I have a static UITableView setup in my storyboard. I have subclassed some cells and added this property:
#property (nonatomic, strong) UILabel *label;
I also have code to add the label to my cell in the layoutSubviews method. My label shows in my cell without an issue. I can see the label saying 'PLACEHOLDER' but it is not updated to say the text I set in cellForRowAtIndexPath.
In the cellForRowAtIndexPath method, I have the following:
APInfoTableViewCell *cell = (APInfoTableViewCell*)[super tableView:tableView cellForRowAtIndexPath:indexPath];
[cell.label setText#"Hello World"];
However, this will not update the text in my label. The label is actually nil.
EDIT:
Here is the full code...
UITableViewCell Subclass:
#property (nonatomic, strong) UILabel *infoLabel;
-(void)layoutSubviews
{
[super layoutSubviews];
[self initUI];
}
-(void)initUI
{
//add long press to show info label
_infoLabel = [UILabel new];
[_infoLabel setText:#"PLACEHOLDER"];
[_infoLabel setFont:[UIFont fontWithName:#"Avenir-Medium" size:10.0f]];
[_infoLabel setTextAlignment:NSTextAlignmentCenter];
[_infoLabel setTextColor:[UIColor apText]];
[_infoLabel setAlpha:1.0f];
[_infoLabel setTranslatesAutoresizingMaskIntoConstraints:NO];
[self addSubview:_infoLabel];
NSArray *infoConstraintH = [NSLayoutConstraint constraintsWithVisualFormat:#"H:|-40-[infoLbl]-40-|" options:0 metrics:nil views:#{ #"infoLbl" : _infoLabel }];
[self addConstraints:infoConstraintH];
NSArray *infoConstraintV = [NSLayoutConstraint constraintsWithVisualFormat:#"V:|-10-[infoLbl]-10-|" options:0 metrics:nil views:#{ #"infoLbl" : _infoLabel }];
[self addConstraints:infoConstraintV];
}
ViewController:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
APInfoTableViewCell *cell = (APInfoTableViewCell*)[super tableView:tableView cellForRowAtIndexPath:indexPath];
[cell.infoLabel setText#"Hello World"];
return cell;
}
If you are using storyboard, and you don't want to add IB outlet then call your initUI method from awakeFromNib method.
If you are not using storyboard implement - (instancetype)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier method and call it from there.
awakeFromNib method is called once the cell(or any UIView subclass) is instantiated from nib(either from storyboard or from xib). And its called only once in the lifetime of the view
Note: This will not get called if you are creating a view subclass programmatically.
As per documentation
Subclasses can override this method as needed to perform more precise layout of their subviews. You should override this method only if the autoresizing and constraint-based behaviors of the subviews do not offer the behavior you want. You can use your implementation to set the frame rectangles of your subviews directly.
That means, use this method to do any additional lay outing of already added. This method is called when some frame/autolayout constraint changes happens.
You need to instantiate a new cell in tableView:cellForRowAtIndexPath: or use dequeueReusableCellWithIdentifier:. cellForRowAtIndexPath: returns visible instantiated cells in the table view. As you aren't instantiating your cells anywhere there are no cells in the table view, so cellForRowAtIndexPath: returns nil.
Additionally layoutSubviews is called a lot and is called late. You should not rely on it to initialise your label. As it stands your cell will keep adding additional labels when ever layoutSubviews is called! The designated initialiser is the place to add that initUI code (as the name implies 😉). If your UITableViewCell subclass doesn't use a XIB/Storyboard for its view, initWithStyle:reuseIdentifier: is the designated initialiser. (Otherwise it is initWithCoder: or awakeFromNib)
Related
I have an Array of 5 items. This array is dynamic therefore the number of items may vary.
I have aUIVIewController as shown in the following image. In my UIView, there are few components (Like buttons, etc). Based on the number of items in the above array i want to add the UIVIew to my UIViewContorlleras shown in the image.
For example: There're 5 items in the Array, then i need to add 5 UIView's to my UIViewController.
1.) I don't want to use a XIBfile for the UIView but want to use only StoryBoard. How can i design the UIView in StoryBoard ?
2.) How can i add UIView to the UIViewController dynamically as the number of items in the array increased ?
