I've been trying to fill a UITableView with data from a NSMutableArray. I have a View-Based application project and so far I've tried every tutorial I found but so far, it just doesn't work. I linked the dataSource and delegate to the File's Owner, I added the procotols UITableViewDelegate and UITableViewDataSource to my UIViewController, I create an array containing 3 strings just to try and debug, everytime I load the app, the table stays empty.
I'm not sure what could be my error, or where I should look to find the problem, if you guys got any idea that would be nice.
Thank you
-(NSInteger) tableView:(UITableView *)table numberOfRowsInSection: (NSInteger)section
{
return [yourArray count];
}
-(UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"CellIdentifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
NSUInteger row = [indexPath row];
cell.textLabel.text = [yourArray objectAtIndex:row];
return cell;
}
That should populate the table from an array. I've used it several times in my app.
I guess you did forget to call -reloadData on the table view.
Make sure the dataSource and delegate are properly connected to the view controller, also make sure your UITableView is property connected with the outlet if you are using storyboards or a xib file.
If nothing works I recommend you to use XLData that makes UITableView data loading much more simple to implement.
Related
I'm new to iOS dev, so I do apologise for asking potentially dumb question.
What I want to do is something very similar to the default Weather app; where the app has a info button, it flips to another view which has a table along with a Done button to go back to the app.
I'm using the 'Utility Application' template which does most of this for me :)
However, I am now struggling to add a tableview into the flipview. Am I on the right path? I'm using storyboard at the moment - beginning to realise this is most likely a limitation on the GUI (after all a GUI can only go so far). If so, is this possible programatically and how would I go about applying it on a default 'Utility Application' template.
I'm using Xcode 4.2.
Any help would be appreciated. Thanks in advance :)
First of all, you'll want to drag and drop a UITableView onto your flipsideViewController in interface builder. Make sure that you like its delegate and data source to the view controller.
Then change flipsideViewController.h to create an instance variable for the array that will store the text for the cells labels and for the controller to conform to the tables delegate and data source methods.
#interface FlipsideViewController : UIViewController <UITableViewDataSource, UITableViewDelegate>
{
NSArray *myArrayOfItems;
}
In flipsideViewController.m alloc/init and populate your array in viewDidLoad
myArrayOfItems = [[NSArray alloc] initWithObjects:#"firstItem",#"secondItem",#"thirdItem",#"fourthItem", nil];
And finally, copy and paste the following and you should have a working table!
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [myArrayOfItems count];
}
- (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];
}
cell.textLabel.text = [myArrayOfItems objectAtIndex:indexPath.row];
return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"Selected cell index:%i",indexPath.row);
}
In my tableview have custom cells that I initialize from a UITableViewCell class. I have sections for first letters of records and have an indexPath that is being created dynamically.
I wanted to add a search display controller to my tableview. So I did, created all methods to filter data. I am sure that my functions are working well because I am printing array count to screen for search results.
My problem is that the first time view loads, the data is on the screen. But when I hit the search input and type a letter, than I get 'UITableView dataSource must return a cell from tableView:cellForRowAtIndexPath:' error. After I used a breakpoint I saw that my custom cell is nil after searching. Data is exist, but cell is not being initialized.
Here is the code I use for custom cell initializing:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"ObjectCell";
SpeakerCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
NSDictionary *myObject = [[sections valueForKey:[[[sections allKeys] sortedArrayUsingSelector:#selector(localizedCaseInsensitiveCompare:)] objectAtIndex:indexPath.section]] objectAtIndex:indexPath.row];
cell.label1.text = [myObject objectForKey:#"myValue"];
return cell;
}
I believe I made a mistake when putting controls in IB. So I added screenshots of objects:
Connections inspector for my table view
Connections inspector for my search display controller
EDIT: Problem is actually solved, I have used a UISearchBar instead of Search Display Controller but I guess this issue remains unsolved. So I'm willing to try any ways to make it work.
As of here search display controller question,
you need to access the self.tableView instead of tableView:
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:#"CellId"];
// do your thing
return cell;
}
For those using iOS 5 and StoryBoards, you would want to use the following method instead of initWithIdentifier:
initWithStyle:(UITableViewCellStyle)stylereuseIdentifier:(NSString *)reuseIdentifier
Example:
NSString *cellIdentifier = #"ListItemCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}
I'm not sure about how this should work in storeboarding.
But normally you would check if the [tableView dequeueReusableCellWithIdentifier:CellIdentifier] returns a cell.
Because if the cell in not loaded before or there aren't any cells to reuse you will have to create a new cell:
SpeakerCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[SpeakerCell alloc] initWithIdentifier: CellIdentifier];
}
Also when in declaring local variables in Objective-C we tent not to capitalize the first letter.
