由于之前做项目的时候，时不时会有无法预见的错误，导致App上线了，Crash的时候，用户体验非常不好。查过各方面的资料后，决定把这些无法预见的Crash给解决的，至少先保证App能正常用。

想了下，其实也不难，就是对NSString、NSMutableString、NSArray、NSMutableArray、NSDictionary、NSMutableDictionary、KVO 这些常用的类方法做了方法替换，数组索引越界、字典数据对象为nil的异常处理

@implementation NSArray (GJNoCrash)
void array_method_exchangeImplementations(Class cls, SEL name, SEL name2) {
    
    Method fromMethod = class_getInstanceMethod(cls, name);
    Method toMethod = class_getInstanceMethod(cls, name2);
    method_exchangeImplementations(fromMethod, toMethod);
}

+ (void)load
{
    Class __NSArray     = objc_getClass("NSArray");
    Class __NSArrayI    = objc_getClass("__NSArrayI");
    Class __NSArray0    = objc_getClass("__NSArray0");
    Class __NSSingleObjectArrayI = objc_getClass("__NSSingleObjectArrayI");
    
    array_method_exchangeImplementations(__NSArray, @selector(arrayWithObjects:count:), @selector(safeArrayWithObjects:count:));
    array_method_exchangeImplementations(__NSArray, @selector(objectsAtIndexes:), @selector(safeObjectsAtIndexes:));
    array_method_exchangeImplementations(__NSArrayI, @selector(objectAtIndexedSubscript:), @selector(safeObjectAtIndexedSubscript:));
    array_method_exchangeImplementations(__NSArray0, @selector(objectAtIndex:), @selector(safeObjectAtIndexedNullarray:));
    array_method_exchangeImplementations(__NSSingleObjectArrayI, @selector(objectAtIndex:), @selector(safeObjectAtIndexedArrayCountOnlyOne:));
    
    array_method_exchangeImplementations(__NSArray, @selector(getObjects:range:), @selector(safeGetObjectsArray:range:));
    array_method_exchangeImplementations(__NSArrayI, @selector(getObjects:range:), @selector(safeGetObjectsArrayI:range:));
    array_method_exchangeImplementations(__NSSingleObjectArrayI, @selector(getObjects:range:), @selector(safeGetObjectsNSSingleObjectArrayI:range:));
    
}

- (instancetype)safeArrayWithObjects:(const id  _Nonnull __unsafe_unretained *)objects count:(NSUInteger)cnt
{
    id instance = nil;
    
    @try {
        instance = [self safeArrayWithObjects:objects count:cnt];
    }
    @catch (NSException *exception) {
        
        //以下是对错误数据的处理，把为nil的数据去掉,然后初始化数组
        NSInteger newObjsIndex = 0;
        id  _Nonnull __unsafe_unretained newObjects[cnt];
        
        for (int i = 0; i < cnt; i++) {
            if (objects[i] != nil) {
                newObjects[newObjsIndex] = objects[i];
                newObjsIndex++;
            }
        }
        instance = [self safeArrayWithObjects:newObjects count:newObjsIndex];
    }
    @finally {
        return instance;
    }
}
@end

大概原理就是这样

常见异常

NSString *s = @"aa";
NSString *ss = [s substringFromIndex:10];
NSLog(@"ss:%@", ss);
        
NSMutableString *s = [NSMutableString stringWithFormat:@"aaaa"];
NSString *ss = [s stringByReplacingCharactersInRange:NSMakeRange(10, 10) withString:@"bb"];
NSLog(@"ss:%@", ss);
        
NSArray *a = [NSArray array];
id v = [a objectAtIndex:10];
NSLog(@"array index 10 :%@", v);
        
NSMutableArray *array = [NSMutableArray array];
[array addObject:nil];
NSLog(@"NSMutableArray:%@", array);
        
NSMutableDictionary *dict = [NSMutableDictionary dictionary];
[dict setObject:nil forKey:@"key1"];
[dict setObject:@"value1" forKey:nil];
[dict setObject:@"value2" forKey:@"key2"];
NSLog(@"NSMutableDictionary:%@", dict);

我把这些整合发布到pod上去了。

pod search GJNoCrash

Crash log 处理有两种方式

#import "GJCrashLog.h"
//方法1 block方法
[[GJCrashLog manager] callbackCrashLog:^(NSString *crashLog) {
          //处理crashlog
}];

//方法2 delegate方式
[GJCrashLog manager].delegate = self;
//GJCrashLog Delegate
-(void)callbackGJCrashLog:(NSString *)crashLog
{
    //处理crashlog
}

github地址在这里