Loop through your array (I have assumed your array contains UIViews, if not you may update accordingly) like:
for(UIView *subView in arrayOfItems){
subView.position = specify the position
[self.view addSubview:subView];
}
1) You need to create a class, where the properties have IBOutlets, like this:
#interface MyView ()
#property (weak, nonatomic) IBOutlet UIView *viewContent;
#end
Than you can design your UIView inside the UIStoryboard and connect them from the class to the ui element. In previous xCode versions there was always a problem if you want to drag from UIStoryboard to the class, have to do it the different way.
2) To add a UIView to your UIViewController you just have to add it as subView inside your UIViewController like this:
[self.view addSubView:anyView]
set the frame of the sub views as per your design
for (int i=0;i<YourViewArrayCount; i++) {
[self.view addSubview:[YourViewArrayCount objectAtIndex:i]];
}
create a UICollectionView in the storyboard , and add a UICollectionViewCell prototype with a UIButton in it , and in the UICollectionViewDataSource method numberOfItemsInSection return your array count:
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
return yourArray.count;
}
and in order to handle the button touch event ,you'll have to set the UIButton tag to 999 for example in the UICollectionViewCell prototype in storyboard,and in the UICollectionViewDataSource method cellForItemAtIndexPath get a reference to the button using its tag then add the touch event handler to it programmatically :
-(UICollectionViewCell*)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"yourCellIdentifier" forIndexPath:indexPath];
UIButton *button = [cell viewWithTag:999];
[button addTarget:self action:#selector(buttonTouchHandler:) forControlEvents:UIControlEventTouchUpInside];
return cell;
}
finally to find out which button was actually touched (at which indexPath) , i suggest subclassing the UIButton class and add a property of type NSIndexPath (don't forget to change the button class in storyboard to your new UIButton subclass) and in the UICollectionViewDataSource method cellForItemAtIndexPath do the following
-(UICollectionViewCell*)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"yourCellIdentifier" forIndexPath:indexPath];
MySepcialButton *button = [cell viewWithTag:999];
button.indexPath = indexPath;
[button addTarget:self action:#selector(buttonTouchHandler:) forControlEvents:UIControlEventTouchUpInside];
return cell;
}
this way in the buttonTouchHandler: method you can check the button property indexPath.
I'm struggling with a problem I encountered while trying to create a custom UITableViewCell.
I subclassed UITableViewCell in SGTableViewCell and added it in the prototype cell in the storyboard.
As you can see the label is connected
and the cell identifier is set correctly
Then I linked the label to the SGTableViewCell.h like this
#property (strong, nonatomic) IBOutlet UILabel *nameLabel;
and in the .m file I have this code
- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {
self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
if (self) {
self.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
[self addGestureRecognizer:recognizer];
self.nameLabel = [[UILabel alloc] init];
_checkView = [[UIView alloc] initWithFrame:CGRectNull];
_checkView.backgroundColor = kGreen;
_checkView.alpha = 0.0;
[self addSubview:_checkView];
self.nameLabel.text = #"Hello";
}
return self;
}
But when I use this cell in my tableview using this code
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
Episode *episode = [self.selectedSeason.episodeList objectAtIndex:indexPath.row];
SGTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Episode"];
UIView *selectionColor = [[UIView alloc] init];
selectionColor.backgroundColor = kSelectionGrey;
cell.selectedBackgroundView = selectionColor;
cell.backgroundColor = kBackgroundGrey;
cell.nameLabel.text = episode.name;
NSLog(#"%#", cell.nameLabel.text);
cell.nameLabel.textColor = [UIColor redColor];
return cell;
}
I get no text at all.
I tried logging the text from each label in each cell and it gives me the right text.
I tried setting programmatically a different disclosure indicator for the custom cell and it did change so everything is allocated and working but label is not displaying.
I honestly have no idea of what's the problem. Did I miss something?
Thank you
PARTIALLY SOLVED:
OK i tried doing the same thing on an empty project and everything worked flawlessly so I checked again my project and found this line
[self.tableView registerClass:[SGTableViewCell class] forCellReuseIdentifier:#"Episode"];
Seeing it was not necessary for the empty project i commented this line and everything started working.
The only problem i have now is that if i don't use this line i can't use the custom cell as was intended. In fact my custom cell is swipable using a pan gesture recognizer but without registering my custom class to the tableview seems like the swipe doesn't work.
Sorry for the trouble, seems like i messed up again :/
You shouldn't alloc init a label that you created in the storyboard, it is already allocated automatically. When you do self.nameLabel = [[UILabel alloc] init];, you reset the self.nameLabel property to point to a new empty memory location and not to the label created in the storyboard, hence you can change its text property and see the result in NSLog but not in the storyboard because it doesn't refer to that label in the storyboard.
