I want to display navigation bar on screen gradually when user scroll on screen. and Want to make it alpha to hide navigation bar (Setting Alpha because i want to show back arrow of navigation controller).
While scrolling upwords its fine.
But while settling scrollview at initial position if i set its translucent property is true i.e. NavigationController.NavigationBar.Translucent = true;
then it shifts content upwords with the same height of navigation bar.
Expected Result : Scrollview should be at initial state after scroll completion.
Can anyone please help me on this ?
If you have enabled the AutomaticallyAdjustsScrollViewInsets on iOS 10- or ContentInsetAdjustmentBehavior on iOS 11 and you have added the correct constraints for your scrollView. The scroll view will auto adjust its insets to make the content show under the NavigationBar.
But If you set the NavigationController.NavigationBar.Translucent = true; and use MyScrollView.SetContentOffset(new CGPoint(0, 0), true); to set scrollview at initial position. This will cause your issue: the content seems covered by the Navigation Bar.
You can use another api the make the scroll view scroll to top:
MyScrollView.ScrollRectToVisible(new CGRect(0, 0, 5, 5), true);
This will place the scroll view's content below the navigation bar. Or try to judge the Translucent state, if this is true use this to get back the initial place:
MyScrollView.SetContentOffset(new CGPoint(0, -NavigationController.NavigationBar.Frame.GetMaxY()), true);
Related
I view imbedded in a Navigation Controller which is slightly transparent. This view contains a UIscrollview. This UIScrollview has the following subviews: UIImageView, UILabel, and UIWebview. All these other views are working correctly. When the view loads, everything is in the correct position (The views are below the Navigation Bar). However, as soon as the screen is tapped, the scrollview repositions itself to the top of the view (aka behind the Navigation Bar, which is at the top, and I can see that this is true because the Nav Bar is slightly transparent)
Any idea why this is happening? I set up the scrollview like this:
self.scrollView.frame = CGRectMake(0, self.navigationController.navigationBar.frame.size.height, self.view.window.frame.size.width, self.view.window.frame.size.height);
Also set these properties:
self.scrollView.scrollEnabled = YES;
self.scrollView.alwaysBounceVertical = YES;
self.scrollView.bounces = YES;
Anybody know why this is happening?
I'd similar problem, but only on iOS 7.0. Try to set the translucent = NO property of the navigationBar. This will make the navigationBar opaque. Although if you want the navigationBar to be transparent, try to change the contentInset of the scrollView to adjust the content as you want. Hope that this will help :)
In my UIViewController I have UIImageView that takes up the full size of the controller (screen) and serves as a background. On top of UIImageView I have a UITableView with a clear background. I set the navigation bar to translucent like this:
self.navigationController.navigationBar.translucent = YES;
UIImageView is underneath the navigation bar as I want it to be. Unfortunately the same happens to UITableView. I want to put UITableView at the bottom of navigation bar, leaving UIImageView underneath. If I set:
[self setEdgesForExtendedLayout:UIRectEdgeBottom]
then UITableView is at the bottom of the navigation bar, but the same happens also to UIImageView. What would be the easiest solution to leave UIImageView underneath the navigation bar and push down the UITableView at the bottom of the navigation bar?
By default in iOS 7 the content extends to the top and bottom of the screen, underneath any navigation bars, tool bars, or tab bars. If you were to set the frame of the table view to be start after the navigation bar, the content of the table view would not scroll beneath the navigation bar providing the nice blur effect.
What you'll probably want to do instead, is keep the y origin of your table view at 0, underneath the navigation bar, and set the content inset so the content starts after the navigation bar.
This is pretty simple. If you're using auto layout the top layout guide of the view controller will recognise the height of the status bar and navigation bar so you don't need to calculate this yourself. The bottom of the navigation bar should end at 66.
//Using Auto Layout
CGFloat navigationBarHeight = self.topLayoutGuide.length;
//Not using Auto Layout
UINavigationBar *nav = self.navigationController.navigationBar;
CGFloat navigationBarHeight = nav.frame.origin.y + nav.frame.size.height;
myTableView.contentInset = UIEdgeInsetsMake(navigationBarHeight, 0, 0, 0)
And of course if you actually do want the frame to start after the navigation bar the height above stays the same, you just need to manually set the frame of the table view.
CGRect tableViewFrame = self.view.bounds;
tableViewFrame.origin = CGPointMake(tableViewFrame.origin.x, navigationBarHeight);
tableViewFrame.size = CGSizeMake(tableViewFrame.size.width, tableViewFrame.size.height - navigationBarHeight*2);
myTableView.frame = tableViewFrame;
EDIT: Ah, almost forgot. You'll also want to change the scrollIndicatorInsets to match the contentInset, so your scroll bars don't move offscreen.
myTableView.scrollIndicatorInsets = myTableView.contentInset;
In iOS 6, you could scroll to the top of a UIScrollView using:
[scrollView setContentOffset:CGPointZero animated:YES];
If you use that code in iOS 7 with a translucent navigation bar, you get a result that is technically correct, but not user friendly. The top of the scroll view will be positioned to the origin of the screen.
