I'm asynchronously loading images via AWS S3 and setting the MkMapView image to this image. My s3 code is long but it works everywhere else-and I think I narrowed this down to a #synchronized problem. I'm using this because in my didSelectAnnotationView, I'm rearranging my NSMutableArray which requires thread safety.
My steps are as follows. First, whenever the map screen changes, I download the users in that area and parse the JSON repsonse. I set these responses to an NSMutableArray via
- (void)mapView:(MKMapView *)mapView regionDidChangeAnimated:(BOOL)animated {
#synchronized(self.trainerArray){
[self.trainerArray removeAllObjects];
for(NSDictionary* item in tempDict){
FSTrainer* tempTrainer = [[FSTrainer alloc] initWith:item];
//adding to temp array and map
[self.trainerArray addObject:tempTrainer];
TrainerPin* trainerPin = [[TrainerPin alloc] initWith:tempTrainer];
[self.mapView addAnnotation:trainerPin];
}
}
}
Now when I set this via the viewForAnnotation (with custom reuse identifiers) this all works fine, UNLESS I zoom really fast or erratically, and then the same image gets set twice (the first one).
- (MKAnnotationView *) mapView: (MKMapView *) mapView viewForAnnotation: (id) annotation {
TrainerPin* trainerPinForView = (TrainerPin*)annotation;
TrainerMapImage *pin = (TrainerMapImage *) [self.mapView dequeueReusableAnnotationViewWithIdentifier: [NSString stringWithFormat:#"trainerAnnotation%ld", (long)trainerPinForView.trainer.id]];
if (!pin) {
pin = [[TrainerMapImage alloc] initWithAnnotation: trainerPinForView reuseIdentifier: [NSString stringWithFormat:#"myPin%ld", (long)trainerPinForView.trainer.id]];
} else {
pin.annotation = trainerPinForView;
}
//custom method in TrainerMapImage
[pin asyonchronouslySetImage];
return pin;
}
Another thing to note is that wrapping this in a GCD queue ALWAYS returns the first image for every MKMapView
Related
Currently I have a uicollection view which displays a specific album in the users photos, (ALAssets library).
In my mainView.m I gather the pictures:
+ (ALAssetsLibrary *)defaultAssetsLibrary {
static dispatch_once_t pred = 0;
static ALAssetsLibrary *library = nil;
dispatch_once(&pred, ^{
library = [[ALAssetsLibrary alloc] init];
});
return library;
}
- (void)beginLoadingPhotoInfo {
...
[library enumerateGroupsWithTypes:ALAssetsGroupSavedPhotos
usingBlock:assetGroupEnumerator
failureBlock:^(NSError *error) {NSLog(#"Probs");}
];
}
Load them (the thumbnail version) all into the collection view and that all works well.
Then when a user selects a photo I call this prepareToSegue method: (still in mainView.m)
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
if([[segue identifier] isEqualToString:#"showDetail"])
{
NSIndexPath *indexPath = [[self.collectionView indexPathsForSelectedItems] lastObject];
DetailViewController *detailviewcontroller = [segue destinationViewController];
detailviewcontroller.photoArrayIndex = indexPath.row;
//photos array
detailviewcontroller.photosArray = _photoListArray;
}
Currently I am sending an array with the info of the photos and attempting to scroll to the position in the array.
I found this resource here for the horizontal paging:
http://adoptioncurve.net/archives/2013/04/creating-a-paged-photo-gallery-with-a-uicollectionview/
Which allows for paging using a collection view. I wrote that a detailViewController class.
Here's the question. How should I connect the two?
Idea 1: Have my mainView send an integer number representing the photo selected and the detailViewController will then load that one and begin lazy loading the photos.
Idea 2: Somehow preload some of the full screen photos and then send the integer with the spot in the array.
Idea 3: Send both the number and my array object over to the detailViewController so that I don't have to enumerate through the assets library again.
Are any of these the correct approach or did I miss the idea completely?
edit:
What I have in my detail controller is an uicollectionview flow layout with paging enabled.