Try removing all initialisation from the initWithStyle method (to make sure nothing is covering it such as that subview you create), and everything related to the label in the cellForRowAtIndexPath method (same reason), and try a simple assignment like self.nameLabel.text = #"Test text" in the cellForRowAtIndexPath method, it should work. Then add all your other initialisation.
And yeah, don't forget to input your cell reuse identifier "Episode" in the storyboard.
Make sure you:
Have linked the delegate and the datasource to the view the tablview is housed in.
Have that view implement UITableViewController and UITableViewDelegate (I'm pretty sure it is both of those).
Implement the necessary methods, which you seem to have done. You need the row size, section size, and the add cell methods
After updating the array linked to your tableview, call [tableView reloadData]
Have a look at this link:Tutorial to create a simple tableview app
I'm trying to clean up my code and use MVC principles by pushing as much view related stuff as i can into the storyboard as well as custom UIView classes (ie as opposed to doing view related stuff on the UIViewController itself)
So I have a custom UITableViewCell (called CustomCell) that has several properties, one of them is my own label. Since I'm loading the cell from the storyboard, I initialize it with initWithCoder rather than initWithStyle:reuseIdentifier:, this is what I have in CustomCell.m which is a subclass of UITableViewCell (for some reason i couldn't figure out how to set a custom font using storyboard.. but that's beside the point of this question):
// CustomCell.m - subclass of UITableViewCell
- (id)initWithCoder:(NSCoder *)aDecoder {
self = [super initWithCoder:aDecoder];
if (self) {
NSLog(#"customizing cell font having text %#", self.label.text);
UIFont *customFont = [UIFont fontWithName:#"Montserrat" size:16];
self.label.textColor = [UIColor redColor];
[self.label setFont:customFont];
}
return self;
}
This simply doesn't work.. the log statement outputs null for the text simply b/c the text hasn't been loaded yet. self.label is also null (I don't know why I thought it should have been inflated from the nib by now) but even if I initialize it here.. it still won't work.
So my work around was to simply put this cell customization part here in the TableViewController:
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell
forRowAtIndexPath:(NSIndexPath *)indexPath {
UIFont *customFont = [UIFont fontWithName:#"Montserrat" size:16];
[((CustomCell *)cell).label setFont:customFont];
}
and it worked just fine.. I'm unhappy with this method and I would like to know how to make it work from within CustomCell.m
update: to make things even more interesting.. if i put customization code for UITableViewCell properties inside initWithCoder, they work! consider this example:
- (id)initWithCoder:(NSCoder *)aDecoder {
self = [super initWithCoder:aDecoder];
if (self) {
UIView *bgColorView = [[UIView alloc] init];
[bgColorView setBackgroundColor:[UIColor blueColor]];
[self setSelectedBackgroundView:bgColorView]; // actually works!
}
return self;
}
which makes this even more weird.
Inspired by andykkt's comment, I found the explanation in awakeFromNib documentation:
The nib-loading infrastructure sends an awakeFromNib message to each
object recreated from a nib archive, but only after all the objects in
the archive have been loaded and initialized. When an object receives
an awakeFromNib message, it is guaranteed to have all its outlet and
action connections already established.
so that explains the weird behaviour above: initWithCoder instantiates a standard UITableViewCell (that already comes pre-baked with a backgroundView etc etc).. however it still doesn't recognize the outlets I've added to it via storyboard.. awakeFromNib does.
I suspect that initWithCoder: method doesn't draw the contents of the cell, it just, initialises the object, and as you have noticed, accessing any of the ui drawing methods of the cell actually 'draws' the cell to apply the changes you have made to the cell. You can see the same behaviour when initing UIViewController's using initWithNibName:bundle: method.
Here is what I have done:
I created a custom xib file that has a small UIView used for a custom table section header.
I classed the custom xib file.
I want to add this to a tableView as the header. I have looked at a few resources, but they seem to be either outdated or missing information.
Looking in the documentation, I see a reference to adding a custom header with the following instructions:
To make the table view aware of your header or footer view, you need to register it. You do this using the registerNib:forCellReuseIdentifier: or registerClass:forCellReuseIdentifier: method of UITableView.
When I added a tableView to my storyboard view, it was easy to assign it a reuse identifier within XCode. I was even able to create a custom cell xib file and it also had a spot for a reuse identifier within XCode.
