I've a collection view with custom cell class.
In each cell I've a player with a specific sound.
When made an Button and link to my code with an IBOutlet, it's doesn't fire even with the fact I have userInteractionEnabled = YES in all my views.
So I decided to play the sound in the collection view controller.
In my cell the player has a property
#property (strong, nonatomic) AVAudioPlayer *voicePlayer;
Then in the collection I have:
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
LHFriendVoiceCollectionViewCell *cell = [self.collectionView dequeueReusableCellWithReuseIdentifier:#"LHFriendVoiceCollectionViewCell" forIndexPath:indexPath];
LHFriendVoiceObject *currentFriendVoice = [[LHFriendVoiceObject alloc] initWithNSDictionnary:[self.friendsArray objectAtIndex:indexPath.row]];
[cell hydrateWithFriendVoiceObject:currentFriendVoice];
[cell.voicePlayer prepareToPlay];
//[self.voicesArray addObject:cell.voicePlayer]; tried to stock them in array but doesn't work
return cell;
}
If I play the sound in this method it's work, but I want the sound to be played when I select the cell.
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath: (NSIndexPath *)indexPath {
LHFriendVoiceCollectionViewCell *cell =
[self.collectionView dequeueReusableCellWithReuseIdentifier:#"LHFriendVoiceCollectionViewCell" forIndexPath:indexPath];
[cell.voicePlayer play];
}
Here the sound doesn't play because voicePlayer is nil.
How I can keep my players ?
This code is the problem:
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath: (NSIndexPath *)indexPath {
LHFriendVoiceCollectionViewCell *cell =
[self.collectionView dequeueReusableCellWithReuseIdentifier:#"LHFriendVoiceCollectionViewCell" forIndexPath:indexPath];
[cell.voicePlayer play];
}
That first line is wrong. You are calling dequeue. Big mistake! It makes a completely new cell. Do not make a new cell like that! Obviously that new cell will not have any AVAudioPlayer in it.
You already have a cell; it just got selected. Use the indexPath and cellForItemAtIndexPath: to learn out which cell got selected. That is the one you want to talk to.
PS You really should figure out why the button approach didn't work, but it's no big deal at this point.
Related
Help me to get rid of with this dilemma that occurred yet when I tried to dequeued the cell (Custom Cell).Below are some steps and Indents that I did with my Project.
The very first is I drag and drop a UITableView in my ViewController and add the ViewController.h doing after this
#interface ViewController : UIViewController <UITableViewDataSource,UITableViewDelegate>
Then I made a Custom Cell with 3 UILabels and change the height of the Cell to 65.
After that I made a property in ViewController.m
#property (nonatomic,strong) NSMutableArray *myTodoTitles;
Then in method(ViewDidLoad) I did.
myTodoTitles = [NSMutableArray arrayWithCapacity:10];
[myTodoTitles addObject:#"Go for ride"];
[myTodoTitles addObject:#"Do University Assignments"];
[myTodoTitles addObject:#"Watch Show"];
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:[self.myTodoTitles count]-1 inSection:1];
[self tableView:self.myTodoTable cellForRowAtIndexPath:indexPath];
After that I just did these things in my ViewController.m
#pragma mark - Table view data source
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
NSString *myIdentifier = #"TodoCell";
TodoCell *todoCell = (TodoCell*)[tableView dequeueReusableCellWithIdentifier:myIdentifier];
todoCell.todoTitleLabel.text = [self.myTodoTitles objectAtIndex:indexPath.row];
return todoCell;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
return [myTodoTitles count];
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView{
return 1;
}
But when I run the project it dequeued nothing.
Please help
Most likely that you have not connected your viewController to be the dataSource of your tableView. This could be done from Interface Builder or from the code. You can easily check it by adding self.myTodoTable.dataSource = self; at the very first of viewDidLoad method.
And also: what did you mean by `
[self tableView:self.myTodoTable cellForRowAtIndexPath:indexPath];`
in viewDidLoad ? Seems like you wanted to do
[self.myTodoTable reloadData];
There are to UITableView methods with similar name:
- (id)dequeueReusableCellWithIdentifier:(NSString *)identifier
and
- (id)dequeueReusableCellWithIdentifier:(NSString *)identifier
forIndexPath:(NSIndexPath *)indexPath
The first one will try to dequeue a reusable cell. If it returns nil you are responsible to create appropriate cell.
The latter one will always return a valid cell: you will have to register a certain class or NIB with that tableview beforehand though. Docs.
EDIT:
As ReDetection pointed out: first method will also return a valid cell as long as you had registered a proper class (or nib) with that tableview.
In your case that means that you should register TodoCell in viewDidLoad with your tableView.
If TodoCell is made without .xib:
[self.tableView registerClass:[ToDoCell class]
forCellReuseIdentifier:#"TodoCell"];
Or if it is made with .xib.
[self.tableView registerNib:[UINib nibWithNibName:#"TodoCell"
bundle:nil]
forCellReuseIdentifier:#"TodoCell"];
EDIT2:
Your code also seems to be missing the dataSource setting. Something like:
self.tableView.dataSource = self;
This will trigger initial reload.
You'd probably want to set a delegate (since your controller claims to adopt that protocol) in the same manner.
I have following issue: I have a UITableView.If you click on a cell, a button is added on cell. No Problem till now... but: After adding button i want the TableView (after its reload) to select the just edited (or added) TableCell.
