我想检查一个NSDictionary
是否为空。我是这样做的。
mutDictValues = [[[NSUserDefaults standardUserDefaults] objectForKey:@"dicValues"]mutableCopy];
NSLog(@"dictValues are %@",mutDictValues);
if(mutDictValues == NULL){
arrCities = [[NSMutableArray alloc]init];
NSLog(@"no cities seleceted");
}else{
arrCities = [[NSMutableArray alloc]init];
arrCities = [mutDictValues objectForKey:@"cities"];
[self placeCities];
}
但总是在这一行崩溃了 arrCities = [mutDictValues objectForKey:@"cities"];
并显示以下错误:
-[__NSCFConstantString objectForKey:]:
有人能帮我解决这个问题吗?