when pressing a row delete button on a table view, I do some validation, and if the user chooses to cancel the operation it all should rollback. Not only want to keep that row (what is happening), but also make disappear the delete button leaving only the "-" round button. How can I do that?
once again, thank you.
Assuming you are implementing your validations in tableView:commitEditingStyle:forRowAtIndexPath: method of your UITableViewDatasource protocol object, you should be able to set the editingAccessoryType and editingAccessoryView on the cell.
//After validation fails....
UITableViewCell *aCell;
aCell = [self tableView:tableView cellForRowAtIndexPath:indexPath];
// validations are done and you need to ignore the delete
if ( aCell.showingDeleteConfirmation ){
aCell.editingAccessoryView = nil;
aCell.editingAccessoryType = UITableViewCellAccessoryNone;
}
If you want, you can wrap the changes in an animation block to animate the change.
Alternatively, you could toggle the editing state of the cell.
//After validation fails....
UITableViewCell *aCell;
aCell = [self tableView:tableView cellForRowAtIndexPath:indexPath];
if ( aCell.showingDeleteConfirmation ){
aCell.editing = NO;
aCell.editingAccessoryView = nil;
aCell.editing = YES;
}
Related
This is related to another question of mine which wasn't answered in a helpful way (message when a UITableView is empty).
I'm trying to show an UIImage graphic that says You haven't saved any bookmarks over an UITableView when it's empty. I have NSNotification set-up so that when bookmarks are added or deleted, a message is sent so that the UITableView can be updated.
I've been trying to do it with this code. Why won't this work?
- (void)bookmarksChanged:(NSNotification*)notification
{
[self.tableView reloadData];
UIImageView* emptyBookmarks = [[UIImageView alloc] initWithFrame:CGRectMake(75, 100, 160, 57)];
emptyBookmarks.alpha = 1;
emptyBookmarks.image = [UIImage imageNamed:#"emptyBookmark.png"];
[self.view addSubview:emptyBookmarks];
[emptyBookmarks release];
if ([self.dataModel bookmarksCount] == 0)
{
emptyBookmarks.alpha = 1;
}
else
{
emptyBookmarks.alpha = 0;
}
}
I'm probably approaching this the wrong way... But if salvageable, what am I doing wrong?
When I initially have an empty bookmarks tableview, there's no image displayed. After I add a bookmark and then delete it, the image shows. Grrh.
Another way (and IMO the correct way) to do this is to manipulate the backgroundView property on the UITableView.
While making a single cell with a custom image cell would certainly works, I think it overly complicates the logic of your UITableViewController's data source. It feels like a kludge.
According to UITableView documentation:
A table view’s background view is automatically resized to match the
size of the table view. This view is placed as a subview of the table
view behind all cells , header views, and footer views.
Assigning an opaque view to this property obscures the background color
set on the table view itself.
While you probably don't want to just set it to your UIImageView, it is very easy to make a UIView that contains the UIImageView that you want.
Well first off if you were going to do it that way, you would need to reload the tableView after updating the image or model etc. and not before.
But you are probably making things more complicated than they need to be!
Why not just check to see if the data for section 0 and indexPath.row 0 are empty and if so in cellForRowAtIndexPath display a text message accordingly.
// First make sure there is always one row returned even if the dataModel is empty.
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
NSInteger numRows = 0;
if ([self.dataModel lastObject]) {
// Return the number of rows in the section.
numRows = [self.dataModel count]; // etc.
}
if (numRows < 1) numRows = 1;
return numRows;
}
// Then display the data if there is some, otherwise a message if empty.
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
}
if ([self.dataModel lastObject]) {
// setup the cell the normal way here.
