Xcode: add TableView into custom Cell - ios

I'm trying to do something but neither found some example on the web or know if it is possible.
I need to add a table into the first cell of a tbaleview programmatically.
The code gives me problem when I try to set delegate and datasource of the second table (the one in the first table)
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
[[NSBundle mainBundle] loadNibNamed:#"CellaMenu" owner:self options:NULL];
cell = cellaMenu;
cell.selectionStyle = UITableViewCellSelectionStyleNone;
cell.userInteractionEnabled = NO;
tabellaMenu = [[UITableView alloc] initWithFrame:self.view.bounds style:UITableViewStylePlain];
tabellaMenu.dataSource = self;
tabellaMenu.delegate = self;
[cell.contentView addSubview:tabellaMenu];
}
In this way the code loops. If I'don't set the delegate and the dataSource the table appears but I need them to create custom handler.
Any hints?

The cleanest way to do is to have another UITableViewDataSource and UITableViewDelegate compliant object in your view controller, then, set the second table view's delegate and dataSource to this object.

The code is going into loop because tabellaMenu table in the cell has the delegate and datasource set to self. So, it keeps on calling table datasource methods on self and create new cells and enters into loop.
You can either create a separate object(subclass of NSObject) and define the table delegate and datasource methods in that and set it to tabellaMenu's delegate and datasource.
Or you can create a subclass of UITableViewCell and create a table view in that programatically. Define the table's datasource and delegate methods in that. So every table view in the cell will refer to its own cell for datasource and delegate. In addition, you get -(void)prepareForReuse(if the cell is reusable) to reload the table in the cell everytime the main table reloads.

Inside -tableView:cellForRowAtIndexPath:, you could write following code after creating cell.
//if first row & table is not present already
if (indexPath.row == 0 && ![cell.contentView viewWithTag:5]) {
UITableView *tabellaMenu =
[[UITableView alloc] initWithFrame:self.contentView.bounds
style:UITableViewStylePlain];
tabellaMenu.tag = 5;
tabellaMenu.dataSource =tabellaMenuDataSource;
tabellaMenu.delegate = tabellaMenuDelegate;
[cell.contentView addSubview:tabellaMenu];
}

You can get the project from here which i created while learning CoreData.Just click on Add button in navigation bar and Add information and save that. Then you will the data in the Table on Main Screen. Just click on the cell and there is another tableView.

Here is the way:
If you need a tableView only in first cell then you can take it globally instead of initialising in cellForRowAtIndexPath: method as it gets recall every time during scrolling.
UITableView *mainTableView;
UITableView *childTableView;
Now you can easily distinguish both tables in their delegates and datasources methods by comparing their instances.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
if (tableView == mainTableView) {
// Do code for your main tableView
if (indexPath.row == 0) {
[[NSBundle mainBundle] loadNibNamed:#"CellaMenu" owner:self options:NULL];
cell = cellaMenu;
cell.selectionStyle = UITableViewCellSelectionStyleNone;
cell.userInteractionEnabled = NO;
if (!childTableView) {
// Initialise only if it is nil (not initialised yet)
childTableView = [[UITableView alloc] initWithFrame:self.view.bounds style:UITableViewStylePlain];
childTableView.dataSource = self;
childTableView.delegate = self;
}
[cell.contentView addSubview:childTableView];
}
}
else {
// Do code for your child tableView
}
}