This is the method where I set up the layout:
- (void) setCollectionView {
[self.collectionView registerClass:[DetailViewCell class] forCellWithReuseIdentifier:#"detailViewCell"];
//Flow Layout
UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];
[flowLayout setScrollDirection:UICollectionViewScrollDirectionHorizontal];
[flowLayout setMinimumInteritemSpacing:0.0f];
[flowLayout setMinimumLineSpacing:0.0f];
[self.collectionView setPagingEnabled:YES];
[self.collectionView setCollectionViewLayout:flowLayout];
CGFloat pageWidth = self.collectionView.frame.size.width;
NSInteger num = _photosArrayIndex + 1;
CGPoint scrollTo = CGPointMake(pageWidth * num, 0);
NSLog(#"scroll to: %#", NSStringFromCGPoint(scrollTo));
[self.collectionView setContentOffset:scrollTo];
}
What It should do is take the value from my main view and move to that image. Unfortunately it does not. I'm not sure why and also I feel like there is a better way of doing this. It just seems sort of Hackish.
How do I connect the two better controller better and what is the correct way of loading the photos/ how do I get to the photo (in the full size detail view) I was on when they were in a grid layout.
Help is appreciated.
OK, there are three parts to this.
First is the UICollectionViewController subclass to display the gallery of photos (UIImage).
Second is the UIPageViewController subclass to manage the swiping from side to side of each individual PhotoViewController.
Third is the UIViewController subclass (PhotoViewController) to display a single photo.
The storyboard will look something like this...
On the left is a UICollectionViewController this has a segue to the UIPageViewController in the middle. On the right is a UIViewController that has an Identifier set in the properties pane (note, there is no segue to this).
Identifier for the PhotoViewController...
In the PhotoPageViewController I have a custom object...
With a Class type PhotoPageModelController set in the properties pane... This is connected as the dataSource of the PhotoPageViewController.
That's pretty much all the storyboard set up required.
So, the first thing to set up is the PhotoPageModelController. This is the dataSource for the PhotoPageViewController as such will dispense subclasses of UIViewController so that the PhotoPageViewController can display them.
The Model Controller
PhotoPageModelController.h
#class PhotoViewController;
#interface PhotoPageModelController : NSObject <UIPageViewControllerDataSource>
// this is the array of the photos. Either an array of UIImages or objects containing
// them or something. My personal project had an array of photoIDs that I could use to
// pull the photos out of Core Data.
// In this example the array will contain instances of UIImage.
#property (nonatomic, strong) NSArray *photos;
- (PhotoViewController *)viewControllerAtIndex:(NSUInteger)index storyboard:(UIStoryboard *)storyboard;
- (NSUInteger)indexOfViewController:(PhotoViewController *)controller;
#end
PhotoPageModelController.m
#import "PhotoPageModelController.h"
#import "PhotoViewController.h"
#implementation PhotoPageModelController
- (UIImage *)photoAtIndex:(NSUInteger)index
{
// check that the index is in bounds and then return the UIImage to display.
// In my project I just returned the ID of the photo and let the photo
// controller load the actual image from core data. (See below)
if ([self.photos count] == 0
|| index >= [self.photos count]) {
return nil;
}
return self.photos[index];
}
#pragma mark - convenience methods
- (PhotoViewController *)viewControllerAtIndex:(NSUInteger)index storyboard:(UIStoryboard *)storyboard
{
UIImage *photo = [self photoAtIndex:index];
if (photo == nil) {
return nil;
}
// This is why we don't have a segue. We are loading it manually
// from the storyboard using the identifier.
EventPhotoViewController *controller = [storyboard instantiateViewControllerWithIdentifier:#"PhotoViewController"];
// The model controller is where the PhotoViewController gets the actual image from.
// Or an object containing the image with a name, date, details, etc...
// The controller doesn't know anything about the other photos. Only the one it's displaying.
controller.photo = photo;
return controller;
}
- (NSUInteger)indexOfViewController:(PhotoViewController *)controller
{
// Return the index of the given data view controller.
// For simplicity, this implementation uses a static array of model objects and the view controller stores the model object; you can therefore use the model object to identify the index.
return [self.photos indexOfObject:controller.photo];
}
#pragma mark - page view data source
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController
{
// We need to find the index of the current controller so we can get the index
// and then the view controller for the one before it.
NSUInteger index = [self indexOfViewController:(PhotoViewController *) viewController];
if ((index == 0) || (index == NSNotFound)) {
// We have reached the beginning of the photos array so return nil.
// This tells the Page View Controller that there isn't another page.
return nil;
}
index--;
return [self viewControllerAtIndex:index storyboard:viewController.storyboard];
}
// This is the same as above but going forward instead of backward.
