I have a button on my TableView header that is an empty box, and when pressed, is a checkmark. I have that same button on the cells for that header. So I basically want to perform an action on each cell that is in that section. I'm using the Animating TableView from WWDC 2010 as my example. The header object has an array of integers that keep track of how many rows are in its section.
I'm not really sure from here, how I can get the custom UITableViewCell to perform my action on. Any thoughts? Thanks.
So far I have something like this:
- (void)selectAllCheckmarksInSectionHeaderView:(SectionHeaderView *)sectionHeaderView forSection:(NSInteger)section {
SectionInfo *sectionInfo = [self.SectionInfoArray objectAtIndex:section];
int totalRows = [[sectionInfo rowHeights] count];
for (int row = 0; row < totalRows; row++) {
NSIndexPath *path = [NSIndexPath indexPathForRow:(NSUInteger)row inSection:section];
OrderTableViewCell *cell = (OrderTableViewCell *)[_orderTableView cellForRowAtIndexPath:path];
cell.CheckmarkButton.selected = YES;
}
}
However my OrderTableViewCell is nil.
To reference a button that is a located in a section header, you'll have to assign it to an instance variable to keep a reference to it. To obtain references to all of the cells in a section and update them, you'll want to try something like this...
CGRect sectionRect = [self.tableView rectForSection:0]; // Rect for first section
NSArray *indexPathsInSection = [self.tableView indexPathsForRowsInRect:sectionRect];
for (NSIndexPath *indexPath in indexPathsInSection)
{
// Obtain the cell at each index path and update its accessory state
UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];
cell.accessoryType = UITableViewCellAccessoryCheckmark;
}
Of course this is an overly simplistic example. A more flexible approach would be to update some model object when a section is "selected" and reload the table. Then in your -tableView:cellForRowAtIndexPath: you would determine whether a cell in a section should be checkmarked based off the model object for the whole section.
Related
Here is what I want in my app. Shown below are two screenshots of the iPhone app Store:
I basically need a "Read More" feature just like it is used in the app store (See the "Description" section in the two images above). I am assuming that each section here (Description, What's New, Information etc.) is a table view cell. And the text inside is a UILabel or UITextField.
Here is what I have tried so far to add this feature:
NSString *initialText = #"Something which is not a complete text and created just as an example to...";
NSString *finalText = #"Something which is not a complete text and created just as an example to illustrate my problem here with tableviews and cel heights. bla bla bla";
NSInteger isReadMoreTapped = 0;
My cellForRowAtIndexPath function:
// Other cell initialisations
if(isReadMoreTapped==0)
cell.label.text = initialText;
else
cell.label.text = finalText;
return cell;
My heightForRowAtIndexPath function:
// Other cell heights determined dynamically
if(isReadMoreTapped==0){
cell.label.text = initialText;
cellHeight = //Some cell height x which is determined dynamically based on the font, width etc. of the label text
}
else{
cell.label.text = finalText;
cellHeight = //Some height greater than x determined dynamically
}
return cellHeight;
Finally my IBAction readMoreTapped method which is called when the More button is tapped:
isReadMoreTapped = 1;
[self.tableView beginUpdates];
[self.tableView endUpdates];
NSIndexPath* rowToReload = [NSIndexPath indexPathForRow:2 inSection:0]; // I need to reload only the third row, so not reloading the entire table but only the required one
NSArray* rowsToReload = [NSArray arrayWithObjects:rowToReload, nil];
[self.tableView reloadRowsAtIndexPaths:rowsToReload withRowAnimation:UITableViewRowAnimationNone];
After doing all this, I do get the required functionality. The new height of that particular cell is calculated and the new text loaded into it. But there is a very unnatural jerk on the TableView which results in a bad User experience. That is not the case with the app store More button though. There is no unnatural jerk in its case. The TableView remains at its place, only the changed cell has its size increased with the text appearing smoothly.
How can I achieve the smoothness as done in the iPhone app store More button?
Your problem might come from reloading the row. You want to try to configure the cell properties directly. I usually use a dedicated method to configure my cell content so I don't have to reload rows.
