Here is my program. I want to create a simple list of items that display a number. When the rows are tapped the number will increment by one.
EDIT: Is it proper to change the UI of a row in the didSelectRowAtIndexPath function?
I created a UIViewController in Xcode 5 through a storyboard and it does everything right except I can't seem to stop the [tableView reloadData] from deselecting my row after being tapped. Specifically, I want the row to turn gray and then fade out normally.
I have tried selecting the row and then deselecting the row programatically after calling [tableView reloadData], but it doesn't work.
I know that if I was using UITableViewController that I could just call [self setClearsSelectionOnViewWillAppear:NO], but I'm not.
Is there a similar property I can set for UIViewController?
Here is the code:
[tableView beginUpdates];
[counts replaceObjectAtIndex: row withObject: [NSNumber numberWithInt:newCount]];
[tableView reloadData];
[tableView endUpdates];
I feel I may not be describing what is going on. I have a row that uses UITableViewCellStyle2, which displays a label to the left and right. On the right aligned text is a number that increments each time the row is tapped. Simply updating the data structure does not solve the problem. I need to update it visually. I don't need or want to replace the row, unless I have too. I just want to update the right-aligned text field AND keep the row from being deselected immediately without animation. I can do one or the other, but not both.
Is there a way to just update the right-aligned text field while still staying true to the MVC model?
Remove the [tableView reloadData]; from the code. It should not be called in the methods that insert or delete rows, especially within an animation block implemented with calls to beginUpdates and endUpdates .
Call reloadData method to reload all the data that is used to construct the table, including cells, section headers and footers, index arrays, and so on. For efficiency, the table view redisplays only those rows that are visible. It adjusts offsets if the table shrinks as a result of the reload. The table view's delegate or data source calls this method when it wants the table view to completely reload its data.
[tableView beginUpdates];
[counts replaceObjectAtIndex: row withObject: [NSNumber numberWithInt:newCount]];
[tableView endUpdates];
See the developer.apple section - reloadData
If you want to keep the selection after reload, the easy way is
NSIndexPath *selectedRowIndexPath = [tableView indexPathForSelectedRow];
[tableView reloadData];
[tableView selectRowAtIndexPath:selectedRowIndexPath animated:NO scrollPosition:UITableViewScrollPositionNone];
Related
I have UITableView with variable height custom cells and multiple sections which are not fixed, i am trying to implement load more functionality while user reach at first cell.
After fetching data i am arranging records into NSMutableArray which contains multi-dimensional array to store data section vice.
My problem is when i load more data i don't have idea about how many sections and how many rows in each section comes. So i can not add fix values to move my UITableView at particular position using methods like scrollToRowAtIndexPath or scrollRectToVisible
So every time after getting new record i called reloadData to update my number Of Sections and number Of Rows In Each Section, which also move control to first row of UITableView. I want to be present at current viewing cell not at first cell.
I have also tried answers at reloadData() of UITableView with Dynamic cell heights causes jumpy scrolling this question but that are not helping me.
Don't use reloadData if you want to stay at the same position. Use reloadRowsAtIndexPaths or insertRowsAtIndexPaths or reloadSections instead.
To refresh modified rows with animation:
[self.tableView beginUpdates];
[self.tableView reloadRowsAtIndexPaths:#[indexPathOfYourModifiedCell] withRowAnimation: UITableViewRowAnimationAutomatic];
[self.tableView endUpdates];
To add rows with animation (number of rows is automatically increased):
[self.tableView beginUpdates];
[self.tableView insertRowsAtIndexPaths:#[indexPathOfYourNewCell] withRowAnimation: UITableViewRowAnimationAutomatic];
[self.tableView endUpdates];
Without animation (untested):
[UIView performWithoutAnimation:^{
[self.tableView beginUpdates];
[self.tableView insertRowsAtIndexPaths:#[indexPathOfYourNewCell] withRowAnimation:UITableViewRowAnimationNone];
[self.tableView endUpdates];
}];
Apple documentation: description here
I have set up my table view with 6 static cells and I'm trying to have one cell (the third cell) expand upon selection. The problem is, it resizes after calling reloadRowsAtIndexPaths:, but then the cell appears blank. If I scroll the cell out of view, it shows the contents properly.
When I call [tableView reloadData] the cell isn't blank, but then, I can't enjoy the animation.
Does anyone know why this is so?
Well if you set the height for a row then you need to reload the content of the cell NOT the content of the whole table. If you call [tableview reloadData] then it simply means that you redraw the whole table(without the height correction).
To reload a single cell in the table:
[tableView beginUpdates];
[tableView reloadRowsAtIndexPaths:indexPath] withRowAnimation:UITableViewRowAnimationNone];
[tableView endUpdates];
I don't know if I was the only one having the problem with a blank static cell issue.
I stumbled on a solution and that is calling [tableView reloadData] after calling reloadRowsAtIndexPaths:
Reload the respective table view row using the main thread.
[[NSOperationQueue mainQueue] addOperationWithBlock:^{
// Reload the respective table view row using the main thread.
[self.tblFiles reloadRowsAtIndexPaths:#[[NSIndexPath indexPathForRow:index inSection:0]]
withRowAnimation:UITableViewRowAnimationNone];
}];
I have a tableview with custom cells with dynamic cell heights depending on the cell content.
My problem is the following, when I ask, programmatically, in the viewDidLoad, to scroll to a given position it works, except for the last row. Sometime the row appears but not fully, and sometimes it even does not appear. In both cases I have to scroll manually to see the row.
Here is the code :
[self.tableView reloadData];
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:aRow inSection:aSection];
[self.tableView scrollToRowAtIndexPath:indexPath atScrollPosition:UITableViewScrollPositionTop animated:YES ];
Is this a bug of iOS ? any workaround ?
