How do I add a UITableView to an existing view?
I have added the control via interface builder, and added the correct delegates to the host view controller (including adding the table cell functions to the .m file)
But nothing gets called and nothing gets populated, the cellForRowAtIndexPath function, for example, never gets called.
in .h file
#interface GameViewController : UIViewController <UITableViewDelegate, UITableViewDataSource>
#property (weak, nonatomic) IBOutlet UITableView *friendsScoresView;
in .m file
init {
_friendsScoresView.delegate = self;
_friendsScoresView.dataSource = self;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// return number of rows
return 3;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"MyBasicCell"];
//NSMutableArray *nearbyScores = gclb->nearbyScores;
GCLeaderboardScore *playerScore = [gclb->nearbyScores objectAtIndex:indexPath.row];
cell.textLabel.text = [NSString stringWithFormat:#"%f",playerScore->score ];
cell.imageView.image = playerScore->photo;
return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// handle table view selection
}
What am I missing? Also how do I tell the table to update / refresh its contents?
If you added the UITableViewController in IB then click on the outlets tab on the right and connect the DataSource and Delegate in IB. If you want to do it in code, then create an IBOutlet variable for your table and set the delegate and datasource property on your variable. Also, you can't do it on init on the UIViewController as the NIB has not yet been loaded. Do it on viewDidLoad.
Related
The app launches without any technical problems, although I can
not get the hardcoded categories to appear in table view cells from the .m file. The table view style is basic, and through that I thought I could reach the title sample through the .m file using:
self.items = #[# {#"name" : #" Chores", #"Category" : #"Home"}].mutableCopy;
At first I thought the problem occurred because I forgot to set a reuse identifier. But fixing that problem didn't help. I get no warnings or errors in Xcode. I have not modified any other files except the ViewController.m and main.Storyboard files.
Code from the .m file
#import "ViewController.h"
#interface ViewController ()
#property (nonatomic) NSMutableArray *items;
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.items = #[# {#"name" : #" Chores", #"Category" :
#"Home"}].mutableCopy;
//self.navigationItem.title = #"What2Do list";
}
-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 1;
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return self.items.count;
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"TodoItemRow";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
NSDictionary *item = self.items[indexPath.row];
cell.textLabel.text = item[#"name"];
return cell;
}
#end
I expected "Chores" to show up in the table cell when I launch the app, but it will not appear.
In the ViewController.h you need to set the Delegate of the table view.
#interface ViewController : UIViewController<UITableViewDelegate,UITableViewDataSource>
Also you need to link the tableview to the viewcontroller as its delegate. The easiest way is adding it in the storyboard.
First drag + ctrl your table to the viewController Symbol on the storyboard.
On the list click on delegate.
Repeat again for dataSource.
I have two UITableViews using Storyboards in Xcode 7. I've set the delegate and dataSource using the Connections Inspector for both table views.
Let the first table view be the main table view and let the table views within each cell of the main table view be the detail table views with cell identifiers named appropriately and respectively.
When [tableView dequeueReusableCellWithIdentifier:#"MainCell" forIndexPath:indexPath] executes, it immediately calls its dataSource method -cellForRowAtIndexPath: for DetailCell preventing me from setting a custom instance variable in time to add the appropriate data to each cell.
The following is a simplified example marked using comments.
MainTableViewController:
#implementation MainTableViewController
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
// Keep in mind the following two (2) lines are set using the Connections Inspector
//cell.detailTableView.dataSource = cell;
//cell.detailTableView.delegate = cell;
// Stepping over the following line will jump to the
// other `-cellForRowAtIndexPath:` (below) used to set
// the detail info.
cell = (MainTableViewCell *)[tableView dequeueReusableCellWithIdentifier:#"MainCell" forIndexPath:indexPath];
CustomObj *obj = self.mainData[indexPath.row];
cell.nameLabel.text = obj.name;
cell.additionalInfo = obj.additionalInfo; // This line is not set before instantiation begins for the detail table view...
return cell;
}
...
