[英]how call nsurlconnection delegate methods continuosly in iphone
[英]how to call delegate method, iphone
鉴于:
- classA及其委托
- classB上有一个按钮
classA.h
@protocol classADelegate <NSObject>
- (void)method:(NSString *) name;
@end
@interface StoreChooser : UIViewController
@end
------------------------------------------------------
classA.m
-(IBAction)buttonCliked{
// invoke delegate method from classA at here
}
classB.h
@interface classB : UIViewController <classADelegate>
@end
------------------------------------------------------
// Conform delegate of classA
classB.m
- (void)method:(NSString *) name {
} @结束 - - - - - - - - - - - - - - - - - - - - - - - - -------
我的目标:我需要classB在buttonClicked动作中从classA调用方法委托
问题 :我应该怎么做才能实现自己的目标。
只是为了确保我们在同一页面上:)
如果ClassA
具有委托ClassADelegate
。 这意味着当ClassA
发生某个“事件”时, ClassA
将要通过其委托通知其他某些类“事件”发生了ClassB
。 ClassA
将通过其委托ClassADelegate
进行此ClassADelegate
。
为此, ClassB
必须让ClassA
知道它将充当ClassA
的委托。 通过实施协议中列出的未标记为@optional的所有方法, ClassB
必须“符合” ClassA
的协议。
在代码中,您可以这样做:
// ClassA's delegate
@protocol ClassADelegate <NSObject>
- (void) didDoSomethingCool:(NSString *) name;
@end
// ClassA definition
@interface ClassA
// We'll use this property to call the delegate.
// id<XXX> means that which ever class is assigned to id MUST conform to XXX
@property (nonatomic, assign) id<ClassADelegate> classADelegate;
- (void) doSomething;
@end
// Class A implementation
@implementation ClassA
@synthesize classADelegate;
- (void) doSomething
{
// Do cool things here.
// Now call delegate, in this example, this will be ClassB
[classADelegate didDoSomethingCool:@"Hello from Class A"];
}
现在我们需要连接ClassB
以便可以通知ClassA
发生了一些事情:
// ClassB definition
@interface ClassB<ClassADelegate>
// ClassB<ClassADelegate> lets the compiler know that ClassB is required to have all the
// non-optional method that are listed in ClassADelegate. In short, we say that
// ClassB conforms to the ClassADelegate.
{
ClassA *_classA;
}
@end
现在,在ClassB
的实现文件中的某处,我们具有以下内容。
// ClassB implementation
@implementation ClassB
- (id) init
{
self = [super init];
if(self)
{
// Just quickly creating an instance of ClassA.
_classA = [ClassA new];
// This is were we tell ClassA that ClassB is its delegate.
_classA.classADelegate = self;
}
return self;
}
- (void) dealloc
{
[_classA release];
[super dealloc];
}
- (void) didDoSomethingCool:(NSString *) name
{
// This is the method that ClassA will be calling via the
// [classADelegate didDoSomethingCool:@"Hello from Class A"] method call.
}
@end
我希望这有帮助 :)
将分配属性添加到classA:
@property (nonatomic, assign) id<classADelegate> delegate;
然后在classB的viewDidLoad方法中,调用:
[myClassAObject setDelegate:self];
然后在A类中,只需调用:
if (_delegate && [_delegate respondsToSelector:@selector(method:)]) {
[_delegate method:@"string"];
}
ClassB需要对ClassA的引用。 该代码虽然不完整,但是应该可以帮助您了解需要创建的关系。
B类
@interface classB: UIViewController <classADelegate>
@property (weak, nonatomic) id<classADelegate> delegate;
@end
班级
-(id)init {
self = [super init];
if (self) {
self.delegate = [[classADelegate alloc] init];
}
}
-(IBAction)buttonClicked {
[delegate method:@"name"];
}
您需要将委托对象存储在classA中:
@interface classA : NSObject
{
id<classADelegate> _delegate;
}
@property (nonatomic, assign, readwrite) id<classADelegate> delegate;
并综合属性:
@implementation classA
...
@synthesize delegate = _delegate;
然后在需要调用委托的方法中,您需要测试委托对象和方法是否有效:
- (void)somethingHappened
{
if ([_delegate respondsToSelector:@selector(method:)])
{
[_delegate method:@"Andy"];
}
}
并最终符合B类中的委托协议:
@implementation classB
...
- (void)method:(NSString *)name
{
[self buttonCliked:nil];
}
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