The detail label on each cell of my UITableViewCotroller gives the size of the folder it represents. The size may change, and whenever it does I need to change all of the detailLabels. One way would be to perform a reload, [tableview reloadData];, however the many images make it slow. Is there a way to just update the label?
I tried the method but I don't seem to be able to get it to work:
[tableView beginUpdates];
…
[tableView endUpdates];
- (UIView *)tableView:(UITableView *)tableView viewForFooterInSection:(NSInteger)section {
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
cell.detailTextLabel.text = #"";
return cell;
}
One solution could be to fast enumerate through [self.tableview visibleCells], and change the labels on those. This is assuming the data that the tableview is getting in cellForRowAtIndexPath will be up to date. That way, all the visible cells will be updated immediately, and the rest will be updated as soon as they get visible.
Was that understandable? Let me know if it wasn't.
Let's try below methods,
- (void)loadDetailsForOnscreenRows
{
if ([self.entries count] > 0)
{
NSArray *visiblePaths = [self.tableView indexPathsForVisibleRows];
for (NSIndexPath *indexPath in visiblePaths)
{
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
cell.detailTextLabel.text = #"Your text";
}
}
}
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{
if (!decelerate)
{
[self loadDetailsForOnscreenRows];
}
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
[self loadDetailsForOnscreenRows];
}
Also, Refer apple's example for more details to load table lazily.
Related
I have a UIWebView inside my custom UITableViewCells. The problem is that I don't quite know how to dynamically size my UITableViewCell cells since the webview inside the cell needs to render before I can know the webview's height.
My proposed solution is as follows:
CustomCell.m conforms to UIWebViewDelegate and it returns its own height with delegate method after the webview inside it has finished loading.
- (void)webViewDidFinishLoad:(UIWebView *)webView {
CGFloat height = [[webView stringByEvaluatingJavaScriptFromString:#"document.body.scrollHeight"] floatValue];
[self.contentWebview setFrameHeight:height];
[self.delegate cellDidFinishLoadingWithCell:self withHeight:height];
}
Then TableViewController.m conforms to the cell's delegate, and redraws by doing something like:
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(nonnull NSIndexPath *)indexPath {
return [self.heights[[NSString stringWithFormat:#"%i%i",indexPath.section,indexPath.row]] floatValue];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UIWebViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"webview-cell" forIndexPath:indexPath];
MyData *d = self.data[indexPath.section];
[cell setUpCellForData:d];
[cell setDelegate:self];
return cell;
}
- (void)cellDidFinishLoadingWithCell:(LessonTableViewCell *)cell withHeight:(CGFloat)height {
NSIndexPath *indexPath = [self.tableview indexPathForCell:cell];
NSString *key = [NSString stringWithFormat:#"%i%i",indexPath.section,indexPath.row];
if (!self.heights[key]) {
[self.heights setObject:[NSNumber numberWithFloat:height] forKey:key];
}
[self.tableview beginUpdates];
[self.tableview endUpdates];
}
Some cells seem to be the correct height, but many of them end up having a height of 0...
