If someone was able to help me with the following, that would be great!
So here is what I'm trying to do. My app is basically a rss reader. The topics of the rss entries are displayed in a table view. Tapping on an entry opens a web view which displays the whole story. To this web view I have added a toolbar with up and down arrows so the user would be able to jump to the next/previous story without leaving the web view and having to tap another entry in the table. My problem is that I have no idea how to archieve this. Maybe this is related to the structure of my app. My guess is that I have to somehow increment the selected row on tapping the button.
As I said, maybe the code is a bit complicated, so I've posted the whole project here: http://www.schimanke.com/flo.zip It would be great if someone could have a look and tell me what to do.
What you need is to know which row is currently selected on your model. Since you have a reference to the model from your webview, that's easy:
int row = [mainModel.blogEntries indexOfObject:mainModel.selectedBlogEntry];
So all you need after that is to show the next (or previous) entry. Based on your code, it goes like this:
- (void) showNextPrevEntry:(int)increment usingTheOldController:(BlogEntryController *)controller {
int row = [mainModel.blogEntries indexOfObject:mainModel.selectedBlogEntry];
if (row+increment<[mainModel.blogEntries count] && row+increment>=0) {
mainModel.selectedBlogEntry = [ mainModel.blogEntries objectAtIndex:row+increment];
controller.mainModel = mainModel;
[controller viewDidLoad];
}
}
I don't think it's healthy to call viewDidLoad. Maybe you need another method just for updating the current loaded view and call that from your viewDidLoad. Also I'm not sure why you are using notifications for handling the button presses from the toolbar, but it works. :)
Related
I'm very new to objective-c and IOS development. I want to create a very simple slot-machine app. For that I used an UIPicker and filled it with the required data. However I'm having trouble to make it roll after the user clicks a button. I don't have any idea how to implement that kind of movement.
Can anyone give me a direction? I don't have any code to add because everything is displayed like it should, except that method to make the picker actually move which I don't know how to implement at all.
You can accomplish this by loop in animating to a specific row , so create a timer that fires every 1 second inside it increment row / component put this
[picker selectRow:row inComponent:component animated:YES];
I want to build some analytics into my app and I would like to send some data when user leaves current screen, though there are multiple ways he can do so (back button, other button, sidebar menu, etc). Is there any efficient way to do this? I really don't feel like implementing it to every possible button that can lead the user to different screen.
You should call your function inside viewWillDisappear, which is called every time the current view controller is about to disappear from screen. See the documentation of viewWillDisappear
Also see the view controller life cycle (thanks #Paolo for the tip) below (documentation).
So, I have this very simple list project with objective-c, where every item on the list should have a title and a description. When clicking on one of the items, the detail view of the item shows up. The title, on the navigation bar is the item's title, and the rest of the view is the item's description. By clicking on the title, the user should be able to change it, and by clicking on the description they should also be able to change it.
Up until changing the title everything is going OK, I've managed to do that. The problem is when it comes to changing the description. I tried using the delegate, but I guess I must be using some command wrong, because it's simply not working. I tried looking for it online, but all I find are solutions for the TextField, which doesn't really help me, since I want to display a possibly multiline description, and I would rather not have to change from a TextView to a TextField every time the user wants to edit it. So if anyone could help me out with that, that would be awesome.
Here is the code where I try using the delegate.
on viewDidLoad I have this:
[self.descriptionLabel setDelegate:self.descriptionLabel.delegate];
and then I have this, where it should perform the actions after the text is changed:
- (void)textViewDidChange:(UITextView *)textView {
NSLog(#"Hello World");
}
P.S.: I was also looking for a way to have the "Done" button show up over the keyboard, because as of now, once the keyboard is brought up, the only way to get it down again is going back to the table view and then into the detail view again. I tried a couple of things already, but I'll admit that I wasn't too thorough on my research. So, as a side note, if you could show that too, it would be great, otherwise, the one thing I'm really after here is the question above. Thanks for any help! :]
Summary of answer based on the comments.
The line:
[self.descriptionLabel setDelegate:self.descriptionLabel.delegate];
needs to be:
self.descriptionLabel.delegate = self;
You want the view controller to be the delegate since the view controller implements the text view delegate methods.
You also need to indicate that the view controller conforms to the UITextViewDelegate protocol.
In your .m file, add the following:
#interface DetailViewController () <UITextViewDelegate>
#end
In the XCode IDE, at the bottom of the view controller in the MainStoryboard editor, are two boxes: First Responder, and Exit.
I know what a firstResponder is programatically within the code, but in the storyboard editor, I can't seem to do anything useful by it.
Am I able to use the first responder in this area to somehow set the first responder of the view? I'd like the first textfield to be active on load and I have tried right+click and dragging to no avail. I know I can set it programatically in the viewDidLoad method, but is there some way of doing it here?
And what is the green Exit for?
There are no good answer for this question, so I am posting my answer:
From here:
Note: You probably won’t be using the First Responder very much. This is a proxy object that refers to whatever object has first responder status at any given time. It was also present in your nibs and you probably never had a need to use it then either. As an example, you can hook up the Touch Up Inside event from a button to First Responder’s cut: selector. If at some point a text field has input focus then you can press that button to make the text field, which is now the first responder, cut its text to the pasteboard.
