Disable right bar button when selected equals 0 - ios

Question

The below code for the most part works when selecting items, the bar button enables, but as soon as I unselect 1 with say 3 still selected, it disables.
How can I use the below code to disable when the count reaches 0 items selected?
- (void)assetsTableViewCell:(WSAssetsTableViewCell *)cell didSelectAsset:(BOOL)selected atColumn:(NSUInteger)column
{
NSIndexPath *indexPath = [self.tableView indexPathForCell:cell];
// Calculate the index of the corresponding asset.
NSUInteger assetIndex = indexPath.row * self.assetsPerRow + column;
WSAssetWrapper *assetWrapper = [self.fetchedAssets objectAtIndex:assetIndex];
assetWrapper.selected = selected;
// Update the state object's selectedAssets.
[self.assetPickerState changeSelectionState:selected forAsset:assetWrapper.asset];
// Update navigation bar with selected count and limit variables
dispatch_async(dispatch_get_main_queue(), ^{
if (self.assetPickerState.selectionLimit) {
self.navigationItem.title = [NSString stringWithFormat:#"%# (%lu/%ld)", [self.assetsGroup valueForProperty:ALAssetsGroupPropertyName], (unsigned long)self.assetPickerState.selectedCount, (long)self.assetPickerState.selectionLimit];
}
});
}
Below is what needs adjusting.
if (selected == 1) {
self.navigationItem.rightBarButtonItem.enabled = YES;
} else if (selected == 0) {
self.navigationItem.rightBarButtonItem.enabled = NO;
}

Answer 1

selected will give you the state of the current asset so it wouldn't be wise to check this.
We need to check for some kinda global thing; basically to check for previous selections.
Looking at your navigationItem.title, it seems assetPickerState.selectedCount should do the trick.
So... maybe this?? (not sure but anyways...)
if (self.assetPickerState.selectedCount == 0) {
self.navigationItem.rightBarButtonItem.enabled = NO;
}
else {
self.navigationItem.rightBarButtonItem.enabled = YES;
}

Answer 2

Looks like you're only explicitly enabling the button when you have 1 selected (not more than that). Just going out on a whim but this might work (only disable if zero, otherwise enable it).
if (selected == 0) {
self.navigationItem.rightBarButtonItem.enabled = NO;
} else {
self.navigationItem.rightBarButtonItem.enabled = YES;
}