Related

TableView won't load ANY data

Pulling out my hair on this one. I've made so many apps with table views and have been looking at my past apps, but for some reason this table view is too stubborn to show anything...
- (void)viewDidLoad
{
[super viewDidLoad];
self.tableView.delegate = self;
self.tableView.datasource = self;
[_myArray addObject:#"Hi"];
[_myArray addObject:#"Hello"];
[_myArray addObject:#"Bye"];
// Uncomment the following line to preserve selection between presentations.
// self.clearsSelectionOnViewWillAppear = NO;
// Uncomment the following line to display an Edit button in the navigation bar for this view controller.
// self.navigationItem.rightBarButtonItem = self.editButtonItem;
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection: (NSInteger)section
{
return [_myArray count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
NSString *currentItem = [_myArray objectAtIndex:indexPath.row];
cell.textLabel.text = #"Hi";
// Configure the cell...
return cell;
}
So basically nothing shows up for me. The table view is blank as always even though i set the delegate, and got the table view delegate and data source in the .h file.
Initialize your array. _myArray = [[NSMutableArray alloc] init];
The way to debug this is straight-forward.
Set a breakpoint in numberOfSectionsInTableView. See if the breakpoint is hit.
Make sure that the value returned from numberOfSectionsInTableView is correct.
Set a breakpoint in numberOfRowsInSection. Make sure the breakpoint is hit.
Make sure that the value returned from numberOfRowsInSection is correct.
Set a breakpoint in cellForRowAtIndexPath. Make sure that the breakpoint is hit.
Step through the logic in cellForRowAtIndexPath and make sure it's all correct.
Very likely you will discover that numberOfRowsInSection is returning the wrong value.
Is this a UIViewController with a tableView or a UITableViewController?
Here are the main steps you need to check:
If it is a UITableViewController, skip the next item.
Make sure the tableView is a IBOutlet if you're not working with a UITableViewController directly, and connect your tableview to your controller on Interface Builder. Also make sure your controller implements protocols
On Interface Builder, connect your tableview to the controller, making the controller the datasource and the delegate
Try calling [tableView reloadData] after you define your data array, on viewDidLoad
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
That line needs to be deleted, but shouldn't prevent the table from displaying stuff. It simply defeats the purpose of the reuse queue.
The only possibility that remains is that the cell identifier hasn't been set in storyboard, or it isn't #"Cell". Note identifiers are case sensitive.

Fails to call delegate/datasource methods in UITableView implementation

I have created .h and .m files for UITableView called mainTableViewgm.h and mainTableViewgm.m resp. and I am calling -initWithFrame: method from my main view controller to this mainTableViewgm.m implementation file
[[mainTableViewgm alloc]initWithFrame:tableViewOne.frame]
Note that this tableview is in my main view controller. But I have created separate files for the tableView and have also set the custom class to mainTableViewgm in storyboard.
the -initWithFrame: methods appears as follows
- (id)initWithFrame:(CGRect)frame
{
//NSLog(#"kource data");
self = [super initWithFrame:frame];
if (self)
{
[self setDelegate:self];
[self setDataSource:self];
[self tableView:self cellForRowAtIndexPath:0];
[self tableView:self numberOfRowsInSection:1];
// Initialization code
}
return self;
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
NSLog(#"kource data");
return 1;
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"kource data2");
UITableViewCell*cellOne =[[UITableViewCell alloc]init];
cellOne.detailTextLabel.text=#"text did appear";
return cellOne;
}
the -initWithFrame: is being called fine along with the 'if (self)' block in this method. But the problem is numberOfRowsInSection: and cellForRowAtIndexPath: are not being automatically called here . kource data/kource data2 never appear in log. What do I do to load the table? Are the delegate/datasource being set incorrectly?
I must mention that I have also set the UITableViewDelegate and UITableviewDataSource protocols:
#interface mainTableViewgm : UITableView <UITableViewDelegate,UITableViewDataSource>
#end
Help will be much appreciated. Thank you.
Your tableview is not loaded when the controller is initializing, so you cannot do that in the init methods. You have to move your code to the viewDidLoad method.
Also you are not setting the delegate and datasource on the tableview object (probably a type, you are setting them on the view controller). It should look like this:
- (void)viewDidLoad:(BOOL)animated {
[super viewDidLoad:animated];
[self.tableView setDelegate:self];
[self.tableView setDataSource:self]; // <- This will trigger the tableview to (re)load it's data
}
Next thing is to implement the UITableViewDataSource methods correctly. UITableViewCell *cellOne =[[UITableViewCell alloc] init]; is not returning a valid cell object. You should use at least initWithStyle:. And take a look how to use dequeueReusableCellWithIdentifier:forIndexPath:. A typical implementation would look like this:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
// Reuse/create cell
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
// Update cell contents
cell.textLabel.text = #"Your text here";
cell.detailTextLabel.text=#"text did appear";
return cell;
}
I can't believe I've been doing XCode programming for two years, and still hit this issue.
I had the same problem with XCode 6.1 - I was setting my UITableView's delegate & dataSource in the viewWillAppear function, but none of the delegate functions were kicking in.
However, if I right-clicked on the UITableView on the Storyboard, the circles for delegate and dataSource were empty.
The solution, then, is to hold down the CTRL key, and drag from each of these circles up to the name of your UIView which contains your UITableView:
After doing this, my UITableView happily populated itself.
(So, we're upto v6.1 of XCode now are we ? Do you think Apple ever going to make this thing, you know, friendly...? I would quite like to add a Bookmark in my code... that'd be a nice feature.)

