objective-c protocol delegateprotocol-协议,就是使用了这个协议后就要按照这个协议来办事,协议要求实现的方法就一定要实现。 delegate-委托,顾名思义就是委托别人办事,就是当一件事情发生后,自己不处理,让别人来处理。当一个A view 里面包含了B viewb view需要修改a view界面,那么这个时候就需要用到委托了。需要几个步骤1。首先定一个协议2。a view实现协议中的方法3。b view设置一个委托变量4。把b view的委托变量设置成a view,意思就是 ,b view委托a view办事情。5。事件发生后,用委托变量调用a view中的协议方法例子:B_View.h:@protocol UIBViewDelegate <NSObject>
@optional- (void)ontouch:(UIScrollView *)scrollView; //声明协议方法@end@interface BView : UIScrollView<UIScrollViewDelegate> { id< UIBViewDelegate > _touchdelegate; //设置委托变量}@property(nonatomic,assign) id< UIBViewDelegate > _touchdelegate; @endB_View.mm:@synthesize _touchdelegate;- (id)initWithFrame:(CGRect)frame { if (self = [super initWithFrame:frame]) { // Initialization code _touchdelegate=nil; } return self;}- (void) touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event{ [super touchesBegan:touches withEvent:event]; if(_touchdelegate!=nil && [_touchdelegate respondsToSelector: @selector(ontouch:) ] == true) [_touchdelegate ontouch:self]; //调用协议委托}@endA_View.h:@interface AViewController : UIViewController < UIBViewDelegate >{ BView *m_BView;}@endA_View.mm:- (void)viewWillAppear:(BOOL)animated{ m_BView._touchdelegate = self; //设置委托 [self.view addSubview: m_BView];}- (void)ontouch:(UIScrollView *)scrollView{ //实现协议}