As so far i came to know that,
All the operations used to before the view is shown on the screen are initialized in the viewDidLoad all the UI objects, data objects can be allocated and initialized in this method.
All the operations data modifications, UI modifications made to view need to be done in viewDidAppear. Or even some operations can be done in viewWillAppear.
So for your issue, the UITableView scrolling must be done after the table is loaded on & shown on screen i.e., in viewDidAppear.
Also note that viewDidAppear & viewWillAppear will be called each time view is shown to user, so if you want to scroll the table only for the first instance you can have a flag in your header indicating the instance.
[self.tableView reloadData];
dispatch_async(dispatch_get_main_queue(), ^{
NSIndexPath *rowIndexPath = [NSIndexPath indexPathForRow:3 inSection:0];
[self.tableView scrollToRowAtIndexPath:rowIndexPath atScrollPosition:UITableViewScrollPositionMiddle animated:YES];
});
I don't know exactly why, but I guess this approach works because when we add(???) rows and call [tableView reloadData] tableView has no time to update some internal counters (like row counter) and calling [tableView scrollToRowAtIndexPath ...] has no effect since there is no such row at that time (again, probably correct in case you add rows or set tableView's data for the first time). Calling
dispatch_async(dispatch_get_main_queue(), ^{
...
});
after [tableView reloadData] gives tableView enough time to update row counter and perform scroll to existing row.
Vishy's approach works just because it gives enough time but applicable only if you need to scroll exactly one time when screen is loaded. Moreover it requires ugly flag to check every time viewDid/WillAppear.
Something weird is going on with my tableview when changing data. I have something like this:
// fadeout existing data
... // change data (new values for the cells are blank)
for{ // loop all rows
[TableView reloadRowsAtIndexPaths: withRowAnimation:]; // smooth fade out
}
// add one new row to the table
... // change data (just add one new row but leave the cells empty)
[TableView reloadData] // reload all of the data (new row should be added)
... // change data (just add values to the existing cells)
for{ // loop all rows
[TableView reloadRowsAtIndexPaths: withRowAnimation:]; // smooth fade in
}
In theory, at least what I think, this should work. But I had some glitches so I added NSLogs in the for loops and in the: - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath so I noticed that my [tableView reloadData] executes after the first row of fade in loop!##
I was thinking about making some kind of a delay between reloadData and fade in loop, but I don't want to force it to work, I want it to work properly.
Is there a better way to accomplish what I'm trying to do?
Can I dynamically add one row at the bottom of the table without calling the 'reloadData' method?
Thanks.
Yes, just use the tableView insertRowsAtIndexPaths method, which will then call your dataSource to load those new rows.
To load a single row at the end of your table, you'd first update your data source to include the new row, then generate the indexpath using:
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:[yourdata count]-1 inSection:0];
NSArray *indexPaths = [NSArray arrayWithObject:indexPath];
[tableView insertRowsAtIndexpaths:indexPaths withRowAnimation:whateveryouwant];
Remember, that will immediately call your tableView:cellForRowAtIndexPath method, so update your dataSource to include the extra row before inserting the new row into your table, and be careful that the row index in the indexPath you specify matches the newly added item in your data source.
Ok, I'm stuck. This is an extension of a previous post of mine. Here is what I am trying to do.
I have an Edit button on a navigation bar that when pressed adds a cell at the beginning of my one section table view. The purpose of this cell if to allow the use to add new data to the table; thus it's editing style is Insert. The remaining cells in the table are configured with an editing style of Delete.
Here is my setediting method:
- (IBAction) setEditing:(BOOL)isEditing animated:(BOOL)isAnimated
{
[super setEditing:isEditing animated:isAnimated];
// We have to pass this to tableView to put it into editing mode.
[self.tableView setEditing:isEditing animated:isAnimated];
// When editing is begun, we are adding and "add..." cell at row 0.
// When editing is complete, we need to remove the "add..." cell at row 0.
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
NSArray* path = [NSArray arrayWithObject:indexPath];
// fill paths of insertion rows here
[self.tableView beginUpdates];
if( isEditing )
[self.tableView insertRowsAtIndexPaths:path withRowAnimation:UITableViewRowAnimationBottom];
else
[self.tableView deleteRowsAtIndexPaths:path withRowAnimation:UITableViewRowAnimationBottom];
[self.tableView endUpdates];
// We nee to reload the table so that the existing table items will be properly
// indexed with the addition/removal of the the "add..." cell
[self.tableView reloadData];
}
I am accounting for this extra cell in my code, except I now have two index paths = [0,0] - the new cell and the old original first cell in the table. If I add a call to reload the table view cell in setEditing, the cells are re-indexed, but now my table view is no longer animated.
I want my cake and eat it too. Is there another way to accomplish what I am trying to do and maintain animation?
--John
You can do what you want but you need to keep your data source consistent with the table. In other words, When the table is reloaded, tableView:cellForRowAtIndexPath and the other UITableViewDataSource and UITableViewDelegate methods responsible for building the table should return the same cells depending on editing state that you are adding/removing in setEditing:antimated:.
So, when you insert/delete a cell in setEditing:animated: you need to also make sure your data source reflects the same change. This can be tricky if you are adding a special cell to the beginning of a section but the rest of the data is from an array. One way to do this is while reloading the table, if editing, make row 0 the add cell and use row-1 for your array index for subsequent cells. If you do that you'd also need to add one to tableView:numberOfRowsInSection: to account for the extra cell.
Another way would be to have a section for the add cell and it would have 0 rows when not editing, 1 row otherwise and you return the appropriate cell. This will also require you to configure your table and cell(s) appropriate depending on how you want things to look.