iPhone：如何在執行選擇器方法中傳遞參數？

Question

在iPhone中有沒有什麼辦法在[self performSelector]方法中傳參數？這個方法中有多少個最大參數？如果是的話，請給我任何鏈接或任何想法來開發此功能。

Answer 1

http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Protocols/NSObject_Protocol/Reference/NSObject.html#//apple_ref/occ/intfm/NSObject/performSelector:withObject：

使用

- (id)performSelector:(SEL)aSelector withObject:(id)anObject 

側擊

Answer 2

可以傳遞只有一個參數與performSelector

[self performSelector:@selector(aSelector) withObject:(id)object]; 

Answer 3

NSObject的有以下：

- (id)performSelector:(SEL)aSelector withObject:(id)anObject 

和

- (id)performSelector:(SEL)aSelector withObject:(id)anObject withObject:(id)anotherObject 

你總是可以讓anObject是一個NSArray，NSDictionary的或其他自定義類，將包含參數爲你

Answer 4

你有三種可能性，整體：

1. – performSelector: 
2. – performSelector:withObject: 
3. – performSelector:withObject:withObject: 

第一個根本沒有論據;第二，一個論點;第三，兩個論點。

Answer 5

如果你想通過不超過兩個參數，使用

- (id)performSelector:(SEL)aSelector 
- (id)performSelector:(SEL)aSelector withObject:(id)anObject 
- (id)performSelector:(SEL)aSelector withObject:(id)anObject withObject:(id)anotherObject 

之一，如果你需要傳遞更多的參數，使用NSInvocation。這裏是docs。

UPD：這裏是一個NSInvocation的例子。再說了，你要發送doThis:andThis:andThis:到targetObjectMyClass類型：

SEL message = @selector(doThis:andThis:andThis:); 
NSMethodSignature *signature = [MyClass methodSignatureForSelector:message]; 
NSInvocation  *invocation = [NSInvocation invocationWithMethodSignature:signature]; 

[invocation setTarget:targetObject]; 
[invocation setSelector:message]; 
[invocation setArgument:&fist atIndex:2]; // Note that you need to put & 
[invocation setArgument:&second atIndex:3]; // as you send a pointer 
[invocation setArgument:&third atIndex:4]; // Also the indexing starts from 2 
              // 0 is for target, 1 is for selector 
[invocation invoke]; 

Answer 6

多個對象 - 只需創建你的對象數組/字典，並通過這個數組/詞典

[self performSelector:@selector(aSelector) withObject:myArray];