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Passing data between view controllers
(45 answers)
Closed 8 years ago.
I have two view controllers.
First one is Custom view controller that loads the images from asset library.
Second view controller shows the full size of selected image with cancel & Delete button
I have used the below code for delete the selected image from custom view controller.
customviewcontroller.m
-(void)deleteItemsFromDataSourceAtIndexPaths:(NSArray *)itemPaths
{
//here i want to control the delete option when cancel pressed
NSMutableIndexSet *indexSet = [NSMutableIndexSet indexSet];
for (NSIndexPath *itemPath in itemPaths) {
[indexSet addIndex:itemPath.row];
}
[self.selectedAssets removeObjectsAtIndexes:indexSet];
}
/* call the delete function*/
- (void) collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
NSArray *selectedItemsIndexPaths = [self.collectionview1 indexPathsForSelectedItems];
[self deleteItemsFromDataSourceAtIndexPaths:selectedItemsIndexPaths];
[self.collectionview1 deleteItemsAtIndexPaths:selectedItemsIndexPaths];
}
This working fine for delete the selected image from custom view controller.
but It works also cancel. Now, I want to control deletion on cancel.
kindly help me to solve this.
I have already tried using button tag for identify which button was pressed. but can't control in custom vc
secondview.m
- (IBAction)CancelPhoto:(id)sender{
[Cancel setTag:1]; //set tag value at cancel
}
There are several ways to pass date between view controllers. I'm giving you a very simple solution as per your requirements:
Assuming you have all your images in a mutable array in first view controller.
NSMutableAray *imagesArray;
Make a property images array of NSMutableArray type in second view controller.
#property(nonatomic, strong) NSMutableAray *imagesArray;
assign your array to property while pushing/presenting view
secondController.imagesArray = imagesArray;
On delete event remove that image from array.
[self.imagesArray removeObjectAtIndex:selectedIndex];
dismiss/pop your second view where ever you want and refresh your first view controller in viewWillAppear of viewDidAppear method.
As you have passed reference of your main images array, both classes (view controllers) share same array through pointer and a change in array from either side will be reflected in both screens
There are 3 ways (in my opinion):
Delegate
Notification
In case: you are using database, just remove image url and reload data
Related
I am trying to learn iOS development but have stalled a bit so I hope that there is some kind soul here who might be able to help me in the right direction.
Let's say I have a UITableViewController that displays a number of items, consisting of a title and subtitle ( Subtitle style of a Tableview Cell). Items.m/h only consist of two properties, title and subtitle and a init method to set the properties. In my app delegate i create some default items and pass them/set them to my tableViewController's property tvc.items, which is a NSMutableArray. What do I need to do / what components do I need, to be able to add more items and then display them in my tableViewController?
I started with the following:
Added a new view controller in the storyboard
Embeddade the viewController in a Navigation Controller
Added a Bar Button Item at my Table View Controller with an identifier of add
Ctrl + drag from BarButtonItem (add) to my new view controller selected modal segue
Created a new class AddNewItemViewController
Entered this as the class under the Identity Inspector for the new view controller
I then added two Bar Button Items, Cancel and Done (with cancel and done as identifiers) in the storyboard for the new View Controller
This was followed by me adding two UITextFields, one for the Title and one for the Subtitle
Ctrl + drag from these outlets into AddNewItemViewController.m, between #interface AddNewItemViewController () ... here ...#end (so they become Private? Should I drag it here or to AddNewItemViewController.h ?, What is the standard way for doing similar outlets?).
In AddNewItemViewController I added two properties, NSString's (nonatomic, copy) * title and *subtitle which I thought would keep the input data from an intended user.
So, after this I now want do two things, and it is here as it becomes difficult (for me at least):
Making so that by clicking on Cancel, one return to the Table View controller, ie a dismissed the modal .
Adding the data within the text fields to that NSMutableArray which is the datasource by clicking Done.
So what is required of me to do the last two steps?
Where should I ctrl + drag from the Cancel and Done (so there will be actions)? I guess they must be submitted to AddNewItemViewController.m, but what must be done to dismiss the modal (by clicking on the 'Cancel') and what should be called at or performed when clicking on 'Done'?
Which or what class (es) must know about the other class?
Last but not least, what should I send in the prepareForSegue call (which I guess I will need to have to use to send the input data back to the table view controller)?
Where to start and what methods should i learn about in order to achieve my mission?
Best Regards,
Rookie
much quesetions :)
I will beginn with the close action.
Have a look at the AppleDocumentation, dismissViewController with sender self (your AddViewController).
To store your data from AddViewController to your TableViewController, it's a better way to use delegation.
