I want to show 3 different screens depending on the option user selects
They are 1. Type Prescription 2.Scribble Prescription 3. Prescription Form
How can i switch views for those 3?
Thanks
UITabBarControllers like SplitViewControllers were intended to only be the Root View Controller and hence you cannot nest a TabBarController in another view, but you can however nest a UITabBar in a view.
I added the Tabbar to the details view at the bottom, a Navigation bar at the top and then a placeholder view between them. All in Interface Builder!, You will want to switch everything on with the autosize on the Placeholder view.
Next, Implement the UITabBarDelegate, you will need:
- (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item {
from that you can use item.tag which if you give each item a unique tag in Interface Builder will let you know which tab the user clicked. I setup defined values for mine:
#define VIEW_TAB_A 0
#define VIEW_TAB_B 1
#define VIEW_TAB_C 2
Then you will then want to...
- (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item {
[self switchToView:item];
}
- (void) switchToView : (UITabBarItem*) item {
if( currentViewController != nil ) {
[currentViewController viewWillDisappear:NO];
[currentViewController.view removeFromSuperview];
}
switch(item.tag) {
case VIEW_TAB_A:
currentViewController = self.viewA;
break;
case SCAN_VIEW_TAB_B:
currentViewController = self.viewB;
break;
case PROMOTIONS_VIEW_TAB_C:
currentViewController = self.viewC;
break;
}
UIView *aView = currentViewController.view;
aView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
aView.frame = placeholderView.frame;
[currentViewController viewWillAppear:NO];
[self.view insertSubview:aView aboveSubview:placeholderView];
if( currentViewController != nil ) {
[currentViewController viewDidDisappear:NO];
}
[currentViewController viewDidAppear:NO];
}
These are my notes that i learned from a similar question, search harder next time
Related
I have set up my class with UITabBarDelegate and implemented its method didSelectItem to detect when a certain tabBar item is pressed. Works great. In each tabBar item I have one containerView that can show a "you have to login"-page if the user is not logged in, and another containerView that present viewControllers that are embedded in a navigationController.
I would like to keep track of the viewController that is presented in the current tab item, and/or the root viewController of that tab.
I have tried a number of different approaches, but most of them return nil or I can't get it to work. I think the whole container situation makes it harder to handle.
It looks something like this:
#interface MyTabBarController () <UITabBarDelegate>
- (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item {
NSUInteger indexOfTab = [[tabBar items] indexOfObject:item];
switch (indexOfTab) {
case 0: {
NSLog(#"🐳PRESSIIING %lu", (unsigned long)[[tabBar items] indexOfObject:item]);
break;
}
case 1: {
NSLog(#"🐳PRESSIIING %lu", (unsigned long)[[tabBar items] indexOfObject:item]);
break;
}
case 2: {
NSLog(#"🐳PRESSIIING %lu", (unsigned long)[[tabBar items] indexOfObject:item]);
//These return nil
NSLog(#"🐳AAAAAA %#", ((UINavigationController*)_appD.window.rootViewController).visibleViewController);
NSLog(#"🐳AAAAAA %#", ((UITabBarController*)_appD.window.rootViewController).selectedViewController);
NSLog(#"🐳AAAAAA %#", self.navigationController.topViewController);
NSLog(#"🐳AAAAAA %#", self.navigationController.visibleViewController);
//This returns with a value, but can't get it to work with conditionals, that is, when I'm in root, the else is triggered
NSLog(#"🐳AAAAAA %#", self.tabBar.window.rootViewController);
if(!self.tabBar.window.rootViewController) {
NSLog(#"🐳🐳🐳THIS IS NOT ROOT🐳🐳🐳");
}else {
NSLog(#"🐳🐳🐳this is ROOT🐳🐳🐳");
}
// This returns nil
((UINavigationController*)_appD.window.rootViewController).visibleViewController;
((UITabBarController*)_appD.window.rootViewController).selectedViewController;
//Doesn't work
if([self.navigationController.viewControllers[0] isKindOfClass:[ExperiencesListViewController class]]) {
NSLog(#"🐳IS KIND OF CLASS LIST");
}
if([self.navigationController.viewControllers[0].childViewControllers isKindOfClass:[ExperiencesContainerViewController class]]) {
NSLog(#"🐳IS KIND OF CLASS CONTAINER");
}
break;
}
case 3: {
NSLog(#"🐳PRESSIIING %lu", (unsigned long)[[tabBar items] indexOfObject:item]);
break;
}
case 4: {
NSLog(#"🐳PRESSIIING %lu", (unsigned long)[[tabBar items] indexOfObject:item]);
break;
}
default:
break;
}
}
So, what else can I try? Seems like I have to use `self.tabBar.window.rootViewController` in some way, no?
