guys i want to set different subview in every section, i put my different view into NSMutableArray, so i hope i can access it depend on indexPath.section, this is my code :
for (int i =0; i<promoCount; i++) {
self.textView.text= [NSString stringWithFormat:#"text view :%d",i];
[self.arrayPromotions addObject:self.textView];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *cellPromotionIdentifier = #"cellPromo";
cell = [tableView dequeueReusableCellWithIdentifier:cellPromotionIdentifier];
if (cell==nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellPromotionIdentifier] autorelease];
}
[cell.contentView addSubview:[self.arrayPromotions objectAtIndex:indexPath.section]];
cell.contentView.layer.masksToBounds = YES;
cell.contentView.layer.cornerRadius = 5.0;
return cell;
}
But it doesn't work, subview just appear in the last section (but content of that subview is right).
iam sure that array have been filled by different view (by doing NSLog).
anybody can help me.????
What are you doing with y? Why divide an int by a float and store it in y?
Looks like you have only one self.textView. You are changing its .text member and adding it to the array multiple times but it is only one object and at the end of the loop you have multiple references to that one object, so all you see is the text it ended up with.
Related
Below is code for UITableView, But when i scroll its behaves weirdly (too annoying)... This problem is due to reuseIdentifier.... but dont know how to solve..
- (UITableViewCell *)tableView:(UITableView *)tableView1 cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView1 dequeueReusableCellWithIdentifier:CellIdentifier];
NSInteger imgTag = 1;
NSInteger lblTag = 2;
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
cell.selectionStyle = UITableViewCellSelectionStyleNone;
UIImageView *imgView = [[UIImageView alloc] initWithFrame:CGRectMake(2, 2, 52, 52)];
// Image:[UIImage imageNamed:[self.glassType objectAtIndex:indexPath.row]]];
imgView.tag = imgTag;
[cell.contentView addSubview:imgView];
[imgView release];
UILabel *lblName = [[UILabel alloc] initWithFrame:CGRectMake(60, cell.frame.size.height/4, 200, 21)];
// lblName.text = [self.glassName objectAtIndex:indexPath.row];
lblName.tag = lblTag;
[cell addSubview:lblName];
[lblName release];
}
NSInteger imgIndex = 2;
NSInteger lblIndex = 3;
((UIImageView *)[cell viewWithTag:imgTag]).image = [[self.glassType objectAtIndex:indexPath.row] objectAtIndex:imgIndex];
((UILabel *)[cell viewWithTag:lblTag]).text = [[self.glassName objectAtIndex:indexPath.row] objectAtIndex:lblIndex];
return cell;
}
- (void)tableView:(UITableView *)tableView1 didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView1 cellForRowAtIndexPath:indexPath];
cell.accessoryType = UITableViewCellAccessoryCheckmark;
}
How to make Cell for row at index so that it remains constant even when scrolled??? Also how to make single selection in UITableView??
The answer is that you should not add subviews to your table cells outside of the "if (cell == nil) { ..." clause or they get added over and over again to the same cell when it gets re-used.
See my answer to this question for a more detailed explanation, including code for how to fix it:
cellForRowAtIndexPath memory management
You also cannot store state in table cells because as soon as they scroll offscreen they are recycled and re-appear at a different index in your table. You need to set up an array of model objects to store state for your table cells (such as what their accessory type should be). A more detailed explanation can be found in my answer to this question:
Looping through UITableViewCells of a UITableView
If you fix how you are adding subviews to the cells, and store your "ticked" state in an array of model objects as well as setting the cell.accessoryType (so that it can be restored when the cell is dequeued), then your approach to row selection is otherwise correct.
So put this in your tableView:cellForRowAtIndexPath: method, just before the return cell;:
MyModelObject *object = [self.arrayOfModelObjects objectAtIndex:indexPath.row];
BOOL isChecked = object.checked;
cell.accessoryType = isChecked? UITableViewCellAccessoryCheckmark: UITableViewCellAccessoryNone;
And in your tableView: didSelectRowAtIndexPath: method, get rid of the current logic and replace it with:
- (void)tableView:(UITableView *)tableView1 didSelectRowAtIndexPath:(NSIndexPath *)indexPath
for (int i = 0; i < [self.arrayOfModelObjects count]; i++)
{
MyModelObject *object = [self.arrayOfModelObjects objectAtIndex:i];
object.checked = (i == indexPath.row); // only check the one we just tapped
}
//refresh table to update the accessory views for all rows
[tableView1 reloadData];
}
Obviously replace the arrayOfModelObjects with your own model implementation. You could just use an array of NSNumber objects containing bools if you don't want to create a custom class for this purpose.
