Im making a IPHONE Phonebook app that has an array of contacts(objects). I am trying to sort this array so it displays the lastName in alphabetical order
But nothing seems to work. I'm not sure where i would put my code in the "MasterViewController". HERE IS PART OF MY CODE
My object looks like the following.
#interface PhoneBookEntry : Person
#property NSString *firstName;
#property NSString *lastName;
#property NSString *address;
#property NSString *phoneNumber;
#end
#interface MasterViewController : UITableViewController
#property NSMutableArray *elements;
#end
#implementation MasterViewController
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
self.elements = [[NSMutableArray alloc] init];
}
Assume that the array already has elements in it.
I need to sort the "self.elements.lastName" array alphabetically
PLEASE HELP!!!!!!!!
[self.elements sortUsingDescriptors:#[[NSSortDescriptor sortDescriptorWithKey:#"lastName" ascending:YES]]];
Related
This is the original codes when I am getting this error
ClassA.h
+(ClassA*)methodA:(NSData*)data;
#property (nonatomic, strong) NSMutableArray *arr;
#property (nonatomic, strong) RXMLElement *rxmlRoot;
#end
ClassA.m
+(ClassA*)methodA:(NSData*)data {
//NSLog(#"class is %#",[name class]);
ClassA *ClassA = [[Stores alloc] init];
arr = [NSMutableArray array];
rxmlRoot = [RXMLElement elementFromXMLData:data];
}
I am reviewing my codes and now I have tow options to fix the code
OptionA
ClassA.h
+(ClassA*)methodA:(NSData*)data;
#property (nonatomic, strong) NSMutableArray *arr;
#property (nonatomic, strong) RXMLElement *rxmlRoot;
#end
ClassA.m
+(ClassA*)methodA:(NSData*)data {
//NSLog(#"class is %#",[name class]);
ClassA *ClassA = [[Stores alloc] init];
ClassA.arr = [NSMutableArray array]; <----- this has been modified
ClassA.rxmlRoot = [RXMLElement elementFromXMLData:data];<----- this has been modified
}
OptionB
ClassA.h
+(ClassA*)methodA:(NSData*)data;
#end
ClassA.m
static RXMLElement *rxlRoot; <----- this has been added as class variable
static NSMutableArray *arr; <----- this has been added as class variable
+(ClassA*)methodA:(NSData*)data {
//NSLog(#"class is %#",[name class]);
ClassA *ClassA = [[Stores alloc] init];
arr = [NSMutableArray array];
rxmlRoot = [RXMLElement elementFromXMLData:data];
}
I try either optionA or optionB and the compiler does not complain anything and the codes work properly.
I see many posts following the optionB which create class variables.
Question: is optionA also a good way to follow when we are dealing with class method and class variable as well.
Please advice me on this issue and by the way if I have made mistakes somewhere, please correct me. Thanks
There is no such thing as a "class variable" in Objective-C. When you declare a variable as static it is, effectively, a global variable that is limited to either the scope of the file it is compiled within or the scope of a method/function (or sub-expression).
Get rid of the Class. part of your calls to set the variables; that'll work in the .m file for the Class only; which is generally the pattern you would want (truly global variables are generally discouraged -- sometimes useful, though).
Create a designated initializer with a data parameter. Every class should have a designated initializer.
In your class method call the designated initializer passing in data.
Here is example code:
//ClassA.h
#class RXMLElement;
#interface ClassA : NSObject
+(ClassA*)methodA:(NSData*)data;
-(id)initWithData:(NSData*)data;
#property (nonatomic, strong) NSMutableArray *arr;
#property (nonatomic, strong) RXMLElement *rxmlRoot;
#end
//ClassA.m
#implementation ClassA
#synthesize arr;
#synthesize rxmlRoot;
+(ClassA*)methodA:(NSData*)data {
return [[ClassA alloc] initWithData:data];
}
-(id)initWithData:(NSData*)data {
self = [super init];
if (self) {
arr = [NSMutableArray array];
rxmlRoot = [RXMLElement elementFromXMLData:data];
}
return self;
}
#end
ARC is assumed in the example.
Hey guys, I have this code within a function inside a class that is a subclass of NSOperation:
//...
#implementation DataLoader
#synthesize addedAnnotations;
#synthesize addedOverlays;
#synthesize loaderFunc;
#synthesize DLDelegate;
//...
