I have a UITableView that once a cell is clicked, it pushes tableViewB, which contains customcells. These cells contain TextFields. Once the user does any updating, they click "Save", which then pops tableViewB and goes to the first UITableView. I would like to get all of the UITextField values from tableViewB when Save is clicked. What is the best way to go about doing that?
The problem is that I need to loop through all UITableView cells. I'm not sure how that is done or if it is even a good approach. Just looking for help on what is a good technique here.
in your tableViewB header, declare:
NSMutableArray *stringArray;
and in the implementation:
- (id) init { //whatever your tableViewB initializer looks like
if ([self = [super init]) {
//oldData is an NSArray containing the initial values for each text field in order
stringArray = [[NSMutableArray alloc] initWithArray:oldData];
}
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
...
//Making the cell
[cell.textfield addTarget:self action:#selector(updateField:) forControlEvents:UIControlEventValueChanged];
....
//Setting up the cell
cell.textfield.tag = indexPath.row;
cell.textfield.text = [stringArray objectAtIndex:indexPath.row];
return cell;
}
- (void) updateField:(UITextField *)source {
NSString *text = source.text;
[stringArray replaceObjectAtIndex:source.tag withObject:text];
}
- (void) dealloc {
[stringArray release];
}
There are several ways you can choose to get your data back to the original table view, either by delegate, or by having the stringArray declared as a variable passed in to the tableViewB initializer rather than allocated there.
You should be aware that, in general, there are only about as many cell allocated as displayed on the screen. The cells that are not visible are actually not persistent but only get created when tableView:cellForRowAtIndexPath: is called. I suggest you create an array to cache the contents of all the text fields and which gets updated whenever a user leaves a text field (e.g. the textField:shouldEndEditing: method or something like that) is called.
If I understand your question - id each cell numerically and reference them in an array/climb the array to loop through them
Related
I'm developing an application in iPad 6.0 using Storyboards.
Let me first explain my goal. I'm trying to achieve a Master-Detail (SplitViewController-like) View Controller using 2 UITableViewControllers.
The first UITableView("Master"), let's call this HeaderTableView, as the name implies, lists down the Headers for the...
...Second UITableView("Detail"), let's call this the EncodingTableView, which contains a programmatically changing CustomTableViewCell (subviews contained within each cell may be a UITextField, UIButton or UISwitch).
See EncodingTableView.m
- (void)updateEncodingFields:(NSArray *)uiViewList
{
// Add logic for determining the kind of UIView to display in self.tableView
// Finally, notify that a change in data has been made (not working)
[self.tableView reloadData];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *encodingFieldsTableId = #"encodingFieldsTableId";
CustomTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:encodingFieldsTableId];
if (cell == nil) {
cell = [[CustomTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:encodingFieldsTableId];
}
// Change text in textView property of CustomTableViewCell
cell.encodingFieldTitle.text = uiViewList.title;
// added methods for determining what are to be added to [cell.contentView addSubView:]
// data used here is from the array in updateEncodingFields:
}
My HeaderTableView.m, contains the didSelectRowAtIndexPath to update the EncodingTableView
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
if (![selectedIndexPath isEqual:indexPath]) {
selectedIndexPath = indexPath;
[self updateDataFieldTableViewForIndexPath:indexPath];
}
}
- (void)updateDataFieldTableViewForIndexPath:(NSIndexPath *)indexPath {
[self.encodingTableView updateEncodingFields:self.uiViewList];
}
Question
- Data is all ok but why doesn't EncodingTableView "redraw"ing the fields? My
suspicion is that reusing cells has something to do with this but I just can't figure out why.
Screenshots on the result:
Initial Selection in HeaderTableView
Second Selection in HeaderTableView
What I've tried :
I kept seeing suggestions such as [UITableView setNeedsDisplay],
[UITableView reloadData] and [UITableView setNeedsLayout] but none of
them worked.