Is it possible to switch view to tableview from same view?

I have a viewcontroller.xib which contains View, buttons,toolbarbutton, text box and a tableview. When I load the initial screen comes without table view which is fine. Now when I click on a toolbarbutton say, viewtable, I want the view to move to tableview. I have filled my tableview data with some default objects like this:
- (void)viewDidLoad
{
tableData = [[NSArray alloc] initWithObjects:#"object1",#"object2",#"object3",#"object4", nil];
[super viewDidLoad];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [tableData count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = nil;
cell = [tableView dequeueReusableCellWithIdentifier:#"My Cell"];
if(cell==nil)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"My Cell"];
}
cell.textLabel.text=[tableData objectAtIndex:indexPath.row];
return cell;
}
So when I click on toolbar view button it should show tableview with toolbar button which also has a back button so when I click on that it should hide the table view and show the initial view. Is it possible to do all this in single xib? I can achieve the result if I create another xib and simply transfer control over to that xib but I wanted to know if its possible do this without creating a second xib file. And also for navigation I can use navigation controller but I want to check and see if its possible to use toolbar to transfer the control. Thanks.
First check if your table view is inside your view, if not put it inside and set delegate of datasource to file owner, then in your view table method write this code
-(void)viewTable
{
self.tableView.hidden = NO;
self.viewToolbar.hidden=YES;
}
On your back button code in toolbar write
-(void)goback
{
self.tableView.hidden = YES;
self.viewToolbar.hidden=NO;
}
If you don't need animation then you can do the following
Get a handle of tableView in your interface like this:
#property(nonatomic,assign)IBOutlet UITableView *tableView;
Hide your table view in initially ( like in viewDidLoad method )
-(void)viewDidLoad
{
[super viewDidLoad];
self.tableView.hidden = YES;
}
Then in the method called by your toolbar's button do the following
-(void)on_click_toolbar_button
{
self.tableView.hidden = !self.tableView.hidden;
//This will keep toggling the table view from hidden to shown & vice-versa.
}
you could use the hidden property to achieve that. Put these in the appropriate ibaction methods.
_tableView.hidden = Yes;
_tableView.hidden = No;
I'd highly recommend to do this in two separate XIBs. The first should contain a UIViewController (your initial view) and the second a UITableViewController (your table view) class. Both should be handled by a UINavigationController - don't fight the API and try your own hacks if it's not necessary. The mentioned controller classes give you everything you need out of the box.
Well this is not recommended but you can do this by removing and adding tableview..