} else { // the datasource is empty - print a message
cell.textLabel.text = nil;
cell.detailTextLabel.text = NSLocalizedString(#"You haven't saved any bookmarks", #"");
cell.detailTextLabel.textColor = [UIColor colorWithRed:0/255.0 green:0/255.0 blue:0/255.0 alpha:0.7];
cell.accessoryType = UITableViewCellAccessoryNone;
}
return cell;
}
Are you sure [self.dataModel bookmarksCount] is equal to 0 ?
While I agree that you are probably going about this the wrong way,
your image is allocated and added in your bookmark changed, your notification does not trigger when there are no bookmarks initially. Hence you don't see the image. Call the bookmar changed when your table view inits or appears.
Probably the best way to achieve this is to perform a check in your numberOfRowsInSection method to return 1 if your data source is empty. Then in cellForRowAtIndexPath check if your data source is empty and if it is, create a custom cell that contains whatever you want. In heightForRowAtIndexPath you need to return your custom cell height if your datasource is empty, but only if you want the cell larger than the default. At least that is how I would approach it.
when bookmarks count is nil add one to your row method:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
int c;
c = bookmarks.count;
if(c == 0){
c = 1;
}
return c;
}
and then the same check again in your cellforrowatindexpath.
Another thing to be aware of in this situation is that if you're using core data and you're datasource is feeding off an entity, you will want to make sure your model matches. You can get some weird side-effect behavior in certain situations. This is especially true if you allow editing and core data has an empty model but you're tableview is still showing a cell.
My application is looking like the below image
I have 3 buttons in my segmented control. Assume that hitting the "Department" button will display 3 departments & hitting "Name" button will show 6 names.
I follow the below steps to make this..
Create UISegmentedControl by this code
segmentedControl = [[UISegmentedControl alloc] initWithItems:[NSArray arrayWithObjects:#"Department", #"Name", #"ID",nil]]; //Initialize Segmented Control
segmentedControl.segmentedControlStyle = UISegmentedControlStyleBar; //Define bar type (optional)
segmentedControl.selectedSegmentIndex = 0; //Define default clicked button
[segmentedControl addTarget:self action:#selector(segmentClicked) forControlEvents:UIControlEventValueChanged]; //Set target and define which method should called when tapping buttons
self.navigationItem.titleView = segmentedControl; //To add UISegmented Control in the title of the navigation bar
Define the method(segmentClicked) for UISegmented Control
segment = segmentedControl.selectedSegmentIndex;
if (segment==0) {
//Do something for Department tab
[self.tableView reloadData];
}
else if (segment==1) {
//Do something for Name tab
[self.tableView reloadData];
}
else {
//Do something for ID tab
[self.tableView reloadData];
}
Create the cells with reference to the value of segment in tableView: cellForRowAtIndexPath: method. (So that we can get various cells for each UISegmentedControl buttons)
if (segment == 0) {
cell.textLabel.text = [listOfDepartments objectAtIndex:indexPath.section]; //listOfDepartments is the NSMutableArray that contains list of Departments names
}
else if (segment == 1) {
cell.textLabel.text = [listOfNames objectAtIndex:indexPath.section]; //listOfNames is the NSMutableArray that contains list of person names
}
else {
cell.textLabel.text = [listOfIDs objectAtIndex:indexPath.section]; //listOfIDs is the NSMutableArray that contains list of person ID's
}
return cell;
So, finally i got the view showed in the above image.
When i press on the UISegmentedControl buttons, the table view reloads its cells & showing corresponding values perfectly. By default, the "Department" button was selected. If i tap the "Name" button(that is, table will show 6 cells instead of 3), The table changes immediately without any animations. It simply hide 3 cells of department names and showing 6 cells that displaying names of persons without any animations. I could not find a way to making the cell changes with smooth animations.
What should i implement to achieve the smooth animations?