Removing the reuse of tableViewCells works fine but this causes parts of my
CustomTableView.encodingFieldTitle to disappear. Not to mention that this might cause performance issues if I were to drop reusing cells.
Restrictions:
I know that a good idea is to use a SplitViewController but this is just a subpart of my app (hence not the RootViewController).
Finally, thanks for reading such a long post. ;)
It looks like you are most likely adding subviews inside tableView:cellForRowAtIndexPath:.
The issue is that if you use cell reuse then are not always starting from a blank slate inside tableView:cellForRowAtIndexPath: instead you can possibly be given a cell back that has already been configured once. This is what you are seeing, a cell that has previously had labels added to it is handed back to you and then you add some more labels over the top.
There are a few way to deal with this:
(My preferred option) Create a subview of UITableViewCell with these extra sub views available as properties.
Ensure the cell setup is only done once
A great place to do this is when you actually create a cell when one does not already exist e.g. inside the if (cell) check
if (cell == nil) {
cell = [[CustomTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:encodingFieldsTableId];
// add subview's here and give them some way to be referenced later
// one way of doing it is with the tag property (YUK)
UILabel *subView = [[UILabel alloc] initWithframe:someFrame];
subView.tag = 1;
[cell.contentView addSubview:subView];
}
UILabel *label = (id)[cell.contentView viewWithTag:1];
label.text = #"some value";
One problem i can see in your code is that the cell identifiers used are different in tableView cellForRowAtIndxPath function.
While dequeueing you are using this identifier - > "encodingFieldsTableId"
&
while creating a cell you are using this identifier - > "dataFieldUiGroupTableId".
Ideally these two identifiers should be same !!!
Try adding,
cell.encodingFieldTitle.text = nil;
Before if(cell == nil)
So that whenever your cellForRowAtIndexPath method is called, the string already present in the cell you are going to reuse will get deleted and the new text in uiViewList.title will be displayed.
A really simple question here. I have a label on one view and a UITableView on the previous view. I have got a segue triggered when the user selects the row and I want the label to be updated with the text from that row. Here's one example, the code is pretty obvious.
- (void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
NSString *countrySelection;
switch (indexPath.section) {
case kFirstSection:
countrySelection = [[NSString alloc]
initWithFormat:#"The country you have chosen is %#",
[self.MyCountries objectAtIndex: indexPath.row]];
[self performSegueWithIdentifier:#"doneResults" sender:self];
self.countryResult.text = countrySelection;
break;
The label isn't updated and I just don't know what should be done.
Thanks in advance!
These kind of things really need to be set on the View Controller that owns them. Use a public property to pass the value of the selected country to that view controller as outlined below:
First, create a property called something like:
#property(non atomic,strong) NSString *countryChosen;
in the destination View Controller, and make sure to #synthesize it
No reason to create another property for the IndexPath. Just use
// Pass along the indexPath to the segue prepareForSegue method, since sender can be any object
[self performSegueWithIdentifier:#"doneResults" sender:indexPath];
in the didSelectRowAtIndexPath method.
Then in the prepareForSegueMethod:
MyDestinationViewController *mdvc = segue.destinationViewController;
NSIndexPath *indexPath = (NSIndexPath *)sender;
mdvc.countryChosen = [self.MyCountries objectAtIndex: indexPath.row]];
On the viewDidLoad event of the Destination VC, just use:
self.countryResult.text = countryChosen;
* EDIT *
To deal with a datasource that has multiple sections, just use the same logic that you have in the cellForRowAtIndexPath.
NSDictionary *selRow = [[self.countriesIndexArray valueForKey:[[[self.countriesIndexArray allKeys] sortedArrayUsingSelector:#selector(localizedCaseInsensitiveCompare:)] objectAtIndex:indexPath.section]] objectAtIndex:sindexPath.row];
Change this to suit your needs, but basically you are implementing the same logic that you would to display a cell, except you are specifying the indexPath (both section and row) that you want.
