How to add enum as datasource in uipickerview? - objective-c

Question

I have created one enum in my ApplicationConstants.h file and enum is as below.
typedef enum {
CurrentLocation = 0,
CurrentCity,
CurrentRegion } enumLocation;
Now the question is I dont know how to set this enum as data source in UIPickerView ! Can anyone give me idea about this ? I have used NSArray as datasource before. But I want enum now. Because of this problem I stuck. Can you help me ? So i can go ahead in my application.

Answer 1

You can't display the identifier of an enum directly. You have to prepare a big if/else/switch block to prepare a string for each element, or add strings for every element in an array and select by index from there.
Enum types are usually used instead of magic numbers in programs and thus are designed to make the code easier to read by a human, but the underlying representation is in one of the base data types (int, char, etc).

Answer 2

For UIPickerViewDataSource
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
return LOCATION_COUNT;
}
Use the trick for enum count
typedef enum { CurrentLocation = 0, CurrentCity, CurrentRegion, LOCATION_COUNT} enumLocation;
for UIPickerViewDelegate
- (NSString *)pickerView:(UIPickerView *)thePickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
[self.enumLocationStringDict objectForKey:[NSNumber numberWithInt:row]]
}
Dictionary can be as follow
self.enumLocationStringDict = [NSDictionary dictionaryWithObjectsAndKeys:
#"CurrentLocation", [NSNumber numberWithInt:CurrentLocation],
#"CurrentCity", [NSNumber numberWithInt:CurrentCity],
#"CurrentRegion", [NSNumber numberWithInt:CurrentRegion],
,nil];

Answer 3

you can choose the way to define a simple macro for it for instace, like this:
in the header file (.h):
#define NAMEOF(var) ##var
typedef enum : NSInteger {
CustomTypeUknown = 0,
CustomTypeSomething,
CustomTypeParticularValue,
CustomTypeBoringValue,
} CustomType;
in the implementaion file (.m)
NSArray *_array = [NSArray arrayWithObjects:NAMEOF(CustomTypeUknown), NAMEOF(CustomTypeSomething), NAMEOF(CustomTypeParticularValue), NAMEOF(CustomTypeBoringValue), nil];
the objects will be strings with the names, but for safety sake you could check the values via logging _array:
NSLog(#"%#", _array);
it should look like this:
(
CustomTypeUknown,
CustomTypeSomething,
CustomTypeParticularValue,
CustomTypeBoringValue
)
if I haven't misunderstood your problem, that is you looked for...