I would like to create a stack with array of int (2 dimensional : int[9][9]), but I can't.
I tried the NSMutableArray which needs objects. So I tried to use NSValue to transform my array to a NSObject, but I keep having lot ouf trouble.
Can you please give me some help ?
I push an array (a grid) in the (void)saveGrid function.
I need to recover the last grid in the (IBAction)undo function.
Here is my last-try code source : (where Im transforming my 2D-array (9*9) to a 1D-array (81))
- (void)saveGrid {
int longGrid[81];
for (int i = 0; i < 9; i++) {
for (int j = 0; j < 9; j++) {
longGrid[(i+1)*(j+1)-1] = matrix[i][j];
}
}
NSValue *valObj;
valObj = [NSValue value:&longGrid withObjCType:#encode(int **)];
[TGrid addObject:valObj];
}
- (IBAction)undo:(id)sender {
[TGrid removeLastObject];
int *valPtr;
[[TGrid lastObject] getValue:&valPtr];
for (int i = 0; i < 9; i++) {
for (int j = 0; j < 9; j++) {
matrix[i][j] = valPtr[(i+1)*(j+1)-1];
}
}
}
(TGrid is NSMutableArray typed.)
Thanks for your help !
I don't really understand your thinking. You want to use an NSArray, correct? Or NSMutableArray? Either way, you can't store ints in these. You can only store objects, so an integer would be an NSNumber object. It's actually a subclass of NSValue, so you don't need to use NSValue.
So with that it's pretty easy to create an NSMutableArray, populate it with the numbers, which are of the NSNumber object, and then create another NSMutableArray and populate that one with a bunch of NSMutableArrays. There you have it, a 2 dimensional array.
Secondly, It's not a good idea to subclass NSArray, NSDictionary, NSString, and the mutable versions of that. In Cocoa, many classes are actually implemented as class clusters, which are a bunch of implementation-specific classes hidden behind a common interface. When you make an NSString object, you might actually end up getting an NSLiteralString, NSCFString, NSSimpleCString, NSBallOfString, or any number of undocumented implementation-detail objects.
You should use NSNumber. Checked that out? Otherwise you could go for an C Array.
If your problem is to put a 2D array of int into an object, why not do just that? Create a class containing one property of type int[9][9], create an object of that class and put your array in it.
* Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[CALayerArray addObject:]: unrecognized selector sent to instance 0x4b36ce0'
I think that TGrid is getting autoreleased. Try this:
TGrid = [[NSMutableArray alloc] initWithCapacity:10];
Then release it in your -dealloc method of course.
Related
How to create an array of non-retained objects in arc? These objects are observers in this array. Currently, I'm creating this array in this way:
_observers = CFBridgingRelease(CFArrayCreateMutable(NULL, 0, NULL));
The problem is the code crashes sometimes when making notifications in this line:
for (NSInteger i = [_observers count] - 1; i >= 0; i--) {
// crash line
id<ListModelObserver> observer = (id<ListModelObserver>)[_observers objectAtIndex:i];
...
I have zombies enabled on, and clearly see observer object classname in debug console. The observer object should be already removed from _observers during dealloc... The only thing that comes to my mind is _observers array somehow retains its objects. Any ideas?
You're releasing the array, not the objects. If you want to have a collection of unsafe unrestrained pointers to objects, then either use a C array or set up a CFArrayRef that doesn't include any call back functions.
I want all the variables names or attributes of a interface or class in objective c.
I am able to get and set the value for a variable dynamically using valueForKey: message.
If you are looking to get all 'properties' for a class, you can utilize the Objective-C runtime to get this data:
unsigned int propertyCount, i;
objc_property_t *properties = class_copyPropertyList([self class], &propertyCount);
for(i = 0; i < propertyCount; i++)
{
objc_property_t property = properties[i];
NSString *propertyName = [NSString stringWithUTF8String:property_getName(property)];
}
free(properties);
With this object you can get all of the metadata associated with a given property. This isn't for the faint of heart though (and it is a C based API). Determining information about each property (like it's policy and type) isn't simple.