#end
DetailTableViewCell (contains a UITableView and implements appropriate protocols):
#interface DetailTableViewCell : UITableViewCell <UITableViewDataSource, UITableViewDelegate>
#property (nonatomic, weak) IBOutlet UILabel *nameLabel;
#property (nonatomic, weak) IBOutlet UITableView *detailTableView;
#property (nonatomic, strong) CustomObj *additionalInfo;
#end
#implementation DetailTableViewCell
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
cell = (DetailTableViewCell *)[tableView dequeueReusableCellWithIdentifier:#"DetailCell" forIndexPath:indexPath];
// Instantiate detail ...
cell.detailLabel.text = self.additionalInfo.text;
// Problem!
// self.additionalInfo == nil thus we cannot set a value to the label.
return cell;
}
...
#end
The problem is when the detail -cellForRowAtIndexPath: method is called, I haven't had a chance to set a value for its dataSource, in this case, additionalInfo.
There are many possible ways to fix your problem, but first I would say that, your design seems not a good one, A UItableViewCell has another UITableView, and another UItableViewCell inside this UITableView? Why you do this? Just use one UITableView and put all of your views into one UItableViewCell as subViews should be enough.
Now get to your problem:
I would suggest not to use IBOutlet for setting up your delegate and dataSource, use code. This can give you a chance to delay setting the dataSource and delgate when you are ready. Once you think it's the proper time, just call [cell.detailTableView reloadData] will trigger your DetailTableViewCell to invoke cellForRowAtIndexPath
#implementation MainTableViewController
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
// Keep in mind the following two (2) lines are set using the Connections Inspector
//cell.detailTableView.dataSource = cell;
//cell.detailTableView.delegate = cell;
// Stepping over the following line will jump to the
// other `-cellForRowAtIndexPath:` (below) used to set
// the detail info.
cell = (MainTableViewCell *)[tableView dequeueReusableCellWithIdentifier:#"MainCell" forIndexPath:indexPath];
CustomObj *obj = self.mainData[indexPath.row];
cell.nameLabel.text = obj.name;
cell.additionalInfo = obj.additionalInfo; // This line is not set before instantiation begins for the detail table view...
// setup dataSource and delegate now
cell.detailTableView.dataSource = cell;
cell.detailTableView.delegate = cell;
// call reloadData whenever you think is proper
[cell.detailTableView reloadData];
return cell;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell* cell = nil;
//Check this call is for which table view.
if(tableView == detailTableView) {
cell = (MainTableViewCell *)[tableView dequeueReusableCellWithIdentifier:#"MainCell" forIndexPath:indexPath];
// Do any additional setup you want with MainCell
} else {
cell = (DetailTableViewCell *)[tableView dequeueReusableCellWithIdentifier:#"DetailCell" forIndexPath:indexPath];
// Do any additional setup you want with DetailCell
}
return cell;
}
I have a custom uitableviewcell and subclassed, and it is containing a uitextfield and delegate is also set, now when return key on keyboard is pressed I want to try few things
perform a segue(but issue is I am in uitableviewcell subclass).
modally present another view controller(but issue is uitableviewcell
do not allow this).
I want to display uiactionsheet(but again limitation is
uitableviewcell).
If i get rootviewcontroller reference then rootviewcontroller's view itself not displayed or not the active view so any thing you do will not present on screen, active view is required.
You could use a block property on your cell that is fired whenever your custom button action occurs. Your cell's block property might look something like this:
#interface CustomTableViewCell : UITableViewCell
#property (nonatomic, copy) void (^customActionBlock)();
#end
Your cell would then invoke this block from the custom button action like this:
#implementation CustomTableViewCell
- (IBAction)buttonTapped:(id)sender {
if ( self.customActionBlock ) {
self.customActionBlock();
}
}
#end
Then finally, you set the block in -cellForRowAtIndexPath: back in your view controller (or wherever) like this:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
CustomTableViewCell * cell = [tableView dequeueReusableCellWithIdentifier:#"customCell" forIndexPath:indexPath];
cell.textLabel.text = [self.colors objectAtIndex:indexPath.row];
cell.customActionBlock = ^{
NSLog(#"Do the stuff!");
// present view controller modally
// present an action sheet
// etc....