***EDIT***
Oh, and I have tried the `tabBarController` delegate but that doesn't trigger. Also, the `tabBar` is constructed programmatically if that helps.
Sorry to have not read your question correctly. Here's what I suggest you do.
All of these view controllers that you're interested in keeping track of: you should have them send a custom notification from within their -viewDidAppear: (or -viewWillAppear:) method. Then let your ApolloTabBarController object register for that notification. When it gets the notification, you could then store a reference to the view controller. That reference will always point to the active view controller.
In your individual view controllers, do something like the following:
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
NSNotificationCenter* nc = [NSNotificationCenter defaultCenter];
[nc postNotificationName:#"XYZViewControllerDidBecomeActiveNotification"
object:self];
}
Of course, you would want to use some kind of constant for the notification name.
In your ApolloTabBarController class, register for XYZViewControllerDidBecomeActiveNotification and implement something like:
- (void)viewControllerDidBecomeActive:(NSNotification *)notification
{
self.activeViewController = [notification object];
}
I hope that helps!
When you're setting up each view controller for each of the tabs, set the tag property of the UITabBarItem to correspond to the index of the view controller in the tab bar's viewControllers array.
UIViewController* myFirstVC = [[UIViewController alloc] init];
UIViewController* mySecondVC = [[UIViewController alloc] init];
// "self" is your ApolloTabBarController.
[self setViewControllers:#[myFirstVC, mySecondVC]];
myFirstVC.tabBarItem =
[[UITabBarItem alloc] initWithTitle:#"First" image:nil tag:0];
mySecondVC.tabBarItem =
[[UITabBarItem alloc] initWithTitle:#"Second" image:nil tag:1];
Then, you'll be able to grab a reference to view controller.
// In your example, your ApolloTabBarController acts as its own delegate.
- (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item
{
UIViewController* activeVC =
[[self viewControllers] objectAtIndex:[item tag]];
}
I am very new to Xcode and Objective-C as a whole. I have begun my first coding project/app this past week and I am running into a quick problem.
When creating my app, I started by dragging ViewControllers from the right Utilities menu section into my workspace area. I then added UIButtons from the same menu and Control+dragged a modal connection between the two (when the button is pressed, the view changes from one controller to the other?). My experience has been largely UI based and very little coding.
My Issue:
I have 5 ViewControllers each individually dragged from the Utilities menu. Four of them are linked by UIButtons titled "Next" and "Prev" according to the order I want them navigated. If at any time, a button present on all for ViewControllers is pressed on any given ViewController, you are presented with a separate "Menu" ViewController that has a "Back" UIButton. When this button is pressed, I want the ViewController to be switched back to whichever of the 4 VC's I was previously on when I pressed "Menu." All of the ViewControllers are in class ViewController.
Logically, this can be accomplished through setting a couple integers:
#implementation ViewController
int buttonPressedHere = 0;
- (IBAction)view1menu:(id)sender{
buttonPressedHere = 1;
}
- (IBAction)view2menu:(id)sender{
buttonPressedHere = 2;
}
- (IBAction)view3menu:(id)sender{
buttonPressedHere = 3;
}
- (IBAction)view4menu:(id)sender{
buttonPressedHere = 4;
}
- (void)setPrevious{
if(buttonPressedHere == 1)
//insert code to return to previous ViewController 1
if(buttonPressedHere == 2)
//insert code to return to previous ViewController 2
if(buttonPressedHere == 3)
//insert code to return to previous ViewController 3
if(buttonPressedHere == 4)
//insert code to return to previous ViewController 4
}
#end
The issue here is, I don't know how to get the identifier of the ViewController I want to switch to. Is there an easier way? Help!