- (void)configureCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
if(isReadMoreTapped==0)
cell.label.text = initialText;
else
cell.label.text = finalText;
// all other cell configuration goes here
}
this method is called from the cellForRowAtIndexPath method and it will configure the cell
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
[self configureCell:cell forRowAtIndexPath:indexPath];
return cell;
}
and you would call this method directly to avoid reloading:
isReadMoreTapped = 1;
[self.tableView beginUpdates];
[self.tableView endUpdates];
NSIndexPath* rowToReload = [NSIndexPath indexPathForRow:2 inSection:0];
UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:rowToReload];
[self configureCell:cell forRowAtIndexPath:rowToReload];
Please try the following changes to your code, I think it will fix your problem.
no need to set cell.label.text in heightForRowAtIndexPath; Please remove them.
in the readMoreTapped, update table is enough:
isReadMoreTapped = 1;
[self.tableView beginUpdates];
[self.tableView endUpdates];
Either remove the calls to:
[self.tableView beginUpdates];
[self.tableView endUpdates];
Or change to ensure that your reloading code is between them. I would remove them as a single row reload is handled well with the method you use:
[self.tableView reloadRowsAtIndexPaths:rowsToReload withRowAnimation:UITableViewRowAnimationNone];
You just need to specify a row animation like fade.
Okay, I finally solved the problem with the help of Matthias's answer (the accepted answer) and my own optimisations. One thing that definitely should be done is to create a dedicated function like configureCell: forRowAtIndexPath: to directly configure cell properties (see Mathias's answer). Everything remains the same with Matthias's answer except:
Before, I was calculating the heights of each cell everytime the heightForRowAtIndexPath function was called without caching(saving) them anywhere and hence when [self.tableView beginUpdates]; and [self.tableView endUpdates]; were called each cell height was calculated again. Instead, what you have to do is to save these cell heights in an array/dictionary so that whenever the More button is tapped, you calculate the height of only the cell that was changed. For the other cells, just query the array/dictionary and return the saved cell height. This should solve any problems with the tableView scroll after the cell height update. If anyone else still face a similar issue as this, please comment on this post. I would be happy to help
I have a prototype table in my app witch I populate with a customTableViewCell class with a UITextField inside.
In my navigation bar I got a save button.
The question is, how to access this dynamic created cell's to get the UITextField content?
This is my code, you can see that I tried to use NSMutableArray
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"customTableCell";
customTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
[self.pfCells addObject:cell];
if(cell == nil)
{
cell = [[customTableViewCell alloc]
initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:CellIdentifier];
}
// Configuration
cell.lblName.text = [self.pfFields objectAtIndex: [indexPath row]];
cell.txtType = [self.pfTypes objectAtIndex: [indexPath row]];
if ([[self.pfTypes objectAtIndex:[indexPath row]] isEqualToString: #"n"]) {
[cell.txtField setKeyboardType:UIKeyboardTypeNumberPad];
} else if ([[self.pfTypes objectAtIndex:[indexPath row]] isEqualToString: #"m"]) {
[cell.txtField setKeyboardType:UIKeyboardTypeEmailAddress];
}
return cell;
}
Here's another way to save content from a UITextField contained in a UITableViewCell:
Inside tableView:cellForRowAtIndexPath: set the delegate and a tag for txtField
Implement textFieldDidEndEditing: check for a UITextField tag value an save data in a private variable
Reload UITableView
The biggest advantage of this implementation if the fact that you doesn't need to iterate over whole tableview everytime you change a textfield value.
Quick answer:
#pragma mark - UITextFieldDelegate
- (void)textFieldDidEndEditing:(UITextField *)textField
{
// grab the row we are working on
NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];
// remove the old key/value pair if it exists and add the new one
[self.modelDictionary removeObjectForKey:indexPath];
[self.modelDictionary setObject:textField.text forKey:indexPath];
}
Be sure to add cell.txtField.delegate = self when configuring your cell. Then in your save button, you'd iterate through the dictionary and save the values -- or just save the dictionary itself.
Also, if you are targeting iOS6 or later, use dequeueReusableCellWithIdentifier:forIndexPath: as this method guarantees a cell is returned and resized properly, so you don't have to check for nil and manually init your cell.
