I have a UITableView in a UINavigationController that contains a rightBarButtonItem which should hide the UITableView and show an MKMapView instead. The button seems to work great: it hides the UITableView, and shows the MKMapView. However, this MKMapView is empty. As in, completely white. I've tried to use a UILabel (just for testing purposes), and that doesn't appear either, so the problem must occur when I add the MKMapView (and UILabel) to the view hierarchy. Some relevant code:
- (void)viewDidLoad {
[super viewDidLoad];
self.mapView = [[MKMapView alloc] init];
mapView.hidden = YES;
[self.view addSubview:self.mapView];
// Some other stuff, table set up, etc.
}
That is the viewDidLoad of a class that inherits from UITableViewController. Now, I use the following method that gets called when tapped on the rightBarButtonItem of the UINavigationController:
- (void) toggleView {
if (self.mapView.isHidden) {
self.mapView.hidden = NO;
self.tableView.hidden = YES;
self.viewButton.title = #"List";
}
else {
self.mapView.hidden = YES;
self.tableView.hidden = NO;
self.viewButton.title = #"Map";
}
}
I am certain that function gets called, I have checked using NSLog. Also, the UITableView correctly disappears, and, I assume, the MKMapView (or whatever other UIView object for that matter) appears, but is empty/completely white. Does anybody see why I'm not seeing maps when trying to switch to Map View?
You should give it a size and position.
CGSize size = self.view.frame.size;
self.mapView =[[MKMapView alloc] initWithFrame:CGRectMake(0,0, size.width, size.height)];
To check the size in the console, add the following line in your toogleview method:
NSLog(#"%#", self.mapView);
Related
I'm building an app for a blog site.
I have a UINavigationController with a UITableViewController as it's root view.
I laid this out in a storyboard no problem, but I'm trying to drag an iAd view to the bottom of the screen and xcode will not let me add it.
It looks like I have to switch from a subclass of UITableViewController to a subclass of UIViewController, and just put my delegate and datasource methods in my subclassed UIViewController.
This seems wrong to me. I'm just trying to end up with a UITableView of article headlines, with a navbar up top, and an iAd at the bottom...
Advice? Suggestions?
Thanks in advance.
One of the easiest ways to accomplish this is using the UITableView's tableFooterView property. Yes, I know the footer stays at the bottom of the table, but it doesn't have to. You can set its frame within the table. Add the iAd as the footer like so:
self.tableView.tableFooterView = iAd;
Then, to adjust the frame of the iAd as the table scrolls, implement the UIScrollView delegate method: (This is possible because UITableView is a subclass of UIScrollView)
-(void)scrollViewDidScroll:(UIScrollView *)scrollView{
CGRect iAdFrame = iAd.frame;
CGFloat newOriginY = table.contentOffset.y + table.frame.size.height - iAdFrame.size.height;
CGRect newIAdFrame = CGRectMake(iAdFrame.origin.x, newOriginY, iAdFrame.size.width, iAdFrame.size.height);
iAd.frame = newIAdFrame;
}
You can see that the implementation is easy enough. We simply use the contentOffset y to determine how far down the frame of the iAd should be.
I tried to use the example above by NJones with adjusting the position of the tableFooterView, but I found out it was hard to manage it when reloading the data or refreshing the table.
Then I found out that this could be done by adding the iAd banner to the superview of the tableViewController's view.
self.bannerViewController = [[BannerViewController alloc] init];
[self.bannerViewController.view setHidden:YES];
[self.bannerViewController.view setFrame:CGRectMake(0, self.view.superview.frame.size.height - self.tabBarController.tabBar.frame.size.height - 50, 320, 50)];
[self.view.superview addSubview:self.bannerViewController.view];
[self.bannerViewController loadBanner];
When the banner is loaded I create a tableFooterView to make space for the last cell in the tableViewController
-(void)bannerDidLoad{
[self.bannerViewController.view setHidden:NO];
self.tableView.tableFooterView = [[UIView alloc];
initWithFrame:self.bannerViewController.view.frame];
}
I had to make some changes to the solution posted by NJones, since there was a problem with the ad not being displayed on top of all other cells/views.
