I have a sectioned tableview with a plist wich is an array filled with dictionaries.
In my app all sections and cells are shown on the first view.
But now I need to change it to look like this: sections have to become cells(with names of sections). When you press this cell the cells contained in section have appear.
Is there a way to do it without too much rewriting the code?
Thanks and sorry for the noob question :o)
I understand, that you still want to use one tableview, where cells are hidden for all sections except one. In that case you can do this:
Implement -tableView:headerForSection: and place a button on the view that you will return. Write the sections number on the buttons tag. Add an action to the button with parameter (UIButton *)sender: `-(void) headerPressed:(UIButton *)sender
You need to implement -tableView:heightforHeaderInSection: as-well.
-(void) headerPressed:(UIButton *)sender writes the senders tag to a member integer and reloads the tableview.
in -tableview:numberOfRowsInSection: you return 0 if the sections int is not equal to the member integer you saved. If it is equal, return the number of rows in that section.
You will need to create two table view classes. One for the one that holds the section names, and the other that holds the rows of each section. In the first one, retrieve the section names from the plist and populate the rows in the table accordingly. Then in the - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath method you need to push another view controller onto the navigation stack(something like this-provided in the template code):
// Navigation logic may go here. Create and push another view controller.
<#DetailViewController#> *detailViewController = [[<#DetailViewController#> alloc] initWithNibName:#"<#Nib name#>" bundle:nil];
// ...
// Pass the selected object to the new view controller.
[self.navigationController pushViewController:detailViewController animated:YES];
[detailViewController release];
Then for the other table view class you populate it by reading in the info from the plist that corresponds to the tapped section. Hope this helps.
Related
I understand this might be covered in parts in answers to other questions (see references) I've seen on the site, but due to my limited experience I haven't been able to understand each part as it relates to my code. Please forgive me for any duplications.
I have a PFQueryTableViewController (essentially a UITableViewController) called threadsViewController that sources cell information from a Parse backend. The table view consists of threads similar to what you would see on a web forum.
I then have a separate class postsViewController which is another PFQueryTableViewController that I wish to display a table of all the responses ('posts') to that particular thread.
The functionality I'm looking for is for a user tapping on a thread (left screen in the image) to be presented with a postsViewController (right screen) containing only those posts/responses related to that thread. (See basic diagram below).
What I do know from my research:
The Parse backend is established with classes for Thread and Post.
I'm probably going to use the didSelectRowAtIndexPath delegate method
What I need help with:
How can I know which thread cell a user tapped on, and then pass that on so that the postsViewController only displays posts from that Thread?
A layman's description of how to use indexPath.row etc
I understand how to complete PFQueries etc to get the data for the cells, I just don't know how to implement the navigation and how to tell postsViewController which posts to show.
In case it helps somehow, here is my implementation so far. I have tried addign a property to the postsViewController called fromThread to somehow store the thread but apart from that I'm out of ideas!
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
[super tableView:tableView didSelectRowAtIndexPath:indexPath];
postsViewController *postsVC = [[postsViewController alloc] init];
postsVC.fromThread = //?
[self performSegueWithIdentifier:#"threadsToPosts" sender:self];
}
References
How to filter a Parse query by an tableview index?
Pass Index Number between UITableView List segue
didSelectRowAtIndexPath and prepareForSegue implementation
You're on the right track. You need know how to do two things: (1) access your parse objects by indexPath, and (2) push a new view controller in a navigation controller.
(1) is simpler: PFQueryTableVC provides a method called objectAtIndexPath: that does just what you need.
// indexPath is the indexPath parameter to the didSelectRow delegate method
PFObject *fromThread = [self objectAtIndexPath:indexPath];
(2) is simple, too. But more complicated because there are a couple ways to do it. Segue is the more modern way, but I think the old way is simpler, and certainly easier to describe in code. View Controllers are given storyboard ids on the "Identity" tab in the storyboard editor. Give your Posts-presenting VC a storyboard id like "PostVC".
To get a new instance, use that storyboard id as follows:
MyPostVC *postVC = [self.storyboard instantiateViewControllerWithIdentifier:#"PostVC"];
// initialize it with the PFObject we got above
postVC.fromThread = fromThread;
// present it on the navigation stack
[self.navigationController pushViewController:postVC animated:YES];
And fromThread is just what the PostVC will need to form a query for posts associated with the selected thread.
You can pass data of cell to next ViewController in prepareForSegue with something like this
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
if ([segue.identifier isEqualToString:#"threadsToPosts"]) {
UINavigationController *navCon = segue.destinationViewController;
postsViewController *postsViewController = [navCon.viewControllers objectAtIndex:0];
// Whatever you are populating your tableView with
Thread *thread = [self.thread objectAtIndex:self.tableView.indexPathForSelectedRow.row];
postsViewController.thread = thread;
}
}
I am developing a master detail view application for iPad. All I have done so far is to get the data populated in my Master view. All these are images which are stored in NSMutableArray. When a user clicks on any row, The corresponding image should appear in the detail view.