The recycling queue is like a pool where previously created Cells are stored before to reuse them. For example when you scrolls up, at the moment the cell disappears above, it is stored in the queue and becomes available for the cell that will appear at the bottom. Ok ?
Actually the number of cells really created is exactly the max simultaneous cell you can display in your table (in most cases from 3 to 8). In other words your if (cell == nil) code is executed (more or less from 3 to 8 times) at the first reloadData to create the pool of cells your table needs.
Then all you make on a cell is kept as it and appears again when you dequeue it. It's now easy to understand that, in your code, you have to make all strictly row-dependant settings outside the if (cell == nil) block. The same way, do not add subViews outside the if (cell == nil) block, you can imagine the thousands of subview you will add each time you reset a dequeued cell !
Tip: if you need some custom cleanup before reusing a cell (like to set an image to blank), you can create a custom UITableviewCell class and implements the prepareForReuse method.
Is it clear ?
Always reload your tableView in viewWillAppear method instead of viewDidLoad.
(void) viewWillAppear:(BOOL)animated{
[self.tableView reloadData];
}
This avoids most of all unexpected and annoying problems. :)
I have scoured the internet looking for a good tutorial or posting about having a UITableView populated with a UITextField in each cell for data entry.
I want to keep track of each UITextField and the text written within it while scrolling. The tableView will be sectioned. I have been using a custom UITableViewCell but I'm open to any method.
Also, is it possible to use the textFields as ivars?
If any of you could point me in the right direction, it would be greatly appreciated.
Thank you in advance!
To solve your problem you have to maintain an array, with some number (number of textFields you added to all cells) of objects.
While creating that array you need add empty NSString objects to that array. And each time while loading the cell you have to replace the respected object to respected textField.
Check the following code.
- (void)viewDidLoad{
textFieldValuesArray = [[NSMutableArray alloc]init];
for(int i=0; i<numberofRows*numberofSections; i++){
[textFieldValuesArray addObject:#""];
}
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
// Return the number of sections.
return numberofSections;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return numberofRows;
}
- (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:identifier];
CustomTextField *tf = [[CustomTextField alloc] initWithFrame:CGRectMake(5,5,290,34)];
tf.tag = 1;
[cell.contentView addSubView:tf];
[tf release];
}
CustomTextField *tf = (CustomTextField*)[cell viewWithTag:1];
tf.index = numberofSections*indexPath.section+indexPath.row;
tf.text = [textFieldValuesArray objectAtIndex:tf.index];
return cell;
}
- (void)textFieldDidEndEditing:(UITextField *)textField{
int index = textField.index;
[textFieldValuesArray replaceObjectAtIndex:index withObject:textField.text];
}
First of all, you must understand that UITableViewCell and UITextField are just views, they are not supposed to hold data, they are just supposed to display them and allow the user to interact with them: The data should remain stored in the controller of the table view.
You have to remember that UITableView allows you to reuse UITableViewCell instances for performance purpose: what's displayed on the screen are actually the only subviews UITableView keep there. It means that you'll reuse one cell that already has a text field in it and set the text on that field directly. When the user will tap on the field it will edit it and you'll have to get the value back from it when the user will have finished.
The fastest way, would be to use what Satya proposes, that is building normal UITableViewCell and insert into a UITextField (there's no need for a CustomTextField class...). The tag will allow you to get back to the text field easily... But you'll have to setup your text field so it behaves properly when the table view resizes or if a label in the same cell changes.
The cleanest way to do that is to subclass UITableViewCell and setup the layout of your label and text field, and you can provide the text field as a property of the custom subclass.
I have used Textfields in tableview for data entry.
I have customised the UITextField class in a separate class called Utility :
In Utility.h
#interface CustomUITextField:UITextField{
NSInteger rowNumber;
}
In Utility.m
#implementation CustomUITextField
#synthesize rowNumber;
#end
My tableView cellForRowAtIndexPath method is
- (UITableViewCell *)tableView:(UITableView *)theTableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *Identifier = #"Cell";
UITableViewCell *cell = [theTableView dequeueReusableCellWithIdentifier:Identifier];
if(cell == nil)
cell = [self reuseTableViewCellWithIdentifier:Identifier withIndexPath:indexPath];
CustomUITextField *itemNameTextField = (CustomUITextField *)[cell.contentView viewWithTag:TEXTFIELD_TAG];//this is the tag I have set in reuseTableViewCellWithIdentifier method for textfield
itemNameTextField.rowNumber = indexPath.row;
itemNameTextField.text = #"";//you can set it for the value you want
if(itemListTable.editing)
itemNameTextField.borderStyle = UITextBorderStyleRoundedRect;
else
itemNameTextField.borderStyle = UITextBorderStyleNone;
return cell;
}
You can customise the delegate methods of UITextField for CustomUITextField & can save the text entered in a particular row's textfield by accessing the CustomTextField's row number.
