I have a View controller, with a tableview inside of it. I have a navigation button called "create". After the user has filled in a couple textfields and selected a cells from the UITableview i want the create button to create a parse object with the selected and inputed information.
I have these arrays..
var name = [String]()
var address = [String]()
var theseItems:[String] = [] //globalArray
im appending the selected cells to "theseItems" array.
//i have already queried and added what i wanted, to the name and address array..so they are filled with information.
didSelectRowAtIndexPath {
self.theseItems.append(name[indexPath.row] as String)
self.theseItems.append(address[indexPath.row] as String)
now with the create Button i want to create an object from this information but am having a hard time accessing the selected cell index path in the button...
#IBAction func createButton(sender: AnyObject) {
let thisObject = PFObject(className:"thisObject")
thisObject["name"] = name.text
thisObject["address"] = address.text
thisObject["selectedCell"] = theseItems(name[indexPath.row])
thisObject["selectedCell2"] = theseItems(address[indexPath.row])
//error** unresolved identifier "indexPath"
I'm not sure the correct way to access the array with a cells information.. to save it to parse. thanks in advance!
thisObject.saveEventually()
You can get the index paths of the currently selected cells by calling the indexPathsForSelectedRows() method on the table view (or indexPathForSelectedRow() if constrained to a single selection at one time).
You're trying to access a an array position from text, but text is a textField, not an array
I have custom and very simple UITableViewCell.
I just want to init my table view by using new technique in ios 6, i.e. registering class and after deque cell with identifier.
So i have UITableViewController, inside the tableview i have one prototype cell , here is the image of it.
at first i forgot to register the class in viewDidLoad method inside the Table View controller and it was working fine. here is the code.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
CustomCell *cell = [tableView dequeueReusableCellWithIdentifier:#"customCellIdentifier" forIndexPath:indexPath];
return cell;
}
but in this case
- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
is not called during the cell init process.
and the after i put the register class functionality inside the viewdidload.
here is the code
- (void)viewDidLoad
{
[super viewDidLoad];
[self.tableView registerClass:[CustomCell class] forCellReuseIdentifier:#"customCellIdentifier"];
}
after it the - (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier starts invoking but in this case the cells are absolutely empty when i'm trying to debug , inside the initwithstyle method all the outlets are nil.
whats going on? what i'm doing wrong?
If you have defined the cell as prototype cell for the table view in your nib/storyboard file, then you don't have to register it, that is done automatically. But in that case, initWithCoder: is called for cells instantiated from the nib/storyboard.
I have some data that is fetched in another thread that updates a UICollectionView's header. However, I've not found an efficient way of reloading a supplementary view such as a header or footer.
I can call collectionView reloadSections:, but this reloads the entire section which is unnecessary. collectionView reloadItemsAtIndexPaths: only seems to target cells (not supplementary views). And calling setNeedsDisplay on the header itself doesn't appear to work either. Am I missing something?
You can also use (the lazy way)
collectionView.collectionViewLayout.invalidateLayout() // swift
[[_collectionView collectionViewLayout] invalidateLayout] // objc
More complex would be to provide a context
collectionView.collectionViewLayout.invalidateLayout(with: context) // swift
[[_collectionView collectionViewLayout] invalidateLayoutWithContext:context] // objc
You can then make a or configure the context yourself to inform about what should be updated see: UICollectionViewLayoutInvalidationContext
It has a function in there that you can override:
invalidateSupplementaryElements(ofKind:at:) // swift
Another option is (if you have already loaded the correct header/footer/supplementary view) and you only want to update the view with the new data than you can use one of the following functions to retrieve it:
supplementaryView(forElementKind:at:) // get specific one
visibleSupplementaryViews(ofKind:) // all visible ones
Same goes for visible cells with visibleCells. The advantage of just getting the view and not reloading a view entirely is that the cells retains it state. This is espically nice with table view cells when they use swipe to delete/edit/etc since that state is lost after reloading the cell.
If you feel fanatic you can of course also write some extensions to retrieve only cells/supplementary views of a given kind using generics
if let view = supplementaryView(forType: MySupplementaryView.self, at: indexPath) {
configure(view, at indexPath)
}
this assumes that you have a function that registers/dequeues views in example with their class name. I made a post about this here
I just ran into the same problem, and I ended up looking up the view using its tag to edit a label:
UICollectionReusableView *footer = (UICollectionReusableView*)[self.collectionView viewWithTag:999];
UILabel *footerLabel = (UILabel*)[footer viewWithTag:100];
Like you said it is unnecessary to reload an entire section, which cancels out any animation on cells as well. My solution isn't ideal, but it's easy enough.