iOS: DequeTableViewCell..a little bit confused

I want to alter the font size and color etc. for my UITableView cells. I've designed the cells custom in Xcode and got everything working.
First of I'll post my code here:
UITableViewController:
- (void)viewDidLoad
{
[super viewDidLoad];
[self.tableView registerClass:MainCategoryTableViewCell.class forCellReuseIdentifier:#"MainCategoryCell"];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"MainCategoryCell";
MainCategoryTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
return cell;
}
And my custom cell:
- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
{
self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
if (self) {
self.title.font = [Theme tableCellTitleFont];
self.title.textColor = [Theme tableCellTitleColor];
self.subcategories.font = [Theme tableCellSubTitleFont];
self.subcategories.textColor = [Theme tableCellSubTitleColor];
self.costs.font = [Theme tableCellValueFont];
self.costs.textColor = [Theme tableCellValueColor];
}
return self;
}
I'm confused now how this dequeue works:
As far as I understood if I register the class in the viewDidLoad, the initWithStyle method of the cell gets ONLY called, when theres no cell for reuse. If theres a cell for reuse it will be used. I've seen a lot of if(cell == nil) calls in other code snippets but is that really necessary? I thought the registerClass method takes care of that anyway?
And at the moment my cells will be displayed completely empty. Before I registered the class everything worked, however the initWithStyle didn't get called..
Complete cellForRowAtIndexPathMethod:
#pragma mark Delegate methods
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"MainCategoryCell";
MainCategoryTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
// Configure the cell...
MainCategory *mainCategory = [self.fetchedResultsController objectAtIndexPath:indexPath];
cell.title.text = mainCategory.name;
cell.subcategories.text = [NSString stringWithFormat:#"%i subcategories", [[mainCategory getNumberOfSpendingCategories] integerValue]];
cell.costs.text = [[mainCategory getMonthlyCostsOfAllSpendingCategories] getLocalizedCurrencyString];
if(!mainCategory.icon){
cell.icon.image = [UIImage imageNamed:#"DefaultIcon.png"];
} else {
cell.icon.image = [UIImage imageNamed:mainCategory.icon];
}
if(!mainCategory.color){
cell.backgroundColor = [PresetColor colorForPresetColor:PresetColorsWhite];
} else {
cell.backgroundColor = [PresetColor colorForPresetColor:(PresetColors)[mainCategory.color intValue]];
}
cell.cellBackground.image = [[UIImage imageNamed:#"content-bkg"] resizableImageWithCapInsets:UIEdgeInsetsMake(10, 10, 10, 10)];
return cell;
}
If you have defined the cell as "prototype cell" for the table view in the xib/storyboard file, then you don't have to register it at all. If the custom cell is in a separate nib file, you register the custom cell with registerNib, not registerClass. For example:
[self.tableView registerNib:[UINib nibWithNibName:#"MainCategoryTableViewCell" bundle:nil]
forCellReuseIdentifier:#"MainCategoryCell"];
For cells instantiated from a nib file, initWithCoder is called, not initWithStyle.
To configure any outlets of your custom cell, override awakeFromNib. The connections are
not yet established in initWithCoder.
For best understanding see the below image for just a deque reference.
Deque means you can add and delete cells from both the ends.
By ends I mean up and down.
Lets say you have 4 cell containg Acell,Bcell,Ccell and Dcell and height for row is for three cells.
so at a time only 3 cells would be visible.
when you scroll to see the Dcell , Acell would become as invisible row and memory for it will be reused for Dcell.
In the same way when you scroll to see the Acell , Dcell would become as invisible row and memory for it will be reused for Acell.
It says clearly in documentation
dequeueReusableCellWithIdentifier:forIndexPath:
For performance reasons, a table view's data source should generally
reuse UITableViewCell objects when it assigns cells to rows in its
tableView:cellForRowAtIndexPath: method. A table view maintains a
queue or list of UITableViewCell objects that the data source has
marked for reuse. Call this method from your data source object when
asked to provide a new cell for the table view. This method dequeues
an existing cell if one is available or creates a new one based on the
class or nib file you previously registered.
.
dequeueReusableCellWithIdentifier:
Return Value : A UITableViewCell object with the associated identifier
or nil if no such object exists in the reusable-cell queue.
Discussion : For performance reasons, a table view's data source
should generally reuse UITableViewCell objects when it assigns cells
to rows in its tableView:cellForRowAtIndexPath: method. A table view
maintains a queue or list of UITableViewCell objects that the data
source has marked for reuse. Call this method from your data source
object when asked to provide a new cell for the table view. This
method dequeues an existing cell if one is available or creates a new
one using the class or nib file you previously registered. If no cell
is available for reuse and you did not register a class or nib file,
this method returns nil.
If you registered a class for the specified identifier and a new cell
must be created, this method initializes the cell by calling its
initWithStyle:reuseIdentifier: method. For nib-based cells, this
method loads the cell object from the provided nib file. If an
existing cell was available for reuse, this method calls the cell’s
prepareForReuse method instead.
Before introducing storyboard.The tableview checks the returned cell which can be nil .So if nil we must reallocate the cell and tehn initialize and provide the cell in the datasource method

Why am I getting a deallocated memory call when I call UICollectionViewCell dequeueReusableCellWithReuseIdentifier?