Take a look at the Objective-C Runtime Reference and in particular the class_copyIvarList and class_copyPropertyList functions. Use of these runtime functions should be what you're looking for.
I have an Object: aObject, it has properties a,b,c.
I can access the properties using:
aObject.a
aObject.b
aObject.c
Is it possible to access all properties of the object using id? such as
[aObject indexOf:0]
[aObject indexOf:1]
[aObject indexOf:2]
or something likes that.
Welcome any comment
Even if I never used it, it seems it's possible with class_copyPropertyList method.
KVC (Key Value Coding) will allow you to set values of properties using the method [anObject setValue:aValue forKey:#"a"].
If you truly want to iterate through each property, setting its value, then you will need to drop down to the objective-c runtime.
unsigned int outCount, i;
objc_property_t *properties = class_copyPropertyList([anObject class], &outCount);
for (i = 0; i < outCount; i++) {
objc_property_t property = properties[i];
const char * name = property_getName(property);
[anObject setValue:anyValue forKey:[NSString stringWithUTF8String:name]];
}
free(properties);
I have two nsmutablearrays
array1: searchedStores = [[NSMutableArray alloc] init];
array2: allStores; ///it holds Stores information and it is also
NSMutableArray
Now if i add objects in "searchedStores" Array
for (int i= 0; i < [allstores count]; i++){
Franchise *store = [allStores objectAtIndex:i];
if ([store.ZipCode hasPrefix:str]) /// where str is searched string
{
[searchedStores addObject:store]; // some stores information will be inserted in "searchedStores" array
}
}
Now if i remove objects from searchedStores array it will also remove objects from "allStores" array
to remove objects i am writing
[searchedStores removeAllObjects];
How can i remove objects only from "searchedStores" array. and "allStores" Array should keep its objects.
IF you are just assigning allstores array with searchedstores array then changes made in searched stores array will be reflected to allstores. You need to allocate new memory to allstores and then add objects from searchedstores array to it upon your logical behavior.
Every array is totally independent. If removing objects from one array effects the other, you don't have two arrays, but only two pointers to the same array. You need to instantiate (alloc/init or mutableCopy) both. Feel free to show your initialization code as well.
I am building my first iPhone/Obj-c app and I have a large amount of data-holding subclasses that I am passing into a cite function. To the cite function these objects are anonymous and I need to find a way to access all the variables of each passed object.
I have been using a pre-built NSArray and Selectors to do this but with more than 30 entries (and growing) it is kind of silly to do manually. There has to be a way to dynamically look up all the variables of an anonymous object.
The obj-c runtime run-time docs mention this problem but from what I can tell this is not available in iPhone OS. If it is then I don't understand the implementation and need some guidance. A similar question was asked before but again I think they were talking about OSX and not iPhone.
Any thoughts?
-(NSString*)cite:(id)source {
NSString *sourceClass = NSStringFromClass([source class]);
// Runs through all the variables in the manually built methodList
for(id method in methodList) {
SEL x = NSSelectorFromString(method);
// further implementation
// Should be something like
NSArray *methodList = [[NSArray alloc] initWithObjects:[source getVariableList]]
for(id method in methodList) {
SEL x = NSSelectorFromString(method);
// Further implementation
}
The runtime is the same on the Mac as it is on the iPhone. If the other question does what you're looking for, then it should work. If it doesn't, file a bug.
In the meantime, given a Class, you can retrieve a list of all of its selectors using the class_copyMethodList() function:
unsigned int numMethods = 0;
Method * methods = class_copyMethodList(sourceClass, &numMethods);
NSMutableArray * selectors = [NSMutableArray array];
for (int i = 0; i < numMethods; ++i) {
SEL selector = method_getName(methods[i]);
[selectors addObject:NSStringFromSelector(selector)];
}
free(methods);
It's certainly possible to do this through the Objective-C runtime functions, but it's probably not the right way to go about it. Since you're creating the objects passed into the cite method, just have them each implement a protocol that cite can use to extract whatever information it needs.
Something like the Key-Value Coding protocol will probably do what you want:
http://developer.apple.com/iphone/library/documentation/cocoa/Conceptual/KeyValueCoding/KeyValueCoding.html