Swift 3/4/5 version:
collectionView.collectionViewLayout.invalidateLayout()
Caution!
If you change the number of collectionView items at the same time (for example you show the footer only if all cells were loaded), it will crash. You need to reload the data first, to make sure that the number of items is the same before and after invalidateLayout():
collectionView.reloadData()
collectionView.collectionViewLayout.invalidateLayout()
I got the same problem. I tried #BobVorks's answer and it is working fine, if only the cell was reused else it won't. So, I tried finding a more cleaner way to achieve this and I came up reloading the whole UICollectionView after the performBatchUpdate (completion block) and it is working great. It reloads the Collection Without any cancellation of animation in the insertItemsAtIndexPath. Actually I personally up voted recent 2 answers cause i find it working but in my case, this is the cleanest way to do it.
[self.collectionView performBatchUpdates:^{
// perform indexpaths insertion
} completion:^(BOOL finished) {
[self.collectionView reloadData];
}];
[UIView performWithoutAnimation:^{
[self.collectionView reloadSections:[NSIndexSet indexSetWithIndex:4]];
}];
[UIView performWithoutAnimation:^{
[self.collectionView reloadData];
}];
Here are two ways you could do it.
1.
Create a mutable model to back the data that will eventually be available. Use KVO in inherited class of UICollectionReusableView to observe the changes and update the header view with the new data as it comes available.
[model addObserver:headerView
forKeyPath:#"path_To_Header_Data_I_care_about"
options:(NSKeyValueObservingOptionNew |
NSKeyValueObservingOptionOld)
context:NULL];
then implement listener method in header view
- (void)observeValueForKeyPath:(NSString *)keyPath
ofObject:(id)object
change:(NSDictionary *)change
context:(void *)context
2.
add notification listener to the view and post a notification when the data has successfully come available. Downside is that this is application wide and not a clean design.
// place in shared header file
#define HEADER_DATA_AVAILABLE #"Header Data Available Notification Name"
// object can contain userData property which could hole data needed.
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(headerDataAvailable:) name:HEADER_DATA_AVAILABLE object:nil];
[[NSNotificationCenter defaultCenter] postNotificationName:HEADER_DATA_AVAILABLE object:nil];
let headerView = collectionView.visibleSupplementaryViews(ofKind: UICollectionView.elementKindSectionHeader)[0] as! UICollectionReusableView
I've used above method to get current header, and successfully updated subviews on it.
Here's what I did to update only the section headers that are currently loaded in memory:
Add a weakToStrong NSMapTable. When you create a header, add the header as the weakly held key, with the indexPath object. If we reuse the header we'll update the indexPath.
When you need to update the headers, you can now enumerate the objects/keys from the NSMapTable as needed.
#interface YourCVController ()
#property (nonatomic, strong) NSMapTable *sectionHeaders;
#end
#implementation YourCVContoller
- (void)viewDidLoad {
[super viewDidLoad];
// This will weakly hold on to the KEYS and strongly hold on to the OBJECTS
// keys == HeaderView, object == indexPath
self.sectionHeaders = [NSMapTable weakToStrongObjectsMapTable];
}
// Creating a Header. Shove it into our map so we can update on the fly
- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
{
PresentationSectionHeader *header = [collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:#"presentationHeader" forIndexPath:indexPath];
// Shove data into header here
...
// Use header as our weak key. If it goes away we don't care about it
// Set indexPath as object so we can easily find our indexPath if we need it
[self.sectionHeaders setObject:indexPath forKey:header];
return header;
}
// Update Received, need to update our headers
- (void) updateHeaders {
NSEnumerator *enumerator = self.sectionHeaders.keyEnumerator;
PresentationSectionHeader *header = nil;
while ((header = enumerator.nextObject)) {
// Update the header as needed here
NSIndexPath *indexPath = [self.sectionHeaders objectForKey:header];
}
}
#end
This question is very old but a simple way to do it is to just set a delay that covers the time your view is animating and disabling the animation while you update the view...usually a delete or insert takes about .35 seconds so just do:
delay(0.35){
UIView.performWithoutAnimation{
self.collectionView.reloadSections(NSIndexSet(index: 1))
}
My problem arose when frame sizes for the supplementary views changed upon invalidating the layout. It appeared that the supplementary views were not refreshing. It turns out they were, but I was building the UICollectionReusableView objects programmatically, and I was not removing the old UILabel subviews. So when the collection view dequeued each header view, the UILabels would pile up, causing erratic appearance.