First make sure your tableViewController is a AdBannerViewDelegate:
#interface MyTableViewController () <ADBannerViewDelegate>
Adding the AdBanner to the tableviewcontroller:
- (void)viewDidLoad {
[super viewDidLoad];
...
ADBannerView *adBanner = [[ADBannerView alloc]initWithAdType:ADAdTypeBanner];
adBanner.delegate = self;
self.tableView.tableFooterView = adBanner;
}
The code to position the ad banner is taken from NJones, I only added the last line to bring the ad banner to the front:
-(void)positionAdBanner {
ADBannerView *adBanner = (ADBannerView *) self.tableView.tableFooterView;
if (adBanner) {
CGRect iAdFrame = adBanner.frame;
CGFloat newOriginY = self.tableView.contentOffset.y + self.tableView.frame.size.height - iAdFrame.size.height;
CGRect newIAdFrame = CGRectMake(iAdFrame.origin.x, newOriginY, iAdFrame.size.width, iAdFrame.size.height);
adBanner.frame = newIAdFrame;
[self.tableView bringSubviewToFront:adBanner];
}
}
This function gets called whenever the view is going to layout its subviews (so you only need it here, no need to check for scrolling, etc):
-(void)viewWillLayoutSubviews{
[super viewWillLayoutSubviews];
[self positionAdBanner];
}
You also should handle the ADBannerViewDelegate methods:
-(void)bannerViewDidLoadAd:(ADBannerView *)banner
{
banner.hidden = NO;
[self positionAdBanner];
}
-(void)bannerView:(ADBannerView *)banner didFailToReceiveAdWithError:(NSError *)error
{
banner.hidden = YES;
}
I have a very curious case (similar to this one):
I have a simple UITextView which is located in a UIView which I load programatically (NIB). Contents are loaded from a TXT file into the UITextView.text. This happens in the viewDidLoad.
Everything is fine if my text is only a couple of lines and if there is no need for scrolling. If the text is longer than the UITextView, however, the text will NOT BE DISPLAYED. Only if I touch the screen and try to scroll, will the text suddenly pop up.
I tried this nudge to get the text appear in the viewDidLoad:
textView.contentOffset = CGPointMake(0.0, 1.0);
textView.contentOffset = CGPointMake(0.0, 0.0);
But it won't work. I also made sure to call [super viewWillAppear] etc., but again, no luck. The only thing which helps a bit is if I init my view and load the text in the viewDidAppear. However, the last part of the UITextView is still not shown unless I scroll.
Any ideas why the UITextView is behaving this way? I have no clue and would be grateful for any suggestions as this is holding me up for days now.
EDIT:
I now know what is causing this strange behaviour, but I still don't know why this can be. The ViewController in which the PageView will be displayed is animated into view (simple animation block to slide the viewController into the screen). If I take away the animation, everything is fine. I have no idea why, though.
Here is a bit more code (not sure if it helps to clarify). This is the viewController where I init the view.
- (void)viewDidLoad {
[super viewDidLoad];
if (self.currentPageView == nil) {
NSLog(#"createPage...");
PageView *cpv = [[PageView alloc] init];
self.currentPageView = cpv;
[cpv release];
[self.view addSubview:currentPageView.view];
}
[self loadContentsFromTXTFile];
[currentPageView setTitle:title
date:date
text:text ];
}
This is the init of the PageView class:
-(id)init {
//self = [super initWithNibName:nil bundle:nil];
self = [super initWithFrame:CGRectZero];
if (self) {
[[NSBundle mainBundle] loadNibNamed:#"PageView" owner:self options:nil];
[self addSubview:self.view];
}
return self;
}
-(void)setTitle:(NSString *)title date:(NSString *)date text:(NSString *)text {
UILabel *mytitle = [self titleOfPage];
[mytitle setText:title];
UILabel *mydate = [self dateOfPage];
[mydate setText:date];
UITextView *mytext = [self textOfPage];
[mytext setText:text];
}
Ok, I solved this by simply using a UINavigationController to handle the views in which the problematic UITextView was found. I still don't understand why this has caused problems, but if you experience this problem, there may be something wrong with the structure of your UIViewControllers and the way they refresh (or don't refresh) the UITextView.
i like to create a second starting screen in my app.
