1、利用NSUserDefaults来传值，这种方法只限于传少量数据的情形：
比如你要传一个float的值，在需要传的时候用
[[NSUserDefaults standardUserDefaults] setFloat:float forKey::@"float"]
接收值的时候用
[[NSUserDefaults standardUserDefaults] floatForKey:@"float"]
2、NSNotificationCenter来传值
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch * touch = [touches anyObject];
CGPoint point = [touch locationInView:self];
CGRect roundRect = [self rectNeedRefreshFromThisPoint:point];
mLastPoint = CGPointMake(-1, -1);
NSLog(@"%s: point(%f,%f)", __FUNCTION__, point.x, point.y);
[self addToCurrentLineWithPoint:point.x y:point.y];
[self endLine];
[self setNeedsDisplayInRect:roundRect];
NSNumber *pointX = [NSNumber numberWithFloat:point.x];
NSNumber *pointY = [NSNumber numberWithFloat:point.y];
NSDictionary *pointDict = [NSDictionary dictionaryWithObjectsAndKeys:pointX,@"pointX",pointY,@"pointY", nil];
[[NSNotificationCenter defaultCenter]postNotificationName:@"passTouchedEndPointMsg" object:self userInfo:pointDict];
}
在消息中心的函数：
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(getTouchedPoint:)
name:@"passTouchedEndPointMsg"
object:nil];
- (void) getTouchedPoint:(NSNotification *)noti
{
NSDictionary *pointDict = [noti userInfo];
touchedEndPointX = [[pointDict objectForKey:@"pointX"] floatValue];
touchedEndPointY = [[pointDict objectForKey:@"pointY"] floatValue];
NSLog(@"%f:%f",touchedEndPointX,touchedEndPointY);
}
用消息来传参数有下面几点说法：object指的是发送者、在poseter端的userInfo里面可以存放要传的参数，必须为NSDictionary类型。在center端获取这个dictionary类型用:[notification userInfo];来获取
本文转自编程小翁博客园博客，原文链接：http://www.cnblogs.com/wengzilin/archive/2012/03/16/2400404.html，如需转载请自行联系原作者