When I created the custom UIView for the section header, it did not have an entry for reuse identifier. Without this, I have no idea how to use registerNib:forCellReuseIdentifier.
More information:
I have a storyboard scene that has a tableView inside. The tableView is of a custom class that is linked and the tableView object has an outlet in the parent view's ViewController file.
The parent ViewController is both the UITableViewDataSourceDelegate and UITableViewDelegate. Again, I was able to implement the custom cells with no issue. I can't even modify the header in any way besides the title.
I tried calling the method [[self tableHeaderView] setBackgroundColor:[UIColor clearColor]]; from the custom tableView class and nothing happens. I tried using this method in the parent ViewController class by using the outlet name like so:
[[self.tableOutlet tableHeaderView] setBackgroundColor:[UIColor clearColor]];
Any help would be greatly appreciated.
EDIT: (Can't change background to transparent)
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {
HeaderView *headerView = [self.TableView dequeueReusableHeaderFooterViewWithIdentifier:#"tableHeader"];
// Set Background color
[[headerView contentView] setBackgroundColor:[UIColor clearColor]];
// Set Text
headerView.headerLabel.text = [self.sectionArray objectAtIndex:section];
return headerView;
}
You don't need to set the identifier in the xib -- you just need to use the same identifier when you register, and when you dequeue the header view. In the viewDidLoad method, I registered the view like this:
[self.tableView registerNib:[UINib nibWithNibName:#"Header1" bundle:nil] forHeaderFooterViewReuseIdentifier:#"header1"];
Then, in the delegate methods:
-(UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {
UIView *headerView = [self.tableView dequeueReusableHeaderFooterViewWithIdentifier:#"header1"];
return headerView;
}
-(CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section {
return 100;
}
On the problem with background color (Unless you want transparent):
You can create an UIView which occupies the whole view then change the background color of that.
If you don't want others to know what's happening, you can overwrite the backgroundColor property:
//interface
#property (copy, nonatomic) UIColor *backgroundColor;
//implementation
#dynamic backgroundColor;
- (void)setBackgroundColor:(UIColor *)backgroundColor {
//self.viewBackground is the created view
[self.viewBackground setBackgroundColor:backgroundColor];
}
- (UIColor *)backgroundColor {
return self.viewBackground.backgroundColor;
}
I make a view like imessage, just input text into the bottom text view. I use table view to do this, and the text view in the last cell. when I input long text that more than one line, I need the text view and the cell become tailer. so I need refresh cell's height. but if I use table view's reload or reload row, the content in text view will disappear and the keyboard will disappear too. Is there any way better to fix it?
May be I should use tool bar to do it easy? but I still doubt table view can do it.
The cells will resize smoothly when you call beginUpdates and endUpdates. After those calls the tableView will send tableView:heightForRowAtIndexPath: for all the cells in the table, when the tableView got all the heights for all the cells it will animate the resizing.
And you can update cells without reloading them by setting the properties of the cell directly. There is no need to involve the tableView and tableView:cellForRowAtIndexPath:
To resize the cells you would use code similar to this
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text {
NSString *newText = [textView.text stringByReplacingCharactersInRange:range withString:text];
CGSize size = // calculate size of new text
if ((NSInteger)size.height != (NSInteger)[self tableView:nil heightForRowAtIndexPath:nil]) {
// if new size is different to old size resize cells.
// since beginUpdate/endUpdates calls tableView:heightForRowAtIndexPath: for all cells in the table this should only be done when really necessary.
[self.tableView beginUpdates];
[self.tableView endUpdates];
}
return YES;
}
to change the content of a cell without reloading I use something like this:
- (void)configureCell:(FancyCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
MyFancyObject *object = ...
cell.textView.text = object.text;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
FancyCell *cell = (FancyCell *)[tableView dequeueReusableCellWithIdentifier:#"CellWithTextView"];
[self configureCell:cell forRowAtIndexPath:indexPath];
return cell;
}
// whenever you want to change the cell content use something like this:
NSIndexPath *indexPath = ...
FancyCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];
[self configureCell:cell forRowAtIndexPath:indexPath];
I've written a subclass of UITableViewCell to handle this functionality.
