如何在应用程序退出之前在内存中保留一个变量 [英] How to keep a variable in memory until the app quits
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问题描述
我在iOS中有一个单例对象,它在实例化时解析一个CSV文件,然后保存结果。我想使这个对象可以普遍访问,并且我希望它不会在应用程序退出之前从内存中释放。我正在运行ARC,因此我无法进行手动保留。
I have a singleton object in iOS that when instantiated parses a CSV file and then holds the results. I would like to make this object universally accessible and I would like it to not be released from memory until the app quits. I am running ARC so I cannot do manual retains.
有没有一种方法可以做到这一点,以便它能与ARC一起工作?
Is there a way I can do this so it will work with ARC?
头文件:
Header File:
#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;
实施档案
Implementation File
#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
推荐答案
+(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;
}
来自任何地方:
From anywhere:
NSLog(@"%@",[MySingleton singleton].someVar);
请注意,您的iOS应用已经有了一个您可以随时访问的单身人士:
Note that your iOS app already has a singleton that you can access anywhere:
AppDelegate *delegate = (AppDelegate*)[[UIApplication sharedApplication] delegate];
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