I am working on an iPad app with a split view controller. I have a stock standard UITableView as the master view.
When the view opens, I would like it to select the first row in the list.
In ViewDidLoad I have:
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
[self.tableView selectRowAtIndexPath:indexPath animated:NO scrollPosition:UITableViewScrollPositionNone];
When I run the app in the simulator it seems to select the first row (flashes) but then it is no longer selected. It is like something is clearing the selection after the ViewDidLoad method. I can touch and select rows just fine. Is there a property on the row or the prototype cell I need to set for this to work correctly?
Thanks in advance,
Richard
Try doing that in the viewDidAppear instead of viewDidLoad.
Edit:
Just one thing Richard, this works because when you actually enter in the viewDidAppear your UITableView has been fully reloaded. In case it hasn't, it wouldn't work. You can actually do something like this, which I recommend (check the comment from Eric Morand).
Related
I had an application in which i want to scrolltoindexpath to a particular section. I am doing like this
[table scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:anIndex] atScrollPosition:UITableViewScrollPositionTop animated:NO];
[table reloadData];
all working fine.but here the issue is tableview always kept to the bottom .
it won't scroll up after that.it will always keeping the last cell to the bottom.not scrolling up after that.I set the constraints as (0,0,0,0).
I think i miss something here .Can anybody guide me on this?
There are mainly 2 issues here.
1)
[table scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:anIndex] atScrollPosition:UITableViewScrollPositionTop animated:NO];
With animated false, you have to forcefully call dispatch_get_main_queue() even if it's running on main thread. This is supposedly an iOS bug.
2) When you are trying to scroll the tableView, it calls cellForRowAtIndexPath for the available cells. However the immediate next line is calling reloadData which tries to call the same dataSource method. So it might be conflicting with others. So I would recommend adding a small delay for [table reloadData];
My current set up is the following:
Root Tab Bar:
Collection view with magazines
Bookmarks (with a table view)
Others
You can add a bookmark from a magazine in the collection view and also remove it from there.
The behaviour I'm seeing is the following:
I start the application, the table view queries the number of sections, number of cells, but not the cellForRowAtIndexPath. I could understand why, as there is no cell in the active view, so no data should be loaded.
When I add a bookmark from the collection view, it adds it to the array (via a notification) and requests the tableview to be reloaded. As there isn't an initial entry, it goes through the motions described above. When I press it again to remove the bookmark the entry is removed from the array. This is where it gets interesting because the first thing the table calls is not the number of sections or rows but the cellForRowAtIndexPath. As the array is empty, the application crashes on a request for data on index 0.
My question is why does the cell creation get called in that order? Is there any way to avoid it?
If you changed the section, try calling - (void)reloadSections:(NSIndexSet *)sections before you call reloadData
https://developer.apple.com/library/ios/DOCUMENTATION/UIKit/Reference/UICollectionView_class/index.html#//apple_ref/occ/instm/UICollectionView/reloadSections:
[self.tableView reloadSections:[NSIndexSet indexSetWithIndex:0] withRowAnimation:UITableViewRowAnimationLeft];
The reason this was happening is because I was attempting to change something about the table before I reloaded the data.
[self.tableView setSeparatorStyle: !_helpText.hidden ? UITableViewCellSeparatorStyleNone : UITableViewCellSeparatorStyleSingleLine];
[self.tableView reloadData];
That was for removing the lines so a message can be displayed. However that update was using old data as reloadData had not been called.
[self.tableView reloadData];
[self.tableView setSeparatorStyle: !_helpText.hidden ? UITableViewCellSeparatorStyleNone : UITableViewCellSeparatorStyleSingleLine];
Reversing them fixed the issue.
I have a problem that is driving me crazy.
I have an UITableView that is always in editing mode (it has to be).
The user can add new rows to it.
The navigationItem.leftbarButton of the tableViewController pushes a new controller just to do it, let's call it "newRowsVC".
Before the push the tableViewController set itself as the delegate of the newRowsVC, the protocol has only a method:
-(void) aNewRowHasBeenCreated
{
[self.tableView reloadData];
}
I start adding rows and everything works fine, each now row is immediately displayed in the tableViewController until the last new row will force the tableView to scroll because there won't be anymore screen real estate for it. Here, I have no idea why, the tableView, only it, is as frozen, with no scrollbar and doesn't respond to input. The app continues to run without a crash and I can even dismiss the tableViewController by tapping the navigationItem.rightbarButtonItem.
