Generic or Single uipickerview to show in multiple viewControllers

Question

I want to know how can i make a generic/single UIPickerView to display in multiple ViewControllers.

I want to show a pickerView in multiple ViewController. Now how can i create it.

I know how to create it like implement and write its delegate for it..

But i don't want to create these delegate in each class and write those method again and agian..

What have i done..

I have created a new File and inherit it with UIPickerView. and create an NSArray property to show in it. and also implemented its delegate but now onward don't know how to do it .

Show me some sort of example to make a generic UIPickerView or help me creating it..

Answer 1

One way to do this would be to create a class with a completion handler that creates the picker and acts as its data source and delegate. For example, in the .h file, you could do something like this,

typedef void(^completionHandler) (NSString *selectedString);

@interface RDPickerController : NSObject <UIPickerViewDataSource, UIPickerViewDelegate>

@property (strong,nonatomic) UIPickerView *picker;

-(instancetype)initWithCompletionHandler:(completionHandler) completion;

In the .m file, implement any of the data source and delegate methods that you need, and call the completion block in the pickerView:didSelectRow:inComponent: method,

@interface RDPickerController ()
@property (strong,nonatomic) NSArray *data;
@property (copy,nonatomic) completionHandler compBlock;
@end

@implementation RDPickerController


-(instancetype)initWithCompletionHandler:(completionHandler)completion {
    if (self = [super init]) {
        _picker = [UIPickerView new];
        _picker.delegate = self;
        _picker.dataSource = self;
        _data = @[@"One", @"Two", @"Three", @"Four", @"Five", @"Six", @"Seven", @"Eight", @"Nine", @"Ten"];
        _compBlock = completion;
    }
    return self;
}


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


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


-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
    return self.data[row];
}


-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
    self.compBlock(self.data[row]);
}

In your controller classes, you can create and use the picker like this,

@interface ViewController ()
@property (strong,nonatomic) RDPickerController *pc;
@end

@implementation ViewController

- (IBAction)showPicker:(UIButton *)sender {
    self.pc = [[RDPickerController alloc] initWithCompletionHandler:^(NSString *selectedString) {
        NSLog(@"%@",selectedString);
        // do whatever with the returned data here
    }];

    [self.view addSubview:self.pc.picker];
}