Then something like the following to set that property on the destination VC:
self.countryResult.text = [selRow valueForKey#"Country"];
In your current view controller create a new property for the indexPath of the cell the user selected, like this:
#property(strong,nonatomic) NSIndexPath *path;
#synthesize it and then when a user selects a row, set it by using
self.path = indexPath;
When you perform a segue, it will always call
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
So what you can do now when prepareForSegue: gets called, is the following:
/* if this is not the only segue you are performing you want to check on the identifier first to make sure this is the correct segue */
NSString *countrySelection = [[NSString alloc]
initWithFormat:#"The country you have chosen is %#",
[self.MyCountries objectAtIndex: self.path.row]];
segue.destinationViewController.countryResult.text = countrySelection;
/* after creating the text, set the indexPath to nil again because you don't have to keep it around anymore */
self.path = nil;
For this to work the view controller you want to show after selecting the cell must have a property for the UILabel, on which you are trying to set the text.
So I've been given an assignment in my Mobile apps class: make a color game app for the iphone.(The description of how to game works is at the top of the pasted viewcontroller.h file below.)
I'm very new to Objective-C and cocoa, but have managed to troubleshoot and fix a lot of things in this app. The problem I have right now is that I don't know how to properly initialize and send UITableViewCells to the view. I'm confused because all of the tutorials I've found online use datasource methods to change different attributes of the UITableView and the cells as well. I'm not sure how these methods will interact with the controls I've already placed. I'm confused because I added them by the storyboard file, not by defining tableview attributes with datasource code.
My immediate issue is that my program won't display the proper text to the cells textlabel and detailtextlabel.
I've looked everywhere online for UITableView and UITableViewCell tutorials, but they are all from years ago and I'm not sure if the advent of the storyboard has changed the way I would treat these controls.
All of the code I've written is either in the viewcontroller.m or viewcontroller.h files.
The method within ViewController.m file, that should call the cell and display text and detail text:
-(IBAction)enterClicked
{
//On enter- send instance colors to the colorTable row[i], perform comparisons and append the resulting symbols to the instanceResults String. Send instanceResults string to the resultTable row[i]. When game counter reaches 6, gameOver. If on comparisons check, the instanceColors are the same as the gameColors, then the player wins.
[self checkForLoss];
if(!self.gameOver)
{
resultOfGuess = [self comparePlayerInputToGameColors:guessColors];
[listOfGuesses addObject:guessColors];
[listOfOutcomes addObject:resultOfGuess];
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:_numberOfTurnsPlayed inSection:0];
UITableViewCell *thisCell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:CellIdentifier];
thisCell.textLabel.text = [self.listOfGuesses lastObject];
thisCell.detailTextLabel.text = [self.listOfOutcomes lastObject];
[guessColors setString:#""];
if([self checkForWin:resultOfGuess])
[UpdateLabel setText:#"You have won!"];
else
[UpdateLabel setText:#""];
self.colorCounter = 0;
self.isStepOne = YES;
_numberOfTurnsPlayed++;
}
else
{
if([self checkForLoss])
[UpdateLabel setText:#"You have lost!"];
}
}
The UITableView DataSource Methods I've called at the bottom of the viewcontroller.m file:
#pragma mark - UITableViewDataSource protocol
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
{
if(section == 0)
return #"Guesses: Results:";
return 0;
}
-(NSInteger) numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
-(NSInteger) tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return 6;
}
-(UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if(cell == nil)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:CellIdentifier];
}
return cell;
}
So my questions are: Can I change a control's properties with datasource methods, if I created the controls through the storyboard? How do I properly display the text in a uitableview's cells?
Edit/update: Thank you, I've used your advice jrturton, but now I've found something peculiar that may be the source of my problems. in my viewController.h file I've changed my header from
ViewController: UIViewController to ViewController: UITableViewController
Thinking that the datasource methods I call within the viewcontroller files have to be able to call the same methods and properties of the class that I call in the header-- Also, I see this done in other UITableView tutorial files.
