Question

有没有办法在iPhone的[self performSelector]方法中传递参数？以及在此方法中传递最大参数的数量是多少？如果是，那么请发送任何链接或任何想法来开发此功能。

Answer 1

如果您想传递不超过两个参数，请使用

之一

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

如果您需要传递更多参数，请使用NSInvocation。以下是docs。

UPD：这是一个NSInvocation示例。比如，您要将doThis:andThis:andThis:发送到targetObject类型的MyClass：

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 2

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

侧击

Answer 3

总体而言，您有三种可能性：

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

第一个根本就没有参数;第二个，一个论点;第三，两个论点。

Answer 4

您只能使用performSelector

传递一个参数

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

Answer 5

NSObject有这些：

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

和

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

您始终可以将anObject设置为NSArray，NSDictionary或其他包含参数的自定义类

Answer 6

对于多个对象 - 只需使用对象创建数组/字典并将此数组/字典传递给

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

iPhone：如何在执行选择器方法中传递参数？

6 个答案: