NSCFArray insertObject:atIndex:崩潰問題

用  [[NSUserDefaults standardUserDefaults]setObject:self.dataArrayforKey:@"exsentionKeysArray"];存數組的時候，取值會遇到[NSCFArray insertObject:atIndex:]: mutating method sent to immutable obje崩潰的問題

在網上搜索下實測：再聲明一個可變數組進行操做就不會崩潰了。

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

    self.dataArray = [NSMutableArray new];

    if (newArray){

        self.dataArray = [NSMutableArray arrayWithArray:newArray];

    }