The problem is that when I change the header to read-- ViewController: UITableViewController -- and I try to compile, I get this error:
Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '-[UITableViewController loadView] loaded the "2-view-3" nib but didn't get a UITableView.'
It compiles fine if I use just :UIViewController in the header file though.
Any ideas?
Further update: I''ve noticed within my storyboard that the only available ViewController object is a UIViewController object, while in the other tutorial files I've seen, this ViewController object is a UITableViewController object. I imagine this is my problem, but I can't seem to switch my UIViewController object to a UITableViewController. All I can do is create a new one, which isn't what I want, I imagine.
Your action method should update the data model (which I think it does, since it changes your listOfGuesses array). You then need to let your table view know that you have added or updated rows so that it can re-load them for you - check the UITableView documentation for reloading data or specific rows.
Creating a cell outside of the datasource methods isn't going to let that cell appear in your table.
At the moment I'm guessing you have 6 empty cells in your table view? You need to populate the text and detail labels in your cellForRowAtIndexPath method. The difference now there are storyboards is that you don't need to do the if (cell == nil) bit, as long as you have set the re-use identifier in your storyboard prototype cell then it will do all that for you. So your cellForRowAtIndexPath method can be reduced to:
-(UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath*)indexPath
{
// This will dequeue or create a new cell based on the prototype in your storyboard
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell"];
// Put your actual configuration here based on your model array
cell.textLabel.text = #"Hello";
return cell;
}
Further hints (this is homework so I'm not giving full samples)
'indexPath.row` in the above method will give you the index from your model array that the cell refers to
You have defined the table as having 6 rows, but you are adding items to your model arrays as you go - so when the table asks for row 5, and your model only has 3 entries, you need to deal with this. Consider changing the number of rows in the table dynamically and using table view methods to indicate that new rows have been added. Again, see the UITableView documentation for this.
Typically the text is set in each cell by accessing the setText property:
[[cell textLabel] setText:#"static string"];
or
[[cell textLabel] setText:someNSString];
or with .dot notation
cell.textLabel.text = someNSString;
return cell;
BTW this is done in the method:
-(UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:
I am using a UISearchDisplayController to be able to display a table with custom cells based on some data I am retrieving from a server.
First I set the UISearchDisplayController inside my UIViewController.
self.searchController = [[UISearchDisplayController alloc]
initWithSearchBar:self.mySearchBar contentsController:self];
self.searchController.delegate = self;
self.searchController.searchResultsDataSource = self;
self.searchController.searchResultsDelegate = self;
My UIViewController also implements the UISearchBarDelegate, so I can determine when a search starts. I set up a block so when my api call returns it gets called and a dictionary of results is saved in the self.searchResults property:
- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar
{
// here we make the api call
[api getSomeInfo:searchBar.text complete:^(NSDictionary *json) {
self.searchResults = json;
[self.searchController.searchResultsTableView reloadData];
}];
}
Now, the problem I have is that in my UITableViewDataSource method, where I return the custom cell. My cell is instantiated, but it's IBOutlets never get initialized, so I cannot set their content (text, images, etc) properly:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
if (tableView == self.searchController.searchResultsTableView) {
cell = [tableView dequeueReusableCellWithIdentifier:#"SearchResultsCellIndentifier"];
if (cell == nil) {
cell = [[SearchResultsCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}
cell.customLabel.text = [self.searchResults objectForKey:#"customText"]; // cell exists but cell.customLabel is nil!!
}
}
Why is the content nil? Is there somewhere in my Custom Cell class where I should be setting the content up?
Thanks!
I think your problem is that you used the variable cellIdentifier when creating the cell, but a string constant when dequeuing.
Simply always recreating a cell will work, but is not efficient at all and leads to major memory leaks.
You should first set the cellIdentifier according to which table view you are in, and which kind of cell you need, then dequeue with that cellIdentifier, and then create a new one if needed.