Thanks in Advance
Use insertRowsAtIndexPaths:withRowAnimation: and deleteRowsAtIndexPaths:withRowAnimation: methods which has options for specifying some build-in cool animations.
typedef enum {
UITableViewRowAnimationFade,
UITableViewRowAnimationRight,
UITableViewRowAnimationLeft,
UITableViewRowAnimationTop,
UITableViewRowAnimationBottom,
UITableViewRowAnimationNone,
UITableViewRowAnimationMiddle,
} UITableViewRowAnimation;
It may help to try:
[self.tableView beginUpdates];
[self.tableView endUpdates];
in your segmentClicked method, instead of [self.tableView reloadData];
These methods sometimes animate table changes better.
Use the method reloadSections: withRowAnimation:
If you are having only one section then pass [NSIndexSet indexSetWithIndex:0] as a first argument in above method. In the second argument you can choose the animation type.
I have a tableview which is being reloaded as new content is added, using [tableview reloadData];
Trouble is I have a UILongPressGestureRecognizer on the TableCells in the Table and because the cells / table are being reloaded quite often the LongPress doesnt always have time to work as, I'm guessing it's internal timers are being reset when the cell/table is being reloaded.
Have you tried looking at the state of your UILongPressGestureRecognizers before [tableView reloadData] is called? For example:
// Returns |YES| if a gesture recognizer began detecting a long tap gesture
- (BOOL)longTapPossible {
BOOL possible = NO;
UIGestureRecognizer *gestureRecognizer = nil;
NSArray *visibleIndexPaths = [tableView indexPathsForVisibleRows];
for (NSIndexPath *indexPath in visibleIndexPaths) {
// I suppose you have only one UILongPressGestureRecognizer per cell
gestureRecognizer = [[tableView cellForRowAtIndexPath:indexPath] gestureRecognizers]
lastObject];
possible = (gestureRecognizer.state == UIGestureRecognizerStateBegan ||
gestureRecognizer.state == UIGestureRecognizerStateChanged);
if (possible) {
break;
}
}
return possible;
}
// ... later, where you reload the tableView:
if ([self longTapPossible] == NO) {
[tableView reloadData];
}
Let me know if it works!
Don't use reloadData if you want existing cells to remain. Instead, when you get new data, use the methods for Inserting and Deleting Cells to inform the table view exactly which cells have changed. The general procedure is:
You get new data.
Call beginUpdates
Call deleteRowsAtIndexPaths:withRowAnimation: to remove cells for any old items that have been deleted in the new data.
Call insertRowsAtIndexPaths:withRowAnimation: to add new cells for any items that have been added in the new data.
If you need to selectively replace a particular cell for some reason (and can't just update the existing cell's subviews with the new data), use reloadRowsAtIndexPaths:withRowAnimation:.
Call commitUpdates. At this point, your UITableViewDataSource methods must reflect the new data (e.g. tableView:numberOfRowsInSection: should reflect the changed count, and tableView:cellForRowAtIndexPath: should use the new items).
The table view will now call your data source methods as needed to update the display. Existing rows will not be changed.
Set a BOOL like aCellIsSelected to YES when you touch the cell
and just reload tableview if aCellIsSelected is NO
In my application I'm doing dynamic resizing of cells and label in it depending upon the text in it.
I'm adding button to cells in uitableview.
I'm taking the label instance and button instance in a new label and button variable respectively and setting their frames to arrange them properly after resizing.
if(cel==nil)
{
//some code
original_label=[[UILabel alloc]init];
original_label.tag=111;
//SOME MORE CODE GOES HERE
original_button=[[UIButton alloc]init];
original_button.tag=222;
//SOME MORE CODE GOES HERE
}
new_label=(UILabel *) [cell viewWithTag:111]; //This' how I'm taking the label instance on cell and below button instance on cell in new variables
new_button = (UIButton * ) [cell viewWithTag:222];
Earlier I kept the tags of all the buttons on cells same, so it was easier to get button instances on cells properly and were being arranged properly. But now I want to recognize these buttons separately as I'm adding some functionality on button_click. I'm giving the buttons that are added to the cells incremental tags[1,2,3...9 and so on]. Now, how can I take these button tags in some range like[suppose 1-9]?