.h file:
#import <UIKit/UIKit.h>
#protocol AECELLSizeableDelegate;
#interface AECELLSizeable : UITableViewCell
#property (weak, nonatomic) id <AECELLSizeableDelegate> delegate;
#property IBOutlet UIView *viewMinimized;
#property IBOutlet UIView *viewMaximized;
#property BOOL maximized;
#property CGFloat height;
- (IBAction)clickedConfirm:(id)sender;
- (IBAction)clickedCancel:(id)sender;
- (void)minimizeForTableview: (UITableView*)tableView;
- (void)maximizeForTableview: (UITableView*)tableView;
- (void)toggleForTableview: (UITableView*)tableView;
#end
#protocol AECELLSizeableDelegate <NSObject>
- (void)sizeableCellConfirmedForCell: (AECELLSizeable*)cell;
- (void)sizeableCellCancelledForCell: (AECELLSizeable*)cell;
#end
.m file:
#import "AECELLSizeable.h"
#implementation AECELLSizeable
- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
{
self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
if (self) {
// Initialization code
}
return self;
}
- (void)setSelected:(BOOL)selected animated:(BOOL)animated
{
[super setSelected:selected animated:animated];
// Configure the view for the selected state
}
- (void)minimizeForTableview: (UITableView*)tableView
{
self.maximized = NO;
[self.viewMinimized setHidden:NO];
[self.viewMaximized setHidden:YES];
self.height = self.viewMinimized.frame.size.height;
[tableView beginUpdates];
[tableView endUpdates];
}
- (void)maximizeForTableview: (UITableView*)tableView
{
self.maximized = YES;
[self.viewMinimized setHidden:YES];
[self.viewMaximized setHidden:NO];
self.height = self.viewMaximized.frame.size.height;
[tableView beginUpdates];
[tableView endUpdates];
}
- (void)toggleForTableview:(UITableView *)tableView
{
if (self.maximized) {
[self minimizeForTableview:tableView];
} else {
[self maximizeForTableview:tableView];
}
}
- (void)clickedConfirm:(id)sender
{
[self.delegate sizeableCellConfirmedForCell:self];
}
- (void)clickedCancel:(id)sender
{
[self.delegate sizeableCellCancelledForCell:self];
}
#end
Example Usage:
Create a UITableViewController with a static UITableView in IB
Add a cell to the tableview that is a AECELLSizeable (or subclass of it)
Create two UIViews in this cell. One UIView will be used for the content visible while minimized, the other will be used for the content visible while maximized. Ensure these cells start at 0 on the y axis and that their height is equal to that of the height you wish to have the cell for each state.
Add any subviews to these two views you desired. Optionally add confirm and cancel UIButtons to the maximized UIView and hook up the provided IBActions to receive delegate callbacks on these events.
Set your tableview controller to conform to the AECELLSizeableDelegate and set the cell's delegate property to the tableview controller.
Create an IBOutlet in your UIViewController's interface file for the AECELLSizeable cell.
Back in IB, ensure the cell's initial height is that of the minimized version and connect the IBOutlet you just previously created.
Define the tableview's heightForRowAtIndexPath callback method in the tableview controller's implementation file as such:
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
if (indexPath.row == 0) {
//Sizeable Cell
return self.cellSizeable.height;
} else {
return [super tableView:tableView heightForRowAtIndexPath:indexPath];
}
}
In your tableview controller's viewDidLoad method, call minimizeForTableview on your cell to ensure it starts off minimized.
Then, call maximizeForTableview: on the cell when it is selected via the didSelectRowAtIndexPath callback from the tableview (or however else you would like to handle it) and call the minimizeForTableview: method on the cell when you receive the canceled / confirmed delegate callbacks from the cell (or, again, however else you'd like to handle it).
Check out this library. This is an implementation of message bubbles using UITableView. Keep in mind that every time a cell is displayed, cellForRow:atIndexPath is called and the cell is drawed.
EDIT
You can use heightForRowAtIndexPath
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
Messages *message = [self.messageList objectAtIndex:[indexPath row]];
CGSize stringSize = [message.text sizeWithFont:[UIFont fontWithName:#"HelveticaNeue-Light" size:13]
constrainedToSize:CGSizeMake(320, 9999) lineBreakMode:UILineBreakModeWordWrap];
return stringSize.height + 78;
}
Table view cells won't smoothly resize. Dot.
However, since your text view is in the last cell, you are lucky because you can easily simulate a row resizing. Having a text view in the middle of the table would be much more difficult.
Here is how I would do it: put your text view on top of the table view. Sync its position with the contentOffset of the tableView in scrollViewDidScroll:. And use the animatable contentInset of the tableView in order to leave room for the textView, as the user types in it. You may have to make sure your textView is not scrollable.