AddViewController.h
#protocol AddViewControllerDelegate;
#interface AddViewController : UIViewController
#property (nonatomic, weak) id<AddViewControllerDelegate>delegate;
#end
#protocol AddViewControllerDelegate <NSObject>
- (void) addViewControllerDidFinishTakingData:(AddViewController *)addViewController withTitle:(NSString *)title andSubtitle:(NSString *)subTitle;
#end
AddViewController.m
- (IBAction)done:(id)sender
{
NSString *title = ...;
NSString *subtitle = .. .;
[self.delegate addViewControllerDidFinishTakingData:self withTitle:title andSubtitle:subtitle];
}
TableViewController.m
#interface TableViewController ()<AddViewControllerDelegate>
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([segue.identifier isEqualToString:#"yourIdentifier"])
{
AddViewController *addViewController = (AddViewController *)segue.destinationViewController;
addViewController.delegate = self;
}
}
Last but not least to implement your new delegate-method
- (void)addViewControllerDidFinishTakingData:(AddViewController *)addViewController withTitle:(NSString *)title andSubtitle:(NSString *)subTitle
{
// handle your data here (store to array)
// reload your table
}
Better way, to create a Class (Model) for every entry.
The simplest thing to do would be to assign tvc.items to the destinationViewController's property during prepareForSegue.
You are correct in thinking that the Cancel and Done buttons belong to the AddNewItemViewController.
In the action for Done, you could add the new item to the items array you passed in during prepareForSegue, then in the presenting view controller (the one you launched the modal from), during viewDidAppear just reload the table. It'll be called when the modal disappears.
Still fairly new to iOS. I've managed to write a basic app to display a list/table of documents. I've included:
cell.accessoryType = UITableViewCellAccessoryDetailButton;
which display a blue i within a circle button which I guess can be used to perform some sort of action.
What I'd like to do now is, upon click, to display a subsequent screen with information about the document, buttons, add, delete functions, date, file size etc...
Is this done via segue or some other method?
Being a novice I am not sure what is/are the next step(s). If I know what steps I must take in order to get to next scree(s) I can search the net for example of how to do any given step.
Thank you for your help
The accessoryButton triggers it's own delegate method, distinct from the row selection, called:
- (void)tableView:(UITableView *)tableView accessoryButtonTappedForRowWithIndexPath:(NSIndexPath *)indexPath
Add that method to your delegate, and then do a vc transition. There are several ways to do that transition, most of the common ones are discussed here...
First, welcome to the iOS developing community!
In order to do this, I would use a segue to a detail view that you can design. When you select a row in your table using didSelectRowAtIndexPath, you would set an #property to the object in your array that was selected: self.selectedObject = self.tableviewarray objectAtIndex:indexPath.row; Then in the prepareForSegue method you can get the destination view controller and do destinationViewController.myObject = self.selectedObject; Now the detail view knows what object to display info for!
You'll need to implement the delegate method
-tableView:(UITableView*) didSelectRowAtIndexPath:(NSIndexPath*)
and handle the row tap in that callback accordingly.
An example would be like this:
-tableView:(UITableView*)tableView didSelectRowAtIndexPath:(NSIndexPath*)indexPath {
YourObject *theModelForRow = [_itemList objectAtIndex:indexPath.row];
YourViewController *someNewViewController = [YourViewController viewControllerWithModel:theModelForRow];
[self.navigationController pushViewController:someNewViewController animated:YES];
}
It's this case again:
I wish to fill the prototype cells with the names of the friends selected in the UIPickerView over there. I have programatically filled the picker with the string representation of my Player object data, and set its properties using the delegate functions.
The "New Game Friends View" you see here has its own viewcontroller subclass, as has the table view, which I attempt to embed into a UIView on the "New Game Friends View". The table view IS an instance of my WHGFriendTableViewController class. I know this because this function does not throw any exceptions:
- (IBAction)addBtnClicked:(id)sender {
WHGFriendTableViewController* tabView = (WHGFriendTableViewController*) [[self childViewControllers] objectAtIndex:0];
NSInteger row = [friendPicker selectedRowInComponent:0];
[[tabView selectedFriends] addObject:[[self friendList] objectAtIndex:row]];
[[tabView tableView] reloadData];
}
Now the problem is: while the function above does not throw any exceptions, it still does not work. It appears that nothing really happens when I insert the objectAtIndex:row into the NSMutableArray selectedFriends (which is a property) in the table view's view controller.
This:
NSLog(#"New length: %d", [[tabView selectedFriends] count]);
prints 0 after inserting the new object. I have no idea why. Printing the count of [self friendList] gives three, just as I expect. The reloadData message does not make anything appear in the table view.
Any ideas why I cannot insert new data into the table view with my code, when this seems to be working with no exceptions whatsoever? Thanks in advance!
