I want to get thumbnail image or blank image first while app is loading image data from parse database. After finish loading, the image view will display the image I load from parse.
So far, I have following codes
PFFile *thumbnail = object1[#"PostFiles"];
NSData *imageData = [thumbnail getData];
UIImage *image = [UIImage imageWithData: imageData];
I use PFtableviewcontroller. when I scroll down, my code will load image, the controller can't move smoothly.
The issue is that you are running a synchronous call for a task that could take a varying amount of time. Try getting the NSData using InBackgroundWithBlock:
image = nil; //prevent images from being shown erroneously
[thumbnail getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
if (data && !error) {
image = [UIImage imageWithData:data];
} else {
//maybe set a default image here if there is none?
}
}];
Related
From my web service i am getting multiple sized images. I m loading them in TableView. When i m loading them new images which haven't cached yet flickers between placeholder and original image, or sometimes the image appear as smaller than the usual size. But just a bit scrolling down or up actually fix the problem but i want them to be at original size from the beginning. But it would appear in original shape from the next time i suppose because the picture was already cached
Initially
After a bit scrolling
My code in cellForRowAtIndexPath:
[cell.image sd_setImageWithURL:[NSURL URLWithString:[NSMutableString stringWithFormat:#"%#app/media/access/pictures?p=%#",baseurl,data.picPath]]
placeholderImage:[UIImage imageNamed: #"image_loader.gif"]];
then in heightForRowAtIndexPath:
NSURL *filePath = [NSURL URLWithString:[NSMutableString stringWithFormat:#"%#app/media/access/pictures?p=%#",baseurl,data.picPath]];
NSString *key = [[SDWebImageManager sharedManager] cacheKeyForURL:filePath];
UIImage *image = [[SDImageCache sharedImageCache] imageFromDiskCacheForKey:key];
self.img = image;
if (self.img.size.width > CGRectGetWidth(self.view.bounds)) {
CGFloat ratio = self.img.size.height / self.img.size.width;
return CGRectGetWidth(self.view.bounds) * ratio+140;
} else {
return self.img.size.height+180;
}
I have visited https://github.com/rs/SDWebImage and in their common problem section they have mentioned about the problem but the suggested solution didn't work for me!!!
Actually what i did, i checked if the image was cached already and if not i have downloaded it asynchronously under heightForRowAtIndexPath:
if(image != NULL)
{
self.img = image;
}
else
{
SDWebImageDownloader *downloader = [SDWebImageDownloader sharedDownloader];
[downloader downloadImageWithURL:filePath
options:0
progress:^(NSInteger receivedSize, NSInteger expectedSize) {
// progression tracking code
}
completed:^(UIImage *image, NSData *data, NSError *error, BOOL finished) {
if (image && finished) {
// do something with image
self.img = image;
}
}];
}
I have a method that I'm calling from cell in the viewForRowAtIndexPath method.
The method containts only this code
NSURL *imageURL = [NSURL URLWithString:urlString];
NSData *imageData = [NSData dataWithContentsOfURL:imageURL];
UIImage *image = [UIImage imageWithData:imageData];
dispatch_async(dispatch_get_main_queue(), ^(void){
completionBLock(image);
});
Images are loading very slowly and sometimes not at all. Everytime the cell goes back into view the method gets called again.
This is in my cellForIndexPathRow
[Method getImage:brochureModel.brochureCoverUrl Oncompletion:^(UIImage *image) {
cell.imageView.image = image;
}];
How can I download images from a url and display it in a collection view reusable cells.
Note: I'm trying to not use any third party libraries for my app
My problem is with the caching of the images. I tried this with self.imageCache being a mutableDictionary.
if (self.imageCache[urlString]) {
UIImage *imageFromCache = self.imageCache[urlString];
onImageDidLoad(imageFromCache);
} else {
[API fetchImageFromUrl:urlString onDidLoad:^(UIImage *image) {
self.imageCache[urlString] = image;
onImageDidLoad(image);
}];
}
NSString *img=[arrImages objectAtIndex:i];
imgScrollView.image=[UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:img]]];
I have displayed my code. The URL links have been stored into an array and the images are also fetching into uiimage view, but only the first two images are loaded into the imageview while the others didn't load .
arrImages:
inside image viewhttp://localhost:8888/welcome/company/0/images/TV Repair.png
this is the link present in the arrImages i don't know why first two images has been loading.
