通過runtime的method_exchangeImplementations(Method m1, Method m2)方法,
可以進行交換方法的實作;一般用自己寫的方法來替換系統的方法實作
例如:數組(字典)中不能添加nil,如果添加程式會崩,用自己的方法替換系統防止系統崩潰
下面直接上代碼
#import "NSMutableArray+YSExtension.h"
#import <objc/runtime.h>
@implementation NSMutableArray (YSExtension)
+ (void)load {
Method orginalMethod = class_getInstanceMethod(NSClassFromString(@"__NSArrayM"), @selector(addObject:));
Method newMethod = class_getInstanceMethod(NSClassFromString(@"__NSArrayM"), @selector(newAddobject:));
method_exchangeImplementations(orginalMethod, newMethod);
}
- (void)newAddobject:(id)obj {
if (obj != nil) {
[self newAddobject:obj];
}else{
[self newAddobject:@""];
}
}
@end
轉載于:https://www.cnblogs.com/lcl15/p/7417688.html