Just try with this.
I had the same problem here is some code i found that treats this problem . it puts the data enterd in a Array Look at the Debugger console to see the results of the text being typed here's the link TextFieldCell. . Happy Codeing
I have a UITableView where I have the backgroud color set via
UIView *myView = [[UIView alloc] init];
if ((indexPath.row % 2) == 0)
myView.backgroundColor = [UIColor greenColor];
else
myView.backgroundColor = [UIColor whiteColor];
cell.backgroundView = myView;
[myView release];
The problem I find is that when I edit a table (via setEditing:YES...) some cells of the same color invariable are next to each other. How do I force UITableView to fully redraw. reloadData is not doing a great job.
Is there are deep-cleaning redraw?
I had this issue before so I'll share with you how I solved it:
You can use a boolean flag (say it's called needsRefresh) to control the behavior of cell creation in -cellForRowAtIndexPath:
An example:
- (UITableViewCell*) tableView:(UITableView *) tableView cellForRowAtIndexPath:(NSIndexPath*) indexPath {
UITableViewCell *cell = [tableView dequeueResuableCellWithIdentifier:SOME_ID];
if(!cell || needsRefresh) {
cell = [[[UITableViewCell alloc] init....] autorelease];
}
//.....
return cell;
}
So, when you need a hard reload, set the needsRefresh flag to YES. Simple as a pimple.
For me the accepted answer didn't really work since I had no idea when to set the needsRefresh back to YES.
What worked for me was:
- (UITableViewCell*) tableView:(UITableView *) tableView cellForRowAtIndexPath:(NSIndexPath*) indexPath {
UITableViewCell *cell = [tableView dequeueResuableCellWithIdentifier:customCellIdentifier];
if(nil == cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:customCellIdentifier];
}
//.....
return cell;
}
And then you change the customCellIdentifier value whenever you need to. This way the cells are also still reusable if you switch back to the original cell identifier.
The accepted method seems dirty, it just makes a bunch of new cells that are stored along with the bad ones. Here are a couple of solutions depending on your situation:
1.
first, for the situation described in the question you should not dump your cells and create new views on every cycle. You need to tag your view and then get it back when from the cell when you get a reuse cell:
- (UITableViewCell*) tableView:(UITableView *) tableView cellForRowAtIndexPath:(NSIndexPath*) indexPath {
UITableViewCell *cell = [tableView dequeueResuableCellWithIdentifier:SOME_ID];
if(!cell) {
cell = [[UITableViewCell alloc] init];
UIView *myView = [[UIView alloc] init];
cell.backgroundView = myView;
[myView setTag:5]; //<------
}
UIView *myView = [cell viewWithTag:5]; //<------
if ((indexPath.row % 2) == 0)
myView.backgroundColor = [UIColor greenColor];
else
myView.backgroundColor = [UIColor whiteColor];
return cell;
}
//then just reload the tableview.
2.
...or even better, why not just use the cell backgrouncolor and update that without creating a view.
3.
A sure way to really clear out old cached cells it to simply recreate the UITableView object.
4.
In most cases you dont need to destroy these cells, just keep track of your elements and update them after getting the reusable cell.You can tag all your elements, keep a array reference to them, find them thought the view hierarchy... Im sure theres a bunch of other ways.
5.
heres a one liner to directly purge all cells, although not best practice to mess with the internals of objects like this as they might change in future versions:
[(NSMutableDictionary*)[tableview valueForKey:#"_reusableTableCells" ] removeAllObjects];
I was able to solve this by adding a refresh variable to the table datasource. I used a dictionary for each cell, but there's an extra key called #"refresh":#"1", indicating the cell needs refreshing. Once it's updated, I set that key's value to #"0". So whenever the table is reloaded, make sure the key goes back to #"0" again.
#define TABLE_VIEW_CELL_DEFAULT_ID #"cellIdentifier"
#property (nonatomic, strong) NSString *tableViewCellIdentifier;
#property (nonatomic) NSUInteger tableViewCellIdentifierCount;
// By using a different cell identifier, this effectively flushes the cell
// cache because the old cells will no longer be used.