remove :
[self.tableView beginUpdates];
[self.tableView endUpdates];
add :
[self.tableView reloadData];
This is Apple Documents:
beginUpdates
reloadData
https://stackoverflow.com/a/8174094/2530660
I have a tableview which can be expanded on selecting the cell and collapses on selecting again. When you select, the cell should expand and display a label and when you select again it collapses and hides the label . The expanding and collapsing works fine, but if i scroll the tableview after expanding a cell it behaves weird. Once it goes out of the view and comes back , the cell will have the expanded cell's height but the label which is supposed to be shown in expanded cell is hidden.If i select the cell again it collapses and displays the label. I use ,
- (CGFloat)tableView:(UITableView *)t heightForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [self tableView:t cellForRowAtIndexPath:indexPath];
if([self cellIsSelected:indexPath])
return cell.frame.size.height+35;
return cell.frame.size.height;
}
- (BOOL)cellIsSelected:(NSIndexPath *)indexPath {
// Return whether the cell at the specified index path is selected or not
NSNumber *selectedIndex = [self.selectedIndexes objectForKey:indexPath];
return selectedIndex == nil ? FALSE : [selectedIndex boolValue];
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
// Deselect cell
NSLog(#"Select cell:%#",indexPath);
[self.tableView deselectRowAtIndexPath:indexPath animated:TRUE];
if([self pickTaskForIndexPath:indexPath].productSpecialMessage){
BOOL isSelected = ![self cellIsSelected:indexPath];
NSNumber *selectedIndex = [NSNumber numberWithBool:isSelected];
[self.selectedIndexes setObject:selectedIndex forKey:indexPath];
PickTaskTableviewCell *cell= [self.tableView cellForRowAtIndexPath:indexPath];
cell.message.hidden=false;
cell.messageLabel.text=[self pickTaskForIndexPath:indexPath].productSpecialMessage;
cell.messageLabel.lineBreakMode=NSLineBreakByTruncatingTail;
cell.messageLabel.numberOfLines=3;
if(cell.messageLabel.hidden==true){
cell.messageLabel.hidden = false;
} else {
cell.messageLabel.hidden = true;
}
NSLog(#"message:%#",cell.messageLabel.text);
[cell layoutIfNeeded];
}
self.tableView.rowHeight=UITableViewAutomaticDimension;
[self.tableView beginUpdates];
[self.tableView endUpdates];
}
indexPath is added to the selectedIndexes on didSelectRowAtIndexPath
Please help me
Cells should be configured only within cellForRowAtIndexPath. When a state change occurs that makes a cell need to look different, just reload that cell.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
PickTaskTableviewCell *cell = (PickTaskTableviewCell *)[tableView dequeueReusableCellWithIdentifier:#"cell"];
// everything else you do to configure the cell goes here, then ...
// check the logic here, we want one condition that tells us whether to show the labels
if([[self cellIsSelected:indexPath] && self pickTaskForIndexPath:indexPath].productSpecialMessage){
// don't need these here
//NSNumber *selectedIndex = [NSNumber numberWithBool:isSelected];
// [self.selectedIndexes setObject:selectedIndex forKey:indexPath];
// PickTaskTableviewCell *cell= [self.tableView cellForRowAtIndexPath:indexPath];
cell.message.hidden=false;
cell.messageLabel.text=[self pickTaskForIndexPath:indexPath].productSpecialMessage;
cell.messageLabel.lineBreakMode=NSLineBreakByTruncatingTail;
cell.messageLabel.numberOfLines=3;
cell.messageLabel.hidden=NO;
} else {
cell.message.hidden=YES;
cell.messageLabel.hidden=YES;
}
NSLog(#"message:%#",cell.messageLabel.text);
// don't need this here
// [cell layoutIfNeeded];
return cell;
}
Selection (and presumably deselection) cause the need to update the cell, so...
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
// don't deselect it here, just reload it
// more on this later...
[self.selectedIndexes setObject:selectedIndex forKey:indexPath];
[self.tableView reloadRowsAtIndexPaths:#[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
}
// probably do the same in didDeselectRowAtIndexPath:
One last (optional) point. There's no need to maintain your own list of selected index paths, UITableView does that for you, so you could delete your selectedIndexes property and just use the table view methods, e.g....
- (BOOL)cellIsSelected:(NSIndexPath *)indexPath {
// Return whether the cell at the specified index path is selected or not
return [[self.tableView indexPathsForSelectedRows] containsObject:indexPath];
}
I have a custom UITableViewCell, and when it's selected, it expands and adds a UILabel to the selected cells UIView that I added in the storyBoard.
When I run the app and select a cell, the label gets added to myView as expected. The problem is, when I scroll down, the label is also shown at another cell.
