I want to add number of images from library to a view. The number we want to add to the view is not known. How can I allocate UIImageViews dynamically. And I also want to drag those imageviews on the UIView. Please help me.
Thanks in advance.
Your 'question' consists of way too many parts (the dragging is a different question entirely, one I advice you to look up on Google). And the adding part is easy. The hard part is; where are you getting those images from? Assuming you have an array with image names, it would be something like this;
for( NSString *imageName in (NSArray *)imageNames )
{
UIImage *image = [UIImage imageNamed:imageName];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
// .. you might want to set a frame to your imageView .. //
[self.view addSubview:imageView];
[imageView release];
}
Of course, this is not what you want, but with the little information provided, it was the best I could do with my spare time.
Related
I'm programming a quiz app in xcode and I have 10 images which I want to use as UIImage views. I want to know how to create an array of all those images.
I also have a switch statement where I want to call 1 image from that array to be the UIImage. If you could explain how to call an image from an array as well I would be very grateful :)
Thanks in advance !!
Instead of storing UIImages in the array you can also store image names in array
NSArray *imagesArray = #[#"<image-name-1>",#"<image-name-2>",...,<image-name-10>];
when you want to get the image to set to UIImageView
UIImageView *imageView = [[UIImageView alloc] initwithFrame:<your-frame>];
[imageView setImage:[UIImage imageNamed:imagesArray[<your-index>]];
Let me know if you need any more info.
If you need to call an object from an array, objectAtIndex: can do the job for you. It doesn't matter whether you store UIImage instances of UIImageView instances, this will work with any form of object.
Here's a little example that will call each item from the array using objectAtIndex::
NSArray *_imageViews = ...
for (int idx; idx < _imageViews.count; idx++)
{
UIImageView *_imageView = [_imageViews objectAtIndex:idx];
/* do whatever you have to do with the image view */
}
I wanted to create a gallery. It loads different images based on the category, that a user selects. I used to populate images in UIImageViews.
My when selecting different categories is that it does not clear the previously selected images. This is my code for populating images.
-(void)refresh{
categoryLabel.text = treatment.treatmentName;
NSMutableArray *galleryImages =[NSMutableArray alloc] ;
galleryImages = [[PatientImage alloc]find:treatment.treatmentId];
int imgCount = [galleryImages count];
for(int i=0;i<imgCount;i++){
PatientImage *apatientImage = [galleryImages objectAtIndex:i];
UIImage *img1 = [UIImage imageNamed:apatientImage.imageBefore];
UIImageView *myImageView = [[UIImageView alloc] initWithImage:img1];
myImageView.contentMode = UIViewContentModeTopRight;
myImageView.frame = CGRectMake(120+i*240,120.0,100.0, 100.0);
[self.view addSubview:myImageView];
UIImage *img2 = [UIImage imageNamed:apatientImage.imageAfter];
UIImageView *myImageView2 = [[UIImageView alloc] initWithImage:img2];
myImageView2.contentMode = UIViewContentModeTopRight;
myImageView2.frame = CGRectMake(120+i*240+300,120.0,100.0, 100.0);
[self.view addSubview:myImageView2];
}
}
First things first, You have some memory leaks there. You are allocating UIImageViews but are not releasing them anywhere, after you have added them to your view. I don't know if that applies to ARC, though. Same applies to your Mutable array, but I suppose you are releasing it after the 'for' loop somewhere, since it seems you posted code after omitting some of it.
As far as your actual question is concerned, I wouldn't do this this way. I would make the mutable array an object variable, and then fill it with my image views. When calling refresh again, I would first call -removeFromSuperview on each image view, then empty the array, then repopulate it and add the new subviews to my view. That is the simple way.
I don't know if you are using ARC, but you should be careful about memory management when using dynamically loaded views. Each time you add a view to another one, you increase its retain counter. You must then call release to remove ownership, and let the iOS runtime handle the rest.
Also note that operations such as this using views are expensive in terms of memory. So, another way of repopulating the gallery view is to just change the image an imageView holds. That will save you some memory, and time. In case the view doesn't have a constant number of images to be displayed, you can refine your algorithm to change the images on the already created image views, and then add more image views if necessary or delete the remaining ones, if any.
I hope I helped.
try at the start of refresh call
[[self subviews] makeObjectsPerformSelector: #selector(removeFromSuperview)];
or
for (id imageView in self.subviews){
if([imageView isKindOfClass:[UIImageView class]]) [imageView removeFromSuperview];
}
call [tableview reloadData] if You are using tableview to show your gallery images
or call view's
[self.view setNeedsDisplay] method for refreshing the view.
Is it possible to set an image over an other image,
respectively to overlay an image above an UIImage.
