I am from C# background and now learning objective C.
I created two NSArrays 1.optionsLabelArray and 2.optionsLabelSubtitleArray initially with two elements each (optionsLabelArray=>Yes & No) and optionsLabelSubtitleArray(acceptable and action). Now requirement changed and I have to add one more item and I am doing it like below. But It still shows only two elements.
I tried using NSMutableArray , no luck. Looks like it's a small issue but couldn't figure it out.. any ideas will be appreciated.
- (UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
optionsLabelArray = [[NSArray alloc] initWithObjects:#"Yes", #"No",#"No" ,nil]; // here is problem
optionsLabelSubtitleArray = [[NSArray alloc] initWithObjects:#"Acceptable",#"Action required",#"No", nil]; // here to
static NSString *CellIdentifier = #"CheckerCell";
CustomCell *cell =[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
cell.optionLabel.text = [optionsLabelArray objectAtIndex:indexPath.row];
cell.optionLabelSubtitle.text = [optionsLabelSubtitleArray objectAtIndex:indexPath.row];
return cell;
}
You need to update the implementation of your - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section method to support more rows. To do so you probably want to have an implementation where the array is either an instance variable of the class or otherwise consistent between the two methods.
you need implement following method and return 3 when you increase cell count
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
see more on https://developer.apple.com/library/ios/documentation/uikit/reference/UITableViewDataSource_Protocol/Reference/Reference.html#//apple_ref/occ/intfm/UITableViewDataSource/tableView:numberOfRowsInSection:
Related
I am creating an app where users can store an object in Core Data. I have the Objects being pulled into a UITableView and everything is working correctly there. I now want to separate the objects into a possible of 1-3 different sections based on choices in a UISegmentedControl.
Currently I have this to create the 1 section and populate the cells of that section with my objects
#pragma mark - Table view data source
- (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 self.fetchedDiscs.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"DiscCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
//Configure Cell
Disc *currentDisc = [self.fetchedDiscs objectAtIndex:indexPath.row];
cell.textLabel.text = currentDisc.name;
cell.detailTextLabel.text = currentDisc.brand;
return cell;
}
So the main question is how to dynamically change the number of sections and number of rows in section?
The Segmented control returns values such as Option 1, Option 2, Option 3. The only way I can think of is to loop through my fetchedDiscs array and separate that into an array for each section. Then I can return the number of arrays if they exists and I can get the count of each array to get the number of rows in each section. But then I get to the problem of How to get the CellForRowAtIndextPath to work correctly with three arrays.
Basically there has to be a better more logical way to do this. I am just not sure how.
Let, you have a dictionary named dataSource that contains 'x' number of array as value for key "key1", "key2", .. "keyX". You can do this:
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return [[dataSource allKeys] count];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
//Get the array object form key. I am considering 'keySection' as an example
return [[dataSource objectForKey:#"keySection"] count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"DiscCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
cell.textLabel.text = [[dataSource objectForKey:keySection] objectAtIndex:indexPath.row]
return cell;
}
Note: I wrote the code in this editor, excuse any mistakes, I just tried to share the idea. Hope this helps.. :)
On my UITableViewI am using custom UITableViewCells. Each of these cells has a number of labels. When the user selects a cell, I need to capture the contents of just one of these labels, but I don't know how to do that. Here is my code. The line that I am using to attempt to get this label text is basically pseudo-code that clearly won't compile. Can somebody please tell me what I need to do here? Thanks!
- (UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
...
Groups *group = [self.fetchedObjects objectAtIndex:indexPath.row];
cell.groupDescriptionLabel.text = group.group_descr;
cell.groupIDLabel.text = [group.group_id stringValue];
return cell;
}
- (void) tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// capture the user selection
Groups *group = [self.fetchedObjects objectAtIndex:indexPath.row];
UITableViewCell *selectedCell = [tableView cellForRowAtIndexPath:indexPath];
NSString *selection = selectedCell.groupDescriptionLabel.text; //<-- pseudo-code
NSLog(#"%#", group.group_descr);
...
}
It's generally a bad idea to get data out of the view. You shouldn't really be using any view objects as a way of storing information.
You are already getting the string when you are in the cellForRowAtIndexPath method.
You should be able to do the same in didSelectRowAtIndexPath to get the same string.
That way you don't have to get the text out of the label at all.
Thanks
If you know that celForRowAtIndexPath is going to be returning one of your custom cell types instead of a generic UITableViewCell, cast the result to your custom cell class:
- (void) tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// capture the user selection
MyCellClass *selectedCell = (MyCellClass *) [tableView cellForRowAtIndexPath:indexPath];
NSString *selection = selectedCell.groupDescriptionLabel.text; //<-- pseudo-code
NSLog(#"%#", selection);
//...
