I made an UITableView and contained some custom UITableViewCells, in the fist cell (named cell0 for example) there are some UITextFields for input, when I scroll the tableView, cell0 will disappear from the top of screen, then How can I get the UITextField's text in cell0?
cellForRowAtIndexPath will return nil.
The only method I found is a tableview delegate
- (void)tableView:(UITableView *)tableView didEndDisplayingCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
[cell dealloc]
}
According to Apple Documentation about cellForRowAtIndexPath:, it returns "An object representing a cell of the table or nil if the cell is not visible or indexPath is out of range."
A UITableViewCell is a view, according to MVC Pattern. So I'd prefer maintaining a model object -- maybe it is as simple as a NSString instance -- to hold the text in the cell if I were you. You can observe UITextField's change by adding an observer of UITextFieldTextDidChangeNotification key to your controller.
- (void)textFieldDidChangeText:(NSNotification *)notification
{
// Assume your controller has a NSString (copy) property named "text".
self.text = [(UITextField *)[notification object] text]; // The notification's object property will return the UITextField instance who has posted the notification.
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
// Dequeue cell...
// ...
if (!cell)
{
// Init cell...
// ...
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(textFieldDidChangeText:) name:UITextFieldTextDidChangeNotification object:yourTextField];
}
// Other code...
// ...
return cell;
}
Don't forget to remove the observer in your -dealloc.
As UITableViewCells leave the viewable area of the UITableView it is actually removed from the tableview and placed back into the reuse queue. If it is the selected for reuse it will be returned by dequeueReusableCellWithIdentifier:.
There is no callback for when a cell is removed from the view. However, prepareForReuse is called on the cell just before it is returned by dequeueReusableCellWithIdentifier:.
What are you ultimately trying to do?
You need to save the text somewhere (e.g. an NSArray) the moment it gets changed.
You can init textfield as instance variable.
look like:
.h
UITextField *textfiled;
.m
-(void)viewDidLoad
{
//init textfield
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
//init cell...
[cell addSubview:textfield];
return cell;
}
Related
I want a tableview inside another tableviewCell like the following image.It shows one complete cell with a few details and a tableview. How can i do this?I was following this link Link.This is an old code .It is using xibs.I dont have any idea where to set the delegate for the inner tableview.Please help.Any suggestion will be realy helpfull.
My first idea would be:
Subclass UITableViewCell ("MainTableViewCell") and extend it with UITableViewDelegate and UITableViewDatasource.
Next to all the properties you need in "MainTableViewCell" add a TableView "tableViewFilms" and an array "films" for the Films. Also don't forget to add the datasource methods for a tableview to the implementation file.
To easily setup a cell I add a setup-method to the header-file. Which can be called once the cell is instantiated. You can modify it as you want, give it as many parameters as you want and in the implementation (see step 4) set datasource and delegate of your inner tableview.
- (void)setupCellWithDictionary:(NSDictionary *)dict AndArray:(NSArray *)filmsForInnerTable;
You can call this method in your datasource method, once a cell is instantiated:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
MainTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"MainTableViewCell" forIndexPath:indexPath];
NSDictionary *dict = (NSDictionary *) allDataDictionaries[indexPath.row];
[cell setupCellWithDictionary:dict AndArray:filmsForInnerTable];
return cell;
}
Subclass UITableViewCell another time: "FilmTableViewCell"
When setting up the a Cell of "MainTableViewCell", set the delegate and the datasource of "tableViewFilms" to self (object of "MainTableViewCell").
- (void)setupCellWithDictionary:(NSDictionary *)dict AndArray:(NSArray *)filmsForInnerTable{
self.films = filmsForInnerTable;
self.tableViewFilms.dataSource = self;
self.tableViewFilms.delegate = self;
[self.tableView reload];
//more instructions
}
Populate the tableview with the data from the array "films" using "FilmTableViewCells".
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
FilmTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"FilmTableViewCell" forIndexPath:indexPath];
Film *film = (Film*)films[indexPath.row];
[cell setupCellWithFilm:film];
return cell;
}
Hope this helps.
Don't forget to use Outlets, the method definitions and to set the reuse-identifiers for the cells!
Check my answer in this ios 8 Swift - TableView with embedded CollectionView. You have replace that UICollectionView with UITableView.
Everything else is pretty much the same. Its just a head start with UITableView and UICollectionView created programmatically.
I can change it accordingly if you don't understand.
