How to check NSArray is null or empty in iOS?

After a NSArray was alloc and init, if there is nothing adde开发者_如何转开发d to the NSArray, how to check it is null or empty ?

Thanks.

if (array == nil || [array count] == 0) {
    ...
}

NSArray has the count method, a common way to do it would be...

if (![self.myArray count])
{
}

That will check if the array has nothing in it, or if it is set to nil.

While we are all throwing out the same answers, I thought I would too.

if ([array count] < 1) {
    ...
}

and another

if(!array || array.count==0)

if([myarray count]) It checks for both not empty and nil array.

Try this one

if(array == [NSNull null] || [array count] == 0) {
}

if([arrayName count]==0)
{
    //array is empty.
}
else
{
   //array contains some elements.
}

You can use this :

if (!anArray || [anArray count] == 0) {
    /* Your code goes here */
}

use

(array.count ? array : nil)

It will return nil if array = nil as well as [array count] == 0

if (array == nil && [array count] == 0) {
...
}

I use this code because I am having trouble to my pickerview when its the array is empty

My code is

- (IBAction)btnSelect:(UIBarButtonItem *)sender { // 52
if (self.array != nil && [self.array count] != 0) {
    NSString *select = [self.array objectAtIndex:[self.pickerView selectedRowInComponent:0]];

    if ([self.pickListNumber isEqualToString:@"1"]) {
        self.textFieldCategory.text = select;
        self.textFieldSubCategory.text = @"";
    } else if ([self.pickListNumber isEqualToString:@"2"]) {
        self.textFieldSubCategory.text = select;
    }

    [self matchSubCategory:select];
} else {
    UIAlertView *myAlertView = [[UIAlertView alloc] initWithTitle:@"Error"
                                                          message:@"You should pick Category first"
                                                         delegate:nil
                                                cancelButtonTitle:@"OK"
                                                otherButtonTitles: nil];
    [myAlertView show];
}

[self hidePickerViewContainer:self.viewCategory];
}