First, define class for previous ViewControllers in Xib or Storyboard:
This is usually needed, you will custom the previous four views' activities further. The custom view controller class should inherit from UIViewController.
Then, you are able to control the pop action by following code:
- (void)setPrevious {
if (buttonPressedHere == 1) {
[self popToPreviousViewControllerWithClass:[FirstViewController class]];
}
else if (buttonPressedHere == 2) {
[self popToPreviousViewControllerWithClass:[SecondViewController class]];
}
else if (buttonPressedHere == 3) {
[self popToPreviousViewControllerWithClass:[ThirdViewController class]];
}
else if (buttonPressedHere == 4) {
[self popToPreviousViewControllerWithClass:[FourthViewController class]];
}
}
- (void)popToPreviousViewControllerWithClass:(Class)class {
for (UIViewController *previousViewController in self.navigationController.viewControllers) {
if ([previousViewController isKindOfClass:class]) {
[self.navigationController popToViewController:previousViewController animated:YES];
break;
}
}
}
There's a behavior in the Line messenger app (the de facto messenger app in Japan) that I'm trying to emulate.
Basically, they have a modal view controller with a scroll view inside. When the scroll action reaches the top of its content, the view controller seamlessly switches to an interactive dismissal animation. Also, when the gesture returns the view to the top of the screen, control is returned to the scroll view.
Here's a gif of how it looks.
For the life of me, I can't figure out how they did it. I've tried a few different methods, but they've all failed, and I'm out of ideas. Can anyone point me in the right direction?
EDIT2
To clarify, the behavior that I want to emulate isn't just simply dragging the window down. I can do that, no problem.
I want to know how the same scroll gesture (without lifting the finger) triggers the dismissal transition and then transfers control back to the scroll view after the view has been dragged back to the original position.
This is the part that I can't figure out.
End EDIT2
EDIT1
Here's what I have so far. I was able to use the scroll view delegate methods to add a target-selector that handles the regular dismissal animation, but it still doesn't work as expected.
I create a UIViewController with a UIWebView as a property. Then I put it in a UINavigationController, which is presented modally.
The navigation controller uses animation/transition controllers for the regular interactive dismissal (which can be done by gesturing over the navigation bar).
From here, everything works fine, but the dismissal can't be triggered from the scroll view.
NavigationController.h
#interface NavigationController : UINavigationController <UIViewControllerTransitioningDelegate>
#property (nonatomic, strong) UIPanGestureRecognizer *gestureRecog;
- (void)handleGesture:(UIPanGestureRecognizer*)gestureRecognizer;
#end
NavigationController.m
#import "NavigationController.h"
#import "AnimationController.h"
#import "TransitionController.h"
#implementation NavigationController {
AnimationController *_animator;
TransitionController *_interactor;
}
- (instancetype)init {
self = [super init];
self.transitioningDelegate = self;
_animator = [[AnimationController alloc] init];
_interactor = [[TransitionController alloc] init];
return self;
}
- (void)viewDidLoad {
[super viewDidLoad];
// Set the gesture recognizer
self.gestureRecog = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(handleGesture:)];
[self.view addGestureRecognizer:_gestureRecog];
}
- (id<UIViewControllerInteractiveTransitioning>)interactionControllerForDismissal:(id<UIViewControllerAnimatedTransitioning>)animator {
if (animator == _animator && _interactor.hasStarted) {
return _interactor;
}
return nil;
}
- (id<UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed {
if (dismissed == self || [self.viewControllers indexOfObject:dismissed] != NSNotFound) {
return _animator;
}
return nil;
}
- (void)handleGesture:(UIPanGestureRecognizer *)gestureRecog {
CGFloat threshold = 0.3f;
CGPoint translation = [gestureRecog translationInView:self.view];
CGFloat verticalMovement = translation.y / self.view.bounds.size.height;
CGFloat downwardMovement = fmaxf(verticalMovement, 0.0f);
CGFloat downwardMovementPercent = fminf(downwardMovement, 1.0f);
switch (gestureRecog.state) {
case UIGestureRecognizerStateBegan: {
_interactor.hasStarted = YES;
[self dismissViewControllerAnimated:YES completion:nil];
break;
}
case UIGestureRecognizerStateChanged: {
if (!_interactor.hasStarted) {
_interactor.hasStarted = YES;
[self dismissViewControllerAnimated:YES completion:nil];
}
_interactor.shouldFinish = downwardMovementPercent > threshold;
[_interactor updateInteractiveTransition:downwardMovementPercent];
break;
}
case UIGestureRecognizerStateCancelled: {
_interactor.hasStarted = NO;
[_interactor cancelInteractiveTransition];
break;
}
case UIGestureRecognizerStateEnded: {
_interactor.hasStarted = NO;
if (_interactor.shouldFinish) {
[_interactor finishInteractiveTransition];
} else {
[_interactor cancelInteractiveTransition];
}
break;
}
default: {
break;
}
}
}
#end
Now, I have to get that gesture handling to trigger when the scroll view has reached the top. So, here's what I did in the view controller.