Hey guys, so in my newest program I use an NSTableView to display words on the left, and thier definitions on the right. these words and definitions are load from a .plist file, and at application startup the table view loads these words and definitions and displays them just fine. My problem comes in when the user tries to add a word and definition using the text boxes and buttons, the word is actually added to the .plist, meaning the method is running fine, but the table view refuses to display the new line. only until after i quit the program and reopen it does the tableview display the new line. I tested to see if the table view was connected properly by sending it other messages such as selectedRow and dataSource, all came back with responces, and proper responces at that. Currently the class that is used as the dataSource and delegate is a subclass to my main class with all my varibles and dictionaries. (I am big on using as little classes as possible). Lastly I tried inserting noteNumberOfRowsChanged in before reloadData, but still nothing.
I have tested everything and it just seems that the reloadData method is not initiating anything. Like I said, my table view is being sent the message, the new info is actually being added to the dicitinoary adn array, the amount of rows is being updated by the count method, and what proves it even more is that when the program is restarted it displays everything just fine. below is the relevent code, where currentWordList and currentDefitionList are the Array and Dictionary suppying the data to the dataSource, and editLibraryCardList is the NSTableView I am trying to reload.
the dataSource class code:
#interface EditorDataTable : SAT_Vocab_MacController {
IBOutlet NSTableColumn *editLibraryWordColumn;
IBOutlet NSTableColumn *editLibraryDefinitionColumn;
}
- (int)numberOfRowsInTableView:(NSTableView *)tableView;
- (id)tableView:(NSTableView *)tableView objectValueForTableColumn:(NSTableColumn *)tableColumn row:(int)row;
#end
#implementation EditorDataTable
- (int)numberOfRowsInTableView:(NSTableView *)tableView {
return ([currentWordList count]);
}
- (id)tableView:(NSTableView *)tableView objectValueForTableColumn:(NSTableColumn *)tableColumn row:(int)row {
if (tableColumn == editLibraryWordColumn) {
return [currentWordList objectAtIndex:row];
}
if (tableColumn == editLibraryDefinitionColumn) {
return [currentDefinitionList valueForKey:[[currentWordList objectAtIndex:row]lowercaseString]];
}
}
#end
method that adds the word to the list:
- (IBAction) editLibraryAddWordToLibrary: (id) sender {
if (self = [super init]) {
currentWordList = [[NSArray alloc] initWithContentsOfFile:userSATWordListPath];
currentDefinitionList = [[NSDictionary alloc] initWithContentsOfFile:userSATDefinitionListPath];
}
[currentWordList addObject:[[editLibraryNewCardWordInput stringValue]capitalizedString]];
[currentDefinitionList setObject:[editLibraryNewCardDefinitionInput stringValue] forKey:[[editLibraryNewCardWordInput stringValue]lowercaseString]];
aWordCounter = [currentWordList indexOfObject:[[editLibraryNewCardWordInput stringValue]capitalizedString]];
[aWordLabel setStringValue: [[NSString alloc] initWithFormat:#"%#", [currentWordList objectAtIndex: aWordCounter]]];
[aDefinitionLabel setStringValue: [[NSString alloc] initWithFormat:#""]];
[currentWordList writeToFile:userSATWordListPath atomically:YES];
[currentDefinitionList writeToFile:userSATDefinitionListPath atomically:YES];
[cardCountdownNumber setStringValue: [[NSString alloc] initWithFormat:#"%i", ([currentWordList count] - (1 + aWordCounter))]];
[editLibraryCardList noteNumberOfRowsChanged];
[editLibraryCardList reloadData];
}
Iv'e been stuck for days and any ideas will help! Thanks.
Zach
Have you tried debugging into your selectRowAtIndexPath method to make sure the reload occurs? (after you call [tableView reloadData] should be able to see this) Are you using UITableViewController?
If you wanted a callback after reload to know when its done, you could try:
[tableView reloadData];
[self performSelector:#selector(selectRowAtIndexPath:) withObject:indexPath afterDelay:0.0];
For those who are curious, i moved my code from the dataSource subclass to the main class, and it worked. i guess you cannot subclass the dataSource. Hope this helps!