My Idea is to use the default.png and load an UIView with an fullscreen UIImageView inside.
In viewDidLoad i thought about placing a sleep option and after this load the real app screen.
But also when my function is called in viewDidLoad, nothing happens.
Seems my superview is empty...
Here is a piece of code:
if (self._pdfview == nil)
{
pdfview *videc = [[pdfview alloc]
initWithNibName:#"pdfview" bundle:nil];
self._pdfview = videc;
[pdfview release];
}
// get the view that's currently showing
UIView *currentView = self.view;
// get the the underlying UIWindow, or the view containing the current view
UIView *theWindow = [currentView superview];
theWindow is empty after this line so that might be the reason why the other view is not loaded.
So my question, how do i create a second starting screen ?
Or three starting screens, like in games when i like to mention another company.
If I understand correctly, your point is that when your function above is executed from viewDidLoad of some controller, theWindow is nil, so your new view (startscreen) is not added to it.
A few observations:
if theWindow is nil, then self.view is the topmost UIView; you can try and replace it, or simply add your view to it:
UIView *currentView = self.view;
// get the the underlying UIWindow, or the view containing the current view
UIView *theWindow = [currentView superview];
UIView *newView = _pdfview.view;
if (theWindow) {
[currentView removeFromSuperview];
[theWindow addSubview:newView];
} else {
self.view = newView; //-- or: [self.view addSubview:newView];
}
if you want to get the UIWindow of your app (which seems what you are trying to do), you can do:
[UIApplication sharedApplication].keyWindow;
and from there you can either set the rootViewController (from iOS 4.0)
[UIApplication sharedApplication].keyWindow.rootViewController = ...;
or add newView as a subview to it:
[[UIApplication sharedApplication].keyWindow addSubview:newView];
in the second case, you should possibly remove all subviews previously added to the UIWindow. (Iterate on keyWindow.subviews and call removeFromSuperview).
OLD ANSWER:
I think that you should try and add your pdfview as a subview to the current view:
[currentView addSubview:videc];
or to what you call theWindow:
[theWindow addSubview:pvidec];
and, please, move the release statement after the `addSubview, otherwise the view will be deallocated immediately.
Is there any way to show a tab bar after it has been hidden?
Got a tabbar-nav structure. For one of the tabs, I need to hide the tab bar for its 2nd and 3rd level view. But at the same time I will need to show its 1st and 4th view.
The sample code from Elements isn't really applicable here I think.
I've found quite a good pragmatic solution to this problem - make the UITabBarController's view larger than it needs to be, so that the actual UITabBar is clipped by the screen.
Assuming that the tab bar view normally fills its superview, this sort of thing should work:
CGRect frame = self.tabBarController.view.superview.frame;
if (isHidden)
{
CGFloat offset = self.tabBarController.tabBar.frame.size.height;
frame.size.height += offset;
}
self.tabBarController.view.frame = frame;
The tab bar is still showing, but it's off the bottom of the screen, so appears to have been hidden.
It might have performance implications if it causes extra clipping, but so far, it seems to work.
The UIViewControllers that are pushed onto the navigation stack can do the something like the following:
- (void)viewWillAppear:(BOOL)animated {
self.tabBarController.tabBar.hidden = NO; // Or YES as desired.
}
EDIT: Added additional code below to deal with the frame. Don't think I particular recommend this idea since it relies on the internal default view structure of a UITabBarController.
Define the following category on UITabBarController:
#interface UITabBarController (Extras)
- (void)showTabBar:(BOOL)show;
#end
#implementation UITabBarController (Extras)
- (void)showTabBar:(BOOL)show {
UITabBar* tabBar = self.tabBar;
if (show != tabBar.hidden)
return;
// This relies on the fact that the content view is the first subview
// in a UITabBarController's normal view, and so is fragile in the face
// of updates to UIKit.
UIView* subview = [self.view.subviews objectAtIndex:0];
CGRect frame = subview.frame;
if (show) {
frame.size.height -= tabBar.frame.size.height;
} else {
frame.size.height += tabBar.frame.size.height;
}
subview.frame = frame;
tabBar.hidden = !show;
}
#end
Then, instead of using the tabBar.hidden change I originally suggested, do the following:
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[self.tabBarController showTabBar:NO];
}
Obviously making sure that the implementation has included the category definition so that 'showTabBar' is known.
