iOS 5.0 SDK
I have a method that took a parameter as a 'type' that I defined. Lets call it 'Places'. This type was defined as the following:
typedef enum {
kBar = 0,
kRestaurant = 1,
kCafe = 2
} Places
My method would take a parameter of Places.
Based on the Place type passed in, I would append the type to the url:
ex: http://www.domain.com/place=1
However, the url parameter cannot be a number it has to be a string.
ex: http://www.domain.com/place=restaurant
I know enums cannot be strings so I am trying to figure out the right approach for this. Do I have a plist and then read the plist into a dictionary? Is there another way?
I would do something like:
typedef enum {
PlaceTypeBar = 0,
PlaceTypeRestaurant = 1,
PlaceTypeCafe = 2
} PlaceType
#interface PlaceTypeHelper : NSObject
+ (NSString *) stringForPlace:(PlaceType)place;
#end
#implementation
+ (NSString *) stringForPlace:(PlaceType)place {
NSArray *places = [NSArray arrayWithobjects:#"Bar", #"Restaurant", #"Cafe", nil];
return [places objectForKey:(NSInteger)place];
}
#end
Headups, I've no tested the code yet.
There's a lot of different approaches you could take. Here's what I might do myself.
Assuming there's a finite and known amount of values, you can do a simple function which returns the string for the given type :
(NSString*) StringForPlaceType(PlaceType thePlace) {
switch(thePlace) {
case kBar:
return #"Bar";
case kRestaurant:
return #"Restaurant";
case kCafe:
return #"Cafe";
default:
// ...
}
}
No need for an object or class unless you want for flexibility such as dynamic values and such.
Related
I am creating an NSMutableDictionary and assigning an NSString (test and test1) to a parameter key.
NSMutableDictionary *dictionary = [[NSMutableDictionary alloc] init];
if (test.length) {
dictionary[#"test"] = test;
}
if (test1.length) {
dictionary[#"test1"] = test1;
}
This method does work. However, I am going to eventually have more strings and don't want a bunch of if statements. I don't want the dictionary keys to exist if the string is empty or nil.
Not sure if there is a way around this.
I thought about creating a separate function that accepts an array of key string and array of string values and use a for loop to see if string value is empty. Then, return a dictionary once the for loop ends. However, you can't insert nil into an NSArray
Something like this
- (void)updateDic:(NSMutableDictionary *)dic withString:(NSString *)str {
if (!str || [str isEqualToString:#""]) {
return;
}
dic[str] = str;
}
And then just iterate over all strings and use that method.
What I'd do is create a NSMutableDictionary category, something like this:
NSMutableDictionary+CustomMethods.m:
- (void)setStringIfNotNil:(NSString *)string forKey:(id <NSCopying>)key {
if (!string || !string.length) { return; }
self[key] = string;
}
Then you can use it like this:
NSMutableDictionary *dictionary = [[NSMutableDictionary alloc] init];
[dictionary setStringIfNotNil:test forKey:#"test"]
[dictionary setStringIfNotNil:test1 forKey:#"test1"]
There are three ways according to me..
The first one use the category in which you have to write if condition only single time and you can use it in any class of your project.
Second one by making a separate method to do that task(to check string nil or not and adding into the dictionary).
And the third one , just add all in an array and and perform the action in a loop.
The syntax:
dictionary[#"test"] = test
will remove the value from the dictionary if test is nil (it's a difference between the normal -setObject:forKey: method and the -setObject:forKeyedSubcript: which that syntax invokes). However, that will not work for empty strings.
As mentioned in another answer, you could make an NSDictionary category method to check, then call that method instead.