How would I position the top of the scroll view to the bottom of the navigation bar instead? I'm looking for a solution that is not hardcoded, because in my application, sometimes the status bar and navigation bar can be hidden. Also, I would like to keep the translucent effect instead of copping out and doing self.edgesForExtendedLayout = UIRectEdgeNone.
Instead of using hard-coded values, use the new API:
[self.scrollView setContentInset:UIEdgeInsetsMake(self.topLayoutGuide.length, 0, self.bottomLayoutGuide.length, 0)];
You are setting the content insets of the scroll view to top and bottom layout guides. So if you have a navigation bar that is 44 points and a status bar of 20 points and no status bar, it will be 64 points top (in portrait) and 0 points bottom.
You should do this in viewDidLayoutSubviews.
You have to use this method -> setContentOffset:animated:
[_scrollView setContentOffset:CGPointZero animated:YES];
Just use -60 for the y coordinate or, better yet, get the statusbar and navigation bar heights dynamically because they both change.
See UIApplication's statusBarFrame and self.navigationController.navigationBar.bounds, I think.
I started building a TableView in my app by using a TableViewController in a storyboard. When you do this, you have a very cool effect when you scroll down your list : the cells moving behind the nav bar get blurred.
Some time later, I had to move from this TableViewController to a ViewController with a TableView inside (I had to add other views at the bottom of the table).
In order to avoid having the first cells hidden by the navigation bar (being over it), I added constraints to the Top and Bottom Layout Guides, and to the left and right edges of the view.
This works fine, but I lost the cool blurred scrolling effect : the cells seem to be disappearing before going behind the navigation bar.
I've seen workarounds with people not using constraints and putting magic numbers in interface builder. I cannot do this, first because I dislike it, and second because I have to be iOS 6 compatible.
What did I miss to be able to benefit again from the blurred navigation bar effect ?
You have to manually adjust the contentInset of the table view and make sure the table view frame origin is 0, 0.
In this way the table view will be below the navigation bar, but there will be some margin between the content and the scroll view edges (the content gets shifted down).
I advise you to use the topLayoutGuide property of the view controller to set the right contentInsets, instead of hard coding 64 (status bar + navigation bar).
There's also bottomLayoutGuide, which you should use in case of UITapBars.
Here is some sample code (viewDidLoad should be fine):
// Set edge insets
CGFloat topLayoutGuide = self.topLayoutGuide.length;
tableView.contentInset = UIEdgeInsetsMake(topLayoutGuide, 0, 0, 0);
By the way, this properties of UIViewController might help you (you should not need to change their default values, but I don't know what your view hierarchy is):
automaticallyAdjustsScrollViewInsets
edgesForExtendedLayout
extendedLayoutIncludesOpaqueBars
The tableView needs to be full screen. That is underneath the top and bottom bars. Note don't use the top and bottom layout guides as they are used for positioning relative to the bars not underneath.
Then you need to manually set the content inset of the tableview. This sets the initial scroll position to under the top bar.
Something like:
CGSize statusBarSize = [[UIApplication sharedApplication] statusBarFrame].size;
CGFloat h=MIN(statusBarSize.width, statusBarSize.height);
UIEdgeInsets e = UIEdgeInsetsMake(self.navigationController.navigationBar.bounds.size.height + h,
0.0f,
0.0f,
0.0f);
self.tableView.contentInset = e;
Not you get this functionality for free when using a tableView controller and the "Automatically Adjust content inset" settings
You probably have the coordinates of your tableView not set to (0, 0) to map to those of the viewController.view.frame or viewController.view.bounds. If you have done that, try setting
self.navigationController.navigationBar.translucent = YES;
UIViewController property edgesForExtendedLayout does the trick. If you are using storyboards just make sure Extended Edges Under Top Bars is on (and it is by default).
If you are creating your view controller programmatically try this:
- (void)viewDidLoad
{
[super viewDidLoad];
self.edgesForExtendedLayout = UIRectEdgeAll;
}
And of course, your table view needs to have proper autoresizing mask/layout constraints
edgesForExtendedLayout is not what you want here, as this will limit the table view underneath the navigation bar. In iOS 7, the view controllers uses fullscreen by default, and the property controlling where the tableview content starts is automaticallyAdjustsScrollViewInsets. This should be YES by default, so check if it is somehow set to NO, or try setting it explicitly.
Check this answer for a good explanation on how this works:
https://stackoverflow.com/a/19585104/1485715
I'm working on a project that needs to have the navigation bar height bigger than the default.
This is how i set the nav bar height:
- (CGSize)sizeThatFits:(CGSize)size {
if (iPad) {
CGSize newSize = CGSizeMake(768,86);
return newSize;
}
return CGSizeMake(320, 44);}
I set an bg image for the navigation bar and that's working ok.
The problem is that the back button and the right button item are not centered.
Does anyone know how to center them?
Thanks
It's generally bad practice to manipulate the navigation bar's height. I tried to do it a number of different ways for one project and every approach had a "gotcha". Namely, the navigation buttons are always justified to the bottom of the navigation bar, so adjusting it's height will cause the buttons to look like they're rendering towards the bottom of the bar. And the buttons will animate oddly as you push and pop other controllers. I would suggest not adjusting the height of the navigation bar.