I have a tableview, where when the user selects the cell it will set the accessorytype to UITableViewCellAccessoryCheckmark.
Now when I navigate to the previous screen, then go forward to this tableview, my cells remains checked.
Is there a way to uncheck all of them? I guess basically set all of them to UITableViewCellAccessoryNone.
I tried using reloadData, when the view appear, but that doesn't seem to trigger the cellForRowAtIndexPath (this is where my logic is to set the accessorytype of the cells)
I think this may do what you want. I assume you want to uncheck all the cells as part of responding to tableView:didSelectRowAtIndexPath: but you could insert this code anywhere:
- (void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// Uncheck any visible, checked cells.
NSArray *visibleCells = [tableView visibleCells];
for (UITableViewCell *cell in visibleCells) {
[cell setAccessoryType:UITableViewCellAccessoryNone];
}
// Now do whatever else you want in response to a row being selected.
}
You should set the accessorytype in tableView:willDisplayCell:forRowAtIndexPath: instead of cellForRowAtIndexPath so that it is updated whenever it is displayed (and not just when created).
There is a tableview method called clearsselectiononviewwillappear that you might have accidentally overwritten. The default behavior should be YES. Check out Apple's doc
on UITab
Related
I have a list of custom cells in my tableview and as I scroll everything appears to fine and the cells appear to be in the same order. I have some functionality with my cells - as i select a cell (and it dynamically expands)the background color changes and a few other custom cell properties. Once I do this and then I start scrolling, different cells that i haven't even touched before show up, selected(expanded) and the cell only updates when I select it manually to the correct data. I seem to see duplicates and all kinds of craziness.
I know there are LOTS of posts about this on here so far but for me, so far nothing has worked. Would like some input on what I could do to stop this ridiculous behavior.
I have posted some code to give you a better idea of what I am doing. I know that 'dequeueReusableCellWithIdentifier' is the culprit but don't know of an alternative.
As side notes, this is a tableview(its own xib) that is a child view of a large view (also a xib). I have also already registered the nib for the tableview.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
MyCustomCell *cell = [tableView dequeueReusableCellWithIdentifier:myIndentifier forIndexPath:indexPath];
if(self.currentSelectedIndex){
if(self.previousSelectedIndex){
//collapse cell
//configure cell in method(change background color etc)
}
else{
//expand cell
//configure cell in method(change background color etc)
}
}
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
self.currentSelectedIndex = indexPath;
[tableView beginUpdates];
if(self.currentSelectedIndex){
if(self.previousSelectedIndex && (self.previousSelectedIndex != self.currentSelectedIndex)){
[tableView reloadRowsAtIndexPaths:#[self.currentSelectedIndex, self.previousSelectedIndex] withRowAnimation:UITableViewRowAnimationAutomatic];
}
else{
[tableView reloadRowsAtIndexPaths:#[self.currentSelectedIndex] withRowAnimation:UITableViewRowAnimationAutomatic];
}
}
[tableView endUpdates];
if(self.previousSelectedIndex == self.currentSelectedIndex){
self.previousSelectedIndex = nil;
}
else{
self.previousSelectedIndex = self.currentSelectedIndex;
}
}
What can I do or how would i make sure that nothing else in the list 'seems' to be selected(expanded) or prevent from appearing to see duplicates as i scroll? I already keep track of my current and last selected index(as shown in the code) so I suppose that I could use that somehow?
Dequeued Cells are Reused
Know that cells are re-used, so that the appearance of a UITableViewCell is persistent for the entire life of that cell.
This means that if you do not explicitly reset all the presentation view of your cell, and just returning it unchanged in cellForRowAtIndexPath, what you are returning may be a currently selected (or deselected) cached cell.
A possible location to reset a table cell is prepareForReuse.
Design note:
How are you maintaining self.currentSelectedIndex and self.previousSelectedIndex? This is typically quite dangerous, since you are attempting to replicate the UITableView behavior. It is for example, unlikely to work with multiple selection. Setting an active selection is unlikely handle situations when the OS didDeselectRowAtIndexPath, as a result of a keyboard dismissal for example.
Hello guys i think almost everyone who is in ios development may come across the issue of reuse of the UITableCell by using following code line.
RZRestaurantListingCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
I have search lot about this but not getting any desire answer so please help me out in this case.
I have the same issue as most of iPhone developer having after reusing the cell.
I have the UIProgressView inside my cell and one button is there for downloading the video and i am showing the progress there in progress view how much is left.
So Now what i have problem is when i have more data and going out of the screen at that time i am press the download button on very first row of the UITableviewCell then i am scrolling down so the progress also shown in bottom random one cell so the UI changes in two cell rather then one.
You need to implement -prepareForReuse method in your custom cell class and set all cell properties to default value.