};
return cell;
}
One word of caution, though. If you use blocks you run the risk of strongly referencing self and creating a memory leak. Blocks are fun and easy to use but you have to play by their rules. Here are some resources to help you get familiar with them:
Retain cycle on `self` with blocks
Reference to self inside block
http://aceontech.com/objc/ios/2014/01/10/weakify-a-more-elegant-solution-to-weakself.html
http://fuckingblocksyntax.com
You can attach action to your buttons even if they are in a tableView
[cell.button addTarget:self action:#selector(presentController:) forControlEvents:UIControlEventTouchUpInside];
presentController is referring to an IBAction
- (IBAction)presentController:(id)sender
{
//present
}
Implement button action in Tableview SuperClass.
Or You can use Custom delegate in UITableViewCell subclass. In UITableView Subclass declare a protocol.
#protocol customCellDelegate <NSObject>
#required
-(void)selectedButtonInIndexPath : (NSIndexPath *)indexpath;
#end
Set this property in UITableView Subclass
#property (nonatomic, strong)NSIndexPath *indexpath;
#property (nonatomic, strong) id <customCellDelegate> delegate;
And then in Your UITableView Subclass Button action add This lines
if(self.delegate){
[self.delegate selectedButtonInIndexPath: self.indexpath];
}
And in your tableview datasource method
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath;
Implement this code
cell.delegate = (id)self;
cell.indexpath = indexPath;
And in Uitableview super class just implement this method
-(void)selectedButtonInIndexPath : (NSIndexPath *)indexpath{
//display uiimagepickercontroller modally or anything else here
}
I have a class like this:
#interface ExerciseLogDetails : UIViewController<UIActionSheetDelegate, UITableViewDelegate, UITableViewDataSource> {
where I am trying to display some elements followed by a UITextView. The UITextView element is created on Interface Builder. When executing this code:
- (void)viewDidLoad {
self.tableView = [[UITableView alloc] initWithFrame:self.view.bounds style:UITableViewStylePlain];
tableView.dataSource = self;
tableView.delegate = self;
[self.view addSubview:self.tableView];
}
a table shows, but not the one I configured in Interface Builder. It is completely blank and unformatted. How can I access my table and populate it progrmmatically with data?
Thank you!
Several of the tips on this thread helped me create this. I am going to offer some more complete code files in order to help others as well:
Step 1. Drag your UITableView onto your View Controller either in Storyboards or XIBs. In my example I am using a story board.
Step 2: Open your ViewController (in my case its just DefaultViewController) and add the two delegates for the UITableView: UITableViewDelegate and UITableViewDataSource. Also add a simple data source for population and the UITableView IBOutlet.
DefaultViewController.h
#import <UIKit/UIKit.h>
#interface DetailViewController : UIViewController <UITableViewDelegate, UITableViewDataSource>
#property (strong, nonatomic) IBOutlet UITableView *tableView;
#property (strong, nonatomic) NSMutableArray *newsArray;
#end
Step 3: Open your implementation file (DefaultViewController.m) and add the following:
#import "DetailViewController.h"
#interface DetailViewController ()
- (void)configureView;
#end
#implementation DetailViewController
#synthesize newsArray;
#synthesize tableView;
#pragma mark - Managing the detail item
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[self configureView];
}
- (void)configureView
{
// Update the user interface for the detail item.
self.newsArray = [[NSMutableArray alloc] initWithObjects:#"Hello World",#"Goodbye World", nil];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#pragma mark UITableViewDelegate
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// typically you need know which item the user has selected.
// this method allows you to keep track of the selection
}
- (UITableViewCellEditingStyle)tableView:(UITableView *)tableView
editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath
{
return UITableViewCellEditingStyleDelete;
}
// This will tell your UITableView how many rows you wish to have in each section.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [self.newsArray count];
}
// This will tell your UITableView what data to put in which cells in your table.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifer = #"CellIdentifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifer];
// Using a cell identifier will allow your app to reuse cells as they come and go from the screen.
if (cell == nil)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifer];
}
// Deciding which data to put into this particular cell.
