Animation in willSelectRowAtIndexPath after validation - ios

Question

I have a table view delegate which checks if a specific cell may be selected. If not, the selection is aborted. In order to give the user a visual feedback I want to dye a label of this cell red and after a short amount of time dye it back to black:
- (NSIndexPath *)tableView:(UITableView *)tableView willSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
if (true) { // Some simplification
MyTableViewCell cell = ... // The correct cell is loaded here
[UIView animateWithDuration:0.5 animations:^{
cellToSelect.labelAmount.textColor = [UIColor redColor];
} completion:^(BOOL finished) {
[UIView animateWithDuration:1.0 animations:^{
cellToSelect.labelAmount.textColor = [UIColor blackColor];
}];
}];
return nil;
}
return indexPath;
}
The animations are not performed. Instead, the cell is just (visually) deselected.
EDIT: I just tried the proposed solutions and neither seemed to work. So I digged a little bit further and found out that I can do animations but am not able to change the textColor of any label inside a cell:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
MyTableViewCell cell = ...
cell.labelAmount.textColor = [UIColor redColor];
// Now, although the property was set (as I can see in the debugger)
// the label is still drawn with standard black text.
}
Also, setting the color via a colorful attributed string does not work.
On the other hand, a change of highlightedTextColor is presented accordingly. So this works.

Answer 1

This property - textColor - is not animatable. Use transitionWithView:duration:options:animations:completion:
[UIView transitionWithView:label duration:0.5 options:UIViewAnimationOptionTransitionCrossDissolve animations:^{
label.textColor = [UIColor redColor];
} completion:^(BOOL finished) {
[UIView transitionWithView:label duration:1.0 options:UIViewAnimationOptionTransitionCrossDissolve animations:^{
label.textColor = [UIColor blackColor];
} completion:nil];
}];

Answer 2

Conforming to apple documentation you can't animate all you want:
From apple :
The following properties of the UIView class are animatable:
#property frame
#property bounds
#property center
#property transform
#property alpha
#property backgroundColor
#property contentStretch
Now this is a trick to animate what you want:
For instance, set alpha to 1.0
- will result in no visual change to the view but launch animation
- (NSIndexPath *)tableView:(UITableView *)tableView willSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
if (true) { // Some simplification
MyTableViewCell cell = ... // The correct cell is loaded here
[UIView animateWithDuration:0.5 animations:^{
//here the trick set alpha to 1
self.view.alpha = 1;
cellToSelect.labelAmount.textColor = [UIColor redColor];
} completion:^(BOOL finished) {
[UIView animateWithDuration:1.0 animations:^{
cellToSelect.labelAmount.textColor = [UIColor blackColor];
}];
}];
return nil;
}
return indexPath;
}