I have taken over an iOS project and have to refactor a list of views into a UITableView. I am using Storyboards and have subclassed UITableViewCell. One subclass is called MenuItemCell and has a headerLabel, detailLabel, and priceLabel which are properties set up in the Storyboard and configured in MenuItemCell. I am able to manipulate these via cellForAtIndexPath like this:
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
static NSString *MenuItemCellIdentifier=#"MenuItemCell";
id dic=self.tmpMenu.listItems[indexPath.row];
if([dic isKindOfClass:[MenuItem class]]){
MenuItemCell *cell = [self.menuTV dequeueReusableCellWithIdentifier:MenuItemCellIdentifier];
MenuItem *menuItem=(MenuItem *)dic;
cell.menuItem=menuItem;
cell.headerLabel.text=menuItem.header;
cell.headerLabel.numberOfLines=0;
cell.priceLabel.text=menuItem.price;
// how to handle this custom spotView
if([menuItem hasInstoreImage]){
UIView *instoreImageDot=[self circleWithColor:[UIColor redColor] radius:4];
[cell.spotView addSubview:instoreImageDot]; // ON SCROLLING, this populates to all the different table cells
}
return cell;
}
return nil;
}
The last piece is that there is a custom UIView called spotView. Currently, I am creating this circle in code in my controller via circleWithColor and trying to add to [cell.spotView] but scrolling causes this to populate on different table cells. How should I set this up? I have added a method to my custom view but this suffers from the same problem.
Cells get reused, you will need to tell the tableView to remove the custom View
if([menuItem hasInstoreImage]){
UIView *instoreImageDot=[self circleWithColor:[UIColor redColor] radius:4];
[cell.spotView addSubview:instoreImageDot];
}else{
//remove it if condition is not met
//or You can add a place holder view instead
}
What is happening is that iOS is reusing cells as you scroll and some of the reused cells already have the instoreImageDot view added as a subview.
You really shouldn't do layout stuff in the cellForRowAtIndexPath method. It should only ever be used to dequeue a reusable cell and then set the data for the cell. All the layout stuff should be handled by the cell itself.
Don't create the instoreImageDot in the controller. Add a method in your custom cell - something like (written in C#, but should be easy to translate):
UpdateCell(MenuItem item, bool hasInstoreIamge)
{
menuItem = item;
headerLabel.text = item.header;
priceLabel.text = item.price;
headerLabel.numberOfLines=0;
if (hasInstoreImage)
{
// code to add the instoreImageDot as a subview of the cell
}
}
Also in the Custom Cell, Implement the prepareForReuse method and inside this method, remove the instoreImageDot view from the cell - so that it can only ever be added once.
- (void)prepareForReuse {
if([self.subviews containsObject:instoreImageDot])
{
[instoreImageDot removeFromSuperview];
}
[super prepareForReuse];
}
Now your cellForRowAtIndexPath method can look like:
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
static NSString *MenuItemCellIdentifier=#"MenuItemCell";
id dic=self.tmpMenu.listItems[indexPath.row];
if([dic isKindOfClass:[MenuItem class]]){
MenuItemCell *cell = [self.menuTV dequeueReusableCellWithIdentifier:MenuItemCellIdentifier];
MenuItem *menuItem=(MenuItem *)dic;
cell.UpdateCell(menuItem, [menuItem hasInstoreImage]);
return cell;
}
return nil;
}
I put a textfield in every cell of the table. And after editing the textfield, an EditingDidEnd Event will trigger. In the method of hanlding this event I try to use
[XXXUITableViewController.tableView reloadData];
but it doesn't work(the delegate method is not called).
If I try to reloadData in someway like hanlding Tapgesture, it works just fine. I can use anthoer way to make my app work, but it's better to know why is reloadData not working. Any ideas, thanks a lot.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"ParCellID";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
for(UIView * old in cell.contentView.subviews){
[old removeFromSuperview];
}
//add a textfield in Table Cell View
ParticleConfigCellView * parCell=[[[NSBundle mainBundle] loadNibNamed:#"ParticleConfigCellView" owner:self options:nil]objectAtIndex:0];
[parCell refreshFromDataSource:[self.dataContainer.data_particleConifig objectAtIndex:indexPath.row]];
[cell.contentView addSubview:parCell];
return cell;
}
- (IBAction)nameChange:(id)sender {
[self savedata];
[self.tableView reloadData];//(not working. Table view delegate methods are not called.)
