I am trying to animate the reloading of a table view. Currently, I download the array of table view items and if the user reloads the table view manually, it downloads into a separate array, compares the current to the newly downloaded, and if they are different, it reloads the table view with the newly downloaded array. Is there an easy way to, somehow, compare the arrays and insert/delete rows (animated, of course) accordingly?
I found the Apple's Table View Programming Guide to be very useful for this question:
http://developer.apple.com/library/ios/#documentation/userexperience/conceptual/TableView_iPhone/ManageInsertDeleteRow/ManageInsertDeleteRow.html
If you are using arrays, you would need to deal with figuring out inserted/deleted rows. If you are dealing with a larget set of data, then you should consider using Core Data with NSFetchedResultsController. See documentation for NSFetchedResultsControllerDelegate for getting inserted/deleted rows.
Related
I'm completely new to swift and Xcode and everything regarding iOS development. I have a UITableView that populates UITableViewCells, I've been able to graps the fundamentals of that. But what if I wanted to add an extra cell at the bottom upon every visit?
I guess it's a mix of dynamic and static, but I can't find any answers whether this is case as of present date, since information in threads shows discrepancy.
You need to use dynamic table view. For example you have an array with some elements and your table view is displaying them. If you want to add a cell on the bottom, simply add another element to your array and then call self.tableView.reloadData()
I'm using xcode 7 swift 2
in my app extension(TodayWidget extension) i'v put 2 table views that store the calculating results.......
2 TableViews
and its work fine, even if i scroll TodayWidget/notification view UP and DOWN again the data is there
Data
BUT sometimes after i scroll TodayWidget/notification view UP and DOWN again all data is lost and reset values to 0 again !!???
how i can prevent that from happening .....!!!
The table view have to reset the data in table view cells automatically. that's how it works. while scrolling, as soon as the cell becomes invisible it will be taked to be reused for other indexpath.
To achieve what you want in quite simple. You just need to have a dataSource to save your data in so you will not lose it while scrolling.
If you share some of your code I'll be able to give you more details how to solve this problem.
I have a generic question about tableview Draw and reload data, and wanted some insight from this scenario. I have a tableView which get's lazily loaded getting the data parsed from a url. Now the concern is when i select a button and move to another view, I can deselect the object from there, which will remove it from the array. Thus, when I go back to the main view of the tableView, it download's the data again and check's if the object of the further view array is there or not, therefore it set it selected the button.
My concern is, when I go back, my previous selected button is highlighted, and then it does all the computation and de-selects it when the data gets loaded. Is there anyway, I can have the tableView redrawn until the data load's everytime?
Thanks.
It Looks like that when you are downloading the data & parsing the downloaded data, you are directly passing the modified variable as a source for the tableview. Instead of it, You may store the source for the tableview into another array, which will get updated from source array if it is downloaded & parsed.
Load the tableview using the secondary array.
This is my understanding. If your problem is not resolved , please provide some piece of code for the problem.
BTW, your problem can be resolved using the above solution.
In my app I have a detail screen for Product objects. The UI calls for the product details to be displayed using a grouped table view type interface with 3 sections.
Some of the cells in this table are conditional. For instance, by default the third section should display a single cell that says "Register Product" and should push the registration view when tapped. If the product is already registered then the third section should instead display two cells one for Warranty and one for Servicing Information. These would each go to different screens when tapped. Also, they both need to display some kind of data on the table cell. The warranty cell says when the warranty expires and the Servicing cell says when the next servicing is due.
QUESTION (finnally): What's the best way to define the cells and sections that the table should have in any given situation. Primarily I'm looking for a maintainable way to do this since I already have some ideas about un-maintainable ways to do it.
Should I create some sort of keyed dictionary and add/remove items from it during viewWillAppear based on the Product being displayed? I'm worried the number Switch statements that I would have to use throughout the various tableView events to check what type of cell is at a given index path.
Any ideas?
Have a look at Matt Gallagher's Tableview Classes. They provide a simple and extensible framework for customizable Tableviews. Cells can be loaded from a NIB or constructed in code. There's a simple interface to provide the data for each cell (- (void)configureForData:(id)dataObject).
Populating the Tableview is easy:
[self addSectionAtIndex:0 withAnimation:UITableViewRowAnimationNone];
[self appendRowToSection:0
cellClass:[NibLoadedCell class]
cellData:#"This is row 0"
withAnimation:UITableViewRowAnimationLeft];
For persistent storage of the data I recommend to create a plist dictionary and load/save data from there. See Property List Programming Guide. For complex database structures use core data for storage.
I am new to iphone Development. I am parsing XML into a mutable array of strings which displays dynamically in a table. I am not able so see the content in the table but as soon as I scroll down the contents are displayed. Please help me out.Thanks
Can't say for certain without seeing the code but it sounds like – tableView:cellForRowAtIndexPath: returns empty cells at first. Most likely it does so because your datasource, in this case the xml parser, has not yet provided data for the cells when the table first loads.
The table only populates the visible rows and then stops. It only fetches more data when you scroll and new cells become visible. In your case, it sounds like the table has no data when it first loads but in the time it takes you to manually scroll it, it has found the data.
You probably need to call reload on the table to force it load the data. Even better, you should alter your design to make sure it has some data to display before the table itself loads. If that is not possible, you should have some placeholder information in the cells e.g. text that says "Loading Data..." and then call reload.
The problem is that when you finish parsing your XML file, you don't reload your table that is already visible.
You have to use something like [myTableView reloadData]; right after finish parsing the XML file.
Cheers,
VFN