@interface NSObject (Exchange)

-(void)swizzleMethod:(SEL)OldSel withNewMethod:(SEL)NewSel;

 @end#import 

 "NSObject+Exchange.h"

@implementation NSObject (Exchange)

-(void)swizzleMethod:(SEL)OldSel withNewMethod:(SEL)NewSel

{

 Class selfclass=[self class]; 

Method oldMethod=class_getInstanceMethod(selfclass, OldSel);

 Method newMethod=class_getInstanceMethod(selfclass, NewSel); 

BOOL addselector=class_addMethod(selfclass, OldSel, class_getMethodImplementation(selfclass, NewSel), method_getTypeEncoding(newMethod));

 if (addselector) {

 NSLog(@"加方法成功"); 

class_replaceMethod(selfclass, NewSel, class_getMethodImplementation(selfclass, OldSel), method_getTypeEncoding(oldMethod)); 

}else { 

method_exchangeImplementations(oldMethod, newMethod); 

} }

 #import "NSObject+Exchange.h"

@interface NSArray (CheckIndex)

@end

#import "NSArray+CheckIndex.h"

@implementation NSArray (CheckIndex)

+(void)load{

 SEL [email protected](objectAtIndex:); 

SEL [email protected](emptycheckObjectAtIndex:); 

SEL [email protected](arrayIcheckObjectAtIndex:); 

SEL [email protected](arrayMcheckObjectAtIndex:);

 [objc_getClass("__NSArray0") swizzleMethod:oldSel withNewMethod:newSel]; 

[objc_getClass("__NSArrayI") swizzleMethod:oldSel withNewMethod:newSel1];

 [objc_getClass("__NSArrayM") swizzleMethod:oldSel withNewMethod:newSel2];

[objc_getClass("__NSSingleObjectArrayI") swizzleMethod:@selector(objectAtIndex:) swizzledSelector:@selector(singleObjectIndex:)];

 }

-(id)emptycheckObjectAtIndex:(NSInteger)index{ 

if (self.count>index) { 

return [self emptycheckObjectAtIndex:index]; }else{ return nil; 

}

}

-(id)arrayIcheckObjectAtIndex:(NSUInteger)index{

 NSLog(@"檢查");

 if (self.count>index) { return [self arrayIcheckObjectAtIndex:index];

 }else{

 return nil;

 }}

-(id)arrayMcheckObjectAtIndex:(NSUInteger)index{ 

NSLog(@"檢查"); if (self.count>index) { 

 return [self arrayMcheckObjectAtIndex:index]; 

 }else{ 

return nil; 

 }

 }

-(id)singleObjectIndex:(NSInteger )index

{

if (index >= self.count || index < 0) {

returnnil;

    }

return [selfsingleObjectIndex:index];

}