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController
{
NSUInteger index = [self indexOfViewController:(EventPhotoViewController *) viewController];
if (index == NSNotFound) {
return nil;
}
index++;
if (index == [self.photoIDs count]) {
return nil;
}
return [self viewControllerAtIndex:index storyboard:viewController.storyboard];
}
#end
OK. So that is the Photo Page Model Controller.
The Page View Controller
Next for the PhotoPageViewController.
PhotoPageViewController.h
#import <Foundation/Foundation.h>
#interface PhotoPageViewController : UIPageViewController
#property (nonatomic, strong) NSArray *photos;
#property (nonatomic) NSUInteger initialIndex;
#end
PhotoPageViewController.m
#import "PhotoPageViewController.h"
#import "PhotoPageModelController.h"
#interface PhotoPageViewController ()
// this property is connected in the storyboard
#property (nonatomic, weak) IBOutlet PhotoPageModelController *modelController;
#end
#implementation PhotoPageViewController
- (void)viewDidLoad
{
[super viewDidLoad];
self.modelController.photos = self.photos;
// We use the initialIndex property to get the first controller and display it.
UIViewController *initialController = (UIViewController *)[self.modelController viewControllerAtIndex:self.initialIndex storyboard:self.storyboard];
[self setViewControllers:#[initialController]
direction:UIPageViewControllerNavigationDirectionForward
animated:NO
completion:^(BOOL finished) {
}];
// That's it. Because we have the datasource class it makes this class really easy and short.
// It doesn't even need to know anything about the view controllers it is displaying.
// It's just a dispensing machine.
}
#end
The Photo View Controller
Next is the view controller that will display the actual photo.
All it needs is a property of type UIImage called photo and then a UIImageView to place it in. I'll leave this up to you as you can do it many different ways.
I've put a zoomable UIScrollView in mine so that the user can pinch zoom the photo. I've also got some extra info such as the name of the person who took the photo and the date it was taken etc... Set this up however you like.
The collection view segue
The final part (at last) is going from the collection view to the page view controller.
This is done in prepareForSegue.
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([segue.identifier isEqualToString:#"PhotoSegue"]) {
PhotoPageViewController *controller = segue.destinationViewController;
NSIndexPath *selectedIndex = [self.collectionView indexPathsForSelectedItems][0];
// The PageViewController doesn't need anything except the index to start on...
// i.e. the index of the photo that the user just selected.
controller.initialIndex = (NSUInteger)selectedIndex.item;
// ...and the array of photos it will be displaying.
controller.photos = self.photos;
// Everything else is done by the PageViewController.
}
}
I'm trying to remove a pin from a map. I have an observer on the #"selected" property of the MKPinAnnotationView so I know which object to delete. When the user taps the trash can icon and a pin is selected, this method gets called:
- (IBAction)deleteAnnotationView:(id)sender {
MKPinAnnotationView *pinView = (MKPinAnnotationView *)[self.mapView viewForAnnotation:self.currentAddress];
[pinView removeObserver:self forKeyPath:#"selected"];
[self.mapView removeAnnotation:self.currentAddress];
[self.map removeLocationsObject:self.currentAddress];
}
This method works fine if I do not drag the pin anywhere. If I drag the pin, my pinView in the above method returns nil, and the MKPinAnnotationView never gets removed from the MKMapView. I'm not sure why. Here's the didChangeDragState delegate method:
- (void)mapView:(MKMapView *)mapView annotationView:(MKAnnotationView *)view didChangeDragState:(MKAnnotationViewDragState)newState fromOldState:(MKAnnotationViewDragState)oldState {
if (newState == MKAnnotationViewDragStateEnding) {
CLLocationCoordinate2D draggedCoordinate = view.annotation.coordinate;
CLGeocoder *geocoder = [[CLGeocoder alloc] init];
CLLocation *location = [[CLLocation alloc] initWithLatitude:draggedCoordinate.latitude longitude:draggedCoordinate.longitude];
[geocoder reverseGeocodeLocation:location completionHandler:^(NSArray *placemarks, NSError *error) {
// Check for returned placemarks
if (placemarks && [placemarks count] > 0) {
CLPlacemark *topResult = [placemarks objectAtIndex:0];
AddressAnnotation *anAddress = [AddressAnnotation annotationWithPlacemark:topResult inContext:self.managedObjectContext];
view.annotation = anAddress;
self.currentAddress = anAddress;
}
}];
}
}
In both the didChangeDragState: and deleteAnnotationView: methods, my self.address object has a valid address. For some reason though, when the pin is dragged, the pinView is nil. Any thoughts? Thanks!