// If it the first row, the data input will be "Data1" from the array.
NSUInteger row = [indexPath row];
cell.textLabel.text = [self.newsArray objectAtIndex:row];
return cell;
}
#end
Step 4: Goto your Storyboards or XIB and select your UITableView and drag the datasource and delegate outlets onto your DefaultViewController to wire them up. Also you will need to wire up the Referencing Outlet for the UITableView to your IBOutlet tableView object you created in your header file.
Once this is finished you should be able to run it and the sample data will be in place.
I hope this along with the other tips on this thread will help others setup a UITableView from scratch on a ViewController.
If you configured a tableView in IB you shouldn't also create one programmatically, you should create #property (nonatomic, retain) IBOutlet UITableView *tableView; and connect it to the tableView you configured in IB.
Try to set a breakpoint in the tableView's
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
delegate method to see if this method get called.
From Apple UITableView docs:
A UITableView object must have an object that acts as a data source
and an object that acts as a delegate; typically these objects are
either the application delegate or, more frequently, a custom
UITableViewController object. The data source must adopt the
UITableViewDataSource protocol and the delegate must adopt the
UITableViewDelegate protocol. The data source provides information
that UITableView needs to construct tables and manages the data model
when rows of a table are inserted, deleted, or reordered. The delegate
provides the cells used by tables and performs other tasks, such as
managing accessory views and selections.
As u can see if u don't set a dataSource to your tableView, the tableView will not know how and what to display, so nothing will happen.
You can set one by calling tableView.dataSource = self; or in IB drag from your tableView to the file's owner (that is your viewController that must implement the UITableViewDataSource Protocol)
There are two methods in the UITableViewDataSource protocol that your dataSource must implement:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
and
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath: (NSIndexPath *)indexPath
If u won't implement those methods u will get a compiler warnings.
You can have more control on how the tableView will look if you implement the UITableViewDelegate protocol - like row/header/footer height, selections and more...
From Apple UITableView docs:
UITableView overrides the layoutSubviews method of UIView so that it
calls reloadData only when you create a new instance of UITableView or
when you assign a new data source. Reloading the table view clears
current state, including the current selection. However, if you
explicitly call reloadData, it clears this state and any subsequent
direct or indirect call to layoutSubviews does not trigger a reload.
ReloadData get called when the tableView is created or when you assign a new dataSource (or when you explicitly call it of course..).
This is when the tableView needs to know what to display (how many sections?, how many rows?, and which cell to display?) - So this is when numberOfRowsInSextion method called.
Like Eyal said, you shouldn't create a UITableView programmatically and in the Interface Builder. Instead, it is much easier to just create one in Interface Builder and assigns it's delegate and datasource properties to File's Owner in IB.
Once you've done this, you don't need to create one programmatically and there's no need for a #property for the tableview.
Instead, you could have your UIViewController's class files look like this:
// YourViewController.h
#import <UIKit/UIKit.h>
#interface YourViewController : UIViewController <UITableViewDelegate, UITableViewDataSource>
#property (strong, nonatomic) NSArray *yourData;
#end
Where the NSArray will contain your data that you will enter into the table programmatically. You may use other data classes too like an NSDictionary depending on what data you have and how you want it to sit in the table.
// YourViewController.m
#import "YourViewController.h"
#implementation YourViewController
#synthesize yourData;
- (void)viewDidLoad
{
[super viewDidLoad];
// Here you are creating some data to go in your table by inputting it as an array.
// I just used some basic strings as an example.
NSArray *array = [[NSArray alloc] initWithObjects:#"Data1", #"Data2", #"Data3", nil];
// Copying the array you just created to your data array for use in your table.
self.yourData = array;
}
- (void)viewDidUnload
{
[super viewDidUnload];
self.yourData = nil;
}
#pragma mark Table View Data Source Methods
// This will tell your UITableView how many rows you wish to have in each section.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return [self.yourData count];
}
// This will tell your UITableView what data to put in which cells in your table.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifer = #"CellIdentifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifer];
// Using a cell identifier will allow your app to reuse cells as they come and go from the screen.