I saw so many examples on this and I figured out that I need to make changes in didSelectRowAtIndexPath and in setDetailItem and configureView. But I don't know what exactly I have to do in these methods. Also, my Master view should be hidden when I select any row in it. This is not happening. Also, in iPad master detail template, there is no seague between the Master view and detail view. I tried creating one but then the data is being displayed in Master view only and not in detail view. I want the detail view to be updated. Please let me know if anyone know how to get this done.
You just need to get value of parameter that you want to pass to detail view.
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
if (!self.detailViewController) {
self.detailViewController = [[[DetailViewController alloc] initWithNibName:#"DetailViewController" bundle:nil] autorelease];
}
// Here you need to pass data object that you want to show in detail view Controller
// Object contains value of particular index in tableView.
self.detailViewController.detailItem = object;
[self.navigationController pushViewController:self.detailViewController animated:YES];
}
First look at this screenshot please. What I want to do is when I click on a cell in the little tableview on the right. Then the labels should change to some other data. I am using a custom controller for my datasource and delegate. I'm setting the controller in my viewDidLoad.
- (void)viewDidLoad
{
tabelPlayers=[[tblPlayersDataSourceDelegate alloc]init];
tblPlayers.dataSource=tabelPlayers;
tblPlayers.delegate=tabelPlayers;
[tabelPlayers setTableSource:_playersArray];
}
In this tblPlayersDataSourceDelegate I do this for my didSelectCellAtIndexPath
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
Team *player = [_tableSource objectAtIndex:indexPath.row];
PlayerDetailController *detail = [[PlayerDetailController alloc]init];
[detail setStrNaam:player.name];
[detail reloadInputViews];
}
But it doesn't change anything. Can somebody help me ?
Thanks in advance
If I understand your question right, what you're trying to do is change the information on the left labels according to the selected player from the little table view on the right.
I don't fully understand your code but what I would do as a general structure to achieve the same result as you are describing you want would be to:
Create an NSDictionary (could be in a *.plist file) that contains "Items" (inner NSDictionary's).
Each "Item" contains keys (player age, player's number or whatever).
The little table on the right will use another NSArray that will be constructed from the main NSArray keys:
NamesArray = [mainPlayersDictionary allKeys];
Whenever a row is selected in your small tableview you simply load all the labels according to the keys in your main NSDictionary:
[ageLabel setText: [[mainPlayersDictionary objectAtIndex:selectedRowIndex] objectForKey:plAge];
[pNumLable setText:[[mainPlayersDictionary objectAtIndex:selectedRowIndex] objectForKey:pNum];
And your set. Hope that helps.
I have set up a demo application with a simple UITableViewController with no contents, but an 'Add' button in the toolbar. This launches a modal view controller which is again empty other than a 'cancel' button. The cancel button just tells its delegate (the UITableViewController) to dismiss the modal.
I then added an NSLog statement in the UITableViewController's numberOfSectionsInTableView method.
Ordinarily, when the table view controller loads I see two calls to numberOfSectionsInTableView. When I open and dismiss the modal (which returns to the UITableViewController) I see no further calls to numberOfSectionsInTableView.
However, if I return 0 from numberOfSectionsInTableView, in addition to the two calls on display, I also see an additional numberOfSections call when the modal is dismissed.
This only happens when numberOfSectionsInTableView returns 0, and I have added no additional code to my project besides that mentioned. This is easily verifiable by setting up a couple of controllers as I've described and modifying the result from numberOfSectionsInTableView.
My questions:
Why is the UITableView calling numberOfSectionsInTableView on return from a modal view?
Why is it only doing this if numberOfSectionsInTableView returns 0?
In addition to numberOfSectionsInTableView, the UITableViewController is also calling cellForRowAtIndex: when the modal is dismissed. In fact, it is attempting to display the new contents of its dataSource. How am I meant to manually animate a row insertion if the first row added is going to already be updated automatically? Shouldn't it be left to me to make sure that my UITableView is consistent with its dataSource?
What property is the UITableViewController checking to know that there is one or more sections (and therefore ask my delegate how many sections)? It can't be numberOfSectionsInTableView itself, since I would see it called whenever I return from the modal, not only when numberOfSections = 0.
From UITableViewController docs:
When the table view is about to appear the first time it’s loaded, the
table-view controller reloads the table view’s data... The
UITableViewController class implements this in the superclass method
viewWillAppear:
If you watch in the debugger, the second call upon app launch is from UITableViewController's viewWillAppear: implementation - specifically the part referred to above, where tableView is sent the reloadData message.
Now, the first call to numberOfSectionsInTableView: on launch is also from UITableViewController's implementation of viewWillAppear: but not directly from that implementation's call to -[UITableView reloadData]. I'm not sure what the first call is all about.
