-(BOOL) isKindOfClass: classObj 用來判斷是否是某個類或其子類的實例
-(BOOL) isMemberOfClass: classObj 用來判斷是否是某個類的實例
-(BOOL) respondsToSelector: selector 用來判斷是否有以某個名字命名的方法(被封裝在一個selector的對象裏傳遞)
+(BOOL) instancesRespondToSelector: selector 用來判斷實例是否有以某個名字命名的方法. 和上面一個不同之處在於, 前面這個方法可以用在實例和類上，而此方法只能用在類上.
-(id) performSelector: selector
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注意：沒有實現notImp方法
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SEL sel = @selector (start:) ; // 指定action
if ([obj respondsToSelector:sel])
{ //判斷該對象是否有相應的方法
[obj performSelector:sel withObject:self]; //調用選擇器方法
}
使用[[UIApplication sharedApplication] keyWindow]查找應用程序的主窗口對象
respondsToSelector判斷是否實現了某方法
Tester.h
#import <Foundation/Foundation.h>
@interface Tester : NSObject {
}
-(void) test:(NSString*) msg;
-(void) notImp;
@end
@interface Tester : NSObject {
}
-(void) test:(NSString*) msg;
-(void) notImp;
@end
Tester.m
#import "Tester.h"
@implementation Tester
-(void) test:(NSString*) msg
{
NSLog(@"%@", msg);
}
@end
@implementation Tester
-(void) test:(NSString*) msg
{
NSLog(@"%@", msg);
}
@end
main.m
#import <Foundation/Foundation.h>
#import "Tester.h"
int main (int argc, const char * argv[])
{
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
id tester = [[Tester alloc] init];//注意，這裏使用id
SEL testSelector = @selector(test:);
SEL notImpSelector = @selector(notImp:);
if([tester respondsToSelector:testSelector])
{
//tester.m中實現了test方法
[tester test:@"invoke test method"];
}
if([tester respondsToSelector:notImpSelector])
{
//test.m中沒有實現此主就去
[tester notImp];
}
[pool drain];
return 0;
}
#import "Tester.h"
int main (int argc, const char * argv[])
{
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
id tester = [[Tester alloc] init];//注意，這裏使用id
SEL testSelector = @selector(test:);
SEL notImpSelector = @selector(notImp:);
if([tester respondsToSelector:testSelector])
{
//tester.m中實現了test方法
[tester test:@"invoke test method"];
}
if([tester respondsToSelector:notImpSelector])
{
//test.m中沒有實現此主就去
[tester notImp];
}
[pool drain];
return 0;
}