You could also just use the regular dictionary[key] = value syntax, then when you are done, do:
[dictionary removeObjectsForKeys:[dictionary allKeysForObject:#""]];
If it's possible to have the keys repeated, and you don't want an empty string overriding an earlier valid valid, you would have to check each time -- either by the category method, or using a local macro or inline function or local method.
static inline void SetValidVal(NSMutableDictionary *dictionary, NSString *key, NSString *val) {
if (val.length) { dictionary[key] = val; }
}
or
#define MY_SET_VALID_VAL(dictionary, key, val) if ((val).length) dictionary[key] = (val)
If the key names need to be the same as the name of the local variable, you can play other games with macros (this also assumes the local variable name "dictionary":
#define MY_UPDATE_VAL(val) if (val.length) dictionary[##val] = (val)
Then MY_UPDATE_VAL(test1); would expand to:
if (test1.length) dictionary[#"test1"] = test1;
That's a bit magic though and probably not recommended.
I know there's a lot of questions like this around, but I think my situation's a tad different.
int i = 0;
while (_data[#"VerticalState%i", i] != nil) {
// do things
i++;
}
For example, one 'level' that has 3 VerticalState properties will be implemented as such: VerticalState0, VerticalState1, VerticalState2.
I want to read in those values using that while loop condition above, and it should stop when i = 3. How can I make the idea of that code above work (with some other configuration obviously). FYI, _data is an NSDictionary* instance variable, already loaded with the plist information.
You appear to want to create a dictionary key from a string format. You need to use NSString stringWithFormat:.
while (_data[[NSString stringWithFormat:#"VerticalState%i", i]] != nil) {
Though it would be better to write the loop like this:
int i = 0;
while (1) {
NSString *key = [NSString stringWithFormat:#"VerticalState%i", i];
id value = _dict[key];
if (value) {
// do things
i++;
} else {
break;
}
}
I have this method and I need to concatenating parameters so the result should be. Any idea how to do it?
getTyreLabels?width=m125.00&aspect=25&rim=13.00&season=SU&time=269742091
- (NSURL *)getTyreLabels:(NSString*)width :(NSInteger*)aspect : (NSInteger*)rim : (NSString*)season : (NSString*)pattern : (NSInteger*)time;
{
return [[self getBaseUrl] URLByAppendingPathComponent:#"getTyreLabels"];
}
I'm guessing that the string you put at the beginning is the desired output.
In which case your method should be something like...
- (NSString *)parameterStringWithWidth:(NSString *)width
aspect:(NSInteger)aspect
rim:(NSInteger)rim
season:(NSString *)season
pattern:(NSString *)pattern
time:(NSInteger)time
{
return [NSString stringWithFormat:#"getTyreLabels?width=m%#&aspect=%ld&rim=%ld&season=%#&time=%ld", width, (long)aspect, (long)rim, season, (long)time];
}
That will return the string. Not the URL but you should be able to get the point from this.
Note the way the method name is constructed. It makes it MUCH easier to call it from somewhere else as you can see what each parameter is relating to.
NSString *theString = [self parameterStringWithWidth:#"125.00" aspect:25 rim:13 season:#"SU" pattern:#"" time:269742091];
This will result in theString being the value you put in your question.
Might be you want something like this -
- (NSURL *)getTyreLabelsWithWidth:(NSString*)width
andAspect:(NSInteger)aspect
andRim:(NSInteger)rim
andSeason:(NSString *)season
andPattern:(NSString*)pattern
andTime:(NSInteger)time
{
NSString *stringToAppend = [NSString stringWithFormat#"getTyreLabels?width=%#&aspect=%d&rim=%d&season=%d&time=%d", width, aspect, rim, season, time];
return [[self getBaseUrl] URLByAppendingPathComponent: stringToAppend];
}
I want to switch NSString in XmlParser because if there are 15 or more web-service then every time the loop check for correct element in IF..ELSE.That I don't want to make processor busy..
I have searched a lot and found using enum I can switch NSString but no luck ..
I have tried each possibilities,but some where i am making mistake.
Please help to solve this big problem for me.
Here I have declare my enum:
Here in "elementName" I am getting Exact value as declared in enum:
But instead of 1, I am getting wrong value Like 202896536:
You cant do it by creating enum. You must need to compare the string.
if([elementName isEqualToString:#"UserLoginComplexType"])
//Do something...