I have a UICollectionView that contains custom UICollectionViewCells (TestReceiptCell is the class name).
I was not having any problems getting the UICollectionView to appear and load the custom cells when the custom cells only contained a UILabel.
I then added a UITableView via IB into the TestReceiptCell NIB file. I set a referencing outlet in TestReceiptCell.h for the UITableView and synthesized in the .m file. I set the delegate and datasource for the UITableView to the ViewController containing the UICollectionView.
Now when running the app I get a EXC_ BAD_ ACCESS exception in this block on the third line:
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
static NSString *cellIdentifier = #"TestReceiptCell";
TestReceiptCell *cell = (TestReceiptCell *)[collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath]; //exception thrown here
return cell;
}
I ran the Zombie Instrument test and found that the deallocated memory call originates here. This is my first time using that instrument so I am not exactly sure how to investigate from here.
For reference, here are some more relevant parts of the code:
ViewController.m
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
[self.myCollectionView registerNib:[UINib nibWithNibName:#"TestReceiptCell" bundle:nil] forCellWithReuseIdentifier:#"TestReceiptCell"];
// Setup flowlayout
myCollectionViewFlowLayout = [[UICollectionViewFlowLayout alloc] init];
[myCollectionViewFlowLayout setItemSize:CGSizeMake(310, 410)];
[myCollectionViewFlowLayout setScrollDirection:UICollectionViewScrollDirectionHorizontal];
[self.myCollectionView setCollectionViewLayout:myCollectionViewFlowLayout];
self.myCollectionView.pagingEnabled = YES;
}
I am implementing the UITableView datasource and delegate methods in the ViewController.m file as well but I am not sure if the problem lies here given the origination of the EXC_BAD_ACCESS exception:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
return 1;
}
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath{
UITableViewCell *cell = nil;
cell = [tableView dequeueReusableCellWithIdentifier:#"eventCell"];
if(!cell){
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:#"eventCell"];
}
return cell;
}
UPDATE:
I am able to get this to run if I change cellForItemAtIndexPath to:
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
static NSString *cellIdentifier = #"TestReceiptCell";
//TestReceiptCell *cell = (TestReceiptCell *)[collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];
TestReceiptCell *cell = [NSBundle.mainBundle loadNibNamed:#"TestReceiptCell" owner:self options:nil][0];
return cell;
}
However, I am not dequeuing cells and know this is not the correct way. There seems to be an issue somewhere in the initWithFrame method that gets called when dequeueReusableCellWithResueIdentifier creates a new cell. Here is that method currently:
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
NSArray *arrayOfViews = [[NSBundle mainBundle] loadNibNamed:#"TestReceiptCell" owner:self options:nil];
if ([arrayOfViews count] < 1) {
return nil;
}
if (![[arrayOfViews objectAtIndex:0] isKindOfClass:[UICollectionViewCell class]]) {
return nil;
}
self = [arrayOfViews objectAtIndex:0];
}
return self;
}
EDIT:
If I do not select a delegate or a datasource for the tableview, the collectionview with tableviews will load. Something in attaching the delegate/datasource to File's Owner is causing the error.
When you register a UINib for cell reuse, dequeueReusableCellWithReuseIdentifier:forIndexPath: is what calls instantiateWithOwner:options: on the UINib that you registered. Whatever it passes for owner, is what becomes the File's Owner outlet in your nib.
It appears that you are expecting the File's Owner to be the UICollectionView, but I don't think that it is.
Even if it were, I don't think you should use the UICollectionView for the delegate of the UITableView contained within each collection cell. That would require your UICollectionView to keep track of the tableViews and contents within each cell.
I'd suggest setting the delegate of the contained tableView to the collection cell itself and have each cell manage its own tableview.
EDIT:
You can define a delegate protocol for your collection view cells to communicate the relevant table view events to the collection view. With this approach, you would set the delegate property you define for each collection cell in the collectionView:cellForItemAtIndexPath method of your collection view datasource.
When the user, for example, selects an item from the table, you can call the cell delegate to inform the collection view which item was selected.
This approach allows you to abstract the fact that your collection cell is using a table view to display the cell information. Later, if you decide you want to use, for example, an embedded UICollectionView to display those items, the delegate protocol can remain unchanged and you can isolate your changes to the collection cell.

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