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];
Related
I have a view which shows a list of entries in a UITableView. The data for the list is an NSArray. When the user is on this view, there is an asynchronous call to a webservice to retrieve the latest entries. When I have downloaded the latest entries, I update the NSArray and then I send off a notification to the notification center. The UITableView is listening to this event and will try to reload the table.
But with this approach I get an error which is on the lines of "The object was mutated during reading".
After going through similar questions here on SO, I see the suggested approach is to remove objects and add objects at individual indexes and ask the table view to reload the data.
Is there a way to replace the array completely and ask the table view to reload the data ?
UITableView's reloadData method should do the trick.
From Apple's documentation:
Call this 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. 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
https://developer.apple.com/library/prerelease/ios/documentation/UIKit/Reference/UITableView_Class/index.html#//apple_ref/occ/instm/UITableView/reloadData
if you have Updated NSArray Object
Then you can use directly following method of UITableView
[tableView reloadData]
I have a tab bar application that displays tableviews in two of the tabs. The tableviews are populated using NSFileManager to read the contents of a plist file stored with user data. One of the tabs displays the "complete" items, the other tab displays the "Incomplete" items. As the user selects a row, a page with the details of the item selected is displayed. In the incomplete table there is a button the user can press to move these details from the "Incomplete" table to a "Completed" table. The plist is then updated using NSFileManager to change a field detailing if the item is in the complete or the incomplete list for this item.
The problem I have is that the changes are not updated on the two tables just by selecting between the two tabs. The user has to quit the application and start it up again to see the item moved from one table to the other.
The data seems to be updated its just the view that doesn't update.
I'm new to cocoa so any help at all would be greatly appreciated.
As you haven't provided the code, so i cannot tell where exactly you should reload your tableview.
You have to call
[self.tableView reloadData];
just after you are finished using NSFileManager to save your data in the plist.
Table views are not updating because you are probably not calling [self.tableview reloadData]; when you call reloadData for a tableview it should update the tableviews.
Since you are using tab bar controllers when each view is pushed to the stack it stays there you need to detect if view is appear again and call reloadData method.
in completed.m add this:
-(void) viewWillAppear:(BOOL)animated{
[self.tableview reloadData];
}
in incomplete.m detect if NSFileManager is saved data then call [self.tableview reloadData];
there are also other ways to solve this problem, you can communicate between viewcontrollers via Delegate or NSNotifications pattern. So lets say you saved the data you call your delegate or NSNotification method and receiver view controller runs your desired method. In your case refreshes the tableview
How do I set up a simple delegate to communicate between two view controllers?
http://mobile.tutsplus.com/tutorials/iphone/ios-sdk_nsnotificationcenter/
I have a UI table view loading data from network. If the user move the finger on one cell, one button will be displayed, just like iPhone style delete button. If the user click this button, the value of one label in the cell will be changed accordingly. However, I didn't find any way to make table view to re-draw this cell, except for reload the whole table. I don't want to use reload data method, because I just need change the value in one cell instead of the whole table. Any suggestion on this?
Take a look at the method
- (void)reloadRowsAtIndexPaths:(NSArray *)indexPaths withRowAnimation:(UITableViewRowAnimation)animation
Calling this method will result in your table view's data source asking its delegate for information about that cell.
For future reference, I found this very easily by checking the documentation on UITableView. I suggest you do that in the future before posting here.
I want to edit UITableView by calling EditTable method on a button click of some other class. In other words, I want to delete rows from UITableview from some other viewcontroller without navigating to that UITableView.
Please tell me the way to achieve this or any sample code for it.
If you want to delete rows from a tableview you just need to delete the corresponding rows from the datasource. When the table is next shown it should know how to reload it's data so the changes in the datasource are applied to the table.
Edit
You shouldn't rely on sending messages to view controllers that are deeper in the stack because they may have been unloaded already.
In my application, I have a UITableView with a few rows (let's call it TV1), now, at the bottom of these rows is a row that drills down into another (TV2). This new TV2 asks you which type of data you would like to add to the first view. Then, when the user selects which kind, they're brought to another view, in which they fill in some fields, the data is saved, and they're sent back to TV1, however, the data they entered, isn't loaded and I'm not really sure how to do this. Any ideas?
Maybe you did this already, but how about using [TV1 reloadData];? This forces the entire table to reload, yet there are also more specific methods for reloading just the cells that have been altered. See also the documentation: UITableView
Reload your table view by calling [self.tableView reloadData] in the viewcontroller's viewWillAppear: method. It will be called when the user switches back to your view. Right before it is actually put on screen.