Edit:
1) First Responder is very useful if you are using text fields with keyboard notifications. I use it to make keyboard disappear, make an outlet to variable currentFirstResponder of your class, and in viewWillDisappear:
[self.currentFirstResponder resignFirstResponder];
2) You can read about unwind segues ("Exit" box) here
I've never used it and probably never will but you can assign an object to be the first in line to receive the events from the UI.
I suppose you could be creating a UIView subclass and add it in to a UIViewController but you actually want some other object to receive and process the events other than the UIViewController you are adding it to.
I found this link which kind of explains it a bit better.
First Responder: The First Responder icon stands for the object that the user is currently interacting with. When a user works with an iOS application, multiple objects could potentially respond to the various gestures or keystrokes that the user creates. The first responder is the object currently in control and interacting with the user. A text field that the user is typing into, for example, would be the first responder until the user moves to another field or control.
Exit: The Exit icon serves a very specific purpose that will come into play only in multiscene applications. When you are creating an app that moves the user between a series of screens, the Exit icon provides a visual means of jumping back to a previous screen. If you have built five scenes that link from one to another and you want to quickly return to the first scene from the fifth, you’ll link from the fifth scene to the first scene’s Exit icon.
More here
You don't see this very often, where a deleted answer is actually correct, and the comment (likely influencing its deletion) on it is totally wrong! I'll try and improve on it.
Usually the IBAction you want to hook up to a button is in the view controller containing the button. However if the IBAction is in a different controller, e.g. a parent controller then drag from the button to the First Responder object and you are able to select the IBAction in the parent controller!
As the hidden answer states, how this is implemented is the action is sent to nil, which has the effect of the responder chain (i.e. view hierarchy) being searched for the action, as follows:
[UIApplication.sharedApplication sendAction:#selector(nextObject:) to:nil from:self forEvent:nil];
An example is a custom UITableViewCell. Add a UIButton to the cell but you want the action to go up to a View Controller that has an embed segue to a UITableViewController. Drag the touch up instead action to the First Responder and select the action in the container view controller. In the action to find the indexPath simply loop the visibleCells and check if the sender is isDescendantOfView:
- (IBAction)cellButtonTapped:(id)sender{
for(UITableViewCell *cell in self.tableViewController.tableView.visibleCells){
if([sender isDescendantOfView:cell]){
NSIndexPath *indexPath = [self.tableViewController.tableView indexPathForCell:cell];
NSLog(#"tapped %#", indexPath);
}
}
}
Another example could be a reload button: say your first view controller shows an downloaded item with an IBAction to reload it to get the latest data, then your child controller shows some detail, but you also want them to be able to reload the main item from within the detail, just add a button in the detail and drag its action to First Responder and select the reload IBAction in the parent controller. This allows you to hook up buttons to parent actions with no additional code like delegate methods!
For this to work the action needs to be in the responder chain hierarchy or it won't be found, you can read how the chain is built up in the docs. Also note if called from code the view needs to have appeared, viewWillAppear is too soon.
This is one of those "it was working a while ago" troubleshooting efforts.
I'm working on the document preview view controller, in which is a scroll view, which itself contains subclasses of UIView that represent each document. I'm modeling this pretty closely to how Keynote handles its document preview, except I build my scroll view horizontally and with paging. But the standard user experience is present: Long press on a document icon causes all document icons to start jiggling, nab bar has + button and Edit button, etc.
The issue at hand is that when you tap on the name of a document, I hide all the others, move the one being edited front and center, build a new text edit field, add it as a subview atop the real name label, and set it as first responder; but the
[editNameTextField setClearButtonMode:UITextFieldViewModeWhileEditing];
while correctly showing in the edit field is not taking any action when the user taps on the clear button.
I can't figure out what I may have done to cause this to not work -- it had been!
My first thought was that somehow my instance of this subclass is no longer the delegate for this text edit field. To try and confirm/deny that, I usurped a tap on the image view of the document preview to compare the delegate property to self, and it passes.
if (editNameTextField) {
NSLog(#"editNameTextField is still active");
if ([editNameTextField.delegate isEqual:self]) {
NSLog(#"we're still the delegate for the editNameTextField");
}
}
Editing the text within the edit field works fine. Pressing the Return/Done key correctly sends the delegate message textFieldShouldReturn:
While investigating this I implemented the delegate method textFieldShouldClear: just to write a log message if the method gets called (and return YES of course). It never gets called.
My next thought was that perhaps a subview had covered up the area where the clear button sits. So I implemented textFieldShouldBeginEditing: and used the opportunity to bring my the text field to the front. That didn't change anything either. I set a debugger breakpoint there to play a sound when it was called, and it got called, so I know my text edit field is frontmost.
I have only one troubleshooting strategy remaining: Go backwards through snap shots until it starts working again. Before doing that I thought I'd see if any of the more experienced folks out here have any suggestions of what to try next.
Where are you adding the textfield? As a subview of the scrollView? If you added the textfield and it is out of bounds of its parent view it won't receive any touches.
You can try and not call becomeFirstResponder and see if clicking it will show keyboard. Another possible error might be that the parent view of the UITextField has userInteractionEnabled = NO.
Without seeing more code I'm afraid I can not offer more solutions.