I've tried this in cellForRowAtIndexPath method
if (bool) {
[cell setSelected:YES animated:YES];
}
UIView *bgColorView = [[UIView alloc] init];
[bgColorView setBackgroundColor:[UIColor colorWithRed:34/255.0 green:139/255.0 blue:34/255.0 alpha:1.0]];
[cell setSelectedBackgroundView:bgColorView];
[bgColorView release];
return cell;
But it didn't work.
Any suggestion or sample code would be appreciated. Thanks .
For the standard selection you use the following method, described at UITableView reference docs
- (void)selectRowAtIndexPath:(NSIndexPath *)indexPath animated:(BOOL)animated scrollPosition:(UITableViewScrollPosition)scrollPosition
Your design might be improved if you use the custom cell storing information of selection count, that is much better than reloading the table and adding a lot of cell logic outside of the cell.
Why are you using
[tableView reloadData];
You can access the selected cell properties and controls without reloading the data using:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath;
Here is some code that can help you:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
CustomTableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
[cell.myButton setHidden:false];
}
I ran into some strange behaviour after I selected a cell using this code :
NSIndexPath * indexPath = [NSIndexPath indexPathForRow:1 inSection:0];
CustomCell * cell = (CustomCell*)[_myTableView cellForRowAtIndexPath:indexPath];
[cell setSelected:YES animated:NO];
After this i couldn't select exactly this cell it just didn't respond and
-(void)tableView:(UITableView *)tableView didDeselectRowAtIndexPath:(NSIndexPath *)indexPath
was never called.
This wasn't called either:
-(void)tableView: (UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
What i am doing wrong guys?
You need to call both methods manually because manually cell selection does not call delegate method.
[cell setSelected:YES animated:NO];
[self tableView:_myTableView didSelectRowAtIndexPath:indexPath];
According to Apple's documentation it is expected behavior that the methods you mention are never called after programmatically selecting a cell. More info is in this post.
I am trying to use UICollectionViewCell, since all I want to display is an image. I can add the image to the cell using UIColor colorWithImage: on the UICollectionViewCell's contentView property.
In my loadView method, I am registering the cell as follows:
[self.collectionView registerClass:[ImageCell class] forCellWithReuseIdentifier:#"MyCell"];
Below is my cellForItemAtIndexPath method:
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"MyCell" forIndexPath:indexPath];
// cell customization
return cell;
}
When I run it, as soon as it hits the dequeue line, it crashes with the following error:
*** Assertion failure in -[UICollectionView _dequeueReusableViewOfKind:withIdentifier:forIndexPath:]
Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'could not dequeue a view of kind: UICollectionElementKindCell with identifier MyCell - must register a nib or a class for the identifier or connect a prototype cell in a storyboard'
I tired setting up a custom cell, and used it as the class and I got the same error. My custom cell subclassed UICollectionViewCell and had nothing implemented, except for the default initWithFrame. That is because I wanted to just change the background colour of the view. I am not sure what the problem is but could someone please take a look at my code and help me? I've been trying to figure this out for quite a while with absolutely no luck at all.
If you just want to display an image, you don't need to do any subclassing, you can set the cell's backgroundColor with colorWithPatternImage:. Register the class like this:
[self.collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:#"Cell"];
Then use it like so:
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"Cell" forIndexPath:indexPath];
cell.backgroundColor = [UIColor colorWithPatternImage:[self.results objectAtIndex:indexPath.row]];
return cell;
}
In this example, results is an array of UIImages.
If you are using xib in applivation then add following in your viewdidLoad method
[self.myCollectionView registerNib:[UINib nibWithNibName:#"CollectionViewCell" bundle:nil] forCellWithReuseIdentifier:#"CellIdentifier"];
otherwise If you using storyboard add following
[self.myCollectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:#"CellIdentifier"];
Finally add this (If not)
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"CellIdentifier" forIndexPath:indexPath];
return cell;
}
Hope above will help.
Try setting a breakpoint on
[self.collectionView registerClass:[ImageCell class] forCellWithReuseIdentifier:#"MyCell"];
I would guess your loadView (did you mean viewDidLoad?) method is not being called, so the class is never registered with the collectionView.
if your collection view is connected on storyboard and the delegate and datasource is set there, and you provide the necessary methods for the datasource and delegate, then adding the register call makes the
- (UICollectionViewCell *)collectionView:(UICollectionView *)cv cellForItemAtIndexPath:(NSIndexPath *)indexPath
return a UICollectionView instead of your own subclass of it. So do either but not both.
set your cell identifier name as in code
I am trying to sync a UITableView with a UILabel to make sure they show the same data; of course, things will be different in the end, but for testing this is what I need to do.
See the arrow? I want that middle cell (from px44-88) to show the cell.textLabel.text in a UILabel when it is the "middle cell".
I tried using - (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath but I was having so many problems I figured I'd come here to ask if anyone has a better way of doing this. I'm not sure if it would make a difference or not but I am using NSFetchedResultsController to populate my UITableView.
UITableView is a subclass of UIScrollView, so probably you can use UIScrollViewDelegate
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
member to detect which cell is currently in the middle.
I.e. assuming you have a plain table with no sections, and tableView is an outlet for the table, label is an outlet for the label, than this will function in your controller will work:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
int row = (scrollView.contentOffset.y + tableView.frame.size.height / 2) / 44;
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:row inSection:0];
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
label.text = cell.textLabel.text;
}
Of course, you need to do some scrolling to make it work ;)
You can use visibleCells method to get layout of visible cells for non-plain table and use it to detect cell in the middle of the table.