Can anybody help?
Thanks in advance.
You can keep the button tags the same as you had before.
Instead, in the button_click method, figure out which row the button is in like this:
- (void)button_click:(UIButton *)button
{
UITableViewCell *cell = (UITableViewCell *)[[button superview] superview];
NSIndexPath *indexPath = [tableView indexPathForCell:cell];
//code to handle this indexPath.section and indexPath.row...
}
This assumes you have added the button to cell.contentView which is what the first superview gets. The second superview gets the cell.
The addTarget for the button should look like this (note colon after button_click):
[original_button addTarget:self action:#selector(button_click:) forControlEvents:UIControlEventTouchUpInside];
I have a UITableView that has a disclosure button on every row. When the table is put into edit mode and the the Deletion control is pressed ("-" sign), the Delete Button shows, however the disclosure button is not replaced, but instead just slides to the left of the delete button.
The apple UITableView guide explains the delegates for everything it seems except for the delegate that is called when the "-" sign is pressed, but before the delete button is displayed.
I would just like to suppress the disclosure indicator while the delete button is shown.
I'm guessing that I am missing something... I have set the setHidesAccessoryWhenEditing:NO
on the cells of the table so that the indicator is displayed to indicate to the user that if they select the row, they can edit it...
The behavior I am trying to copy is done in the contacts app when a contact is edited. Any help would be greatly appreciated...
Thanks, Greg
The standard way to do this is to use cell.hidesAccessoryWhenEditing = YES, and that editing is a modal action in which navigation is typically disabled.
The Contacts application actually uses custom table cells, and I wouldn't be surprised if it didn't so much use an accessory as have an image located on the cell's right edge, judging by its behaviour.
If you want to know when the delete button appears, I'd suggest that you try installing a Key-Value observer on the cell's showingDeleteConfirmation property, like so:
[cell addObserver: self forKeyPath: #"showingDeleteConfirmation"
options: NSKeyValueObservingOptionNew context: NULL];
Then you implement the observer callback method:
- (void)observeValueForKeyPath: (NSString *) keyPath ofObject: (id) object
change: (NSDictionary *) change context: (void *) context
{
if ( [keyPath isEqualToString: #"showingDeleteConfirmation"] )
{
UITableViewCell * cell = (UITableViewCell *) object;
BOOL isShowing = [[change objectForKey: NSKeyValueChangeNewKey] boolValue];
if ( isShowing == NO )
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
else
cell.accessoryType = UITableViewCellAccessoryNone;
}
}
I should note that I'm not sure whether the UITableViewCell class is KVO-compliant for this property, but it's got to be worth a try…
Or when you are creating your cell you can define the accessory type: cell.editingAccessoryType = UITableViewCellAccessoryNone;
The disclosure indicator is managed by tableView:accessoryTypeForRowWithIndexPath: so maybe you could change the accessory type while in editing mode.
I believe there's a tableView:accessoryButtonTappedForRowWithIndexPath:, maybe there you can note that you're going to edit mode and then change what the tableView:accessoryTypeForRowWithIndexPath: returns for each row - no accessory when in edit mode.
I would give it a try.
Here is a calling sequence (not sure if that helps) description/tutorial/examples from Apple reference about how to go about Inserting and Deleting Rows in Editing Mode.
My comment to Jim's solution didn't come across very well... Here is the version that solved the problem for me... Thanks again Jim!
- (void)observeValueForKeyPath: (NSString *) keyPath ofObject: (id) object
change: (NSDictionary *) change context: (void *) context
{
UITableViewCell * cell = object;
if ( [keyPath isEqualToString: #"showingDeleteConfirmation"] )
{
BOOL isShowing = [[change objectForKey: NSKeyValueChangeNewKey] boolValue];
if ( !isShowing )
{
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
}
else
{
cell.accessoryType = UITableViewCellAccessoryNone;
}
}
}