UIPickerView和空核心数据数组

Question

我有一个viewcontroller显示来自核心数据实体的项目。我还有一个tableview列出来自同一实体的记录。该表是可编辑的，用户可以删除所有记录。发生这种情况时，视图控制器持有pickerview炸弹，因为它正在寻找空数组中的记录。怎么预防这个？我假设我需要在objectAtIndex做一些不同的事情：row ...

# pragma mark PickerView Section

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
    return 1;  // returns the number of columns to display.
}

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
    return [profiles count];  // returns the number of rows
}

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    // Display the profiles we've fetched on the picker
    Profiles *prof = [profiles objectAtIndex:row];
    return prof.profilename;

}

//If the user chooses from the pickerview

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
    selectedProfile = [[profiles objectAtIndex:row]valueForKey:@"profilename"];
}

编辑*的 *

好的，我找到了导致问题的原因......在PickerView上我设置了默认值..

self.profiles = [[self.managedObjectContext executeFetchRequest:fetchRequest error:nil] mutableCopy];

selectedProfile = [[profiles objectAtIndex:0]valueForKey:@"profilename"];

[pickerView reloadAllComponents];

当我把它拿出来时，它就像一个冠军。