WebViewController.m
#import "WebViewController.h"
#import "NavigationController.h"
#interface WebViewController ()
#property (weak, nonatomic) IBOutlet UIWebView *webView;
#end
#implementation WebViewController {
BOOL _isHandlingPan;
CGPoint _topContentOffset;
}
- (void)viewDidLoad {
[super viewDidLoad];
[self.webView.scrollView setDelegate:self];
}
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
if ((scrollView.panGestureRecognizer.state == UIGestureRecognizerStateBegan ||
scrollView.panGestureRecognizer.state == UIGestureRecognizerStateChanged) &&
! _isHandlingPan &&
scrollView.contentOffset.y < self.navigationController.navigationBar.translucent ? -64.0f : 0) {
NSLog(#"Adding scroll target");
_topContentOffset = CGPointMake(scrollView.contentOffset.x, self.navigationController.navigationBar.translucent ? -64.0f : 0);
_isHandlingPan = YES;
[scrollView.panGestureRecognizer addTarget:self action:#selector(handleGesture:)];
}
}
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate {
NSLog(#"Did End Dragging");
if (_isHandlingPan) {
NSLog(#"Removing action");
_isHandlingPan = NO;
[scrollView.panGestureRecognizer removeTarget:self action:#selector(handleGesture:)];
}
}
- (void)handleGesture:(UIPanGestureRecognizer*)gestureRecognizer {
[(NavigationController*)self.navigationController handleGesture:gestureRecognizer];
}
This still doesn't work quite right. Even during the dismissal animation, the scroll view is still scrolling with the gesture.
End EDIT1
That is a custom interactive transition.
First, you need set transitioningDelegate of UIViewController
id<UIViewControllerTransitioningDelegate> transitioningDelegate;
Then implment these two method to
//Asks your delegate for the transition animator object to use when dismissing a view controller.
- animationControllerForDismissedController:
//Asks your delegate for the interactive animator object to use when dismissing a view controller.
- interactionControllerForDismissal:
When drag to top, you start the transition, you may use UIPercentDrivenInteractiveTransition to control the progress during scrolling.
You can also refer to the source code of ZFDragableModalTransition
Image of ZFDragableModalTransition
As explained here the solution is quite complex. The person who answered, #trungduc, programmed a little demo published on github doing the sought behaviour. You can find it here.
The easiest way of making this work is to copy the 4 files found in /TestPanel/Presentation/ in the attached github repository, to your project. Then add the PanelAnimationControllerDelegate to your View Controller containing the scroll view (i.e. using the protocol).
