ios share extension post button title - ios

Question

I want to change the title of post buttons in SLComposeServiceViewController.
I managed to get the UIButton:
NSArray* subviews =[self.navigationController.navigationBar subviews];
UIButton* postButton =[subviews lastObject];
and i tried to set title like this:
[postButton setTitle:#"Save" forState:UIControlStateNormal];
but the title not changed.
Can anyone help me with this?
I saw Evernote's share extension on my iPad and it looks like this:
UPDATE
My Solution:
I found solution for my question,I removed the original navigation bar and create custom nav bar.
I have two nav bar:
1. with "cancel"\"save" buttons
2. with "back" button
and I change them when navigate to other viewcontroller
(in my case I needed to upload file and user need select location from list)
NOTE: if you not implement configurationItems you need only the first nav bar. (just call to set custom nav bar from viewDidAppear
So my code is here:
#property (strong, nonatomic) UINavigationBar *customNavBar;
-(void) viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
self.customNavBar = [[UINavigationBar alloc] initWithFrame:self.navigationController.navigationBar.bounds];
[self.navigationController.navigationBar removeFromSuperview];
[self.navigationController.view addSubview:self.customNavBar];
[self setCancelSaveNavigationItem];
}
setCancelSaveNavigationItem--> called from viewDidAppear of shareViewController
-(void)setCancelSaveNavigationItem
{
UINavigationItem *newItem = [[UINavigationItem alloc] init];
UIBarButtonItem *cancelBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:NSLocalizedString(#"Cancel",nil) style:UIBarButtonItemStylePlain target:self action:#selector(cancelButtonTapped:)];
UIBarButtonItem *saveBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:NSLocalizedString(#"Done",nil) style:UIBarButtonItemStyleDone target:self action:#selector(saveButtonTapped:)];
newItem.leftBarButtonItem = cancelBarButtonItem;
newItem.rightBarButtonItem = saveBarButtonItem;
[self.customNavBar setItems:#[newItem]];
[self.navigationItem setBackBarButtonItem:cancelBarButtonItem];
[self.navigationItem setRightBarButtonItem:saveBarButtonItem];
if(self.item.value == nil){
saveBarButtonItem.enabled = NO;
}
}
setBackNavigationItem--> called in configurationItems -->in self.item.tapHandler function
-(void)setBackNavigationItem
{
UINavigationItem *newItem = [[UINavigationItem alloc] init];
UIBarButtonItem *selectBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:NSLocalizedString(#"Select",nil) style:UIBarButtonItemStylePlain target:self action:#selector(selectButtonTapped:)];
UIBarButtonItem *backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:[NSString stringWithFormat:#"❮ %#", NSLocalizedString(#"Back",nil)] style:UIBarButtonItemStylePlain target:self action:#selector(backButtonTapped:)];
newItem.leftBarButtonItem = backBarButtonItem;
newItem.rightBarButtonItem = selectBarButtonItem;
[self.customNavBar setItems:#[newItem]];
[self.navigationItem setBackBarButtonItem:backBarButtonItem];
[self.navigationItem setRightBarButtonItem:selectBarButtonItem];
}
Handle buttons tapped:
- (void)backButtonTapped:(id)sender {
if([self.navigationController.viewControllers count] ==2){
[self setCancelSaveNavigationItem];
}
[self.navigationController popViewControllerAnimated:YES];
}
- (void)cancelButtonTapped:(id)sender {
[self cancel];
}
- (void)selectButtonTapped:(id)sender {
...
[self setCancelSaveNavigationItem];
[self popConfigurationViewController];
}
- (void)saveButtonTapped:(id)sender {
...
[self cancel];
}
And it's work for me!!!
The result:

Answer 1

Simply in viewDidAppear
self.navigationController?.navigationBar.topItem?.rightBarButtonItem?.title = "Save"

Answer 2

Your code:
NSArray* subviews =[self.navigationController.navigationBar subviews];
UIButton* postButton =[subviews lastObject];
...is a really bad idea. It only works because the post button is in subviews and is the last item in the array. But the content of subviews is undocumented and might change at any time. Also, since there's no public API for this button, it's entirely possible that there's framework code to prevent or override changes to the button text-- so even if we assume you have the right UI element, you still might not be able to change it.
Evernote's UI is almost certainly a full custom design that only resembles SLComposeServiceViewController. Share extensions are not required to use SLComposeServiceViewController, that's just there for convenience. If it doesn't meet your needs, design your own.
Update: out of curiosity I unzipped the Evernote IPA and had a look at EvernoteShare.appex with nm. There's no reference to SLComposeServiceViewController, which confirms that Evernote is not using that class in their extension.