- (void) flushTableViewCellCache
{
self.tableViewCellIdentifierCount++;
self.tableViewCellIdentifier = [NSString stringWithFormat:#"%#%i", TABLE_VIEW_CELL_DEFAULT_ID, self.tableViewCellIdentifierCount];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
MyTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:self.tableViewCellIdentifier];
if (cell == nil) {
cell = [[MyTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:self.tableViewCellIdentifier];
}
// rest of method...
}
I have a UITableView in that some cells are marked with UITableViewCellAccessoryCheckmark at the initialization of the view.
When the user selects another row, I have to check if the maximum number of selected rows was achieved before. To do that, I used the code bellow:
- (NSInteger)tableView:(UITableView *)tableView numberOfSelectedRowsInSection:(NSInteger)section{
NSInteger numberOfRows = [self tableView:tableView numberOfRowsInSection:section];
NSInteger numberOfSelectedRows = 0;
for (int i = 0; i < numberOfRows; i++) {
UITableViewCell *otherCell = [tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:i inSection:section]];
if (otherCell.accessoryType == UITableViewCellAccessoryCheckmark) {
numberOfSelectedRows++;
}
}
return numberOfSelectedRows;
}
If my number of rows is, as example, 20, the variable numberOfRows is setted correctly with 20. Lets say that 13 rows already are marked with UITableViewCellAccessoryCheckmark. So, numberOfSelectedRows should be 13 after the loop, but only the marked and VISIBLE cells are considered. So, if I have 9 cells showed and 7 are marked, the numberOfSelectedRows returns 7 instead of 13 (but the for iterate 20 times, as expected).
Is this a correct behavior of UITableView or it is a bug of iPhone simulator?
Thanks in advance.
Yes, it works as designed. You should never store model data in your views. UITableView knows nothing about the data, it only displays cells (and throws them aways as soon as they scroll off the screen). You need to store the checkmark state of each cell in a model object (e.g. an array) that you then access from your view controller.
This is correct behavior.
The UITableView is not a list. The system caches cell that are off screen to save memory and CPU and they can not be iterated over in a manner that makes sense.
Ok, you should keep track of the model/data and the tableView will keep track of displaying it. I have had some problems with this until I accepted that uitableView is not a list:)
So, have an array of objects that each corresponds to the data in the a cell. When building the individual cells like this:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"categoryCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];
}
Item *item = [self.itemList objectAtIndex:indexPath.row];
[cell.textLabel setText:[item itemBrand]]; //notice that here we set the cell values
return cell;
}
The when a user clicks you change you model like this:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
NSLog(#"IndexPat.row%i", indexPath.row);
Item item = (Item*) [self.itemList objectAtIndex:indexPath.row];
//change the state of item
}
This way the tableView will update to resemble the model/data, you just managed the model.
In a lot of iPhone apps, I see a UITableViewController being used as a checkbox list. (See, for an example of what I mean, Auto-Lock under Settings)
While trying to implement this myself, I had to jump through a lot of hoops in order to have an item selected programmatically by default (ie., the current value for what the list represents). The best I've been able to come up with is by overriding the viewDidAppear method in my view controller class:
- (void)viewDidAppear:(BOOL)animated {
NSInteger row = 0;
// loop through my list of items to determine the row matching the current setting
for (NSString *item in statusItems) {
if ([item isEqualToString:currentStatus]) {
break;
}
++row;
}
// fetch the array of visible cells, get cell matching my row and set the
// accessory type
NSArray *arr = [self.tableView visibleCells];
NSIndexPath *ip = [self.tableView indexPathForCell:[arr objectAtIndex:row]];
UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:ip];
cell.accessoryType = UITableViewCellAccessoryCheckmark;
self.lastIndexPath = ip;
[super viewDidAppear:animated];
}
Is this the best/only/easiest way to get a reference to a particular cell and indexPath if I want to mark a row by default?
In order to display the status items, you have to implement tableView:cellForRowAtIndexPath: anyway, don't you? So, why not just set the accessory type of the cell before returning the cell, like this:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
// dequeue or create cell as usual
// get the status item (assuming you have a statusItems array, which appears in your sample code)
NSString* statusItem = [statusItems objectAtIndex:indexPath.row];
cell.text = statusItem;
// set the appropriate accessory type
if([statusItem isEqualToString:currentStatus]) {
cell.accessoryType = UITableViewCellAccessoryCheckmark;
}
else {
cell.accessoryType = UITableViewCellAccessoryNone;
}
return cell;
}
Your code is extremely fragile, especially because you use [self.tableView visibleCells]. What if there are more status items than rows fitting on the screen (as the name suggests, visibleCells only returns the currently visible cells of the table view)?