Add the following to your View Controller, to satisfy the protocol:
func shouldHandlePanelInteractionGesture() -> Bool {
return (scrollView.contentOffset.y == 0);
}
Add this to deactivate the bouncing effect at the top:
func scrollViewDidScroll(_ scrollView: UIScrollView) {
scrollView.bounces = (scrollView.contentOffset.y > 10);
}
Set scrollView.delegate = self
Before presenting your View Controller containing the scroll view set the following propreties to your View Controller:
ScrollViewController.transitioningDelegate = self.panelTransitioningDelegate
ScrollViewController.modalPresentationStyle = .custom
If you want to change the size of your ScrollViewController, you will need to comment out the override of the frameOfPresentedViewInContainerView in the PanelPresentationController file (one of the 4). Then in the presentationTransitionWillBegin method, you will need to set let frameOfPresentedViewInContainerView = self.frameOfPresentedViewInContainerView.insetBy(dx: 0, dy: 20) with the wanted inset of dx and dy.
Thank you to trungduc for this amazing solution!!
Setting:
Assume I have 2 TableViewControllers(All in their own NavigationControllers), which contain TypeA&B items correspondingly.
In any TableView, If I tap "+" button, it will segue to a Add[?]ItemViewController("?" is The Type of Item: A or B).So normally, even if I already in the AddView, I can also switch to another View By tapping Tab Bar Icon, right?
SO How can I inhibit user to switch if they already entered one AddView?
Use the Swift code? or just change the storyboard structure?
Here is the Structure of Main.storyboard:
We've done exactly the same in our application. To hide the default
TabBar, simply override the hidesBottomBarWhenPushed method in your
parent view controller (or in every view controller in your App)
#pragma mark - Overriden UIViewController methods
- (BOOL)hidesBottomBarWhenPushed {
return YES;
}
another Solution
You can also Hide Tab bar
// pass a param to describe the state change, an animated flag and a completion block matching UIView animations completion
- (void)setTabBarVisible:(BOOL)visible animated:(BOOL)animated completion:(void (^)(BOOL))completion {
// bail if the current state matches the desired state
if ([self tabBarIsVisible] == visible) return;
// get a frame calculation ready
CGRect frame = self.tabBarController.tabBar.frame;
CGFloat height = frame.size.height;
CGFloat offsetY = (visible)? -height : height;
// zero duration means no animation
CGFloat duration = (animated)? 0.3 : 0.0;
[UIView animateWithDuration:duration animations:^{
self.tabBarController.tabBar.frame = CGRectOffset(frame, 0, offsetY);
} completion:completion];
}
// know the current state
- (BOOL)tabBarIsVisible {
return self.tabBarController.tabBar.frame.origin.y < CGRectGetMaxY(self.view.frame);
}
// illustration of a call to toggle current state
- (IBAction)pressedButton:(id)sender {
[self setTabBarVisible:![self tabBarIsVisible] animated:YES completion:^(BOOL finished) {
NSLog(#"finished");
}];
}
another Solution
You can set the UIViewController.hidesBottomBarWhenPushed instead:
DetailViewController *detailViewController = [[DetailViewController alloc] init];
detailViewController.hidesBottomBarWhenPushed = YES;
[[self navigationController] pushViewController:detailViewController animated:YES];
I am new to iPad development. I know how to use images for Page view controller. My problem is i have 3 charts which i have done in three view controllers.. How can i combine all the view controllers in a single page view controller. I have for now kept three view controllers.
I have tried lot of tutorials but none explains me how to use three view controllers
I have done like this now but this is wrong
-(IBAction)handleSwipeLeft:(UISwipeGestureRecognizer*)sender {
LastLearningSessionViewController *last=[[LastLearningSessionViewController alloc]init];
[self presentViewController:last animated:YES completion:nil];
}
From what I can see it appears you may have done this slightly wrong.
First you need to create a controller for the UIPageViewController, that is a datasource and delegate.
Please note all code has been written directly to the answer and has not been tested.
MyUIPageViewController.h
#interface
MyUIPageViewController : UIViewController <UIPageViewControllerDataSource, UIPageViewControllerDelegate>
{
NSNumber *currentIndex //Using NSNumber to handle 32bit/64bit easier.