I had the same issue, with custom cells (built in Storyboard) not being drawn as soon as the first letter was put in the search field. The search was successful however.
Finally I found a good tutorial from Brenna Blackwell suggesting to configure manually the cell drawing in the corresponding subclass of UITableViewCell, adding UILabels and other items.
I'm stuck with a seemingly very simple app that I'm trying to develop
Basically, I have a UITable, and two buttons: red/blue
When a button is pressed, a row with corresponding title of that button is append to the table
I'm overwhelmed by how complicated UITableView has to be implemented (datasource, delegate, resuable identifier, etc)
Can anyone help me out with this, preferably show me detailed codes
For my Buttons, I have something like this
- (IBAction)buttonPressed:(UIButton *)sender{
NSString *item = sender.currentTitle;
[self.cellArray addObject:item];
[self.myTable reloadData];
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return self.cellArray.count;
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"The Table Cell";
self.myTableCell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (self.myTableCell == nil) {
self.myTableCell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
self.myTableCell.textLabel.text = [self.cellArray objectAtIndex:indexPath.row];
return self.myTableCell;
}
Since you are learning this..i will post a simple solution.
Make add a member variable NSMutableArray *cellArrays;
initialize it in your viewDidLoad
in buttonPressed check;
if([#"red" isEqualToString:[YourButton titleForState:UIControlStateNormal]])
{
[self.cellArrays addObject:#"red"];
}
else
{
[self.cellArrays addObject:#"blue"];
}
[self.YOURTABLEVIEW reloadData];
Now in your table view datasource method
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return self.cellArrays.count;
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
//in between your code;
YOURCELL.textlabel.text = [self.cellArrays objectAtIndex : indexpath.row];
}
Try this ..
I'd recommend subclassing UITableViewController, then override the dataSource and delegate methods and you should be good to go. Going straight to UITableView is more complicated without any obvious benefits.
You may not be using Core Data, but I still recommend this lecture because it hooks up a TableViewController and works great - all code included. Check it out:
http://www.stanford.edu/class/cs193p/cgi-bin/drupal/node/289
The lectures in iTunes U explain everything further.
Enjoy,
Damien
I wanted to add that "One more thing, the compiler shows a warning says no reusable identifier. what exactly is that?" above...
His answer is correct, but to get rid of that compiler warning...
The tableviewcell of your tableview has to have an identifier. In IOS 5, in your storyboard, highlight the TableViewCell in your TableView, and enter a value in the Identifier. This must match the value in your code of the cell that you are creating.
I have a table and I want to show there some text; but I can't, I don't know why. My app is a view-based app, and I don't want to change it for a Table View Controller. Here's the code:
.h
{
NSArray *array;
IBOutlet UITableView *table;
}
.m
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
// Return the number of sections.
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// Return the number of rows in the section.
return [array count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
cell.textLabel.text = [array objectAtIndex:indexPath.row];
// Configure the cell
return cell;
}
Please help me because I'm trying to solve this and I don't know what's wrong, why the Table doesn't show the array!
Thank you!
You almost certainly haven't connected your datasource and delegates properly in IB.
Your UIViewController needs to implement UITableViewDelegate and UITableViewDatasource, and you need to then connect it to your UITableView (table) as such in Interface Builder.
For details, read through Apple's documentation here.
On your .H file are you using this interfaces <UITableViewDelegate, UITableViewDataSource>?
The answer is that you've never ever created single cell. The call you make dequeueReusableCellWithIndentifier only recycles cells you've already created. Add this code after the dequeueResusable... line:
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
This is the code for cellForRowAtIndexPath: method.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *SimpleTableIdentifier = #"SimpleTableIdentifier";
UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier: SimpleTableIdentifier];
if (cell == nil) { cell = [[[UITableViewCell alloc]
initWithStyle:UITableViewCellStyleDefault reuseIdentifier:SimpleTableIdentifier] autorelease];
}
NSUInteger row = [indexPath row];
cell.textLabel.text = [array objectAtIndex:row];
return cell;
}
When i use [self.tableView reloadData]; nothing happening?
You need to implement at least the tableView:numberOfRowsInSection: method as part of the UITableViewDataSource protocol, and tableView:cellForRowAtIndexPath: (which you already did). You should also implement numberOfSectionsInTableView:.
Then you need to make sure that your class is actually used as a data source:
self.tableView.dataSource = self;
That needs to be either done via Interface Builder or in awakeFromNib or some other method like viewDidLoad:.
Do you check your dataSource and delegate of UITableView ? I think the dataSource is nil or something else.
Try putting a break point in cell for row and see if it is called when u call reloadData. Also pls check if the changes are already made to array from which the cells are populated and make sure the table view is connected to its datasource and delegate.