Have you alloced & init your NSMutableArray selectedFriends?
Also have you set the dataSource and delegate of your table view?
I am a novice Ios developer and this a my first project which is ipad specific.I am having some issues with UIPopOverControl class implementation. In my project i have a View controller subclass and In that view i have several buttons . What I need to do is after pressing a button show a Popover with UIPopOvercontrol class.The data shown in the popover would be different for tapping different button and all the data would be presented in UITableView style. I have been able to show one button and one popOver using one UIViewController and UITableViewController subclass and loading data from a nib file. But how can I perform my desired task??
Thanks in advance
In your application, not need to use multiple UIPopoverViewController, you can also do this by using single UIPopoverViewController.
simple create new Class of UIPopoverViewController;
and also create UITableView in UIPopoverViewController.
In your application you have multiple UIButton, just give tag of each buttons and pass your data base on tag of button, and display this data on UITableView.
iOS purposely restricts having only one Popover visible at a time. The API is intrinsically designed to prevent having multiple open at the same time. You will need to consider an alternative approach that satisfies your requirements.
I had made the requirement done here.
Check this out.
It will help you for sure.Code for showing 2 popViewController at the same time and different data in both
You can set a variable in your AppDelegate to check which button is pressed?
Then, In viewWillAppear of your Controller, take the reference of that variable and check which button is pressed?
Then reload the data as per requirement in cellForRowAtIndexPath.
Hope this helps
AppDelegate.h
#interface AppDelegate : UIResponder
#property int buttonPressed; // Set this on click of any button
#end
YourController.h
int buttonPressed;
YourController.m
(void) viewWillAppear:(BOOL)animated
{
AppDelegate *app = (AppDelegate *) [[UIApplication sharedApplication] delegate];
buttonPressed = app.buttonPressed;
}
(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
if (buttonPressed == 1) { // do this}
else if (buttonPressed == 1) { // do this}
else // do this
}
I have a tableview with UITextFields to build a form. I then have a button in the toolbar which launches a modal view controller to select some data which is then passed back to the tableview. However, the new data that was selected does not get refreshed into the UITextField using textField.text = valueReturnedFromModal syntax. Is there something I'm missing?
I see that the data is being returned properly from the modal so that is not the issue. I'm just having trouble forcing the UITextField to refresh with the new data. I've tried forcing a reloadData on the tableview as well.
So from the modal view, here's the code that passes data back:
- (void)doneAccountSelection:(id)sender
{
[delegate didSelectAccount:currentAccount];
[self dismissModalViewControllerAnimated:YES];
}
and here's the actual method in the delegate:
- (void)didSelectAccount:(SFAccount *)selectedAccount
{
//Ensure a valid deal exists for the account to be attached to
[self createDealObjectIfNeeded];
//Set the deal account
[self.deal setAccount:selectedAccount];
//Refresh the text fields
//Tag 3: Account Name field
UITextField *acct_name = (UITextField *) [self.view viewWithTag:3];
[acct_name setText:self.deal.account.field_acct_name_value];
//Tag 4: Account City field
UITextField *acct_city = (UITextField *) [self.view viewWithTag:4];
[acct_city setText:self.deal.account.field_acct_city_value];
//Save the context changes. A new deal gets created above if one does not exist.
if ([self saveModel]) NSLog(#"Acct object created, attached to deal successfully!");
[self.tableView reloadData];
}
Would you mind posting the code that sets the text fields data and the code that passes the data back to the table view?
Answer:
It appears that you are properly setting the data, however, you are dismissing the modal view controller after sending the delegate message. In this scenario, the table view is not even created until after the dismissModalViewControllerAnimated: has ended. Which means the textfields are NULL until the view is present. What I suggest is call
[self dismissModalViewControllerAnimated:YES];
as the first line in the didSelectAccount: delegate method. This would dismiss the modal view and then continue on with your setting the data to valid textfields as -viewWillAppear: / -viewDidAppear: would have already been called. Everything seems ok it's just the order that may be tripping you up. Although
-dismissModalViewControllerAnimated:
is passed to its parent if a view controller does not have a modal view (because it is the modal view), it seems more appropriate to call this method in the delegate method where you will eventually manipulate the view due to new data, etc.
use this after getting Value in text field:
[self.tableView ReloadData];
After some serious debugging found that self.account was being used in cellForRowAtIndexPath to set the initial UITextField values within the UITableViewCell. Then after modal selection completed, I was only updating the account reference for the deal object and not updating the self.account object.
I then added to this by creating a new method called updateTextFieldsAfterModalFinished and moved the code to update the UITextFields there. This method was then called from didSelectAccount which is the delegate method for modal view that is dismissed. Things are now working as expected and the UITextFields get updated after modal selection is finished.