第17月第7天 iOS 數組越界，防Crash處理

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上面方法已經可以避免crash，為了避免冗餘的代碼，寫一個NSArray的分類，利用runtime替換NSArray的對象方法objectAtIndex：，在這裡進行判斷，捕獲異常：#import <Foundation/Foundation.h>@interface NSArray (Crash)@end/*** ---------------分割線--------------- ***/ #import "NSArray+Crash.h"#import <objc/runtime.h>@implementation NSArray (Crash)+ (void)load{    [super load];        //替換不可變數組方法    Method oldObjectAtIndex = class_getInstanceMethod(objc_getClass("__NSArrayI"), @selector(objectAtIndex:));    Method newObjectAtIndex = class_getInstanceMethod(objc_getClass("__NSArrayI"), @selector(objectAtSafeIndex:));    method_exchangeImplementations(oldObjectAtIndex, newObjectAtIndex);        //替換可變數組方法    Method oldMutableObjectAtIndex = class_getInstanceMethod(objc_getClass("__NSArrayM"), @selector(objectAtIndex:));    Method newMutableObjectAtIndex =  class_getInstanceMethod(objc_getClass("__NSArrayM"), @selector(mutableObjectAtSafeIndex:));    method_exchangeImplementations(oldMutableObjectAtIndex, newMutableObjectAtIndex);}- (id)objectAtSafeIndex:(NSUInteger)index{    if (index > self.count - 1 || !self.count) {        @try {            return [self objectAtSafeIndex:index];        }        @catch (NSException *exception) {            NSLog(@"exception: %@", exception.reason);            return nil;        }            }else {        return [self objectAtSafeIndex:index];    }}- (id)mutableObjectAtSafeIndex:(NSUInteger)index{    if (index > self.count - 1 || !self.count) {        @try {            return [self mutableObjectAtSafeIndex:index];        }        @catch (NSException *exception) {            NSLog(@"exception: %@", exception.reason);            return nil;        }            }else {        return [self mutableObjectAtSafeIndex:index];    }}@end

http://blog.csdn.net/hero_wqb/article/details/78531218

 

第17月第7天 iOS 數組越界，防Crash處理