-(id)initWithFunction:(LoaderFunc)func withDelegate:(id)delegate {
if (self = [super init]) {
self.addedOverlays = nil;
self.addedAnnotations = nil;
self.loaderFunc = func;
self.DLDelegate = delegate;
return self;
}
return nil;
}
//...
//inside a function
for (ParkingAnnotations *annotation in fetchedObjects) {
ParkingAnnotation *parkingAnnot = [[ParkingAnnotation alloc] init];
workingCoordinate.latitude = [[annotation latitude] doubleValue];
workingCoordinate.longitude = [[annotation longitude] doubleValue];
[parkingAnnot setCoordinate:workingCoordinate];
[parkingAnnot setTitle:[annotation valueForKey:#"lotName"]];
[parkingAnnot setAnnotationType:[annotation iconTypeRaw]];
[self.addedAnnotations addObject:parkingAnnot];//parkingAnnot not added to array here
[parkingAnnot release];
}
//...
Added annotations is an NSMutable array, I have been walking through this code with the debugger and for some reason the parkingAnnot object is not getting added to the array. Here is the relevant header code for the class:
//...
#interface DataLoader : NSOperation {
NSMutableArray *addedAnnotations;
NSMutableArray *addedOverlays;
LoaderFunc loaderfunc;
id <DataLoaderProtocol> DLDelegate;
}
#property (nonatomic, retain) NSMutableArray* addedAnnotations;
#property (nonatomic, retain) NSMutableArray* addedOverlays;
#property (nonatomic) LoaderFunc loaderFunc;
#property (assign) id DLDelegate;
//...
It is an astonishing problem because the function in which I am experiencing the problem was copied from my MapViewController and is essentially the same, but instead of mapView addAnnotation: I am adding to an NSMutable array instead. Any idea of what's up? Thanks in advance!
Where are you actually instantiating the addedAnnotations array? I only see it being assigned nil in your initialize function, maybe it should change to something like:
self.addedAnnotations = [[[NSMutableArray alloc] init] autorelease];
I have a NSString that is taken from a UITextField in a ViewController. Every of my other ViewController will use this NSString as well. How can I pass this NSString to others ViewControllers?
You want to have a property in each of your controllers
#interface MyViewController : UIViewController{
NSString *title;
}
#property (retain) NSString *title;
#end;
#implementation MyViewController
#synthesize title;
#end;
Use it like:
MyViewController *myVC = [[MyViewController alloc] initWithFrame:...];
myVC.title = #"hello world";
You should be familiar with Memory Management
Create a class for sharing your common objects. Retrieve it using a static method, then read and write to its properties.
#interface Store : NSObject {
NSString* myString;
}
#property (nonatomic, retain) NSString* myString;
+ (Store *) sharedStore;
#end
and
#implementation Store
#synthesize myString;
static Store *sharedStore = nil;
// Store* myStore = [Store sharedStore];
+ (Store *) sharedStore {
#synchronized(self){
if (sharedStore == nil){
sharedStore = [[self alloc] init];
}
}
return sharedStore;
}
// your init method if you need one
#end
in other words, write:
Store* myStore = [Store sharedStore];
myStore.myString = #"myValue";
and read (in another view controller):
Store* myStore = [Store sharedStore];
myTextField.text = myStore.myString;
If the string remains the same, and never changes, you could make a file named defines.h (without the .m file) and have this line:
#define kMyString #"Some text"
Then wherever you need the string, just import the defines file and use the constant.
#import "defines.h"
Much simpler than making custom classes.
EDIT:
Didn't see you needed to grab from the text field.
In that case, you could have it stored as property of your app delegate class and get it from there. The delegate can be accessed from anywhere in your app.
I've been trying to figure this out but I can't figure out what I'm doing wrong.
I wrote a class and whenever I try to initialize it, I get a EXC_BAD_ACCESS error. I can't even step into the initialization.
Anyone have any idea what I'm doing wrong?
User *myUser = [myUser init];
.h file:
#import <Foundation/Foundation.h>
#interface User : NSObject {
long rowId;
NSString *email;
NSString *password;
NSString *fileVersion;
}
#property long rowId;
#property (assign) NSString *email;
#property (assign) NSString *password;
#property (assign) NSString *fileVersion;
#end
.m file
#import "User.h"
#implementation User
#synthesize rowId, email, password, fileVersion;
-(id)init {
self = [super init];
return self;
}
#end
You have to actually allocate the object:
User *myUser = [[User alloc] init];
Don't forget to release it when you're done using it.
