根据先前选择器的选择更新选择器视图

Question

I am having a picker view which appears upon button clicked. I need to update picker data based on selection of previous picker data.I may need to update picker 3-4 times based on previous picker selection. I tried but can't solve. I referred from MMPickerView library.
I am getting picker on button click. But on selection in picker nothing happens.

Here is my code:

PickerView.h

#import <UIKit/UIKit.h>

extern NSString * const pBackgroundColor;
extern NSString * const pToolbarColor;
extern NSString * const pFont;
extern NSString * const pYValue;
extern NSString * const pSelectedObject;
extern NSString * const pShowsSelectionIndicator;
extern NSString * const pTextAlignment;

@class PickerView;
@protocol PickerViewDelegate <NSObject>

-(void)didSelectTitle:(NSString*)title withPickerView:(PickerView >*)pickerView;
@end

@interface PickerView : UIView<UIPickerViewDelegate, UIPickerViewDataSource>

@property (weak, nonatomic) id<PickerViewDelegate> pickerDelegate;
@property (strong, nonatomic) NSArray *pickerDataArray;
@property (strong, nonatomic) UIPickerView *pickerView;
@property (nonatomic, assign) BOOL pickerViewShowsSelectionIndicator;

+(void)showPickerViewInView: (UIView *)view
                withStrings: (NSArray *)strings
                withOptions: (NSDictionary *)options
                 completion: (void(^)(NSString *selectedString))completion;

+(void)dismissWithCompletion: (void(^)(NSString *))completion;

-(void)reloadPickerView;

@end

PickerView.m

#import "PickerView.h"
NSString * const pBackgroundColor = @"backgroundColor";
NSString * const pToolbarColor = @"toolbarColor";
NSString * const pFont = @"font";
NSString * const pYValue = @"yValueFromTop";
NSString * const pSelectedObject = @"selectedObject";
NSString * const pShowsSelectionIndicator = @"showsSelectionIndicator";
NSString * const pTextAlignment = @"textAlignment";

@interface PickerView()

@property (nonatomic, assign) CGFloat yValueFromTop;
@property (nonatomic, strong) UIView *pickerContainerView;
@property (nonatomic, strong) UIView *pickerViewContainerView;
@property (nonatomic, strong) UIView *pickerTopBarView;
@property (nonatomic, strong) UIToolbar *pickerViewToolBar;
@property (nonatomic, strong) UIBarButtonItem *pickerViewDoneBarButtonItem;
@property (nonatomic, strong) UIBarButtonItem *pickerViewCancelBarButtonItem;
@property (copy) void (^onDismissCompletion)(NSString *);
@property (copy) NSString *(^objectToStringConverter)(id object);
@property (nonatomic, assign) NSInteger pickerViewTextAlignment;

@end

@implementation PickerView

#pragma mark - singleton

+(PickerView *)sharedView {
    static dispatch_once_t once;
    static PickerView *sharedView;
    dispatch_once (&once, ^{sharedView = [[self alloc] init];});
    return  sharedView;
}

+(void)showPickerViewInView:(UIView *)view
                withStrings:(NSArray *)strings
                withOptions:(NSDictionary *)options
                 completion:(void (^)(NSString *))completion{

    [[self sharedView] initializePickerViewInView:view
                                        withArray:strings
                                      withOptions:options];

    [[self sharedView] setPickerHidden:NO callBack:nil];
    [self sharedView].onDismissCompletion = completion;
    [view addSubview:[self sharedView]];

}

-(void)initializePickerViewInView: (UIView *)view
                        withArray: (NSArray *)array
                      withOptions: (NSDictionary *)options {

    _pickerDataArray = array;
    id chosenObject = options[pSelectedObject];
    NSInteger selectedRow = 0;

    if (chosenObject!=nil) {
        selectedRow = [_pickerDataArray indexOfObject:chosenObject];
    }else{
        selectedRow = [[_pickerDataArray objectAtIndex:0] integerValue];
    }

    NSNumber *textAlignment = [[NSNumber alloc] init];
    textAlignment = options[pTextAlignment];
    //Default value is NSTextAlignmentCenter
    _pickerViewTextAlignment = 1;

    if (textAlignment != nil) {
        _pickerViewTextAlignment = [options[pTextAlignment] integerValue];
    }


