I'm using a PFQueryTableViewController from Parse.
I'm using a segmented control to retrieve two types of items from the database. Depending on which segmented button is selected, it retrieves one type or the other and reloads the same tableView. The problem is that when I am loading one type and then I switch to the other while the first is still loading, the tableView populates with items of the first type. Any way to cancel a tableView data retrieval?
The PFQueryTableViewController's data retrieval is handled by overriding queryForTable, you should be able to call cancel just as you would on any other query.
Alternatively, it is very easy to build your own table view controller which populates it's data source using Parse. Using this, you could maintain two separate query result containers to avoid conflicts between the two segments.
Here's another post which will show you how you could go about creating your own table view controller.
Related
So I want users to be able to enter a search query, and should it return an empty or non-empty result the appropriate view is displayed (shown below):
As I'm fairly new to iOS I thought about the following possible ways of implementing this. I'm not sure if any one of these is deemed as good practice or maybe another better solution exists:
Create two separate view controllers with their own views that will display a message for empty search results or show non-empty results respectively
Create a single view that will house all of the components and show/hide certain components based on whether or not the results are empty/non-empty
Create a single view, but programmatically implement the methods for drawing the relevant components and just initialise the VC with the respective designated initializer (one for empty and the other for non-empty results)
The best practice is to manage the empty state of tableview meaning have a single tableview and display data when available, if no data is available display a friendly message in the tableview itself.
Below is the link that will help you implement the code:
http://www.ryanwright.me/cookbook/ios/objc/uitableview/empy-table-message
There are ots of examples available on net for managing the empty state of tableview.
I have an array of users
var selectedUsers = [User]()
users are added to this array as they are selected in a UITableView (see screenshot: https://www.dropbox.com/s/uk03mhgi3x4jesy/File%2006-10-2015%2C%2018%2003%2044.png?dl=0)
What I'm having difficulty with is when I press back and then reload the view controller, all the checkmarks disappear.
Is there anyway I can keep track of the selected cells?
Thanks in advance
You could use a delegate to pass a array between the two viewcontrollers. For example, each time you select a row, you can store the userId's associated with the row, in the array. So if you were to press back and then open the view with the UITableView, before you load the UITableView, you can first check if there is an array being passed to the viewcontroller containing the UITableView / if there is an array, check if the count is greater than 0. If the array is not empty, then use a for loop to cycle through the array of users being displayed with the array being passed containing all of the previously selected id's, then add the check marks that match up to the Id's in the array.
Here is a tutorial that possesses a similar example: http://makeapppie.com/2014/08/04/the-swift-swift-tutorial-why-do-we-need-delegates/
The answer to this question is kinda dependent on what you want the application to do... Do you want the User selections to persist even if the app is closed? If so consider using NSUserDefaults or CoreData. Otherwise store the data somewhere that does not get blown away (maybe the root view controller of your application). You could for instance implement the delegate pattern on the view controller with the table view and pass the values to the container view controller.. Just some ideas.
So you can use class NSUserDefaults to save small amount of data. If you want to have persistent store so you have to use Core Data that helps you store you data with scheme you provide.
If you just want to pass data from one view controller to another view controller so you just need use delegation pattern or you can use method prepareForSegue where you can pass some data as well but you can't store this way, just pass.
If you make your question more detailed you will get more explicit answer.
I want to create one application that read many data from json and show them in tableview.
I want to create one button that when to click on it this page for a second time to be refresh and take data from json (check json again and if this json changed tableview also changed)
I dont know how create this function that refresh this page and run code at first.
please tell me about it.
[self.tableView reloadData]
to load more data from webserver in to table
Put a button in header of section. I think that is the best place. In target method of that button call json and download all data. then call [self.tableView reloadData]. It will call all table methods like number of row , sections, cellForRow.
Why don't you use the Default RefreshControl provided in iPhoneSDK.
A UIRefreshControl object provides a standard control that can be used to initiate the refreshing of a table view’s contents. You link a refresh control to a table through an associated table view controller object. The table view controller handles the work of adding the control to the table’s visual appearance and managing the display of that control in response to appropriate user gestures.
Check this to learn about its implementation : Working with UIRefreshControl
You can place a UIToolBar above the tableview. In that you can have a barbutton, to which you could give an action to fetch the data again. Once the data fetch is done, call
[self.tableview reloadData];
I am trying to create an application with multiple table views that uses and implements Core Data. I would like the user to be able to select cells in one table and move them to another (like in Apple's mail application) using either a check accessory or a selectedCell method with an action sheet. I'm stuck because I don't know if you are actually moving the cell to another table or if you are adding a copy to the new table and deleting the original. Basically, I'm asking for a basic example of cell movement to give me a push in the right direction.
You won't be moving cells. The model for a table view is an array. Move things between the arrays and tell the tables that their model has changed.
id somePartOfMyModel = [self.arrayA objectAtIndex:someIndexPath.row];
[self.arrayA removeObject:somePartOfMyModel];
[self.arrayB addObject:somePartOfMyModel];
// the simplest, non-animated way to update the tables.
// I'd advise getting this working first, then later trying fancier UI to indicate changes
[self.tableViewA reloadData];
[self.tableViewB reloadData];
You would not be technically moving the cell to the other table. The way I would go about doing this would be to pass the NSManagedObjectContextID of the item between the tables, depending on how large your entities are and if the tables are in the same view controller.
I am looking for a sample code, showing what is the best way to populate an UITableView with the response of JSON data. Let me explain in details.
The situation is the following:
When I navigate to the current view controller(the one with the table view), I send a request to my server in order to send me a JSON response. Meanwhile, I display an Activity indicator in foreground, showing the user that an activity is loading. When the response arrives, I need to parse it, store it with Core Data and then populate my Table View with the data.
My question is:
What is the best practice, best way to populate the table view? Should I grab the whole data that I need and use a NSArray while populating the table view? Or may be use NSFetchedResultsController for this purpose? How should I reload the table view? Is [self.tableView reloadData] good enough for my purpose?
I hope I was clear enough with my question(s) :) Thanks in advance
If the view controller always needs to call out to the server on every view, you can simply retain the response dictionary (or convert it to your own plain objects and retain an array of those) and bind the tableview in the afnetworking callback.
If you do not always need to call it, you could save the objects to core data on call back then create your retained NSFetchedResultsController and set the delegate on it (just in case the data gets modified/altered elsewhere).