Observing an annotation view's selected property via KVO should be unnecessary since there's the didSelectAnnotationView delegate method and (even better in your case) the selectedAnnotations property in MKMapView.
Assuming the user taps the trash can after selecting a pin, the trash can tap method can get the currently selected annotation through the selectedAnnotations property. For example:
if (mapView.selectedAnnotations.count == 0)
{
//No annotation currently selected
}
else
{
//The currently selected annotation is the first object in the array...
id<MKAnnotation> ann = [mapView.selectedAnnotations objectAtIndex:0];
//do something with ann...
}
In the above example, there was no need to access the annotation's view, no observer and no need for your own "currentAddress" property.
If instead you want to do some action immediately when an annotation is selected, you can put the code in the didSelectAnnotationView delegate method. There, the annotation selected is view.annotation.
Regarding the issue on the drag-end, the current code is completely replacing the view's annotation. I think this is only a good idea when the view is being created or re-used in the viewForAnnotation delegate method. In the drag-end method, you should instead try updating the view.annotation's properties instead of replacing with an entirely new object.
I am a newbie to iOS development. I have gone through a couple of tutorials and know the basics, but currently I am stuck on how to proceed further. I am planning to create an app for basic home automation (i.e. switching lights, measuring temperature etc.). The backend is all set, so this is just about the frontend. This is what I am planning to do:
The main view of the app should display a floor plan or the layout of the house
On this floor plan you should be able to add lights/sensors/etc. - lets say objects to keep it generic
These objects should be draggable so that you can arrange them on the floor plan according to where they really are (physically) - ideally this drag mode is toggable similar to rearranging icons on the home screen
Each object should have a popover view (i.e. to set the dimmer intensity, switch lights etc.)
I know there is a lot of work to do, but I don't really know how to set this up. Current alternatives:
Create a custom UIView subclass that contains all the logic an do the drawing in custom code, i.e. the dragging, the popover positioning etc. - but I have the feeling that I wouldn't really be leveraging the iOS framework capabilities
Display the floor plan as an UIImageView and one UIButton for each object. This has the advantage that I can use StoryBoard to do the layouting and wiring (i.e. create segues for popovers etc.) - but I simply can't figure out how to do this with a variable number of buttons (since I don't know in advance how many buttons there will be). Is there some way to create these buttons in code?
Use a custom UITableView. I have seen a couple of examples where they seem to use table views even if the layout has nothing to do with tables (like in my example) but I haven't found any tutorials that explain this concept in more detail
Or am I totally on the wrong track? Any input is appreciated.
Thanks
D.
UPDATE:
After some more research and thought on this I think the way to go with iOS 6 is to use an UICollectionView with a custom layout. Once I have come up with a complete solution I will post it here. For older iOS versions I think it would be promising to go with Option Nr. 2 - i.e. creating each UIButton (for the automation objects e.g. lights) in code and having a custom UIView subclass to do the layouting of these buttons.
Ok I think UICollectionView is ideal for this usage scenario and I am just lucky to have started with iOS programming just as it was introduced to the framework. The following example is a UICollectionView that displays its elements according to their inherent coordinates. This example could also be applied to positioning objects on a map. I couldn't find any examples elsewhere so I'll post the main steps here (since I am a beginner please correct any mistakes).
To start off I created a simple project with one view and storyboard in XCode. I removed the standard view and inserted a Collection View Controller instead and configured my UICollectionViewController subclass as the class that should be used (in the properties of the controller in storyboard).
For the demo just set the background of the default UICollectionViewCell to a color and set the Identifier to "AutomationCell" for this example (if you change it be sure to adjust the code below).