    BOOL showSelectionIndicator = [options[pShowsSelectionIndicator] boolValue];

    if (!showSelectionIndicator) {
        _pickerViewShowsSelectionIndicator = 1;
    }
    _pickerViewShowsSelectionIndicator = showSelectionIndicator;

    UIColor *pickerViewBackgroundColor = [[UIColor alloc] initWithCGColor:[options[pBackgroundColor] CGColor]];
    UIColor *toolbarBackgroundColor = [[UIColor alloc] initWithCGColor:[options[pToolbarColor] CGColor]];
    UIFont *pickerViewFont = [[UIFont alloc] init];
    pickerViewFont = options[pFont];
    _yValueFromTop = [options[pYValue] floatValue];

    [self setFrame: view.bounds];
    [self setBackgroundColor:[UIColor clearColor]];

    UIImage *toolbarImage = options[toolbarBackgroundColor];

    if (toolbarImage!=nil) {
        [_pickerViewToolBar setBackgroundImage:toolbarImage forToolbarPosition:UIToolbarPositionAny barMetrics:UIBarMetricsDefault];
    }

    //Whole screen with PickerView and a dimmed background
    _pickerViewContainerView = [[UIView alloc] initWithFrame:view.bounds];
    [_pickerViewContainerView setBackgroundColor: [UIColor colorWithRed:0.412 green:0.412 blue:0.412 alpha:0.7]];
    [self addSubview:_pickerViewContainerView];

    //PickerView Container with top bar
    _pickerContainerView = [[UIView alloc] initWithFrame:CGRectMake(0.0, _pickerViewContainerView.bounds.size.height - 260.0, 320.0, 260.0)];

    //Default Color Values (if colors == nil)

    if (pickerViewBackgroundColor==nil) {
        pickerViewBackgroundColor = [UIColor whiteColor];
    }


    _pickerContainerView.backgroundColor = pickerViewBackgroundColor;
    [_pickerViewContainerView addSubview:_pickerContainerView];


    //Content of pickerContainerView

    //Top bar view
    _pickerTopBarView = [[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, _pickerContainerView.frame.size.width, 44.0)];
    [_pickerContainerView addSubview:_pickerTopBarView];
    [_pickerTopBarView setBackgroundColor:[UIColor whiteColor]];


    _pickerViewToolBar = [[UIToolbar alloc] initWithFrame:_pickerTopBarView.frame];
    [_pickerContainerView addSubview:_pickerViewToolBar];

    UIBarButtonItem *flexibleSpace = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];

    _pickerViewDoneBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(dismiss)];
    //    _pickerViewCancelBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(cancelButtonClicked:)];
    _pickerViewToolBar.items = @[flexibleSpace, _pickerViewDoneBarButtonItem];

    //Add pickerView
    _pickerView = [[UIPickerView alloc] initWithFrame:CGRectMake(0.0, 44.0, 320.0, 216.0)];
    _pickerView.frame = CGRectMake(0.0, 44.0, 320.0, 216.0);

    [_pickerView setDelegate:self];
    [_pickerView setDataSource:self];
    [_pickerView setShowsSelectionIndicator: _pickerViewShowsSelectionIndicator];//YES];
    [_pickerContainerView addSubview:_pickerView];

    [_pickerContainerView setTransform:CGAffineTransformMakeTranslation(0.0, CGRectGetHeight(_pickerContainerView.frame))];

    //Set selected row
    [_pickerView selectRow:selectedRow inComponent:0 animated:YES];

}

#pragma mark - Show/hide PickerView methods

-(void)setPickerHidden: (BOOL)hidden
              callBack: (void(^)(NSString *))callBack {

    [UIView animateWithDuration:0.3
                          delay:0.0
                        options:UIViewAnimationOptionCurveEaseOut
                     animations:^{

                         if (hidden) {
                             [_pickerViewContainerView setAlpha:0.0];
                             [_pickerContainerView setTransform:CGAffineTransformMakeTranslation(0.0, CGRectGetHeight(_pickerContainerView.frame))];
                         } else {
                             [_pickerViewContainerView setAlpha:1.0];
                             [_pickerContainerView setTransform:CGAffineTransformIdentity];
                         }
                     } completion:^(BOOL completed) {
                         if(completed && hidden){
                             [PickerView removePickerView];
                             callBack([self selectedObject]);
                         }
                     }];

