I hope someone can help...
I've setup a static UITableView Controller with four sections. The top two sections are for inputting data. The third section has 1 cell and contains a save button.
The final section has 6 cells and I want to be able to populate these six cells with the data from the first two sections, in the long run anyway...
So i tried to a small example, but it's not working. The console returns the following error:
UITableView dataSource must return a cell from tableView:cellForRowAtIndexPath:'
* First throw call stack:
Here's an example:
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
NSIndexPath *EditRow = [NSIndexPath indexPathForRow:1 inSection:4];
UITableViewCell *cell = [tableView cellForRowAtIndexPath:EditRow];
NSString *test = #"Test";
cell.textLabel.text = test;
NSLog(#"Index Path: %d", indexPath.row);
NSLog(#"Cell ID:, %#", CellIdentifier);
return cell;
}
So my question comes down to.. How do I update a specific cell in a specific section?
Thanks
When I implement static cells, I delete the cellForRowAtIndexPath, numberOfSectionsInTableView, and numberOfRowsInSection methods from the generic UIViewController stub that Xcode generates; these seem to be necessary only when you're dealing with dynamic cells.
Then, by control-dragging in the storyboard, I create named outlets for all UI elements in the cells that need to be set programmatically; in my case, these are usually UILabels. In the viewDidLoad method of the controller, I set the appropriate initial values of these outlets, for example:
self.nameLabel.text = self.dataSource.name;
Once you've got this wired up, you can change any of the values at will.
I hope that this works for you. I'd be happy to learn from anyone who has a better (more appropriate?) way of doing this.
Simply call - [UITableView (void)reloadRowsAtIndexPaths:(NSArray *)indexPaths withRowAnimation:(UITableViewRowAnimation)animation], then your data source will be called for the appropriate index paths.
Related
I haven't developed any iOS apps in a while. I am fine with both swift and Objective-C but what I find different is adding a UITableView to ViewController. Before, I used to add a UITableView to ViewController, add the required datasource methods and the typical UITableViewCell object, and return the cell in cellForRowAtIndexPath:, which would display empty cells depending on the number of rows I return. Now, I did everything the same, but the UITableView is empty and when I scroll I see the lines but not my cell.textlabel.text value, which I set. It seems now I am supposed to add UITableViewCell to the UITableView and remove the
#pragma-mark TableView Datasource
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [_formTitles count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell =[tableView dequeueReusableCellWithIdentifier:#"cell"];
if(cell==NULL)
{
cell=[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:#"cell"];
}
cell.textLabel.text=[_formTitles objectAtIndex:indexPath.row];
cell.detailTextLabel.text=#"Kaushik";
return cell;
}
I can't find a simple post online regarding the same.
Can someone post what are the changes in the new iOS 9 in a simple manner?
Thank you
Right..For those of you who are still prefer to add a tableview to a viewcontroller.Here are the steps
In the ViewController drag and drop the tableview.Now instead of the lines which you see in the old Xcode.This time you would see a blank table view with the text " Table View prototype content" in the middle.
We usually create a tableviewcell only we doing anything different like adding more labels or image etc but hereafter it is required to add a tableviewcell in the tableview.Drag and drop a tableview onto the tableview.It will display as protype cells.One can select type of cell here itself as basic,value 1,value 2 or subtitle.Also NEED TO SET THE REUSE IDENTIFIER IN THE STORYBOARD UTILITIES PANEL ON YOUR RIGHT. At the end, you can select the tableview and add the missing constraints.
Implement the typical required datasource methods in your viewcontroller class.
(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return 5;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell =[tableView dequeueReusableCellWithIdentifier:#"cell"];
cell.textLabel.text=#"text";
cell.detailTextLabel.text=#"DetailedText";
return cell;
}
The change here is that we dont require the usual if(cell==nil)
{..}
piece of code since we added the prototype cells to the storyboard.
Don;t forget to connect the delegate and datasource of the tableview to the viewcontroller.