I give some code:
Headerfile:
#property (nonatomic,assign)UIImageView* imageView;
Implementationfile
UIImage *overlayImage = [UIImage imageNamed:#"lamp.png"];
The "imageView.image" has got an image and above that I will have this lamp, but later on it has to be possible to move it.
I searched some methods, but all methods gave me warnings.
Could you help me how to manage it? And is Core Animation an alternative to handle that?
Just add it as a subview. UIImageView is a UIView like any other.
UIImage *overlayImage = [UIImage imageNamed:#"lamp.png"];
UIImageView *overlayImageView = [[UIImageView alloc] initWithImage:overlayImage];
[self.imageView addSubview:overlayImageView];
You should use another UIImageView. A UIImage doesn't refer to an actual view in the interface, it's used as a reference to an image to be reused in code.
UIImageView* lampImageView= [[UIImageView alloc] initWithImage:overlayImage];
This way you can move it around anywhere over the first image view.
is it possible to convert the HTML page to image in cocoa?
Actually i have created the complete view in the HTML and now i want to convert the whole html preview to the image (any jpeg or png etc.).
I couldn't find any resource or sample on the web, which provides some sort of help on my above queries.It's highly appreciated if someone could share his wisdom on how I can achieve this.
Thanks in advance..
First off, I'd like to thank sergio... his answer got me started but I thought I'd share some of the code that I didn't find obvious that I had to write to make it work:
Here's how to make a thumbnail for a page without ever having it displayed:
// Your width and height can be whatever you like, but if you want this to render
// off screen, you need an x and y bigger than the superview's width and height
UIWebView* webView = [[UIWebView alloc] initWithFrame:CGRectMake(largerScreenDimension, largerScreenDimension, largerScreenDimension, largerScreenDimension)];
[self.view addSubview:webView]; // UIWebViews without an assigned superview don't load ever.
webView.delegate = self; // or whoever you have implement UIWebViewDelegate
webView.scalesToFit = YES; // This zooms the page appropriately to fill the entire thumbnail.
[webView loadRequest:[NSURLRequest requestWithURL:url]];
Then implement this in your delegate:
- (void)webViewDidFinishLoad:(UIWebView *)webView {
UIGraphicsBeginImageContext(webView.bounds.size);
[webView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *webViewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
NSData *thumbnailData = UIImagePNGRepresentation(webViewImage);
[webView removeFromSuperview];
}
Finally, to display this thumbnail you'll need something like:
thumbnailImageView.image = [UIImage imageWithData:thumbnailData];
As a bonus thing I'll mention, I wanted multiple thumbnails to be generated at once. I found using objc_setAssociatedObject() and objc_getAssociatedObject() to be very helpful with keeping track of which webView was loading which thumbnail. Going into detail on how that worked is beyond the scope of this question, though.
You can draw your view in an image context, like this:
UIWebView* view = ...
....
UIGraphicsBeginImageContext(view.bounds.size);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
NSData *imagedata = UIImagePNGRepresentation(viewimage);
NSString *encodedString = [imageData base64Encoding];
Another option would be using Quartz PDF engine to create a PDF.
I was hoping there was some sort of function that could take the real size of my picture
CGRect myImageRect = CGRectMake(0.0f, 0.0f, 320.0, 210.0f); // 234
UIImageView *myImage = [[UIImageView alloc] initWithFrame:myImageRect];
[myImage setImage:[UIImage imageNamed:#"start.png"]];
And with CGRectMake which does something like this ..( imageViewHeight ,
CGFloat imageViewHeight = [myImage frame].size.height;
So that I could get the real size instead of having to define it like you can seen above.
I don't really get what you're asking, but here's a shot:
If you have a UIImage, and you want to know its size, you can ask it for its -[UIImage size] property.
However, if you want to create a UIImageView that's the same size as a UIImage, then you can just use -[UIImageView initWithImage:], which will automatically set the frame of the UIImageView to correspond to the dimensions of the image.
If, however, you're just looking to change the dimensions of a currently existing view, there's really no easy way to do that without messing around with the view's frame. You could maybe apply an affine transform to scale it, but it's easier to manipulate the frame.
It looks like you're asking to add the image to the imageview without first creating a frame. If this is the case, you can do the following:
UIImageView *myImage = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"start.png"]];
As far as I understood, you are looking for the size of the image used in UIImageView object. To do that, there is not a function built in UIImageView but you can do it this way:
NSString* image= [myImage image].accessibilityIdentifier; // Get the image's name
UIImage *img = [UIImage imageNamed:image]; // Create an image object with that name
CGSize size = img.size; // Get the size of image
Hope this helps your question.