- (void)prepareForReuse
If a UITableViewCell object is reusable—that is, it has a reuse
identifier—this method is invoked just before the object is returned
from the UITableView method dequeueReusableCellWithIdentifier:. For
performance reasons, you should only reset attributes of the cell that
are not related to content, for example, alpha, editing, and selection
state. The table view's delegate in tableView:cellForRowAtIndexPath:
should always reset all content when reusing a cell. If the cell
object does not have an associated reuse identifier, this method is
not called. If you override this method, you must be sure to invoke
the superclass implementation.
Refer here for more, https://developer.apple.com/library/ios/documentation/UIKit/Reference/UITableViewCell_Class/#//apple_ref/occ/instm/UITableViewCell/prepareForReuse
You need to assign a progress value inside the - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
RZRestaurantListingCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
// If the cell is reused, the `-prepareForReuse:` of `UITableViewCell` will be called.
//!! Assign current progress value to this cell, otherwise, the progressBar.value may look like a random value.
//!! Because the current cell is reused from a disappeared cell.
cell.progressBar.value = ... ;
return cell;
}
The design may be complex, because the progress may be updated continuously when the cell is on the screen.
Use prepareforreuse method to clear content of cell before using it... e.g.
-(void)prepareForReuse
{
[super prepareForReuse];
self.textLabel.text = #"";
self.detailTextLabel.text = #"";
self.imageView.image = nil;
}
I have a UITableView with Dynamic Prototypes.
I implemented the code below so that when I select a row, it will be marked and the previously selected row will be unmarked.
However, for example, the row I selected is displayed in the middle of the screen, then when I scroll up or down, another cell (which is in the same middle position of the screen) is marked. In short, every view, there is a selected cell at the middle.
Please advise.
- (NSIndexPath *)tableView:(UITableView *)tableView willSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NSIndexPath *oldIndexPath = [self.tableView indexPathForSelectedRow];
[self.tableView cellForRowAtIndexPath:oldIndexPath].accessoryType = UITableViewCellAccessoryNone;
[self.tableView cellForRowAtIndexPath:indexPath].accessoryType = UITableViewCellAccessoryCheckmark;
return indexPath;
}
Probably you are overwriting accessoryType in your cellForRowAtIndexPath method - this is called each time table is about to draw new rows which were invisible before (as you described when you scroll up / down).
You need to handle it also in that function and update accessoryType there - otherwise it will randomly reuse a cells with different accessoryTypes.
You are modifying just the visuals of cell, you're not updating the data model. Store the selected index path in a #property somewhere, and adjust accessoryType inside cellForRowAtIndexPath.
It's My first time to post a question, thank you for you all in advanced.
Now, i want to implement a default style grouped UITableView contains multiple group of data. for each row, there will be a detail Disclosure button as accessoryType icon. when people click on the disclosure button, i want the Cell expand with detail info for the selected row.
i was trying to fulfill this task by add a customized cell to selected row, however, it was very complex. So currently, i am trying to finish this task by reload a specific row with Customized cell xib. i knew there is a delegate method for reloadRowsAtIndexPaths. but can i use this to reload a specific cell? Thanks
please suggest!
Great Thanks
Have you tried something like this:
(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
if(indexPath.row == mySpecialSelectedCell)
{
//Load all your custom stuff here
}
else
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier: CellIdentifier];
}
if (cell == nil)
{
}
return cell;
}
You would have to get the cell's indexPath when you click the expand button.
Or you could look at this answer. And then, like the code above, just load that one cell that you have specified with that NIB and load the rest the way you would normally.
You can implement the tableview delegate methods to set the height for the cell which needs to expand. Add some condition check in heightForRow method and when user taps on button, change the condition to increase the height. When table is reloading it will call this method and will reload cell with bigger height.
How could I easily dim the complementary set of rows, when one gets selected.
Right now I have the code to select a cell so I can call a method on it, but I would like to set opacity of all the other rows.
-(void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
SummaryCell * selectedCell = [tableView cellForRowAtIndexPath:indexPath];
[selectedCell manageContent];
}
Edit: I dont want to iterate through all the other cells (because there will be a lot of them) - wouldn't it be easier to add an UIView above all other cell (this would also prevent user interaction) and place the selected cell above that view (something like increasing z-index in HTML).
It depends what you mean by "dim" the other rows. The process to iterate over all visible rows and to set a property on all the rows other than the one selected is as follows:-
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
for (UITableViewCell *otherCell in self.tableView.visibleCells) {
NSIndexPath *otherIndexPath = [self.tableView indexPathForCell:otherCell];
if (![indexPath isEqual:otherIndexPath]) { // exclude the selected cell
// Do whatever you want with otherCell here
}
}
}
Where my comment is, you can set whatever properties you like on otherCell. For example, otherCell.alpha which is the alpha (transparency) of that cell.
You can iterate all the visible cells, configure them to be dimmed, then on the datasource cellForIndex method check if there's a selected cell, if there is, check if it is at the asked index, if so configure the cell as selected, if not as dimmed.