}

-(void)pickerVwHidden: (BOOL)hidden{


    if (hidden) {
        [_pickerViewContainerView setAlpha:0.0];
        [_pickerContainerView setTransform:CGAffineTransformMakeTranslation(0.0, CGRectGetHeight(_pickerContainerView.frame))];
    } else {
        [_pickerViewContainerView setAlpha:1.0];
        [_pickerContainerView setTransform:CGAffineTransformIdentity];
    }
}

#pragma mark - Dismiss Methods

+(void)dismissWithCompletion:(void (^)(NSString *))completion{
    [[self sharedView] setPickerHidden:YES callBack:completion];
}

-(void)dismiss{
    [PickerView dismissWithCompletion:self.onDismissCompletion];
}

+(void)removePickerView{
    [[self sharedView] removeFromSuperview];
}

#pragma mark - UIPickerViewDataSource

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

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent: (NSInteger)component {
    return [_pickerDataArray count];
}

- (NSString *)pickerView: (UIPickerView *)pickerView
             titleForRow: (NSInteger)row
            forComponent: (NSInteger)component {
    if (self.objectToStringConverter == nil){
        return [_pickerDataArray objectAtIndex:row];
    } else{
        return (self.objectToStringConverter ([_pickerDataArray objectAtIndex:row]));
    }
}

#pragma mark - UIPickerViewDelegate

-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
    NSString *title = [_pickerDataArray objectAtIndex:row];

    if ([_pickerDelegate respondsToSelector:@selector(didSelectTitle:withPickerView:)])  {

    if (self.objectToStringConverter == nil) {
        self.onDismissCompletion ([_pickerDataArray objectAtIndex:row]);
        [self.pickerDelegate didSelectTitle:title withPickerView:self];

    }
    else{

            NSString *title = [_pickerDataArray objectAtIndex:row];
            self.onDismissCompletion (self.objectToStringConverter ([self selectedObject]));
            [self.pickerDelegate didSelectTitle:title withPickerView:self];

        }

    }

}

- (id)selectedObject {
    return [_pickerDataArray objectAtIndex: [self.pickerView selectedRowInComponent:0]];
}

-(void)reloadPickerView
{
    [_pickerView reloadAllComponents];
}

@end

ViewController.h

#import <UIKit/UIKit.h>
#import "PickerView.h"

@interface ViewController : UIViewController <PickerViewDelegate>

@property (strong, nonatomic) IBOutlet UIButton *sellerTypeButton;

@property (nonatomic, strong) NSArray *stringsArray;
@property (nonatomic, strong) NSString * selectedString;
@end

ViewController.m

#import "ViewController.h"

@interface ViewController ()
@property (strong, nonatomic) PickerView *pickrView;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.


}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (IBAction)sellerTypeButtonClicked:(id)sender {


    _stringsArray = @[@"China",@"India",@"Sri Lanka"];
    _selectedString = [_stringsArray objectAtIndex:0];


    [PickerView showPickerViewInView:self.view
                         withStrings:_stringsArray
                         withOptions:@{pBackgroundColor:[UIColor whiteColor],
                                       pSelectedObject:_selectedString,
                                       pToolbarColor:[UIColor whiteColor],
                                       pFont:[UIFont systemFontOfSize:18],
                                       pYValue:@3} completion:^(NSString *selectedString){

                                           [_sellerTypeButton setTitle:selectedString forState:UIControlStateNormal];
                                           _selectedString = selectedString;
                                       }];
}

-(void)didSelectTitle:(NSString*)title withPickerView:(PickerView *)pickerView
{
    if ([_pickrView.pickerDataArray objectAtIndex:1]) {
    _pickrView.pickerDataArray = [NSMutableArray arrayWithObjects:@"Mumbai",@"Kanpur",@"Bangalore", nil];
    }
    [_pickrView reloadPickerView];
}

@end

Answer 1

Simply declare +(PickerView *)sharedView in PickerView.h. Then simply update the pickerDataArray after getting instance from sharedView like

PickerView *_pickerView = [PickerView sharedView];
_pickerView.pickerDataArray = [@"a",@"b",@"c"];
//then reload the picker after updating array
[_pickerView.pickerView reloadAllComponents];