I am relatively new to Objective C and need some array help.
I have a plist which contains a Dictionary and an NSNumber Array, with more arrays to
be added later on.
NSMutableDictionary *mainArray = [[NSMutableDictionary alloc]initWithContentsOfFile:filePath];
NSArray *scoresArray = [mainArray objectForKey:#"scores"];
I need to retrieve all the values from the array and connect them to 10 UILabels which
I've set up in interface builder. I've done the following to cast the NSNumber to a String.
NSNumber *numberOne = [scoresArray objectAtIndex:0];
NSUInteger intOne = [numberOne intValue];
NSString *stringOne = [NSString stringWithFormat:#"%d",intOne];
scoreLabel1.text = stringOne;
This seems a very long winded approach, I'd have to repeat the 4 lines above ten times to retrieve all the array values. Could I use a for loop to iterate through the array with all of the values converted to Strings at the output?
Any info would be greatly appreciated.
// create NSMutableArray* of score UILabel items, called "scoreLabels"
NSMutableArray *scoreLabels = [NSMutableArray arrayWithCapacity:10];
[scoreLabels addObject:scoreLabel1];
[scoreLabels addObject:scoreLabel2];
// ...
NSUInteger _index = 0;
for (NSNumber *_number in scoresArray) {
UILabel *_label = [scoreLabels objectAtIndex:_index];
_label.text = [NSString stringWithFormat:#"%d", [_number intValue]];
_index++;
}
EDIT
I'm not sure why you'd want to comment out _index++. I haven't tested this code, so maybe I'm missing something somewhere. But I don't see anything wrong with _index++ — that's a pretty standard way to increment a counter.
As an alternative to creating the scoreLabels array, you could indeed retrieve the tag property of the subviews of the view controller (in this case, UILabel instances that you add a tag value to in Interface Builder).
Assuming that the tag value is predictable — e.g., each UILabel from scoreLabel1 through scoreLabel10 is labeled with a tag equal to the values of _index that we use in the for loop (0 through 9) — then you could reference the UILabel directly:
// no need to create the NSMutableArray* scoreLabels here
NSUInteger _index = 0;
for (NSNumber *_number in scoresArray) {
UILabel *_label = (UILabel *)[self.view viewWithTag:_index];
_label.text = [NSString stringWithFormat:#"%d", [_number intValue]];
_index++;
}
The key to making that work is that the tag value has to be unique for the UILabel and must be something you can reference with -viewWithTag:.
The code above very simply assumes that the tag values are the same as the _index values, but that isn't required. (It also assumes the UILabel instances are subviews of the view controller's view property, which will depend on how you set up your interface in Interface Builder.)
Some people write functions that add 1000 or some other integer that allows you group types of subviews together — UILabel instances get 1000, 1001, and so on, and UIButton instances would get 2000, 2001, etc.
try using stringValue...
scoreLabel1.text = [(NSNumber *)[scoresArray objectAtIndex:0] stringValue];
Related
i have 9 IBOutlets for imageView named imageView1,imageView2,....
i have to assign first object of array to imageView1 & second object to imageView2,.....
Now my question is- is there any way to iterate through the property name
example-
for(int i=0;i<[randomizedArray count];i++)
{
NSString *imageViewName=[NSString stringWithFormat:#"%#%i",#"imageView",i];
imageViewName.image=[appDelegate.splittedImageArray ObjectAtIndex:i];
}
that means it automatically assign value as
imageView1.image=[appDelegate.splittedImageArray ObjectAtIndex:i];
imageView2.image=[appDelegate.splittedImageArray ObjectAtIndex:i];
The closest you could get to something like that without changing the IBOutlets would be this:
NSArray *imageViews = #[imageView1,imageView2,imageView3, ...];
for(int i=0; i<[randomizedArray count]; i++) {
[[imageViews objectAtIndex:i] setImage:[appDelegate.splittedImageArray objectAtIndex:i]];
}
But there is a better solution - IBOutletCollection
You can define a property like this:
#property (nonatomic, retain) IBOutletCollection(UIImageView) NSArray *imageViews;
And connect all of your imageViews like so:
Then you will have an array containing all of your UIImageViews, and you can use the above code without having to declare such an array manually...
dont think it complexly. This is very simple. put tag for the imageviews like tag 1 for imageview1, 2 for imageview2 and so on. Then run a for loop and pick the object and assign to the array. Thats all.
Like assume you put tag from 1 to 7 (don't put duplicate tag or 0 for any of your views)
NSMutableArray *arr = [[NSMutableArray alloc] init];
for(int ii = 1; ii<=7; ii++){
UIImageView *imgView = (UIImageView *)[self.view viewWithTag:ii];
[arr addObject:imgView];
}
yourArray = arr;
[arr release];//if your array is a property otherwise no need to release.
