viewDidLoad {  
  
    _titleSelectionData = [NSArray arrayWithObjects:@"", @"Mr", @"Ms", @"Mrs", @"Miss", @"Dr", nil];
    
    _titleTextField.pickerDelegate = self;
    _titleTextField.pickerDataSource = self;
    _titleTextField.tag = 1;
}

-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
    if(pickerView.tag == 1) _titleTextField.text = [_titleSelectionData objectAtIndex:row];
}

-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
    return 1;
}

-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
    return _titleSelectionData.count;
}

-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
    return [_titleSelectionData objectAtIndex:row];
}