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifer];
}
// Deciding which data to put into this particular cell.
// If it the first row, the data input will be "Data1" from the array.
NSUInteger row = [indexPath row];
cell.textLabel.text = [yourData objectAtIndex:row];
return cell;
}
#end
This should just create a simple UITableView with three entries of data that you have entered programmatically.
If you have any problems or questions just post a comment. :)
Hope this helps.
I'm a newbie programming iOS and I've a problem adding a new cell to a UITableView object. I'm using an storyboard and one of the scenes is a UIViewController that has several subviews: textfields, a tableview, etc. I intend to add rows to this tableView from a detail scene.
I'm able to initially add rows to the table, but I'm not able to add a row afterwards. When I press a button to add the row I call the method '[self.stepsListTableView reloadData];' which produces a call to the method '- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section' and it returns a correct value, including the new array element. But method '- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath' is not called to update the table.
I do not understand what I'm doing wrong.
Details of my source code:
WorkoutDetailsViewController.h
(…)
#interface WorkoutDetailsViewController : UIViewController <StepDetailsViewControllerDelegate, UITextFieldDelegate, UITableViewDelegate, UITableViewDataSource>
#property (nonatomic, weak) id <WorkoutDetailsViewControllerDelegate> delegate;
#property (nonatomic, strong) Workout *workout;
(…)
#property (nonatomic, retain) IBOutlet UITableView *stepsListTableView;
(…)
WorkoutDetailsViewController.m
(…)
#synthesize stepsListTableView;
(…)
- (void)viewDidLoad
{
[super viewDidLoad];
addButton.enabled = FALSE;
workoutNameField.delegate = self;
if (self.workout == nil) {
self.workout = [[Workout alloc] init];
self.stepsListTableView = [[UITableView alloc] init];
}
self.stepsListTableView.delegate = self;
self.stepsListTableView.dataSource = self;
}
(…)
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
// Customize the number of rows in the table view.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
//return [self.workout.stepsList count];
NSInteger counter = 0;
counter = [self.workout.stepsList count];
return counter;
}
// Customize the appearance of table view cells.
- (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];
}
// Set up the cell...
// Pending
return cell;
}
- (void)stepDetailsViewControllerDidDone:(StepDetailsViewController *)controller
{
[self.workout.stepsList addObject:controller.step];
NSInteger counter = [self.workout.stepsList count];
[self.stepsListTableView beginUpdates];
NSArray *paths = [NSArray arrayWithObject:[NSIndexPath indexPathForRow:(counter-1) inSection:0]];
[self.stepsListTableView insertRowsAtIndexPaths:paths withRowAnimation:UITableViewRowAnimationTop];
[self.stepsListTableView endUpdates];
[self.stepsListTableView reloadData];
}
(…)
Also in the storyboard, I have setup the outlets delegate and dataSource to be the controller view.
Any idea ?
Regards,
JoanBa
I have solved the issue. I have discovered using debugger that method reloadData was called for a different UITableView than the one initialized in viewDidLoad.
I reviewed the UITableView settings in storyboard, which aparently were correct but I have deleted them and created again. Now it works.
In UIViewController header I have the line
#property (nonatomic, retain) IBOutlet UITableView *stepsListTableView;
and in implementation I have commented lines
//self.stepsListTableView.delegate = self;
//self.stepsListTableView.dataSource = self;
And, of course, in storyboard I have defined for the UITableView the following relationships:
Outlets: dataSource, delegate --> UIViewController
Referencing outlet: UITableView --> UIVIewController
That's it !!
You may have the table view set to static content. Select the UITableView in Storyboard and in the "Attributes Inspector" section of the menu on the right of screen select the "Content" field under the "Table View" header and set the value to "Dynamic Prototypes".
Screenshot for clarity:
This little trick caught me out several times when I was starting out.