}
Here in this method also reload your array which is showing in table view because after saving new data you are not reloading new data so that its showing old data only.
- (IBAction)nameChange:(id)sender {
[self savedata];
[yourArray removeAllObjects];
//then here put new that in yourArray
[self.tableView reloadData];//(not working)
}
Edit:
Also call this method [self.tableView reloadData]; in the last line of your savedata method.
Each time you create a cell, you must assign a delegate text field that is in it. If you are using a dynamic table, add this code cell.yourTextField.delegate = self in this method - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath.
Or maybe you forgot to subscribe your class to the protocol?
In any case, the method reloadData updates the data in the table from its data source, and I do not understand why you need to call this method after you enter text in a field that is in the table. If you don't save this text, it will disappear after call reloadData method.
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.)
I have a UITableView tall enough that it necessitates scrolling. The top-most cell in the table contains a UITextField for the user to enter some text.
The standard way to build this might be to create and add the text field and add it to a cell created or recycled in cellFOrRowAtIndexPath: However, this constant re-creation means that the text entered in the field is erased when the cell is scrolled out and back into view.
The solutions I've found so far suggest using UITextField delegation to track the text as it changes and store it in an iVar or property. I would like to know why this is recommended instead of the simpler approach I am using:
I am creating the UITextField in the init method of the UITableViewController and immediately storing it in a property. In cellFOrROwAtIndexPath I am simply adding the pre-existing field instead of initializing a new one. The cell itself can be recycled without issue, but because I am always using the one and only UITextField, the content is maintained.
Is this a reasonable approach? What might go wrong? Any improvements (perhaps I could still create the field in cellForRowAtIndexPath but first check if the property is nil?)
When you are creating cells in cellForRowAtIndexPath you have to use one reusable identifier for that first cell (ie. cellId1) and another for the rest (ie. cellId2).
If you do this, when you get the cell for the first element by calling [tableView dequeueReusableCellWithIdentifier:#"cellId1"] you will always get the same Object and will not be reused by other cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
MyCell *cell = nil;
// Only for first row
if (indexPath.row == 0) {
static NSString *cellId1 = #"cellId1";
cell = [tableView dequeueReusableCellWithIdentifier:cellId1];
if (cell == nil) {
cell = [[MyCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellId1];
}
}
else {
static NSString *cellId2 = #"cellId2";
cell = [tableView cellId2];
if (cell == nil) {
cell = [[MyCell alloc] initWithStyle:UITableViewCellStyleDefault cellId2];
}
}
// do whatever
return cell;
}
If there is only one UITextField, then I agree that your approach would be better/same as compared to using UITextField delegation (I think).
However, let us assume that you want to "expand" your view so that there are about 7-8 or more TextFields now. Then if you go about using your approach, then the problem will be that you will be storing 7-8 or more TextFields in memory and maintaining them.
In such a situation, a better approach would be that you create only that number of textfields as visible on screen. Then you create a dictionary which would maintain the content present in the textfield (which you can get by UITextFieldDelegate methods). This way, the same textfield can be used when the cell is reused. Only the values will change and will be dictated by the values in the dictionary.
On a sidenote, do minimal creation in cellForRowAtIndexPath as that is called during every table scroll and so creating a textField in cellForRowAtIndexPath can be expensive.
#import "ViewController.h"
#import "TxtFieldCell.h"
#define NUMBER_OF_ROWS 26
#interface ViewController ()<UITableViewDataSource, UITableViewDelegate, UITextFieldDelegate>
#property (weak, nonatomic) IBOutlet UITableView *tablView;
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.tablView.datasource = self; //set textfield delegate in storyboard
textFieldValuesArray = [[NSMutableArray alloc] init];
for(int i=0; i<NUMBER_OF_ROWS; i++){
[textFieldValuesArray addObject:#""];
}
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
#pragma mark - TableView Datasource
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
TxtFieldCell *cell = [tableView dequeueReusableCellWithIdentifier:#"TxtFieldCellId" forIndexPath:indexPath];
cell.txtField.tag = indexPath.row;
if (textFieldValuesArray.count > 0) {
NSString *strText = [textFieldValuesArray objectAtIndex:indexPath.row];
cell.txtField.text = strText;
}
return cell;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return NUMBER_OF_ROWS;
}
#pragma mark - TextField Delegate
- (void)textFieldDidEndEditing:(UITextField *)textField {
[textFieldValuesArray replaceObjectAtIndex:textField.tag withObject:textField.text];
}