Hope this will help you.
use NSClassFromString
for(int i=0;i<[randomizedArray count];i++)
{
NSString *imageViewName=[NSString stringWithFormat:#"%#%i",#"imageView",i];
Class theClass = NSClassFromString(imageViewName);
theClass.image=[appDelegate.splittedImageArray ObjectAtIndex:i];
}
One way I have used to do this . Created the array of IBOutlets so you can iterate through it and assign the corresponding image.
for(int i=0;i<[randomizedArray count];i++)
{
UIImageView *imageView=[imageOutlets objectAtIndex:i];
UIImage *image=[images objectAtIndex:i];
imageView.image=image;
}
I'm having trouble making the sections in a UITableView. I've looked at the documentation for UILocalizedIndexedCollation as well as this sample code project:
https://developer.apple.com/library/ios/#samplecode/TableViewSuite/Listings/3_SimpleIndexedTableView_Classes_RootViewController_m.html#//apple_ref/doc/uid/DTS40007318-3_SimpleIndexedTableView_Classes_RootViewController_m-DontLinkElementID_18
What I have below is basically a straight copy/paste from the sample project. However, the sample project uses a custom object (TimeZoneWrapper.h) and then places the object in the correct section based on the object's instance variable (TimeZoneWrapper.localeName). However, I'm not using custom objects. I'm using just a bunch of regular NSStrings. So my question is what method on NSString should I pass to the #selector() to compare and place the string in the correct section array?
Currently, I'm calling NSString's copy method as a temporary hack to get things working (which it does), but I'm not sure if this is correct. A little explanation would be much appreciated!
- (void)configureSections {
// Get the current collation and keep a reference to it.
self.collation = [UILocalizedIndexedCollation currentCollation];
NSInteger index, sectionTitlesCount = [[collation sectionTitles] count]; // sectionTitles are A, B, C, etc.
NSMutableArray *newSectionsArray = [[NSMutableArray alloc] initWithCapacity:sectionTitlesCount];
// Set up the sections array: elements are mutable arrays that will contain the locations for that section.
for (index = 0; index < sectionTitlesCount; index++) {
NSMutableArray *array = [[NSMutableArray alloc] init];
[newSectionsArray addObject:array];
}
// Segregate the loctions into the appropriate arrays.
for (NSString *location in locationList) {
// Ask the collation which section number the location belongs in, based on its locale name.
NSInteger sectionNumber = [collation sectionForObject:location collationStringSelector:#selector(/* what do I put here? */)];
// Get the array for the section.
NSMutableArray *sectionLocations = [newSectionsArray objectAtIndex:sectionNumber];
// Add the location to the section.
[sectionLocations addObject:location];
}
// Now that all the data's in place, each section array needs to be sorted.
for (index = 0; index < sectionTitlesCount; index++) {
NSMutableArray *locationsArrayForSection = [newSectionsArray objectAtIndex:index];
// If the table view or its contents were editable, you would make a mutable copy here.
NSArray *sortedLocationsArrayForSection = [collation sortedArrayFromArray:locationsArrayForSection collationStringSelector:#selector(/* what do I put here */)];
// Replace the existing array with the sorted array.
[newSectionsArray replaceObjectAtIndex:index withObject:sortedLocationsArrayForSection];
}
self.sectionsArray = newSectionsArray;
}
Thanks in advance!
You should use #selector(self).
Using #selector(copy) will cause memory leaks in your project
is is possible to access objects using variables in a FOR statement?
Say i have declared:
UIImageView *UIImageView0;
UIImageView *UIImageView1;
UIImageView *UIImageView2;
and i have 3 objects in an array and i call a FOR statement if x in the array is equal to 2 i want it to add the value of x to the UIImageView name like UIImageView1 etc
I have tried:
for (int x=0; x<[theArray count]; x++) {
UIImageView[x].image = etc....
}
but it gives me a error on UIImageView[x]
subscript requires size of interface 'UIImageView'
any ideas? or is it even possible with a UIImageView?
Thanks
You don't have three elements in an array, though; you have three independent variables with similar names. If you created an actual array, containing the values of the three variables, then you could use the for loop -- and in fact, the syntax would be just as you've shown (using the actual name of the array variable, of course.)
You could say
UIImageView * views[3] = {UIImageView0, UIImageView1, UIImageView2};
and then use, for example, views[i].image in your loop.
In order to put your UIImageView into an array you need to create an instance NSMutableArray (for instance)
The above code does not show any array, instead you have three ivars
UIImageView *UIImageView0;
UIImageView *UIImageView1;
UIImageView *UIImageView2;
and to access those you would use the name, not an array.
If you however put them into an NSMutableArray you can access them using
NSMutableArray array = [[NSMutableArray alloc]
initWithObjects:UIImageView0, UIImageView1, UIImageView2, nil];
[array objectAtIndex:i ]; // where i is 0,1 or 2
...
[array release];
You can put your UIImageView to another array, and get the UIImageView from that array.
NSArray *imagesArray = #[imageView0, ...]
for(size_t i = 0; i<theArray.count; i++)
{
UIImageView *imageView = [imagesArray objectAtIndex:i];
}
Or you can use the "tag" property of UIView like:
UIImageView *image0 = ...;
image0.tag = 100; //or 0 or something else
[self.view addSubview:image0];
And then get the UIImageView by tag in your FOR statement:
for(size_t i = 0; i<theArray.count; i++)
{
UIImageView *imageView = [self.view viewWithTag:100+i];
}
I know I can concatenate a variable name using stringwithformat, but is it possible to concatenate an object name? I'm not having any luck working around this one.
image+1.hidden = YES; for example.