Apparently the reason its behaving like so, is because I'm reusing the cell and I don't clean them as Emilie stated. I'm trying to call the method of prepareForReuse and 'cleaning' the cell, but I'm having trouble doing that. Here is my code:
- (void)prepareForReuse {
NSArray *viewsToRemove = [self.view subviews];
for (UILablel *v in viewsToRemove) {
[v removeFromSuperview];
}
Doing that, cleans even the selected cells label.
- (void)viewDidLoad {
self.sortedDictionary = [[NSArray alloc] initWithObjects:#"Californa", #"Alabama", #"Chicago", #"Texas", #"Colorado", #"New York", #"Philly", #"Utah", #"Nevadah", #"Oregon", #"Pensilvainia", #"South Dekoda", #"North Dekoda", #"Iowa", #"Misouri", #"New Mexico", #"Arizona", #"etc", nil];
self.rowSelection = -1;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
CategorieCell *customCell = [tableView dequeueReusableCellWithIdentifier:#"cellID" forIndexPath:indexPath];
customCell.title.text = [self.sortedDictionary objectAtIndex:indexPath.row];
return customCell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
[tableView deselectRowAtIndexPath:indexPath animated:YES];
CategorieCell *customCell = (CategorieCell *)[tableView cellForRowAtIndexPath:indexPath];
if (self.info) {
[self.info removeFromSuperview];
}
self.info = [[UILabel alloc] init];
[self.info setText:#"Hello"];
[self.info setBackgroundColor:[UIColor brownColor]];
CGRect labelFrame = CGRectMake(0, 0, 50, 100);
[self.info setFrame:labelFrame];
[customCell.infoView addSubview:self.info];
NSLog(#"%ld", (long)indexPath.row);
self.rowSelection = [indexPath row];
[tableView beginUpdates];
[tableView endUpdates];
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
if ([indexPath row] == self.rowSelection) {
return 159;
}
return 59;
}
The answer is quite simple : you reuse your cell like you should, but never clean them
Reusing your UITableViewCell means that the cell you clicked on previously will be reused when it will go off-screen.
When clicked, you add a view to your UITableViewCell. When reused, the view is still there because you never remove it.
You have two choices : One, you could set a tag of the self.info view (or check with the indexpath you're keeping in memory), then check when you dequeue the cell if the info view is there, and remove it. The cleaner solution would be to implement the view removal by overriding the prepareForReuse method of your custom UITableViewCell
Precision
The first thing you need to do is set a tag for your self.info view after initializing it:
[self.info setTag:2222];
If you want to keep it as simple as possible, you could check and remove the self.info view directly in your cellForRowAtIndexPath method :
CategorieCell *customCell = [tableView dequeueReusableCellWithIdentifier:#"cellID" forIndexPath:indexPath];
customCell.title.text = [self.sortedDictionary objectAtIndex:indexPath.row];
if [customCell.infoView viewWithTag: 2222] != nil {
[self.info removeFromSuperview]
}
return customCell;
I am not a percent sure this code compiles, I cannot test it on my side for now. Hope it works !
I would like to make something like expandable cells. Result I'm trying to achieve is:
Actually I have:
Here is my code:
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
DoctorCell *cell = self.prototypeCell;
DoctorModel *doctor = [self.fetchController objectAtIndexPath:frcIndexPath];
// depending on isActive property I add (or do not add) some content.
[cell cellForDoctor:doctor isActiveCell:[self.activeCellIndexPath isEqual:indexPath]];
[cell setNeedsUpdateConstraints];
[cell setNeedsLayout];
[cell layoutIfNeeded];
CGFloat height = [cell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height;
return height + 1;
}
Here is my cell selection method
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
[tableView deselectRowAtIndexPath:indexPath animated:NO];
NSIndexPath *oldIndexPath = self.activeCellIndexPath;
if ([indexPath isEqual:self.activeCellIndexPath]) {
self.activeCellIndexPath = nil;
oldIndexPath = nil;
} else {
self.activeCellIndexPath = indexPath;
}
[self.doctorTableView beginUpdates];
[self.doctorTableView reloadRowsAtIndexPaths:[NSArray arrayWithObjects:indexPath, oldIndexPath, nil] withRowAnimation:UITableViewRowAnimationNone];
[self.doctorTableView endUpdates];
[self.doctorTableView scrollToRowAtIndexPath:indexPath atScrollPosition:UITableViewScrollPositionTop animated:YES];
}
As you can see, my animation looks weird (kind of moving to wrong position, jumps, etc). What I'm doing wrong? Or do I need to pick another approach for expanding cells?
