Configuring UITableView - ios

I'm trying to make a custom UITableView that will store a textLabel and detailLabel in each cell, but all the tutorials I find are for UITableViewController. When I try to implement just the UITableView, I can't figure it out.
I actually will have 2 table views on this view controller. It's almost like a webpage in layout, or at least how I want it.
2 tables, and be able to put anything I want inside each cell. For some, a couple strings, for others, maybe 3 small images.
Here's a screenshot of what I want. I just can't figure out how to configure the tableviews so I can put content in them.
Edit: Im on swift, just FYI, and now have the code below (minus screenshot). It stalls and I get SIGABRT at the declaration of the cell, even though that was the default implementation.
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
var cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as UITableViewCell
if (tableView == self.topTableView) {
// do stuff for the first tableView
cell.textLabel.text = "Size"
cell.detailTextLabel.text = "750.32MB"
} else {
//do stuff for tableView2
}
return cell
}

Take a look at the answer to this question for information on the minimum implementations of the table view delegate and datasource protocols.
Since you have two table views, you'll need a way to determine which table view is asking for information. Note that the first argument to all of the table view delegate functions is a pointer to the table view itself. You can compare that with the IBOutlet's to the table view to determine which table view is requesting information.
For example,
#property (weak, nonatomic) IBOutlet UITableView *tableView1;
#property (weak, nonatomic) IBOutlet UITableView *tableView2;
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
if ( tableView == self.tableView1 )
return 5;
else if ( tableView == self.tableView2 )
return 10;
else
return 0; // should never happen
}

The premise is the same in terms of the tableView delegate methods you need to implement. Assuming you have connected the tableviews to your viewController in IB or storyboard or whatever, just make sure you set the viewController to be the delegate and dataSource of both tableViews, then you need your ViewController to be a UITableViewDataSource and UITableViewDelegate in your interface declaration. Then be sure to implement the appropriate delegate methods and inspect the tableView to determine which one the viewController is working with at the time.
In your header file:
#interface MyViewController : UIViewController <UITableViewDelegate,UITableViewDataSource>
In viewDidLoad:
self.tableView1.delegate = self;
self.tableView1.dataSource = self;
self.tableView2.delegate = self;
self.tableView2.dataSource = self;
In your delegate methods, check which tableView you are working with, something like this:
- (UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
if (tableView == self.tableView1) {
// do stuff for the first tableView
} else {
//do stuff for tableView2
}
return cell;
}

Related

How to configure UITableView inside custom UITableViewCell in a Storyboard?

I have a layout in which I will have 2 UITableViews with custom cells. The second UITableView must be inside the first.
My question is: how to delegate second UITableView?
Can I delegate both to my ViewController? In that case it will use the same methods and I have to find out which UITableView is managed right now.
Or I have to delegate it inside custom UITableViewCell of the first UITableView?
Any recommendations are appreciated.
EDIT: I don't know how to implement solutions here, because I have Storyboard. Inside my current UIViewController I set delegate and dataSource of the first UITableView to my View Controller.
My problem is that I don't know how to set the same properties of the second Table View (which will be inside UITableViewCell). I can not set them to UITableViewCell (IB does not allow that).
Where and how to set then in the IB?
A far better solution would be to abstract the DataSource and Delegate implementations away from your view controller so that they can be personalised per tableview as required (please note that the code is taken from the objc.io article Lighter View Controllers.
E.g.
#implementation ArrayDataSource
- (id)itemAtIndexPath:(NSIndexPath*)indexPath {
return items[(NSUInteger)indexPath.row];
}
- (NSInteger)tableView:(UITableView*)tableView
numberOfRowsInSection:(NSInteger)section {
return items.count;
}
- (UITableViewCell*)tableView:(UITableView*)tableView
cellForRowAtIndexPath:(NSIndexPath*)indexPath {
id cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier
forIndexPath:indexPath];
id item = [self itemAtIndexPath:indexPath];
configureCellBlock(cell,item);
return cell;
}
#end
Then you could utilise it as follows:
void (^configureCell)(PhotoCell*, Photo*) = ^(PhotoCell* cell, Photo* photo) {
cell.label.text = photo.name;
};
photosArrayDataSource = [[ArrayDataSource alloc] initWithItems:photos
cellIdentifier:PhotoCellIdentifier
configureCellBlock:configureCell];
self.tableView.dataSource = photosArrayDataSource;
The same process could be followed with the UITableViewDelegate implementations to provide you with a very clean, separated and de-coupled code base. Your requirement for two tableviews will then be intrinsically easier to implement.
My answer is
For identifying two table view data source and delegate method is,better to set tag for the table views.
Set this below coding in your tableview delegates method.
if(tableView.tag==0)
{
}
else
{
}
Also you can vary this by assigning different name to these table view.
if(tableView==FirstTableView)
{
}
else
{
}
You just check table condition for every delegate method
Use this code to register custom cell.
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
if(tableView == self.yourFirstTable)
{
CustomCell *cell=[tableView dequeueReusableCellWithIdentifier:#"cellModifier"];
// your code
}
else
{
// second table cell code
}
return cell;
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if(tableView == self.yourFirstTable)
{
// first tableView number of row return
}
else
{
// second table number of row return
}
}
And create prototype cell in TableView
And Set CellReusableId like this way

How can I allocate and initialize a custom UITableViewCell NOT in cellForRowAtIndexPath?