}
#property (nonatomic, strong) UIPageViewController *pageViewController
#property (nonatomic, strong) NSArray *controllersArray //Used to help navigate between controllers
#end
MyUIPageViewController.m
#import MyUIPageViewController.h
#implementation MyUIPageViewController
- (instancetype)initWithNibName:(NSString *)nibName
bundle:(NSBundle *)nibBundle
{
if(self = [super initWithNibName:nibName bundle:nibBundle])
{
//Create ChartViewController1 (UIViewController *ChartViewController1 = [[ChartViewController1Class alloc] init];)
//Create ChartViewController2
//Create ChartViewController3
//Now we have created all 3 chartViewControllers, create our controllers Array with the controller objects.
self.controllersArray = [[NSArray alloc] initWithObjects:ChartViewController1, ChartViewController2, ChartViewController3];
//Currently setting to 0. A proper way of handling with Multi-tasking is to store the index value from before, but not dealing with that right now.
currentIndex = [NSNumber numberWithInt:0];
//Create our PageViewController. Currently set to PageCurl and all pages will go from left to right.
//These options can be changed, if so desired (Scroll Effect like iBooks Textbooks and a page change from bottom to top like a flip book.
self.pageViewController = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStylePageCurl navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal options:nil];
//Set ourselves as the datasource and delegate to handle the pages etc.
self.pageViewController.datasource = self;
self.pageViewController.delegate = self;
//We need to set the viewControllers for the PageViewController, because this is the initial load, we will not animate the change.
[self.pageViewController setViewControllers:self.controllersArray direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:^ (BOOL finished) {
//No animation is being done so no need to worry.
}];
//Set our view to be the pagecontroller's view, so we can see it all.
self.view = self.pageViewController.view;
}
return self;
}
//DataSource Methods:
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController
viewControllerBeforeViewController:(UIViewController *)viewController
{
//As this method looks for the previous view controller. If our current index is 0, there is no previous VC. But using the objectAtIndex method on the array would throw a outOfRange exception
if([self.currentIndex intValue] <= 0)
{
return nil;
}
else
{
return [self.controllersArray objectAtIndex:([self.currentIndex intValue] - 1)];
}
}
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController
viewControllerAfterViewController:(UIViewController *)viewController
{
//As this method looks for the next view controller. If our current index is the maximum value the array count and be (2), there isn't a new VC to push. But using the objectAtIndex method on the array would throw a outOfRange exception
if([self.currentIndex intValue] >= self.controllersArray.count)
{
return nil;
}
else
{
return [self.controllersArray objectAtIndex:([self.currentIndex intValue] + 1)];
}
}
//Delegate Methods
- (void)pageViewController:(UIPageViewController *)pageViewController didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray *)previousViewControllers transitionCompleted:(BOOL)completed
{
if(transitionCompleted)
{
//We will update our currentIndex, only if the transition has happened.
switch (previousViewControllers)
{
case 0:
//Something went wrong :S
break;
case 1:
//We are either in Vertical Orientation of the first viewController is only being shown.
if([pageViewController.viewControllers contains:[self.controllersArray objectAtIndex:([currentIndex intValue]+ 1)]])
{
currentIndex = [NSNumber numberWithInt:([currentIndex intValue] + 1)];
}
else
{
if([currentIndex intValue] == 0)
{
//Saftey Net.
}
else
{
currentIndex = [NSNumber numberWithInt:([currentIndex intValue] - 1)];
}
}
break;
case 2:
//We are in horizontal Orientation.
//With 3 View Controllers the only ViewController that will be in both arrays is the ViewController at index 1. We just need to see if the pageViewControllers viewcontrollers array contains the ViewController at index 0 or index 1.
if([pageViewController.viewControllers contains:[self.controllersArray objectAtIndex:([currentIndex intValue]+ 1)]])
{
currentIndex = [NSNumber numberWithInt:([currentIndex intValue] + 1)];
}
else
{
if([currentIndex intValue] == 0)
{
//Saftey Net.
}
else
{
currentIndex = [NSNumber numberWithInt:([currentIndex intValue] - 1)];
}
}
break;
default:
//Should never reach here.
break;
}
}
}
#end
It is also handy to look at the reference documentation:
Class Reference - Apple Docs