I am having an issue with my picker view rotating. I am using a normal UIPickerView and autorotation, all of which is done in code (but the autorotation isn't what I'm concerned about). The picker view does exactly what I want it to do after rotation. The issue is that my background is black, and during rotation the background of the picker view turns white in places. I am pretty sure that these are the deep subviews of the picker view simply because of debugging using Xcode's visual debugger and taking mid-rotation screen shots.
My question is, how do I get the background of the picker view to not appear momentarily white?
I have tried something along these lines:
-(void)setBackgroundBlackForSubviews:(NSArray *)subviews
{
if (subviews.count) {
for (UIView *view in subviews) {
[view setBackgroundColor:[UIColor blackColor]];
[self setBackgroundBlackForSubviews:view.subviews];
}
}
}
and pass in pickerView.subviews as the initial parameter, but this doesn't produce the desired result.
So, what solution should I try to get the background to appear black throughout the entire rotation process?
Related
I have a UIViewController that displays a form with several text fields. In order to prevent the text fields from getting blocked by the keyboard, I resize the controller's view when the keyboard appears and disappears.
However, when the keyboard is up, the user presses the home button, and then returns to the app, the controller's view will be resized again to the size it was before the keyboard was up and the keyboard will still be showing.
What's causing my controller's view to be resized on return from background, and how can I prevent it?
Maybe you need to nest a UIView，for example
_backgroundView = [UIView new];
_backgroundView.backgroundColor = [UIColor whiteColor];
_backgroundView.frame = CGRectZero;
[self.view addSubview:_backgroundView];
[_backgroundView mas_makeConstraints:^(MASConstraintMaker *make) {
make.left.right.top.mas_equalTo(self.view);
make.height.mas_equalTo(self.view.mas_height);
}];
then you need add your custom UIView to this backgroundView.
as you said，UIViewController's view will be resized after return from background. so you can nest a UIView of the same size as self.view，and add your custom UIView to this UIView.
In order to prevent the text fields from getting blocked by the keyboard, you can resize this backgroundView when the keyboard appears and disappears. and this time when you click the home button to enter the background or return from background，self.view won't be resized and backgroundView won't be resized too.
Although it is a bit of a hassle, this will solve your problem and will not affect the user experience anymore. And if you have a better solution, please let me know
It sounds like you are setting the frame and not using autolayout. When the view reappears viewDidLayoutSubviews gets called and your frame gets recalculated obliterating your previous change. You can either:
1) Move your frame to viewDidLayoutSubviews and change its size only if the keyboard is showing.
2) Use autolayout and simply pull up your bottom constraint .constant by an amount equal to your keyboard height.
In both cases you should call layoutIfNeeded to trigger autolayout/viewDidLayoutSubviews when the keyboard appears/disappears. This behavior is a good example of why you should not manipulate your frames outside of viewDidLayoutSubviews except for transitory animations.
I'm loading a view controller modally via another view controller and I'm trying to change the background color using:
override func viewDidLoad() {
super.viewDidLoad()
transparentBG.backgroundColor? = UIColor.black.withAlphaComponent(0.4)
// transparentBG is a UIView defined in storyboard
}
While the view is animating into position (sliding up) it maintains the alpha value I set. But once it reaches the top of the screen it removes the alpha component and is changing the color to what looks like the color with the alpha component, so like a gray color, but with no transparency as seen in the image below.
Is there anyway to maintain the alpha component after if finishes loading?
Step one: Change this to an overFullScreen presentation.
Step two: There is no step two.
just set presentaion style on viewContriller
[myViewcontroller setModalPresentationStyle:UIModalPresentationCustom];
[myViewcontroller setModalTransitionStyle:UIModalTransitionStyleCrossDissolve];
[self.navigationController presentViewController:myViewcontroller animated:true completion:nil];
What is happening is that the alpha is being kept, but the previous view is being removed once the animation is complete.
There are a couple approaches you can take.
Take a screen shot of the previous view and insert that as a background in the new view. Look at the drawViewHierarchyInRect function. You can grab the screen shot in the new view controller's init method, then set it as a background image in the viewDidLoad.
The other approach would be to add the overlay as a subview, either to the existing view, or even the window itself.
I've used both methods successfully.
I'm pushing a UIViewController (A) with clearColor as background in a UINavigationController (N).
N is placed inside a Container View. This view has a background that I want to show always.
Then, when Push is animated it shows a grey/transparent background in my VC (A) and when it finishes its animation, it shows correctly.
Is there any way to avoid this grey color?
I have 'done' it by putting a white view background in A and making it disappear in viewDidAppear but I think it can be done without that trick...