Longer answer:
You generally never want to store your model in your view as you are doing. Aside from it breaking the MVC design patterns, it also causes issues with UITableViews. Specifically, a UITableViewCell will be recycled when it scrolls off the screen. So any values you have in those fields are lost. While you can get away with doing this if you only have visible rows that never scroll off the screen, I would encourage you to avoid this approach altogether.
Instead, you should store the values entered into the textboxes in your model object. The easiest way to do this is to use UITextFieldDelegate's textFieldDidEndEditing: to grab the values after the user enters them, then add these values to your model. You model could be something as simple as an NSDictionary using the indexPath as the key.
I have 10 UITableViewCells in my UITableView. Each cell has a UITextField. They load fine, but I need a way to set each cell's text to its associated string.
Is there a delegate of UITextField that I can use to do this, and how can I determine which textfield belongs to what NSString, etc?
Edit:
Here is a picture of my tableView. I want it to load text into each cell's textfield from the server then the user can edit it. Or if there is no data on the server, the textfield will be blank and the user can add data and it will sync back.
I have created an NSString for each cell, such as temperatureString, pulseString, etc.
Edit: In respect to the new info this is my new solution
So by the looks of it you are inserting UITextField into each cell, instead of setting the tag of each cell set the tag for each UITextField
First Define your tags
#define DESCRIPTIVE_TAG_VALUE_1 10
#define DESCRIPTIVE_TAG_VALUE_2 11
#define DESCRIPTIVE_TAG_VALUE_3 12
...
Use these in your UITextField Delegate to determine which UITextField belongs to which NSString that is if you are syncing with each update, if your not. Then obtain a reference to the UITableView and retrieve each of the text values of each subview of a cell that has a tag equal to one of your defines (again in a switch statement).
Once again in when working with iOS use tags they are your friends
OR
Also you said that you are holding a reference to each NSString, you could just hold a reference to each UITextField instead that way when you sync you just have to retieve from each of your UITextField references.
But the Apple's best practises say to exercise the use of unique tags when dealing with mutliple views. It's really up to you
UITextfield is a subclass of UIView which has a 'tag' property. You can assign the cell's indexPath.row to be it's text field's tag as identification.
Based on your comment in response to #Javy (which contains extra information you should consider adding to your original question), you could do something like the following:
UITableViewCell *cell = nil;
NSString *key = nil;
switch (indexPath.row)
{
case 0:
cell = self.temperatureCell;
key = #"temperature";
break;
case 1:
// Do other cases similarly ...
}
NSString *text = [self.childAppointmentDictionary objectForKey:key];
cell.textField.text = text;
You should be setting the text in tableView: cellForRowAtIndexPath:
It sounds like you have a specific order that you want your items to appear in which would be a good time to use an NSArray, rather than an NSDictionary.
You could, in init, or initwithNibName, create a retained array property:
self.myListArray = [NSArray arrayWithObjects:#"fever", #"cough", #"runny nose", nil];
Then, assuming that you only have 1 section, you would do cell.textField.text = [self.myListArray objectAtIndex:indexPath.row];
Is there a reason that you're using an NSDictionary for this rather than an NSArray?
You must store a reference to each text field when they are created, so in the:
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
Method, you would add this line:
[myTextFieldArray addObject: cell.textField];
Assuming textField is the property for your custom tabel view cell.
You would also set the text within the text field just after the if (cell == nil) method.
The delegate methods simply allow you to know when text is being typed, etc.
EDIT:
Considering what you've added, I agree with Sid and CStreel. Create the tags for each value:
#define kTemperatureTag 0
#define kPulseTag 1
// etc.
As an alternative to CStreel, I would assign/retrieve info matching the indexPath row, and not worry about assigning tags, because they will be the same thing if you start your tags at zero.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
// setup / retrieve cell
NSInteger index = [indexPath row];
switch(index)
{
case kTemperatureTag:
cell.textField.text = [self.childAppointmentDictionary objectForKey:#"temperature"];
break;
// case ...
}
// ..
}
And:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
NSInteger index = [indexPath row];
switch(index){
case kTemperatureTag:
[self.childAppointmentDictionary addObject:cell.textField.text forKey:#"temperature"];
I have a UITableView in that some cells are marked with UITableViewCellAccessoryCheckmark at the initialization of the view.