I won't go into the WHY on this one, I'll just explain what I need.
I have a property in my implementatioon file like so...
#property (nonatomic, strong) MyCustomCell *customCell;
I need to initialize this on viewDidLoad. I return it as a row in cellForRowAtIndexPath always for the same indexPath, by returning "self.customCell".
However it doesn't work, I don't appear to be allocating and initializing the custom cell correctly in viewDidLoad. How can I do this? If you know the answer, save yourself time and don't read any further.
Ok, I'll put the why here in case people are curious.
I had a table view which was 2 sections. The first section would always show 1 row (Call it A). The second section always shows 3 rows (Call them X, Y, Z).
If you tap on row A (which is S0R0[Section 0 Row]), a new cell would appear in S0R1. A cell with a UIPickerView. The user could pick data from the UIPickerView and this would update the chosen value in cell A.
Cell X, Y & Z all worked the same way. Each could be tapped, and they would open up another cell underneath with their own respective UIPickerView.
The way I WAS doing this, was all these cell's were created in the Storyboard in the TableView, and then dragged out of the View. IBOutlets were created for all. Then in cellForRAIP, I would just returned self.myCustomCellA, or self.myCustomCellY.
Now, this worked great, but I need something more custom than this. I need to use a custom cell, and not just a UITableViewCell. So instead of using IBOutlets for all the cells (8 cells, 4 (A,X,Y,Z) and their 4 hidden/toggle-able UIPickerView Cell's), I created #properties for them in my implementation file. But it's not working like it did before with the standard UITableViewCell.
I'm not sure I'm initializing them correctly? How can I properly initialize them in/off viewDidLoad so I can use them?
.m
#interface MyViewController ()
#property (strong, nonatomic) MyCustomCell *myCustomCellA;
...
viewDidLoad
...
self.myCustomCellA = [[MyCustomCell alloc] init];
...
cellForRowAtIndexPath
...
return self.myCustomCellA;
...
If only I understood your question correctly, you have 3 options:
I would try really hard to implement table view data source with regular dynamic cells lifecycle in code and not statically – this approach usually pays off when you inevitably want to modify your business logic.
If you are certain static table view is enough, you can mix this method with overriding data source / delegate methods in your subclass of table view controller to add minor customisation (e.g. hiding certain cell when needed)
Alternatively, you can create cells using designated initialiser initWithStyle:reuseIdentifier: to instantiate them outside of table view life cycle and implement completely custom logic. There is nothing particular that you should do in viewDidLoad, that you wouldn't do elsewhere.
If you have a particular problem with your code, please post a snippet so community can help you
I suggest you to declare all your cells in storyboard (with date picker at right position) as static table and then override tableView:heightForRowAtIndexPath:
Define BOOL for determine picker visibility and its position in table
#define DATE_PICKER_INDEXPATH [NSIndexPath indexPathForRow:1 inSection:0]
#interface YourViewController ()
#property (assign, nonatomic) BOOL isPickerVisible;
#end
Then setup initial value
- (void)viewDidLoad {
[super viewDidLoad];
self.isPickerVisible = YES;
}
Override tableView delegate method
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
if ([indexPath isEqual:DATE_PICKER_INDEXPATH] && !self.isPickerVisible) {
return 0;
} else {
return [super tableView:tableView heightForRowAtIndexPath:indexPath];
}
}
And finally create method for toggling picker
- (void)togglePicker:(id)sender {
self.isPickerVisible = !self.isPickerVisible;
[self.tableView beginUpdates];
[self.tableView endUpdates];
}
which you can call in tableView:didSelectRowAtIndexPath:
According to your problem, you can create pairs (NSDictionary) of index path and bool if its visible and show/hide them according to that.
Here's what I was looking for:
MyCustomCell *cell = (MyCustomCell *)[[[UINib nibWithNibName:#"MyNibName" bundle:nil] instantiateWithOwner:self options:nil] firstObject];