You can not cast a string to ENUM value, you will need to parse it, ENUM values are integers not strings.
You will have to use an if statement.
You could use a helper method:
WebServiceList.h
typedef NS_ENUM(NSUInteger, WebServiceList) {
WebServiceListNone = 0,
UserLoginComplexType = 1,
RegisterUserResult = 2,
RecoverPasswordResult = 3,
....
};
FOUNDATION_EXTERN WebServiceList WebServiceListForString(NSString *string);
WebServiceList.m
WebServiceList WebServiceListForString(NSString *string) {
WebServiceList list = WebServiceListNone;
if (![type isKindOfClass:[NSString class]]) {
return CallRecordTypeNone;
}
else if ([string isEqualToString:#"UserLoginComplexType"] {
list = UserLoginComplexType;
}
else if ([string isEqualToString:#"UserLoginComplexType"]) {
list = UserLoginComplexType;
}
else .....
return list;
}
As seen in your commented codes, you're parsing a XML and saving in a NSMutableArray named arrProductList in App Delegate.
After finishing the parsing of XML, the variable should contain the data in array. You should look into the variable & fetch the corresponding value. Since you didn't post any further details about parsing / XML structure, I'm unable to write some codes related to result fetching.
For easy readability and to avoid lots of if-else statements, I like to do mine as a dictionary:
(also makes it easy to update in the future when you add more to your enum)
NSString* elementName = ...;
// Default value
WebServiceList value = UserLoginComplexType;
NSDictionary* stringToEnum = #{#"UserLoginComplexType":#(UserLoginComplexType),
#"RegisterUserResult":#(RegisterUserResult),
#"RecoverPasswordResult":#(RecoverPasswordResult)};
NSNumber* enumValue = stringToEnum[elementName];
if(enumValue != nil)
value = (WebServiceList)enumValue.integerValue;
I i'm getting the error "Implicit conversion of 'int' to 'id' is disallowed with ARC" at the line marked with "faulty line". I guess it have something to do with that i'm checking for an integer in an array, that contains objects instead of integers.
#import "RandomGenerator.h"
#implementation RandomGenerator
NSMutableArray *drawnNumbers;
-(int) randomNumber:(int)upperNumber {
return arc4random_uniform(upperNumber);
}
-(NSMutableArray*) lotteryNumbers :(int)withMaximumDrawnNumbers :(int)andHighestNumber {
for (int i = 1; i <= withMaximumDrawnNumbers; i++)
{
int drawnNumber = [self randomNumber:andHighestNumber];
if ([drawnNumbers containsObject:drawnNumber]) { //faulty line
//foo
}
}
return drawnNumbers;
}
#end
NSArrays can only contain objective-c objects. So actually the method containsObject: is expecting an object, not an int or any other primitive type.
If you want to store number inside an NSArray you should pack them into NSNumber objects.
NSNumber *someNumber = [NSNumber numberWithInt:3];
In your case, if we assume that drawnNumbers is already an array of NSNumbers, you should change the randomNumber: generation to:
-(NSNumber*) randomNumber:(int)upperNumber {
return [NSNumber numberWithInt:arc4random_uniform(upperNumber)];
}
And then when picking it up on the lotteryNumbers method, you should:
NSNumber *drawnNumber = [self randomNumber:andHighestNumber];
Another note would go for the method you defined for lotteryNumbers. You used a really strange name for it, I think you misunderstood how the method naming works in objective-c. You were probably looking for something more like:
-(NSMutableArray*) lotteryNumbersWithMaximumDrawnNumbers:(int)maximumDrawnNumbers andHighestNumber:(int)highestNumber;
Late edit:
Objective-C now allows a way more compact syntax for creating NSNumbers. You can do it like:
NSNumber *someNumber = #(3);
And your method could be rewritten as:
-(NSNumber*) randomNumber:(int)upperNumber {
return #(arc4random_uniform(upperNumber));
}
You are using an int where an object (presumably NSNumber) is expected. So convert before use:
if ([drawnNumbers containsObject:#( drawnNumber )])