You need to implement a delegate method
- (BOOL)tabBarController:(UITabBarController *)tabBarController2 shouldSelectViewController:(UIViewController *)viewController
Inside that you can check which index is selected and show the tab bar
if([[tabBarController.viewControllers objectAtIndex:0] isEqual:viewController])// it is first tab
{
tabBarController.tabBar.hidden = FALSE;
}
I know this is an old post but i think the below code would help to hide the tabbar on the viewcontroller you don't want it on and has the added benefit of automatically readding the tabbar when you come back from that view controller
UIViewController *hideTabbarViewController = [[UIViewController alloc] init];
hideTabbarViewController.hidesBottomBarWhenPushed = YES;
[[self navigationController] hideTabbarViewController animated:YES];
I added a UITableView as a subview to a custom UIView class I'm working on. However I noticed that whenever I scroll the table it calls my classes layoutSubviews. I'm pretty sure its the UIScrollview that the table is inheriting from which is actually doing this but wanted to know if there is a way to disable this functionality and if not why is it happening? I don't understand why when you scroll a scrollview it needs its superview to layout its subviews.
Code:
#implementation CustomView
- (id)initWithFrame:(CGRect)frame {
if ((self = [super initWithFrame:frame])) {
self.clipsToBounds = YES;
UITableView *tableView = [[UITableView alloc] initWithFrame:CGRectMake(0.0, 15.0, 436.0, 132.0) style:UITableViewStylePlain];
tableView.dataSource = self;
tableView.delegate = self;
tableView.separatorStyle = UITableViewCellSeparatorStyleNone;
tableView.backgroundColor = [UIColor clearColor];
tableView.showsVerticalScrollIndicator = NO;
tableView.contentInset = UIEdgeInsetsMake(kRowHeight, 0.0, kRowHeight, 0.0);
tableView.tag = componentIndex;
[self addSubview:tableView];
[tableView release];
}
return self;
}
- (void)layoutSubviews {
// This is called everytime I scroll the tableview
}
#end
Yes, a UIScrollView does call layoutsubviews whenever it scrolls. I could've sworn this was stated in the documentation somewhere, but I guess not.
Anyways, the prevailing idea for this is that a UIScrollView should layout its stuff so that views that currently can't be seen shouldn't be laid out. As users scroll in the scroll view, it should add and remove subviews as necessary. I'm guessing this is what TableViews use to enqueue table cells that get hidden.
Is there any reason why you would care if layoutsubviews gets called or not?
UITableView at least does appear to layout its superview. This behavior can be problematic when you have a layoutSubviews method that might be expensive (e.g. if you call some JavaScript).
The quick fix is add an intermediary subview that prevents the scroll view from laying out your superview. Instead, it will layout the intermediate subview.
This could be somewhat imperfect but it should work for most cases:
Assume UIView * intermediateView is defined as an instance variable:
-(id) initWithFrame:(CGRect)frame
{
self = [super initWithFrame: frame];
if (self)
{
UIScrollView * theScrollView; // = your scroll view or table view
intermediateView = [[[UIView alloc] initWithFrame:CGRectZero] autorelease];
// Ensures your intermediate view will resize its subviews.
intermediateView.autoresizesSubviews = YES;
// Ensure when the intermediate view is resized that the scroll view
// is given identical height and width.
theScrollView.autoresizingMask = UIViewAutoresizingFlexibleWidth |
UIViewAutoresizingFlexibleHeight;
[intermediateView addSubview: theScrollView];
// Ensure the frame of the scroll view is exactly the bounds of your
// intermediate view.
theScrollView.frame = bottomContainerView.bounds;
[self addSubview: intermediateView];
}
return self;
}
-(void) layoutSubviews
{
intermediateView.frame = CGRectMake(0, 50, 42, 42); // replace with your logic
}
Not sure i understand your issue correctly but when you scroll a tableview it removes the cells not shown from the memory and loads them again when they are scrolled back into visibility (cells are allocated on demand, only the visible ones) , in effect doing what you seem to be describing.