Example.m

+ (void)load
{
    [self textFieldsCycleInThisOrder:@[@"_name", @"_address", @"_phone"]];
}

NSObject+TabOrder.h

#import <Foundation/Foundation.h>

@interface NSObject (TabOrder)
+ (void)textFieldsCycleInThisOrder:(NSArray *)fieldOrder;
@end

NSObject+TabOrder.m

#import "NSObject+TabOrder.h"
#import <objc/runtime.h>

@interface TabOrderInfo : NSObject
@property (readwrite, retain) NSArray *fieldOrder;
@property (readwrite, assign) IMP oldImplementation;
@end
@implementation TabOrderInfo
@end

static NSMutableDictionary *fieldOrders = nil;

@implementation NSObject (TabOrder)

+ (void)textFieldsCycleInThisOrder:(NSArray *)fieldOrder
{
    TabOrderInfo *info = [[[TabOrderInfo alloc] init] autorelease];
    info.fieldOrder = fieldOrder;
    
    Method newMethod = class_getInstanceMethod([self class], @selector(TabOrder_textFieldShouldReturn:));
    info.oldImplementation = class_replaceMethod([self class], @selector(textFieldShouldReturn:), method_getImplementation(newMethod), method_getTypeEncoding(newMethod));
    
    if (!fieldOrders)
        fieldOrders = [[NSMutableDictionary alloc] init];
    [fieldOrders setObject:info forKey:NSStringFromClass([self class])];
    
}

+ (TabOrderInfo *)TabOrder_info
{
    return [fieldOrders objectForKey:NSStringFromClass([self class])];
}

+ (NSArray *)TabOrder_fieldsInOrder
{
    return [self TabOrder_info].fieldOrder;
}

- (BOOL)TabOrder_textFieldShouldReturn:(UITextField *)textField
{
    UIView *nextField = [self TabOrder_fieldAfter:textField];
    if (nextField)
        [nextField becomeFirstResponder];
    else
        [textField resignFirstResponder];
    
    IMP oldImplementation = [[self class] TabOrder_info].oldImplementation;
    if (oldImplementation)
        return ((BOOL (*) (id,SEL, UITextField*))oldImplementation)(self, _cmd, textField);
    return NO;
}

- (int)TabOrder_indexOfField:(UIView *)field
{
    NSArray *fieldsInOrder = [[self class] TabOrder_fieldsInOrder];
    for (int fieldIndex = 0; fieldIndex < [fieldsInOrder count]; ++fieldIndex) {
        if ([self valueForKey:fieldsInOrder[fieldIndex]] == field)
            return fieldIndex;
    }
    return -1;
}

- (UIView *)TabOrder_fieldAfter:(UIView *)field
{
    int fieldIndex = [self TabOrder_indexOfField:field];
    if (fieldIndex == -1)
        return nil;
    
    if (fieldIndex+1 < [[[self class] TabOrder_fieldsInOrder] count])
        return [self valueForKey:[[self class] TabOrder_fieldsInOrder][fieldIndex+1]];
    return nil;
}

@end