NSCFArray insertObject:atIndex:崩溃问题

用  [[NSUserDefaults standardUserDefaults]setObject:self.dataArrayforKey:@"exsentionKeysArray"];存数组的时候，取值会遇到[NSCFArray insertObject:atIndex:]: mutating method sent to immutable obje崩溃的问题

在网上搜索下实测：再声明一个可变数组进行操做就不会崩溃了。

NSMutableArray *newArray = [[NSUserDefaults standardUserDefaults]objectForKey:@"exsentionKeysArray"];

    self.dataArray = [NSMutableArray new];

    if (newArray){

        self.dataArray = [NSMutableArray arrayWithArray:newArray];

    }