First I create a simple object with some properties that represents an object that should be displayed on the floor plan:
#interface AULYAutomationObject : NSObject
#property NSString *title;
#property CGPoint position;
#end
Then I need my own delegate as subclass to the standard UICollectionViewDelegate since my custom UICollectionViewLayout will not have direct access to the dataSource objects. Therefore I provide a method that will give me the position of the object:
#protocol AULYAutomationObjectLayoutDelegate <UICollectionViewDelegate>
- (CGPoint)getPositionForItemAtIndexPath:(NSIndexPath *)indexPath;
#end
Make sure to implement this protocol in your controller like this:
#interface AULYViewController : UICollectionViewController <AULYAutomationObjectLayoutDelegate>
Then I implemented the standard datasource and delegate methods along with my custom one in the view controller subclass:
#interface AULYViewController ()
#property NSArray *objects;
#property (strong, nonatomic) IBOutlet UICollectionView *collectionView;
#end
#implementation AULYViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// Set up the data source
NSMutableArray *automationObjects = [[NSMutableArray alloc] initWithCapacity:10];
// add some objects here...
self.objects = [automationObjects copy];
UILongPressGestureRecognizer *longPressRecognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(handleTapGesture:)];
[self.collectionView addGestureRecognizer:longPressRecognizer];
}
#pragma mark - UICollectionViewController
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
return 1;
}
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
return self.objects.count;
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
AULYAutomationObjectViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"AutomationCell" forIndexPath:indexPath];
// If you have a custom UICollectionViewCell with a label as outlet
// you could for example then do this:
// AULYAutomationObject *automationObject = self.objects[indexPath.row];
// cell.label.text = automationObject.title;
return cell;
}
#pragma mark - AULYAutomationObjectLayoutDelegate
- (CGPoint)getPositionForItemAtIndexPath:(NSIndexPath *)indexPath
{
AULYAutomationObject *automationObject = self.objects[indexPath.item];
return automationObject.position;
}
In a real project you would probably do some conversion from the object model position to the position on screen (e.g. GPS data to pixels) but here this is left out for simplicity.
After having done that we still need to set up our layout. This has the following properties:
#interface AULYAutomationObjectLayout : UICollectionViewLayout
#property (nonatomic, strong) NSIndexPath *draggedObject;
#property (nonatomic) CGPoint dragPosition;
#end
And the following implementation:
#implementation AULYAutomationObjectLayout
- (void)setDraggedObject:(NSIndexPath *)draggedObject
{
_draggedObject = draggedObject;
[self invalidateLayout];
}
- (void)setDragPosition:(CGPoint)dragPosition
{
_dragPosition = dragPosition;
[self invalidateLayout];
}
- (UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewLayoutAttributes *layoutAttributes = [UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath:indexPath];
id viewDelegate = self.collectionView.delegate;
if ([viewDelegate respondsToSelector:#selector(getPositionForItemAtIndexPath:)])
{
CGPoint itemPosition = [viewDelegate getPositionForItemAtIndexPath:indexPath];
layoutAttributes.center = itemPosition;
layoutAttributes.size = CGSizeMake(ITEM_SIZE, ITEM_SIZE);
}
if ([self.draggedObject isEqual:indexPath])
{
layoutAttributes.center = self.dragPosition;
layoutAttributes.transform3D = CATransform3DMakeScale(1.5, 1.5, 1.0);
layoutAttributes.zIndex = 1;
}
return layoutAttributes;
}
- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect
{
NSMutableArray *allAttributes = [[NSMutableArray alloc] initWithCapacity:4];
for (NSInteger i = 0; i < [self.collectionView numberOfItemsInSection:0]; i++)
{
NSIndexPath *indexPath = [NSIndexPath indexPathForItem:i inSection:0];
UICollectionViewLayoutAttributes *layoutAttributes = [self layoutAttributesForItemAtIndexPath:indexPath];
[allAttributes addObject:layoutAttributes];
}
return allAttributes;
}
- (BOOL)shouldInvalidateLayoutForBoundsChange:(CGRect)newBounds
{
return YES;
}
- (CGSize)collectionViewContentSize
{
return [self.collectionView frame].size;
}
#end
To set the custom layout in the storyboard just go to the properties of the controller view and select custom as the layout type - then select your custom class.