Calling methods when UITableViewCell is pressed

I would like to call a method when a UITableViewCell is selected/tapped. I could do it easily with a static table view, but it requires a UITableViewController which is not good for me in this case, therefore I'm using a normal vc.
I have 10 specified methods like this:
- (void) methodOne {
NSLog(#"Do something");
}
- (void) methodTwo {
NSLog(#"Do something");
}
....
And I would like to call the methodOne when the first cell was tapped, call the methodTwo when the second cell was tapped and so on..
As a first step I set the numberOfRowsInSection to return 10 cells, but have no idea how could I connect the selected cells with the methods. Is there any quick way to do it? It would be a dirty solution to create 10 custom cells and set the every method manually for the custom cells, and there is no free place for it.
You can create an array of NSStrings with method names in the order they should be called from their corresponding UITableViewCells.
NSArray *selStringsArr = #[#"firstMethod", #"secondMethod", #"thirdMethod];
Then create a selector in tableView:didSelectRowAtIndexPath: from the strings array and call it using performSelector:.
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
NSString *selString = selStringsArr[indexPath.row];
SEL selector = NSSelectorFromString(selString);
if ([self respondsToSelector:#selector(selector)]) {
[self performSelector:#selector(selector)];
}
}
Of course, there are some limitations to using performSelector: which you can read here.
You can use this method for whenever any cell is tapped on the table view
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NSInteger selectedRow = indexPath.row; //this is the number row that was selected
switch (selectedRow)
{
case 0:
[self methodOne];
break;
default:
break;
}
}
Use selectedRow to identify which row number was selected. If the first row was selected, selectedRow will be 0.
Don't forget to set the table view's delegate to your view controller. The view controller also has to conform to the UITableViewDelegate protocol.
#interface YourViewController : UIViewController <UITableViewDelegate, UITableViewDataSource>
As long as the table view has a data source and a delegate, it doesn't matter what kind of view controller it is on. All a UITableViewController really is is a UIViewController that already has a table view on it and is that table view's delegate and data source.

How to address a specific UITableViewCell?

I am using a static cell layout in a UITableView. During the workflow I need to address the attributes of a specific cell. All cells have an identifier but i did not found a way to actually address the cell using the identifier.
Thanks,
em
The reason why cellForRowAtIndexPath: is not reliable is probably this (from the documentation):
An object representing a cell of the table or nil if the cell is not visible or indexPath is out of range.
If you ask for a cell that is not visible on screen, it may have been purged from the table view.
Since you mention that you use a static cell layout in your tableview (I assume you don't rely on cell reuse), you could consider keeping the cells as private properties:
In the private interface:
#interface MyViewController ()
#property (nonatomic, readonly) MyTableViewCellClass *myStaticCell;
#end
In the implementation:
#implementation MyViewController {
MyTableViewCellClass* _myStaticCell;
}
- (MyTableViewCellClass*) myStaticCell {
if (!_myStaticCell) {
// Initialize _myStaticCell
}
return _myStaticCell
}
You can then call this lazy loaded property when tableView:cellForItemAtIndexPath:is called and whenever you need to modify it.
Note that this approach is only recommended if you have a tableview with static content and don't rely on cell reuse.
Here indexPathSelected is the selected specific cell
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *oldCell = [tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:indexPathSelected inSection:0]];
indexPathSelected = indexPath.row;
}

empty grid of UItableView using storyboard

I try to display objects of an array in a tableview.
This is a single screen app, I'm using storyboard.
When running - the tableview appears as an empty grid. the data of the objects is not displayed. what may cause this?
Having 2 required methods numberOfRowsInSection and cellForRowAtIndexPath I suspect the last one.
The .h file contains this row:
#interface MYViewController : UIViewController <UITableViewDataSource, UITableViewDelegate>
I set the delegate & datasource via the code as you suggested. still empty grid.
This is my implementation:
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return [listRecipes.recipeArray count]; }
-(UITableViewCell )tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString cellIdentifier = #"ListCellIdentifier"; MYCustomListCell* listCell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier]; NSString* dataString = listRecipes.recipeArray[indexPath.row]; listCell.listName.text = dataString; listCell.imageView.image = [UIImage imageNamed:dataString]; return listCell; }
I try to display data from an array in MVC .
If the array is local - the data is displayed
Can you please advise what to do?
Thank you in advanced.
Always remember to hook up your table's delegate and datasources.
Being a UIElement on a UIViewController that conforms to these two protocols is not enough for Xcode to assume that that UIViewController should be the delegate and/or datasource for the table.
Right click on your tableview, drag from delegate & datasource to your UIViewController.
You can also set these programmatically via:
self.table.datasource = self;
self.table.delegate = self;
And if you're still having trouble after this, you'll have to show us how you're implementing the datasource protocol methods.
Check if your initialisation of tableview delegate and datasource would be before the recipeArray is initialised. In this case you will have to tableView.reload() after the items are added to recipeArray .

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