FOR LOOP:
for(NSDictionary *DicHoleCategories in ArrCategory)
{
StrName=[DicHoleCategories objectForKey:#"image"];
if(StrName!=nil)
{
subimages=[NSString stringWithFormat:LocalImage"%#",StrName];
[DicAllValues setObject:subimages forKey:#"image"];
NSError *error =nil;
}
[arrImages addObject:[DicAllValues objectForKey:#"image"]];
}
Can anyone find the issue and help me please?
Go through the below coding
//url string
NSString *ImageURL = #"yoururl";
//string to data conversion
NSData *imagedata = [NSData dataWithContentsOfURL:[NSURL URLWithString:ImageURL]];
//set image
imageView.image = [UIImage imageWithData:imageData];
please follow the below code
if(StrName!=nil)
{
subimages=[NSString stringWithFormat:LocalImage"%#",StrName];
[DicAllValues setObject:subimages forKey:#"image"];
NSError *error =nil;
[arrImages addObject:[DicAllValues objectForKey:#"image"]];//add here!
}
Plz check now and tell me if its working or not!
I have successfully retrieved the image (lets say user profile pic) from parse, and i'm displaying it in the ios app. But if there is no image in the file column, then i want to display default image which is stored in the locally (not in parse), not successful.
My simple question is, how to check if there is image or not ? Below is the simple code;
PFFile *userImage = [object objectForKey:#"profilePic"]; __block UIImage *userProfilePic =[[UIImage alloc]init];
[userImage getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
if (!error) {
//this block will execute only if there is image
if(data) {
userProfilePic = [UIImage imageWithData:data];
userPic.image=userProfilePic;
}
//this block is not at all executing. This block should execute when user doesn't have their profile uploaded
if(!data) {
UIImage *userProfileDefaultPic = [[UIImage alloc]init];
userProfileDefaultPic=[UIImage imageNamed:#"defaultprofile.png"];
userPic.image=userProfileDefaultPic;
}
}
}];
Hope you can help me. Thanks in advance.
Pradeep
At last found the solution !
(!data) will not execute , instead we need to check if the PFFile and the UIImage to store PFFile has image or not, like below;
PFFile *userImage = [object objectForKey:#"profilePic"];
__block UIImage *userProfilePic =[[UIImage alloc]init];
if(userImage && ![userProfilePic isEqual:[NSNull null]]) //This is important to check if the file if image is there or not and if not, then display default pic in else part
{
[userImage getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
if(!error)
{
userProfilePic = [UIImage imageWithData:data];
userPic.image=userProfilePic;
}
}];
}
else
{
userProfilePic =[UIImage imageNamed:#"defaultprofilepic.png"];
userPic.image=userProfilePic;
}
Your code already does that. You just need to set your image on the main thread and not background thread.
if(!data) { [dispatch_async(dispatch_get_main_queue(), ^{
UIImage *userProfileDefaultPic = [[UIImage alloc]init];
userProfileDefaultPic=[UIImage imageNamed:#"defaultprofile.png"];
userPic.image=userProfileDefaultPic;
}}];
I'm working with a UICollectionView and I need to load images in to the collection cell.
Here is the code
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0ul);
dispatch_async(queue, ^{
NSURL *imageURL = [NSURL URLWithString:post.cover_img_url];
NSData *data = [NSData dataWithContentsOfURL:imageURL];
UIImage *image = [UIImage imageWithData:data];
dispatch_async(dispatch_get_main_queue(), ^{
[cell.cover_img setImage:image];
});
});
post.cover_img_url = the_url_for_the_image;
cell.cover_img = the_UIImageView_object;
When I set the image not from the web, it works perfectly.
But when I try from the web, the UIImageView is blank not image.
Anyone have any ideas?
Your code looks like it should be working, but there are a couple of things that you need to test. First, you need to check to make sure that imageURL is both non-nil, and points to exactly where you think it's pointing. Copy paste a log result to your desktop browser if you have to.
NSLog(#"%#",imageURL);
Second, in the event that fetching the image fails, you need to be able to detect this. I recommend that if you continue to use the dataWithContentsOfURL: route that you at least use the following to check the error:
NSError *error = NULL;
NSData *data = [NSData dataWithContentsOfURL:imageURL options:NSDataReadingMappedIfSafe error:&error];
if (error) {
// ...
}