When the user selects another row, I have to check if the maximum number of selected rows was achieved before. To do that, I used the code bellow:
- (NSInteger)tableView:(UITableView *)tableView numberOfSelectedRowsInSection:(NSInteger)section{
NSInteger numberOfRows = [self tableView:tableView numberOfRowsInSection:section];
NSInteger numberOfSelectedRows = 0;
for (int i = 0; i < numberOfRows; i++) {
UITableViewCell *otherCell = [tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:i inSection:section]];
if (otherCell.accessoryType == UITableViewCellAccessoryCheckmark) {
numberOfSelectedRows++;
}
}
return numberOfSelectedRows;
}
If my number of rows is, as example, 20, the variable numberOfRows is setted correctly with 20. Lets say that 13 rows already are marked with UITableViewCellAccessoryCheckmark. So, numberOfSelectedRows should be 13 after the loop, but only the marked and VISIBLE cells are considered. So, if I have 9 cells showed and 7 are marked, the numberOfSelectedRows returns 7 instead of 13 (but the for iterate 20 times, as expected).
Is this a correct behavior of UITableView or it is a bug of iPhone simulator?
Thanks in advance.
Yes, it works as designed. You should never store model data in your views. UITableView knows nothing about the data, it only displays cells (and throws them aways as soon as they scroll off the screen). You need to store the checkmark state of each cell in a model object (e.g. an array) that you then access from your view controller.
This is correct behavior.
The UITableView is not a list. The system caches cell that are off screen to save memory and CPU and they can not be iterated over in a manner that makes sense.
Ok, you should keep track of the model/data and the tableView will keep track of displaying it. I have had some problems with this until I accepted that uitableView is not a list:)
So, have an array of objects that each corresponds to the data in the a cell. When building the individual cells like this:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"categoryCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];
}
Item *item = [self.itemList objectAtIndex:indexPath.row];
[cell.textLabel setText:[item itemBrand]]; //notice that here we set the cell values
return cell;
}
The when a user clicks you change you model like this:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
NSLog(#"IndexPat.row%i", indexPath.row);
Item item = (Item*) [self.itemList objectAtIndex:indexPath.row];
//change the state of item
}
This way the tableView will update to resemble the model/data, you just managed the model.
In a lot of iPhone apps, I see a UITableViewController being used as a checkbox list. (See, for an example of what I mean, Auto-Lock under Settings)
While trying to implement this myself, I had to jump through a lot of hoops in order to have an item selected programmatically by default (ie., the current value for what the list represents). The best I've been able to come up with is by overriding the viewDidAppear method in my view controller class:
- (void)viewDidAppear:(BOOL)animated {
NSInteger row = 0;
// loop through my list of items to determine the row matching the current setting
for (NSString *item in statusItems) {
if ([item isEqualToString:currentStatus]) {
break;
}
++row;
}
// fetch the array of visible cells, get cell matching my row and set the
// accessory type
NSArray *arr = [self.tableView visibleCells];
NSIndexPath *ip = [self.tableView indexPathForCell:[arr objectAtIndex:row]];
UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:ip];
cell.accessoryType = UITableViewCellAccessoryCheckmark;
self.lastIndexPath = ip;
[super viewDidAppear:animated];
}
Is this the best/only/easiest way to get a reference to a particular cell and indexPath if I want to mark a row by default?
In order to display the status items, you have to implement tableView:cellForRowAtIndexPath: anyway, don't you? So, why not just set the accessory type of the cell before returning the cell, like this:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
// dequeue or create cell as usual
// get the status item (assuming you have a statusItems array, which appears in your sample code)
NSString* statusItem = [statusItems objectAtIndex:indexPath.row];
cell.text = statusItem;
// set the appropriate accessory type
if([statusItem isEqualToString:currentStatus]) {
cell.accessoryType = UITableViewCellAccessoryCheckmark;
}
else {
cell.accessoryType = UITableViewCellAccessoryNone;
}
return cell;
}
Your code is extremely fragile, especially because you use [self.tableView visibleCells]. What if there are more status items than rows fitting on the screen (as the name suggests, visibleCells only returns the currently visible cells of the table view)?