NSTimer的暂停与恢复

NSTimer+Pausing.h

 

#import <Foundation/Foundation.h>

@interface NSTimer (Pausing)

- (NSMutableDictionary *)pauseDictionary;
- (void)pause;
- (void)resume;

@end

 

NSTimer+Pausing.m

 

#import "NSTimer+Pausing.h"

NSString *kIsPausedKey = @"IsPaused Key";
NSString *kRemainingTimeIntervalKey	= @"RemainingTimeInterval Key";

@implementation NSTimer (Pausing)

- (NSMutableDictionary *)pauseDictionary {
	static NSMutableDictionary *globalDictionary = nil;
    
	if(!globalDictionary)
		globalDictionary = [[NSMutableDictionary alloc] init];
	
	if(![globalDictionary objectForKey:[NSNumber numberWithInt:(int)self]]) {
		NSMutableDictionary *localDictionary = [[[NSMutableDictionary alloc] init] autorelease];
		[globalDictionary setObject:localDictionary forKey:[NSNumber numberWithInt:(int)self]];
	}
	
	return [globalDictionary objectForKey:[NSNumber numberWithInt:(int)self]];
}

- (void)pause {
	if(![self isValid])
		return;
	
	NSNumber *isPausedNumber = [[self pauseDictionary] objectForKey:kIsPausedKey];
	if(isPausedNumber && YES == [isPausedNumber boolValue])
		return;
	
	NSDate *now	= [NSDate date];
	NSDate *then = [self fireDate];
	NSTimeInterval remainingTimeInterval = [then timeIntervalSinceDate:now];
    
	[[self pauseDictionary] setObject:[NSNumber numberWithDouble:remainingTimeInterval] forKey:kRemainingTimeIntervalKey];
	
	[self setFireDate:[NSDate distantFuture]];
	[[self pauseDictionary] setObject:[NSNumber numberWithBool:YES] forKey:kIsPausedKey];
}

- (void)resume {
	if(![self isValid])
		return;
    
	NSNumber *isPausedNumber = [[self pauseDictionary] objectForKey:kIsPausedKey];
	if(!isPausedNumber || NO == [isPausedNumber boolValue])
		return;
	
	NSTimeInterval remainingTimeInterval = [[[self pauseDictionary] objectForKey:kRemainingTimeIntervalKey] doubleValue];
	
	NSDate *fireDate = [NSDate dateWithTimeIntervalSinceNow:remainingTimeInterval];
	
	[self setFireDate:fireDate];
	[[self pauseDictionary] setObject:[NSNumber numberWithBool:NO] forKey:kIsPausedKey];
}

@end