The solution was to build each UICollectionReusableView completely inside the viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath method, starting by a) removing all subviews from the dequeued cell, then b) getting the frame size from the item's layout attributes to allow adding the new subviews.
- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
{
yourClass *header = (yourClass *)[collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:#"identifier" forIndexPath:indexPath];
[[header viewWithTag:1] removeFromSuperview]; // remove additional subviews as required
UICollectionViewLayoutAttributes *attributes = [collectionView layoutAttributesForSupplementaryElementOfKind:kind atIndexPath:indexPath];
CGRect frame = attributes.frame;
UILabel *label = [[UILabel alloc] initWithFrame: // CGRectMake based on header frame
label.tag = 1;
[header addSubview:label];
// configure label
return header;
}
I have got a Perfect solution:
let footerView = self.collectionView.visibleSupplementaryViews(ofKind: UICollectionView.elementKindSectionFooter)
Now you can access all subview of footerView by using:
footerView[0].subviews[0]
If you have label in your footerView then :
let label: UILabel = footerView[0].subviews[0] as? UILabel ?? UILabel()
Final Step:
label.text = "Successfully Updated Footer."
if let footerView = collectionView.subviews.first(where: {$0 is LoadingFooterCell}) as? LoadingFooterCell {
footerView.isLoading = .loading
}
I've tried to get this app going but I don't know how to go about it. I have tried googling for days getting a good answer but to no avail. Therefor I turn to you.
I want to have a typical database (sql or core data) with all data collected. Then display first criteria in a tableview, pass data to next tableview, and in the third tableview display cells depending on the two choices made previously (like: where (x=1 & y=2) then display cells ). Finally get a detailview where I can load optional data from the database.
Any which way you can help or point me in any direction would be great.
//KeLLoGsX
RayWenderlich Tutorials has a number of tutorials that might apply.
More specifically, when a user selects a row in a view use the prepareForSegue method to set a property on the new view indicating the selection so you can taylor the new view accordingly. For example:
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([[segue identifier] isEqualToString:#"editTemplate"]) {
[[segue destinationViewController] setManagedObjectContext:self.managedObjectContext];
NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];
self.selectedTemplate = [self.fetchedResultsController objectAtIndexPath:indexPath];
[[segue destinationViewController] setSelectedTemplate:self.selectedTemplate];
}
if ([[segue identifier] isEqualToString:#"returnToNotes"]) {
// do nothing special
}
}
The segue identifier like "editTemplte" are set in storyboard by selecting the segue and using the attributes inspector to name them.
I am setting up routing to a TTTableViewController as follows:
[map from:#"myurl://filter/(initWithName:)"
toViewController:[FilterViewController class]];
and then, in another view controller I set up a mutable dictionary to pass through as my query:
// Set up dictionary and populate a field
NSMutableDictionary *filterDictionary;
filterDictionary = [[NSMutableDictionary alloc] init];
[filterDictionary setObject:#"test entry" forKey:#"test key"];
// Attach a query to the URL and open it
TTURLAction *theAction = [[TTURLAction actionWithURLPath:#"myurl://filter/search"]
applyQuery:filterDictionary];
[[TTNavigator navigator] openURLAction:theAction];
Finally, in the filter view controller, I can correctly access the values:
in .h:
#property (nonatomic, retain) NSMutableDictionary *filterDictionary;
in .m:
- (id)initWithName:(NSString *)filterName query:(NSMutableDictionary *)filters {
if (self = [self init]) {
self.filterDictionary = filters;
NSLog(#"Filter Dictionary assigned : %#", self.filterDictionary);
}
return self;
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
if (filterDictionary)
[filterDictionary setObject:textField.text forKey:#"searchAddress"];
[textField resignFirstResponder];
return YES;
}
The dictionary is correctly mutable and I can add values etc. without problem. However, when my filterViewController is dismissed, I assumed the changed dictionary would be reflected in the parent - it was passed by reference correctly.
Am I missing something? Is my dictionary in the filterVC actually a copy due to a base class of Three20 somewhere?
I'm running into a similar issue. I suspect we may need to pass in a delegate (via that query), along with your dictionary as a separate object. Then have the parent honor a protocol defined in this new VC, wherein you can now pass back that dictionary at the proper time.
TTNavigator also has viewControllerForURL:query: (among others) for obtaining a VC without opening it, but perhaps passing in the query and having the VC "do the right thing" is enough, plus I think - accent on think - the idea is to start using URL Actions and not just URLs (in the Three20 sense).