But, to your question, the call to numberOfSectionsInTableView: that happens when dismissing the modal has exactly the same call stack as the second call from applicationDidFinishLaunching:withOptions:. My hypothesis then is that UITableView interprets having zero sections as being in a state where it has not loaded at all. That does make some sense actually. I'd consider an "empty" table view to be one without any rows, but one without any sections seems almost "uninitialized" to me. Furthermore the UITableViewDataSource documentation implies UITableView has by default one section. Returning zero from this method would be inconsistent with that assumption of the docs as well.
Now, to your concern about animation - if you give the table an empty section to work with, you will be able to have full control over inserting the first row with whatever animation you'd like, and not be locked in to when you need to reload.
I think the moral of the story is, don't return zero sections unless you really, really need to for some reason. The title of your post refers to this table view being "empty" as well but I think it's clear the framework finds zero sections to not be empty but unloaded.
Hope this helps! And thanks for posting the sample project for me to play around with.
Perhaps the delegate just couldn't believe its eyes. But seriously, since a table view has to have at least one section, passing 0 doesn't make any sense. Why do it? You pass it an invalid argument and it gives you back a weird response. As to why it doesn't ask for number of sections when you pass 1, I think it's because it doesn't need to know at that point (coming back from the modal view controller) -- the table view has already been populated (if there were some data) and you haven't changed anything in the model, so it doesn't need to update.
I added a few lines to your example project to slide in a row each time you return from the modal view controller, which is what I think you're trying to do. I added an int property num for the return value of numberOfRowsInSection, added an array to populate the table, and a call to insertRowsAtIndexPaths from the modal view controller dismissal method.
- (void)viewDidLoad
{
_num = 0;
self.theData = #[#"one",#"two",#"three"];
[super viewDidLoad];
self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd
target:self
action:#selector(addRecipe)];
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
NSLog(#"# sections requested");
//when 0, this fires on return from the modal. When 1, it does not.
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
NSLog(#"in numberOfRows in section");
return _num;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"in cellForRowAtIndexPath");
UITableViewCell *cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:nil];
cell.textLabel.text = [self.theData objectAtIndex:indexPath.row];
return cell;
}
- (void)addRecipe
{
//create the modal and suscribe for delegate notifications
AddRecipeViewController *addRecipeController = [[AddRecipeViewController alloc]initWithStyle:UITableViewStyleGrouped];
addRecipeController.delegate = self;
//display the modal in a navigation controller
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:addRecipeController];
[self.navigationController presentModalViewController:navController animated:YES];
}
- (void)addRecipeVC:(AddRecipeViewController *)addRecipeVC didAddRecipe:(NSString *)recipe
{
[self dismissModalViewControllerAnimated:YES];
_num += 1;
[self performSelector:#selector(addRow) withObject:nil afterDelay:.5];
}
-(void)addRow {
[self.tableView insertRowsAtIndexPaths:#[[NSIndexPath indexPathForRow:_num-1 inSection:0]] withRowAnimation:UITableViewRowAnimationRight];
}
The tableview checks number of sections when it's populating the table view with data!
Since the table can be divided into sections, it has to know specifically how many sections to divide it into.
When you reload the data, the number of sections is also checked.
Because every time the table view has to take action in accessing either the data of the table, like what row you tapped, and in what section, or populating the data table, the number of sections has to be known!
Hope this helped!
I have a Split-View iPad application and I fixed the selections in the popover (RootViewController) to be static, let's say red, yellow, and blue. When my app starts I have preselected red or the top static text in the cell. I was able to add UITableViewDelegate and UITableViewDataSource with the other templates in DetailViewController. It's the one with the popover-no-popover default split-view app.
I added the row count and the cell method and voila' my test array populated the detail table. I want a separate controller (delegate and source) for each selection the user chooses to be driven from didSelectRowAtIndexPath in the RootViewController.
Should I just add the delegate and datasource templates to the DetailViewController and switch the data based on selections in the RootViewController view?
Or, would my multiple controller pattern be better design?
I would like some assistance as to how to get the outside controller to have control of the DetailViewController's UITableView. The DetailViewController is where I instantiate the add button and such to the toolbar. E.g. when I added the single (Red) test controller to the DetailViewController, any connection to the TableView wasn't seemingly automatic in IB. You could hover and then it would eventually connect to "View" (ultimately the UITableView). I've tried everything and I cannot get a simple delegate and datasource controller with a simple NSArray to populate the DetailViewController's table view from RootViewController's didSelectRowAtIndexPath. This method works because I've debugged and NSLogged the selections. I'm not creating my ProjectViewController (test or first static text in RootViewController) correctly. I'll paste some code that I've tried here too.
- (void)tableView:(UITableView *)aTableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// select static row and view controller
Punch *obj = [self.punchList punchAtIndex:indexPath.row];
NSLog(#"Selected punch object: %#", obj.name);
ProjectViewController *projectViewController = [[UITableViewController alloc] init];
[projectViewController tableView:detailViewController.tmpView];
}
The ProjectViewController code works if hard-coded in DetailViewController, i.e. the required methods, the count, and the array loaded cells and the I want this data population in separate controllers because I'm going to use Core-Data in the end.