If I wanted to loop through that, say 10 times, how would I create the 'image+1' part?
Thanks for any help.
I don't think that it is possible to concatenate object names in objective c, but you could create an array of images, and then reference each image like
image[0].hidden = YES;
That would fit the for loop. You could also add the images (I assume that they are UIImages) to an NSArray, then loop through like so:
NSArray* arrayOfImages;
for(UIImage* image in arrayOfImages)
{
image.hidden = YES;
}
Add the objects to an NSArray or NSMutableArray. Then loop through the array to set each object's properties.
For the purposes of discussion mainly, you can use key-value coding to set a property by its name. So, supposing you had instance, an instance of a class that provides the properties image1, image2 and image3 then you could perform:
for(int x = 1; x < 4; x++)
{
// produce the name of the property as an NSString
NSString *propertyName = [NSString stringWithFormat:#"image%d", x];
// use key-value coding to set the property
[instance setValue:someValue forKey:propertyName];
}
For the full list of accessor methods that compliant classes export, see the NSKeyValueCoding Protocol Reference. NSObject implements NSKeyValueCoding, and all properties declared as #property and implemented as #synthesize are compliant, as are any other properties with suitable accessors.
As already noted in the other answers, when what you want is an ordered list of objects so that you can do something with each in turn, either a C-style array or an NSArray is the correct way to proceed, with an NSArray being preferred for style reasons.
NSArray *array = [[NSArray alloc] initWithObjects:image1, image2, image3, image4, image5, image6, image7, image8, image9, image10, nil]; // or use NSMutableArray
for (int x = 0; x < 10; x++) {
((UIImage*)[array objectAtIndex:x]).hidden = YES;
}
Been searching for the answer to this for a while now and I think due to the nature of my array set up, I may be searching for the wrong answer!
I have a class which handles adding items to my array:
// Item.h
#interface Item : NSObject {
NSString *name;
NSNumber *seconds;
}
#property(nonatomic,copy) NSString *name;
#property(nonatomic,copy) NSNumber *seconds;
- (id)initWithName:(NSString *)n seconds:(NSNumber *)sec;
#end
and...
//item.m
#implementation Item
#synthesize name, seconds;
- (id)initWithName:(NSString *)n seconds:(NSNumber *)sec {
self.name = n;
self.seconds = sec;
return self;
}
#end
So to add an item, I use
Item *item1 = [[Item alloc] initWithName:#"runnerA" seconds:[NSNumber numberWithInt:780]];
I have some code which allows a user to edit a textfield (runner name) and the time which is a UIdatepicker set to hours and minutes. In the save method, that's working fine. It's the UPDATE that I cannot get to work. I've tried alsorts! Here's the code at the moment...
mainAppDelegate *appDelegate = (mainAppDelegate *)[[UIApplication sharedApplication] delegate];
Item *item = [[Item alloc] initWithName:inputName.text seconds:[NSNumber numberWithInt:secs]];
[appDelegate.arrItems replaceObjectAtIndex:rowBeingEdited withObject:item];
The above is simply adding a new item to the array (which is what I don't want). I'm not sure how to replace values. At the function, I have the row I need to update (rowBeingEdited) and the fields inputName.text and secs are both OK. (NSLog out confirms this).
How do I use the replaceObjectAtIndex to actually replace it with the values?! It's driving me mad now!!
Since you are simply trying to edit a particular row, why not use those property accessors that you already have set up in Item? It would look something like this:
Item *item = (Item *)[appDelegate.arrItems objectAtIndex:rowBeingEdited];
[item setName:inputName.text];
[item setSeconds:[NSNumber numberWithInt:secs]];
An a side note, are you using garbage collection, or do you manually release the Item objects that you create when adding items to the array? If you are doing it manually, it should look like this:
Item *item1 = [[Item alloc] initWithName:#"runnerA"
seconds:[NSNumber numberWithInt:780]];
[appDelegate.arrItems addObject:item1];
[item1 release];
This follows the rule of thumb: if you alloc, copy or retain anything, you must also release it. Note that this works because the array will retain the item when it is added.
Are you using NSArray or NSMutableArray?
Assuming you are using NSMutableArray, how did you initialize and populate the array in the first place?
For example, it's not enough to use -initWithCapacity: or +arrayWithCapacity: which only sets aside space. You have to use -addObject: for the first round of population, before you can use -replaceObjectAtIndex:withObject::
Note that NSArray objects are not like C arrays. That is, even though you specify a size when you create an array, the specified size is regarded as a “hint”; the actual size of the array is still 0. This means that you cannot insert an object at an index greater than the current count of an array. For example, if an array contains two objects, its size is 2, so you can add objects at indices 0, 1, or 2. Index 3 is illegal and out of bounds; if you try to add an object at index 3 (when the size of the array is 2), NSMutableArray raises an exception.