Now to enable drag and drop support with the long press gesture simply add the following to your controller:
- (void)handleTapGesture:(UITapGestureRecognizer *)sender
{
AULYAutomationObjectLayout *automationLayout = (AULYAutomationObjectLayout *)self.collectionView.collectionViewLayout;
if (sender.state == UIGestureRecognizerStateBegan)
{
CGPoint initialPinchPoint = [sender locationInView:self.collectionView];
NSIndexPath* tappedCellPath = [self.collectionView indexPathForItemAtPoint:initialPinchPoint];
[self.collectionView performBatchUpdates:^{
automationLayout.draggedObject = tappedCellPath;
automationLayout.dragPosition = initialPinchPoint;
} completion:nil];
}
else if (sender.state == UIGestureRecognizerStateChanged)
{
automationLayout.dragPosition = [sender locationInView:self.collectionView];
}
else if (sender.state == UIGestureRecognizerStateEnded)
{
AULYAutomationObject *automationObject = self.objects[automationLayout.draggedObject.item];
automationObject.position = [sender locationInView:self.collectionView];
[self.collectionView performBatchUpdates:^{
automationLayout.draggedObject = nil;
automationLayout.dragPosition = CGPointMake(0.0, 0.0);
} completion:nil];
}
}
One important note:(this cost me at least an hour): When using the transform3D you should make sure to import QuartzCore into your linked frameworks (in the project properties below the orientation settings). Otherwise you will get a Mach-O Linker Error saying that _CATransform3DMakeScale can not be found.
Is there a way to change MKAnnotationView style (like from red label with number to green colored label with number).
I want to change this style according to distance from target. My annotation is moving, with user.
I dont want to use remove / add annotation, because it causes "blinking".
Can it be done someway?
UPDATE:
I am adding code, how I am doing it right now
MKAnnotationView *av = [mapView viewForAnnotation:an];
if ([data->type isMemberOfClass:[UserAnnotationImage class]])
{
UIImage *img = [UIImage imageNamed: ((UserAnnotationImage *)data->type)->url];
[av setImage:img];
}
else if ([data->type isMemberOfClass:[UserAnnotationLabel class]])
{
UIView * v = [av viewWithTag:0];
v = ((UserAnnotationLabel *)data->type)->lbl;
av.frame = ((UserAnnotationLabel *)data->type)->lbl.frame;
}
else if ([data->type isMemberOfClass:[UserAnnotationView class]])
{
UIView * v = [av viewWithTag:0];
v = ((UserAnnotationView *)data->type)->view;
av.frame = ((UserAnnotationView *)data->type)->view.frame;
}
Sadly, its not working :(
Yes, basically you get a reference to the annotation view and update its contents directly.
Another way, if you have a custom annotation view class, is to have the annotation view monitor the changes it is interested in (or have something outside tell it) and update itself.
The first approach is simpler if you are using a plain MKAnnotationView or MKPinAnnotationView.
Wherever you detect that a change to the view is needed, get a reference to the view by calling the map view's viewForAnnotation instance method. This is not the same as calling the viewForAnnotation delegate method.
Once you have a reference to the view, you can modify as needed and the changes should appear immediately.
An important point is that the logic you use to update the view outside the delegate method and the logic you have in the viewForAnnotation delegate method must match. This is because the delegate method may get called later (after you've updated the view manually) by the map view and when it does, the code there should take the updated data into account.
The best way to do that is to have the annotation view construction code in a common method called both by the delegate method and where you update the view manually.
See change UIImage from MKAnnotation in the MKMapView for an example that updates just the annotation view's image.
For an example (mostly an idea for an approach) of updating the view using a custom annotation view class, see iPad Mapkit - Change title of "Current Location" which updates the view's pin color periodically (green, purple, red, green, purple, red, etc).
There are too many unknowns in your code to explain why it doesn't work. For example:
What is data? Is it annotation-specific (is it related to an)? What is type? Does it change after the annotation has been added to the map?
Why is data storing entire view objects like a UILabel or UIView instead of just the underlying data that you want to show in those views?
imageNamed requires the image to be a resource in the project (not any arbitrary url)
Don't use a tag of 0 (that's the default for all views). Start numbering from 1.
You get a view using viewWithTag but then replace it immediately with another view.
I'll instead give a more detailed but simple(r) example...
Assume you have an annotation class (the one that implements MKAnnotation) with these properties (in addition to coordinate, title, and subtitle):
#property (nonatomic, assign) BOOL haveImage;
#property (nonatomic, copy) NSString *labelText;
#property (nonatomic, copy) NSString *imageName;
#property (nonatomic, assign) CLLocationDistance distanceFromTarget;
To address the "important point" mentioned above (that the viewForAnnotation delegate method and the view-update-code should use the same logic), we'll create a method that is passed an annotation view and configures it as needed based on the annotation's properties. This method will then be called both by the viewForAnnotation delegate method and the code that manually updates the view when the annotation's properties change.