You can use UITableViews animation automation like this:
Call [tableView beginUpdates];
Change the data source.
Insert or delete rows and sections, or reload them
This should cause new heights to be calculated, etc.
Make sure you use something appropriate for the withRowAnimation parameter of these methods
Call [tableView endUpdates];
Your animation should now perform as expected.
Maybe your problem is that you selected UITableViewRowAnimationNone for the row animation.
I have a UIViewController with a UITableView which has multiple accessory checkmark implemented into it. My problem is, when I click some cells in the tableview it gets checked but there will be some other cell also checked below. I can view it when I scroll down the tableview. I would only want the cell to be checked whichever the user is clicking and not the extra cells. Please let me know how can I do it. Thanks.
Here is the code:
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return [someData count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
[self.tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:#"Cell"];
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell" forIndexPath:indexPath];
cell.textLabel.text=[self.someData objectAtIndex:indexPath.row];
cell.textLabel.font=[UIFont fontWithName:#"Times New Roman" size:11];
cell.textLabel.lineBreakMode = NSLineBreakByWordWrapping;
[cell.textLabel setNumberOfLines:2];
return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
UITableViewCell *selectedCell = [tableView cellForRowAtIndexPath:indexPath];
if ([selectedCell accessoryType] == UITableViewCellAccessoryNone) {
[selectedCell setAccessoryType:UITableViewCellAccessoryCheckmark];
NSArray *arrayOfIndexPathsTableOne = [self.tableView indexPathsForSelectedRows];
for (int i = 0; i < [arrayOfIndexPathsTableOne count]; i++) {
NSIndexPath *indexPathImInterestedIn = [arrayOfIndexPathsTableOne objectAtIndex:i];
UITableViewCell *currentCell = [self.tableView cellForRowAtIndexPath:indexPathImInterestedIn];
[saveData addObject:[NSString stringWithFormat:#"%#", currentCell.textLabel.text]];
}
} else {
[selectedCell setAccessoryType:UITableViewCellAccessoryNone];
NSArray *arrayOfIndexPathsTableOne = [self.tableView indexPathsForSelectedRows];
for(int i = 0; i < [arrayOfIndexPathsTableOne count]; i++) {
NSIndexPath *indexPathImInterestedIn = [arrayOfIndexPathsTableOne objectAtIndex:i];
UITableViewCell *currentCell = [self.tableView cellForRowAtIndexPath:indexPathImInterestedIn];
[saveData removeObject:[NSString stringWithFormat:#"%#", currentCell.textLabel.text]];
}
}
[tableView deselectRowAtIndexPath:indexPath animated:NO];
}
This is a cell reuse problem.
To fix, ensure that each time you return a cell from cellForRowAtIndexPath: you always set the selection (checkmark) status. That means explicitly setting it true and false as appropriate.
There are only 2 things you need:
Disable multiple selection on your UITableView.
Implement setSelected:(BOOL)selected in your UITableViewCells and make it select/deselect the cell's sub-views (your checkmarks) accordingly.
When you select table you show check box on it but when you scroll and the cell desapeare and it goes to reusable pool after you scroll back the cell is taken from this pool and it doesn't remember the 'state'.
The solution is create NSMutableArray and in didSelectCellAtIndexPath: method add or remove the indexPath for that cell to the array and in cellForRowAtIndexPath: check this array and show/hide checkmark base on that table.
dont write this line in cell for row at index path
[self.tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:#"Cell"];
it must be in loadview or viewdidload