This should display the tableview in your viewcontroller but i am getting a space on top of the tableview which i don't know why.Anyway this is how you add a tableview to a view controller using Objective-C language in iOS 9.3.
FYI: Guys if i've missed anything, please mention it in the comments
Thank you
Put tableView to view controller and link it to viewcontroller.
link delegate and datasource of tableview to viewcontroller.
in
viewcontroller.h
#interface ViewController :<UITableViewDelegate, UITableViewDataSource>
in viewWillAppear put
tblService.delegate=self;
tblService.dataSource=self;
and your array elements.
5.Impliment your tableview delegate method and datasource method .
6.be sure you cell identifier equal the one put on storyboard.
this link will help you more to implement your first app and this video.
I want a tableview inside another tableviewCell like the following image.It shows one complete cell with a few details and a tableview. How can i do this?I was following this link Link.This is an old code .It is using xibs.I dont have any idea where to set the delegate for the inner tableview.Please help.Any suggestion will be realy helpfull.
My first idea would be:
Subclass UITableViewCell ("MainTableViewCell") and extend it with UITableViewDelegate and UITableViewDatasource.
Next to all the properties you need in "MainTableViewCell" add a TableView "tableViewFilms" and an array "films" for the Films. Also don't forget to add the datasource methods for a tableview to the implementation file.
To easily setup a cell I add a setup-method to the header-file. Which can be called once the cell is instantiated. You can modify it as you want, give it as many parameters as you want and in the implementation (see step 4) set datasource and delegate of your inner tableview.
- (void)setupCellWithDictionary:(NSDictionary *)dict AndArray:(NSArray *)filmsForInnerTable;
You can call this method in your datasource method, once a cell is instantiated:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
MainTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"MainTableViewCell" forIndexPath:indexPath];
NSDictionary *dict = (NSDictionary *) allDataDictionaries[indexPath.row];
[cell setupCellWithDictionary:dict AndArray:filmsForInnerTable];
return cell;
}
Subclass UITableViewCell another time: "FilmTableViewCell"
When setting up the a Cell of "MainTableViewCell", set the delegate and the datasource of "tableViewFilms" to self (object of "MainTableViewCell").
- (void)setupCellWithDictionary:(NSDictionary *)dict AndArray:(NSArray *)filmsForInnerTable{
self.films = filmsForInnerTable;
self.tableViewFilms.dataSource = self;
self.tableViewFilms.delegate = self;
[self.tableView reload];
//more instructions
}
Populate the tableview with the data from the array "films" using "FilmTableViewCells".
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
FilmTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"FilmTableViewCell" forIndexPath:indexPath];
Film *film = (Film*)films[indexPath.row];
[cell setupCellWithFilm:film];
return cell;
}
Hope this helps.
Don't forget to use Outlets, the method definitions and to set the reuse-identifiers for the cells!
Check my answer in this ios 8 Swift - TableView with embedded CollectionView. You have replace that UICollectionView with UITableView.
Everything else is pretty much the same. Its just a head start with UITableView and UICollectionView created programmatically.
I can change it accordingly if you don't understand.
What I have
1). Container has UITableView, which has two custom UITableViewCells.
2). Core Data has certain entity which has a text to be displayed at
UITableViewCell each time I get into the View.
What i am doing ?
1) I have chosen -viewWillAppear method which gets invoked each time the view is visible.
2) In -viewWillAppear, I retrieved the data from core data.
3) Retrieved particular cell from UITableView
NSUInteger idxArr[] ={2,0}; // 2 nd section, 0th Row.
NSIndexPath *cPath = [NSIndexPath indexPathWithIndexes:idxArr length:2];
myCell *tCell = (myCell *)[self.settings cellForRowAtIndexPath:cPath];
tCell.myLabel.text = rec.servername; // rec.servername is from DC.
When I checked in the lldb,
tCell was nil.
Questions:
1) It is the right way of getting the Cell ?
2) Or, By the time -viewWillAppear, does the UITableView not Ready ?
I am sure.