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
__weak TestsViewController *weakSelf = self;
[UIView animateWithDuration:.3 animations:^{
TestsViewController *ownSelf = weakSelf;
ownSelf.backgroundView.alpha = 0;
}];
}
Set your app's window's background colour to white:
// applicationDidFinishLaunching
self.window.backgroundColor = [UIColor whiteColor];
The push animation often ends up using the background colour of the window behind the transparent areas, and the window background colour is clear by default, so it shows black through the transparent navigation bars and toolbars.
EDIT: Sorry, misunderstood what the issue was. When you push a view controller with a transparent background colour, the background you see behind the view controller is the shadow that is rendered behind your view controller (you can see the edge of it when in a non-transparent view controller).
This question has an answer to your issue. Basically, you have to implement a custom animation controller, to provide the transition animation yourself (as described here). It would probably be easier to continue using your trick than implementing your own custom navigation transition.
The iOS7 Facebook App has a right side menu that can be shown by swiping right to left or clicking on the upper right button. When this menu is opened the there is a color transition in the entire status bar from blue to black and vice-versa when closed.
This image shows both status bar side-to-side
This looks like a very good solution for iOS Apps with side menus.
Any ideas or ways about how to accomplish this?
I am currently using JASidePanels.
Thanks!
I managed to find a very simple, elegant way to do this, that mimics the Facebook app functionality perfectly.
Here's my approach:
Create view with status bar frame
Set view background color to black, opacity to 0
Add view as subview to any root view (you need a view that will cover both the center view and the menus, so that it won't be confined to any single view - a good option for this is the container view controller used by your menu controller implementation)
Set view's opacity in your menu controller implementation's menu animation method
Here's my specific implementation, using MMDrawerController:
I subclassed MMDrawerController (I actually already had a subclass for using MMDrawerController with storyboards), and added this code to the class's init method:
// Setup view behind status bar for fading during menu drawer animations
if (OSVersionIsAtLeastiOS7()) {
self.statusBarView = [[UIView alloc] initWithFrame:[[UIApplication sharedApplication] statusBarFrame]];
[self.statusBarView setBackgroundColor:[UIColor blackColor]];
[self.statusBarView setAlpha:0.0];
[self.view addSubview:self.statusBarView];
}
// Setup drawer animations
__weak __typeof(&*self) weakSelf = self; // Capture self weakly
[self setDrawerVisualStateBlock:^(MMDrawerController *drawerController, MMDrawerSide drawerSide, CGFloat percentVisible) {
MMDrawerControllerDrawerVisualStateBlock block;
block = (drawerSide == MMDrawerSideLeft) ? [MMDrawerVisualState parallaxVisualStateBlockWithParallaxFactor:15.0] : nil; // Right side animation : Left side animation
if(block){
block(drawerController, drawerSide, percentVisible);
}
[weakSelf.statusBarView setAlpha:percentVisible]; // THIS IS THE RELEVANT CODE
}];
I also added self.statusBarView as a private property.
The first section of code creates a view, configures it, and adds it as a subview of the MMDrawerController subclass's view. The OSVersionIsAtLeastiOS7() method is a custom method that simplifies the check to see if the device is running iOS 7 (if it isn't, your custom view will show up below the status bar, which you don't want).
The second section of code is MMDrawerController's setDrawerVisualStateBlock method, which sets the animations code to be performed when a menu is being opened and closed. The first few lines of code are boilerplate code that sets one of the prebuilt animations blocks to each menu (I wanted parallax on the left, but nothing on the right). The relevant code is the last line of the block: [weakSelf.statusBarView setAlpha:percentVisible];, which sets the status bar view's opacity to match the percentage that the menu is currently open. This allows for the smooth cross animation you see in the Facebook app. You'll also notice I've assigned self to a variable weakSelf, so as to avoid the "retain cycle" compiler warning.
This is my specific approach using MMDrawerController and a subclass, which I did more for convenience because I already had the subclass in place, than because it is necessarily the best approach or the only way to do it. It could probably be implemented in several other ways, using MMDrawerController without a subclass, or using any other side-drawer menu implementation.
The ending result is a smooth fading to black animation behind the status bar, exactly as you see in the new Facebook app.
I've been trying to accomplish the same thing. The method I am using to do this is based on the following concepts:
A background image with a height of 64 points will fill both the
UINavigationBar and the UIStatusBar.
A background image with a height of 44 points will fill the UINavigationBar and leave the
UIStatusBar black.
You can add an subview to the top of the current navigationController's view and it will sit underneath the UIStatusBar.