In this example, I made it so that the annotation view shows the image if haveImage is YES otherwise it shows the label. Additionally, the label's background color is based on distanceFromTarget:
-(void)configureAnnotationView:(MKAnnotationView *)av
{
MyAnnotationClass *myAnn = (MyAnnotationClass *)av.annotation;
UILabel *labelView = (UILabel *)[av viewWithTag:1];
if (myAnn.haveImage)
{
//show image and remove label...
av.image = [UIImage imageNamed:myAnn.imageName];
[labelView removeFromSuperview];
}
else
{
//remove image and show label...
av.image = nil;
if (labelView == nil)
{
//create and add label...
labelView = [[[UILabel alloc]
initWithFrame:CGRectMake(0, 0, 50, 30)] autorelease];
labelView.tag = 1;
labelView.textColor = [UIColor whiteColor];
[av addSubview:labelView];
}
if (myAnn.distanceFromTarget > 100)
labelView.backgroundColor = [UIColor redColor];
else
labelView.backgroundColor = [UIColor greenColor];
labelView.text = myAnn.labelText;
}
}
The viewForAnnotation delegate method would look like this:
-(MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id<MKAnnotation>)annotation
{
if ([annotation isKindOfClass:[MyAnnotationClass class]])
{
static NSString *myAnnId = #"myann";
MKAnnotationView *av = [mapView dequeueReusableAnnotationViewWithIdentifier:myAnnId];
if (av == nil)
{
av = [[[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:myAnnId] autorelease];
}
else
{
av.annotation = annotation;
}
[self configureAnnotationView:av];
return av;
}
return nil;
}
Finally, the place where the annotation's properties change and where you want to update the annotation view, the code would look something like this:
ann.coordinate = someNewCoordinate;
ann.distanceFromTarget = theDistanceFromTarget;
ann.labelText = someNewText;
ann.haveImage = YES or NO;
ann.imageName = someImageName;
MKAnnotationView *av = [mapView viewForAnnotation:ann];
[self configureAnnotationView:av];
I want to update the images of some of my annotations on a mapview every 5 seconds, however I dont' want to remove and re-add them to the map as this causes them to 'flash' or refresh, (ie disapear then reappear). I want it to be seamless.
I've tried the following:
//get the current icon
UserAnnotation *annotation = [self GetUserIconWithDeviceId:deviceId];
//make a new annotation for it
UserAnnotation *newAnnotation = [[UserAnnotation alloc]
initWithCoordinate: userCoordinates
addressDictionary:nil];
newAnnotation.title = name;
newAnnotation.userDeviceId = deviceId;
NSInteger ageIndicator = [[userLocation objectForKey: #"ageIndicator"] integerValue];
newAnnotation.customImage = [UserIconHelpers imageWithAgeBorder:ageIndicator FromImage: userImage];
//if its not there, add it
if (annotation != nil){
//move it
//update location
annotation.coordinate = userCoordinates;
//add new one
[self.mapView addAnnotation: newAnnotation];
//delete old one
[self.mapView removeAnnotation: annotation];
} else {
//just addd the new one
[self.mapView addAnnotation: newAnnotation];
}
as a thought that if I added the new icon on top I could then remove the old icon, but this still caused the flashing.
Has anyone got any ideas?
In the case where the annotation is not nil, instead of adding and removing, try this:
annotation.customImage = ... //the new image
MKAnnotationView *av = [self.mapView viewForAnnotation:annotation];
av.image = annotation.customImage;
Swift version of Anna answer:
annotation.customImage = ... //the new image
let av = self.mapView.viewForAnnotation(dnwl!)
av?.image = annotation.customImage
It seems you are using your own custom views for the annotations, in that case you can simply add a "refresh" method to your custom view and call it after you have updated the underlying annotation (ie: a custom view -a derived class from MKAnnotationView- is always attached to a potentially custom "annotation" class that conforms to the MKAnnotation protocol)
*) CustomAnnotationView.h
#interface CustomAnnotationView : MKAnnotationView
{
...
}
...
//tell the view to re-read the annotation data it is attached to
- (void)refresh;
*) CustomAnnotationView.m
//override super class method
- (void)setAnnotation:(id <MKAnnotation>)annotation
{
[super setAnnotation:annotation];
...
[self refresh];
}
- (void)refresh
{
...
[self setNeedsDisplay]; //if necessary
}
*) Where you handle the MKMapView and its annotations
for(CustomAnnotation *annotation in [m_MapView annotations])
{
CustomAnnotationView *annotationView = [m_MapView viewForAnnotation:annotation];
[annotationView refresh];
}