You should populate the cells by conforming to tableView dataSource protocol and then in your viewWillAppear you should call reloadData on your tableView.
After calling reloadData for tableview, We need to call -scrollToRowAtIndexPath: before getting cell from -cellForRowAtIndexPath:.
Because, As we are calling a row in section 2, it might not be in the visible area until we scroll. So, cellForRowAtIndexPath: returns nil.
Method -cellForRowAtIndexPath: shouldn't be called programically. It's a data source method for UITableView and it contain some cell reuse optimalizations. If you update the view after scrolling down and up -tableView:cellForRowAtIndexPath will be called again and your changes won't be visible.
If you want to update specific cell you should update make changes in:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
YourCell *cell = [tableView dequeueReusableCellWithIdentifier:#"CellId" forIndexPath:indexPath];
YourData *data = //Get your data here
if (data.isReady) {
cell.tf.text = data[indexPath.row].text;
} else {
cell.tf.text = #"Not ready yet. Need to reload this cell later";
}
return cell;
}
And then call method below when you finish fetch your data.
[self.tableView reloadRowsAtIndexPaths:(NSArray *) withRowAnimation:UITableViewRowAnimationFade];
If you want to reload whole tableView (usually it's not slow) as #salaman140 says you can call [self.tableView reloadData] to update all visible cells.
If I were you I wouldn't use:
NSUInteger idxArr[] ={2,0}; // 2 nd section, 0th Row.
NSIndexPath *cPath = [NSIndexPath indexPathWithIndexes:idxArr length:2];
I would (is much more clear):
NSIndexPath *cPath = [NSIndexPath indexPathForRow:0 inSection:2];
I'm really new to Objective-C here so what I'm asking may be trivial to most of you but any guidance will help.
Here's a picture of my storyboad.
My current objective is to allow for the user to enter in the number of sets (NSInteger *numReps) and then press the "Log Reps" button and have the table initialize with numReps cells that look like the prototype cell.
Now where I'm at a loss for the implementation. I've never done this kind of thing before so I'm not exactly sure what the best way to go about it is. I have thought of making a custom class for the UITableView table that would take info from the view after the Log Reps button is pushed. I'm not entirely sure how this would need to be implemented. Or can I simply add the table to the properties of the view controller and setup the table within the view controller? That was my initial idea and seems ideal so that I would have everything in one place.
Pleas advise. I am new to all of this and come from a C++ background so I'm still learning a lot of the notation.
Try this:
-(IBAction)btnLogClicked {
int iSet = 4 //Number of row in table
UITableView *tblView= [[UITab;eView alloc]initWithFrame:CGRectMake(0,50,320,100)];
tblView.delegate = self;
tblView.dataSource = self;
[self.view addSubView:tblView];
}
Table View Data Source and Delegate Methods
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return iSet;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
// Display what you want to display in each cell
return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
[tableView deselectRowAtIndexPath:indexPath animated:YES];
}
It's not clear what you want to present in your prototype cells, but you need an array (or probably an array of dictionaries) to populate the cells. The number of rows is determined by the number of entires (the count) of that array. So, if you take the number entered by the user, and add that many object to your array, then call reloadData on the table, you will get the number of rows that you want. What those object are that you add to the array, depends on what you're trying to show there.
you could start reading: Table View Programming Guide for iOS
But I can answer you:
You can add the UITableView to the UIViewController, but you need set your UIViewController like the TableView's delegate and dataSource. Your ViewController need to implement the protocol: UITableViewDataSource
The method that you are looking for is: tableView:numberOfRowsInSection:
But I really recommend you that read the Apple Reference.
I HAVE READ apple documentation and it's not understandable for such a beginner in Objective-C as me. I'm trying to implement multicolumn UITableView following this link example and it just doesn't work so i need to comprehend how cellForRowAtIndexPath work, cause for me personally this method seems pretty complicated.
1) What does it return? UITableViewCell? But why does it look so odd?
-(UITableViewCell *)tableView:(UITableView *)tableView
What is that? Could you please explain?
