如何保持内存中的variables，直到应用程序退出
我在iOS中有一个单例对象，在实例化时parsing一个CSV文件，然后保存结果。 我想使这个对象普遍可访问，我希望它不会从内存中释放，直到应用程序退出。 我正在运行ARC，所以我不能手动保留。
有没有办法可以做到这一点，所以它会与ARC工作？
头文件：
#import <Foundation/Foundation.h> #import "CHCSV.h" #import "RCParserObject.h" @interface ParserStore : NSObject <CHCSVParserDelegate> { // CSV Variables RCParserObject *item; NSMutableArray *data; NSMutableArray *parsedData; int fields; bool open; } @property (atomic, retain) RCParserObject *item; @property (atomic, retain) NSMutableArray *data; @property (atomic, retain) NSMutableArray *parsedData; @property (atomic) int fields; @property (atomic) bool open; + (ParserStore *) defaultStore; - (void) parseCSVFile:(NSString*)file; - (void) categorizeData; 实施文件
#import "ParserStore.h" #import "RCParserObject.h" #import "RCDetailItem.h" static ParserStore *defaultStore; @implementation ParserStore @synthesize item, data, parsedData, fields, open; # pragma mark - # pragma mark Singleton Methods + (ParserStore *) defaultStore { if (!defaultStore) { defaultStore = [[super allocWithZone:NULL] init]; } return defaultStore; } + (id) allocWithZone:(NSZone *)zone { return [self defaultStore]; } - (id) init { NSLog(@"Running init on parser store"); if (defaultStore) { NSLog(@"Self data count is %d, right before return", self.parsedData.count); return defaultStore; } // NSLog(@"This better only happen once"); self = [super init]; [self setParsedData:[[NSMutableArray alloc] init]]; [self parseCSVFile:@"ContentNoPathFileExt2ASCII"]; [self categorizeData]; // NSLog(@"Self data count is %d when first created", self.parsedData.count); return self; } @property (atomic, retain) RCParserObject *item; @property (atomic, retain) NSMutableArray *data; @property (atomic, retain) NSMutableArray *parsedData; @property (atomic) int fields; @property (atomic) bool open; + (ParserStore *) defaultStore; - (void) parseCSVFile:(NSString*)file; - (void) categorizeData; @end
+(MySingleton *)singleton { static dispatch_once_t pred; static MySingleton *shared = nil; dispatch_once(&pred, ^{ shared = [[MySingleton alloc] init]; shared.someVar = someValue; // if you want to initialize an ivar }); return shared; }
从任何地方：
NSLog(@"%@",[MySingleton singleton].someVar);
请注意，你的iOS应用程序已经有一个你可以在任何地方访问的单身人士：
AppDelegate *delegate = (AppDelegate*)[[UIApplication sharedApplication] delegate];
一个简单的单身人士会像…在.h：
@interface Foo : NSObject + (Foo *)sharedInstance; @end
在.m中：
static Foo *_foo = nil; @implementation Foo + (Foo *)sharedInstance { if (!_foo) _foo = [[Foo alloc] init]; return _foo; } @end