So, first, you need to create two images with your desired UINavigationBar look:
A 640x128px image to cover navigation bar and status bar (ImageA)
And a 640x88px image to cover the navigation bar but leave the status bar black (ImageB).
In the application:didFinishLaunchingWithOptions: method, set the background of your UINavigationBar with ImageA with [[UINavigationBar appearance] setBackgroundImage:[UIImage imageNamed:#"ImageA.png"] forBarMetrics:UIBarMetricsDefault];
When the side menu starts to open, you are going to want switch the UINavigationBar so it uses ImageB and create a view which you will add underneath the UIStatusBar. Here is some sample code for doing just that:
// Add a property for your "temporary status bar" view
#property (nonatomic, strong) UIView *temporaryStatusBar;
And in the code where the side menu starts to open:
// Create a temporary status bar overlay
self.temporaryStatusBar = [[UIView alloc] initWithFrame:[[UIApplication sharedApplication] statusBarFrame]];
self.temporaryStatusBar.backgroundColor = [UIColor yourColor];
[self.navigationController.view addSubview:self.temporaryStatusBar];
// Update both the current display of the navigationBar and the default appearance values
[[UINavigationBar appearance] setBackgroundImage:[UIImage imageNamed:#"imageB.png"] forBarMetrics:UIBarMetricsDefault];
[self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:#"imageB.png"] forBarMetrics:UIBarMetricsDefault];
[self.navigationController.navigationBar setNeedsDisplay];
As the side menu animates open, or as the user pans the menu, all you need to do then is adjust the alpha level of the UIStatusBar overlay. When the side menu is fully open, the UINavigationBar should have ImageB as its background image and the UIStatusBar overlay should have an alpha of 0. When the side menu closes, you'll want to replace the UINavigationBar background with ImageA and remove the UIStatusBar overlay.
Let me know if this works for you!
You can use this awesome slide menu library
https://github.com/arturdev/AMSlideMenu
In this demo project you can see how to do that by writing 4 lines of code.
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
// Setting navigation's bar tint color
self.navigationController.navigationBar.barTintColor = [UIColor colorWithHex:#"#365491" alpha:1];
// Making view with same color that navigation bar
UIView *statusBarView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, 20)];
statusBarView.backgroundColor = [UIColor colorWithHex:#"#365491" alpha:1];
// Replace status bar view with created view and do magic :)
[[self mainSlideMenu] fixStatusBarWithView:statusBarView];
}
I've been experiencing some troubles with animating the alpha of certaing subviews of my Navigation Bar. Here is the initial state of the bar:
Here is how far did I get by now:
The thing is that I need to make all this "star", "new" and other round buttons transparent when the search is active (I need to reduce their alpha to zero). I am trying to make them transparent in the following methods of the delegate:
- (void)searchBarCancelButtonClicked:(UISearchBar *)asearchBar
- (void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar
- (void)searchBarTextDidEndEditing:(UISearchBar *)searchBar
- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar
In all of them I do quite the same code:
//parent is just a pointer of a search delegate, which points to view controller
for (UIView * someViewToFade in parent.navigationController.navigationBar.subviews) {
if (someViewToFade.tag == 88 || someViewToFade.tag == 11) {
NSLog("someViewToFade.alpha before changes = %f", someViewToFade.alpha);
someViewToFade.alpha = 0.0; //or 1.0, depending on the method
}
}
However, I couldn't achieve the desired result this way, though I am getting right alpha values at that NSLog, buttons don't fade at all. Are there any suggestions on what can I possibly be doing wrong?
EDIT 1:
I think I should add some description of the view hierarchy in my case. Well, I have the UISegmentedConrol, which holds these round buttons and also two UIImageViews, the background for segmented control, and the triangle pointer. All of these views are added to the navigation bar as it's subviews. Also there is a rectangular view, which holds the searchbar, and is also added as a subview to the navigation bar later, so it's the top view in the hierarchy. Also, I am animating my searchBar by simply animating the frame of its superview (expanding or condensing it, when the events above occur in the delegate). I hope I've given all the necessary information.
Its been a while since I did ios programming. It is possible that even though you are setting the alpha, but not triggering a repaint. [UIView setNeedsDisplay] might help to refresh the drawing in the next drawing cycle.
For a reference: What is the most robust way to force a UIView to redraw?
1) This is UI update problem,write this statement after any UI update code.
[[NSRunLoop currentRunLoop] runUntilDate:[NSDate date]];
this will update your GUI.
or
2) use perform selector on main thread and update your UI in selector method.
[self performSelectorOnMainThread:#selector(UpdateUIMethod) withObject:self waitUntilDone:NO];