}
I want to only show some of the items in an array, but can't figure out how to do it.
This is the code I have that currently shows all objects in the array:
#property (strong, nonatomic) NSArray *springs;
#property (strong, nonatomic) NSMutableArray *leafs;
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"standardCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
Spring *spring = [springs objectAtIndex:indexPath.section]; // 13 objects
Leaf *leaf = [spring.leafs objectAtIndex:indexPath.row]; // 30 objects
cell.textLabel.text = league.shortName;
return cell;
}
So I would like to only show 5 of the 30 leaf objects from that array I created, and not show all of them. Is there any way to do that?
(I'm using an API to pull the items into the Array)
Thanks for the help, will post any specific code or other info needed!
EDIT
Added per request:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
Spring *spring = [springs objectAtIndex:section];
return spring.leafs.count;
}
I'm using RestKit for the object mapping.
Use [NSArray objectsAtIndexes:] (reference) to get a subset of the array.
Leaf *leaf = [spring.leafs objectAtIndex:indexPath.row];
// This will include objects 0-4:
NSRange range = NSMakeRange(0, 5);
NSArray *subset = [leaf objectsAtIndexes:[NSIndexSet indexSetWithIndexesInRange:range]];
Just adjust range to whatever start/length you want in the subset.
EDIT: Of course any subset logic in this method will also have to be duplicated in the numberOfRowsInSection: delegate method, else your app with throw an exception.
How about in your tableView:numberOfRowsInSection, don't return a full count full spring.leafs? For instance,
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return 5;
}
Are you trying to lazy load them, or do the rest of them just not matter? Good luck.
My question is that is it possible to get text data and read it in my ViewController from php when the cell is tapped?
I'm guessing didSelectRowAtIndexPath is the key to do this, but I'm not sure how to write.
I am able to get data from php into my TableViewController as below;
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView{
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
return [json count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil){
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
}
NSDictionary *info = [json objectAtIndex:indexPath.row];
cell.textLabel.text = [info objectForKey:#"Artist"];
cell.detailTextLabel.text = [info objectForKey:#"Song"];
return cell;
}
The code you have written kind of contradicts what you explained in the beginning. However, This is how it should be done:
First off you will need to get the data you want to display. You can get this from an external website (php, as you call it), plist, xml or whatever you want. You can do this when you have your tableview initiated (e.g. using ASIHTTPRequest) or before you initiate your tableview and just send it in using a custom init method.
Second, you need to read the contents you have recieved. Usually it great to get is in a NSArray format. This depends on your implementation of the data source you are fetching data from.
If you are new to objective-c and cocoa-touch, you should start off with some quick tutorials regarding UITableView. I have written one myself, but currently I guess its (very) outdated. You could still have a look at it though: http://paulpeelen.com/2009/08/14/developing-with-iphone-3-0-x-simple-uitableview/
Your code is I think wrong. Check if there any data in json by checking
NSLog(#"%# and %#",[info objectForKey:#"Artist"], [info objectForKey:#"Song"]);
and tell me if any result comes out. if not then there is some mistake in your php else your data should show there.
use this method of code.
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
//retrive your data here.
}
In a tabbed application developed in Xcode 4.2, I found a confusing problem: In one of tabs, there is a tableview to show something like index. So I initialized an array in viewDidLoad() method. for example:
- (void)viewDidLoad
{
NSArray *array = [NSArray arrayWithObjects:#"abc", #"def", #"ghi", #"jkl", #"mno", nil];
self.arrayList = array;
[array release];
[super viewDidLoad];
}
Then I use this arrayList in other methods:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [arrayList 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] autorelease];
}
cell.textLabel.text = [arrayList objectAtIndex:indexPath.row];
return cell;
}
But Xcode gives me the "EXC_BAD_ACCESS" signal every time I run it. I put some breakpoints, and found that the array was created successfully in viewDidLoad(), but before running the method cellForRowAtIndexPath:(NSIndexPath *)indexPath, it became a freed object. That's the reason why I got that signal and the application crashed. So, how to solve this problem?
Btw, the view controller where the problem occurs is created from UIViewController, not UITableViewController. But I put a table view and linked its datasource and delegate to File's Owner. Does that matter?
You must not release the array. The +arrayWithObjects: convenience method returns an unowned array. You never took ownership of the array, therefore you must not relinquish ownership. Remove the the line [array release] and you will not see this error anymore (at least not for that reason).