I can keep creating new rows, they are added to the array, the number of row in the tableView data source is computed correctly. But the table is like dead.
If I dismiss the tableViewController and then I come back to it, I see that all the rows previously created, also the ones not shown as soon as they were created are there!
I really do not have idea of how I can fix this.
The first thing I tried was to force the scroll after the reload of the table but it didn't fix it.
-(void) aNewRowHasBeenCreated
{
[self.tableView reloadData];
[self.tableView setScrollEnabled:YES];
}
I also tried forcing the tableView to scroll to the last row but it didn't fix it.
-(void) aNewRowHasBeenCreated
{
[self.tableView reloadData];
[self.tableView setScrollEnabled: YES];
[self.tableView scrollToRowAtIndexPosition: [self.tableView indexPathsForVisibleRows]last object] atScrollPosition: UITableViewScrollPositionBottom animated:YES];
}
I check the number of rows each time the table is reloaded. No error, the number is perfect and the new rows data are correctly in the array, also the data for the cells not shown.
I thought it could be because the tableView is always in editing mode so I tried setting it to NO but nothing changes, id din't fix the problem.
Two notes:
1)the tableView has to be the delegate of each one of it's custom cells. They have an UITextField and an UIStepper, handled by the tableViewController. I already tried to not set the tableViewController as the delegate of its custom cells but nothing changes so the problem is not this.
2) self.tableView.bounces = NO but this has nothing to do with the scrolling issue, the scroll is enabled.
Update: After more tests I found that if I remove the dequeue of the reusable custom cell everything works fine, so the problem should be about the reuse.
static NSString *CellIdentifier=#"MyCell"
CustomCell *cell = [tableView dequeueReusableCellWithIdentifier: CellIdentifier];
Nicola
After hours I got it. As pointed out by Amit the problem was hidden in cellForRowAtIndexPath... It was hard to catch because it didn't happened all the times and the first times I enabled/disabled the cell reusing everything seemed the same so I did not link the problem to it. I got back on it after I tried about all the other options I had been able to think about.
The problem was in the reuse of the cells and the fact that the custom cell has the tableView as its delegate to handle its textView and the stepper without exposing them.
I got rid of all the delagion stuff and exposed the textView and the stepper as public properties of the view. By doing this I was able to set the tableViewController directly to be the delegate of the cell.textView and to add directly a target/action for the stepper.
Everything works flawslessly now.
Thanks to everyone who tried to help me!
Nicola
I got an app with a UITTableView. This table is updatable. And when in the next update the number of rows are less than in previous version, i implement the UITableView's method - deleteRowsAtIndexPaths.
I do it in this way:
[table beginUpdates];
[table deleteRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationNone];
[table reloadRowsAtIndexPaths:indexPathsReload withRowAnimation:UITableViewRowAnimationNone];
[table endUpdates];
But when i implement this code there are animations. And this animation is really bad. A lot of black leaks. But i did write - withRowAnimation:UITableViewRowAnimationNone in both methods: delete and reload.
Why? How can i reload and delete rows without animation?
Usually the way this is done is by modifying the data source of the table, and calling reloadData on the table.
maybe you try to work with NSMutableArray (delete row by removeObjectAtIndex:indexPath.row) in TableView and reload the whole tableview by using [tableView reloadData] ?
You can try to make that "gesture" out of the table,and try reload table
Unlike what the name suggests *UITableViewRowAnimationNone* doesn't help at all.
Maybe setting the alpha on the cell works as suggested here. Not sure though.
problems with animation when deleting the last row of a TableView in ios7
I currently set the selected row of a UITable via
selectRowAtIndexPath:animated:scrollPosition:
and as described in the documentation, this does not call
tableView:didSelectRowAtIndexPath:
so I have set up a selector call to perform this action.
However, the end result is that the row in the table is highlighted, but not selected. When I touch the highlighted row, the font color changes to white.
Is there a way to not only highlight, but also have the row "selected" so tapping that row again does not result in any changes or updates?
Try calling didSelectRowAtIndexPath directly and then scrolling to it. I have this in a UITableViewController and it works fine (and the selection event does not fire again when you tap on it, I just tested it). I'm wondering if there is some other code messing you up.
[self tableView:self.tableView didSelectRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:0]];