2) How does it get called and what is more important how am i to connect it to a certain UITableView??? What if i have two UITableView's named firstTableView and secondTableView and i want them to be different (to perform cellForRowAtIndexPath differently)? How am i supposed to link my UITableViews to this
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
the method accepts NSIndexPath, not UITableView. What am i gonna do?
I'll try and break it down (example from documention)
/*
* The cellForRowAtIndexPath takes for argument the tableView (so if the same object
* is delegate for several tableViews it can identify which one is asking for a cell),
* and an indexPath which determines which row and section the cell is returned for.
*/
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
/*
* This is an important bit, it asks the table view if it has any available cells
* already created which it is not using (if they are offScreen), so that it can
* reuse them (saving the time of alloc/init/load from xib a new cell ).
* The identifier is there to differentiate between different types of cells
* (you can display different types of cells in the same table view)
*/
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"MyIdentifier"];
/*
* If the cell is nil it means no cell was available for reuse and that we should
* create a new one.
*/
if (cell == nil) {
/*
* Actually create a new cell (with an identifier so that it can be dequeued).
*/
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:#"MyIdentifier"] autorelease];
cell.selectionStyle = UITableViewCellSelectionStyleNone;
}
/*
* Now that we have a cell we can configure it to display the data corresponding to
* this row/section
*/
NSDictionary *item = (NSDictionary *)[self.content objectAtIndex:indexPath.row];
cell.textLabel.text = [item objectForKey:#"mainTitleKey"];
cell.detailTextLabel.text = [item objectForKey:#"secondaryTitleKey"];
NSString *path = [[NSBundle mainBundle] pathForResource:[item objectForKey:#"imageKey"] ofType:#"png"];
UIImage *theImage = [UIImage imageWithContentsOfFile:path];
cell.imageView.image = theImage;
/* Now that the cell is configured we return it to the table view so that it can display it */
return cell;
}
This is a DataSource method so it will be called on whichever object has declared itself as the DataSource of the UITableView. It is called when the table view actually needs to display the cell onscreen, based on the number of rows and sections (which you specify in other DataSource methods).
1) The function returns a cell for a table view yes? So, the returned object is of type UITableViewCell. These are the objects that you see in the table's rows. This function basically returns a cell, for a table view.
But you might ask, how the function would know what cell to return for what row, which is answered in the 2nd question
2)NSIndexPath is essentially two things-
Your Section
Your row
Because your table might be divided to many sections and each with its own rows, this NSIndexPath will help you identify precisely which section and which row. They are both integers. If you're a beginner, I would say try with just one section.
It is called if you implement the UITableViewDataSource protocol in your view controller. A simpler way would be to add a UITableViewController class. I strongly recommend this because it Apple has some code written for you to easily implement the functions that can describe a table. Anyway, if you choose to implement this protocol yourself, you need to create a UITableViewCell object and return it for whatever row. Have a look at its class reference to understand re-usablity because the cells that are displayed in the table view are reused again and again(this is a very efficient design btw).
As for when you have two table views, look at the method. The table view is passed to it, so you should not have a problem with respect to that.
Basically it's designing your cell, The cellforrowatindexpath is called for each cell and the cell number is found by indexpath.row and section number by indexpath.section . Here you can use a label, button or textfied image anything that you want which are updated for all rows in the table.
Answer for second question
In cell for row at index path use an if statement
In Objective C
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *CellIdentifier = #"CellIdentifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if(tableView == firstTableView)
{
//code for first table view
[cell.contentView addSubview: someView];
}
if(tableview == secondTableView)
{
//code for secondTableView
[cell.contentView addSubview: someView];
}
return cell;
}
In Swift 3.0
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
{
let cell:UITableViewCell = self.tableView.dequeueReusableCell(withIdentifier: cellReuseIdentifier) as UITableViewCell!
if(tableView == firstTableView) {
//code for first table view
}
if(tableview == secondTableView) {
//code for secondTableView
}
return cell
}