This is really twisting my mind… I'm trying to access an NSMutableArray in an IBAction which I defined in viewDidLoad. Unfortunately I keep getting a EXC_BAD_ACCESS.
I'm new to all this so I'd really appreciate some insight in what I'm doing wrong.
Below find the corresponding code excerpts.
CounterViewController.h:
#interface CounterViewController : UIViewController{
NSMutableArray *countHistoryArray;
}
#property(nonatomic, retain) NSMutableArray *countHistoryArray;
CounterViewController.m:
#implementation CounterViewController
#synthesize countHistoryArray;
- (void)viewDidLoad {
[super viewDidLoad];
//Fill array with some dummy data
self.countHistoryArray = [[NSMutableArray alloc] init];
NSDate *now = [[[NSDate alloc] init] autorelease];
CurrentCount *historicCount = [[[CurrentCount alloc]
initWithCount:[NSNumber numberWithInteger:22]
description:#"Testcount"
dateAndTime:now] autorelease];
[self.countHistoryArray addObject: historicCount];
//Do some logging - everything is working fine here!
NSLog(#"%#", [self.countHistoryArray description]);
}
//Later on we click on a button and want to use the array
- (IBAction)doSomeStuff {
//Let's look at the array again - and now it crashes with EXC_BAD_ACCESS
NSLog(#"%#", [self.countHistoryArray description]);
}
Thanks a lot!
Manuel
EDIT Additional code as asked for by #jamapag
CurrentCount.h
#import <Foundation/Foundation.h>
#interface CurrentCount : NSObject {
NSNumber *counterLevel;
NSString *description;
NSDate *dateAndTime;
}
- (id)initWithCount:(NSNumber *)newCounterLevel description:(NSString *)newDescription dateAndTime:(NSDate *)newDateAndTime;
#property(nonatomic, copy) NSNumber *counterLevel;
#property(nonatomic, copy) NSString *description;
#property(nonatomic, copy) NSDate *dateAndTime;
#end
CurrentCount.m
#import "CurrentCount.h"
#implementation CurrentCount
#synthesize counterLevel;
#synthesize description;
#synthesize dateAndTime;
- (id)initWithCount:(NSNumber *)newCounterLevel description:(NSString *)newDescription dateAndTime:(NSDate *)newDateAndTime{
self = [super init];
if(nil != self){
self.counterLevel = newCounterLevel;
self.description = newDescription;
self.dateAndTime = newDateAndTime;
}
return self;
}
-(void) dealloc{
self.counterLevel = nil;
self.description = nil;
self.dateAndTime = nil;
[super dealloc];
}
#end
Are you sure that your code actually looks like this?
- (IBAction)doSomeStuff {
//Let's look at the array again - and now it crashes with EXC_BAD_ACCESS
NSLog(#"%#", [self.countHistoryArray description]);
}
Your question title says "NSMutableArray count causes EXC_BAD_ACCESS" - if that line of code actually says NSLog(#"%#", [self.countHistoryArray count]);, you'll almost certainly get a crash, since NSLog will attempt to treat a primitive type (the type returned by -[NSArray count]) as an object. In order to use -[NSArray count] in NSLog, use %u instead of %#:
- (IBAction)doSomeStuff {
// This time it should work!
NSLog(#"Array Count = %u", [self.countHistoryArray count]);
}
Remove autorelease from:
currentCount *historicCount = [[[CurrentCount alloc]
initWithCount:[NSNumber numberWithInteger:22]
description:#"Testcount"
dateAndTime:now] autorelease];
It looks like you are accidentally releasing countHistoryArray somewhere. Try removing all calls to it except for those two you showed. Additionally you can try enabling zombies to debug the problem.
Oh and by the way you probably don't really want a public NSMutableArray property and if you do you probably want it to be copy, not retain. Otherwise incapsulation kinda goes down the drain.
I know this question has already been solved and accepted but its for others who are or will face this issue.
I was facing the same issue, I tried all solutions but no solution worked for me. The project I am working on is NON-ARC.
I tried and made a simple change in property
Previously my property for NSMUTABLEARRAY was
#property (nonatomic, assign) NSMutableArray * dataArray;
I changed it to:
#property (nonatomic, retain) NSMutableArray * dataArray;
Changed it from ASSIGN to RETAIN
And it solved my problem