I'm trying to save a list of assets to upload in a sqllite3 db, but when i parse the database and set the assets to an array, then try to use the asset i get a SIGABRT error.
ALAsset *asset = (ALAsset *) assets[indexPath.row];
cell.textLabel.text = [NSString stringWithFormat:#"image%d: ready to upload.",indexPath.row];
cell.detailTextLabel.text = #"1.3MB to folder <server folder>";
[[cell imageView] setImage:[UIImage imageWithCGImage:[asset thumbnail]]];// SIGABRT ERROR
Im saving the ALAsset to the database as a string (TEXT) with UTF8formatting
NSMutableArray *tmpArray = [NSMutableArray alloc]init];
///get sql
[tmpArray addObject:someStringFromSQL];
///end sql loop
assets = [tmpArray mutableCopy];
in the code above I tried:
[[cell imageView] setImage:[UIImage imageWithCGImage:[(ALAsset *) asset thumbnail]]];// SIGABRT ERROR
and that didn't work.
This is the error:
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFString thumbnail]: unrecognized selector sent to instance 0xc0a7800'
Any suggestions?
Also as a side question: Does anyone know how to get the file size (i.e. 1.3MB) from the asset?
BLOCK:
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
}
//do stuff in cell
NSURL *aURL =[NSURL URLWithString:[assets objectAtIndex:indexPath.row]];
[assetsLibrary assetForURL:aURL resultBlock:^(ALAsset *asset){
dispatch_async(dispatch_get_main_queue(), ^{
cell.imageView.image = [UIImage imageWithCGImage:[asset thumbnail]];
});
[[NSNotificationCenter defaultCenter] postNotificationName:#"newAssetImageRetrieved" object:nil];
//in this notificaton I'm reloading the data; its putting the tableview in an infinite loop - but the images display...
}
failureBlock:^(NSError *error){
// error handling
NSLog(#"Can't get to assets: FAILED!");
}];
//cell.imageView.image = [UIImage imageWithCGImage:[asset thumbnail]];
cell.textLabel.text = [NSString stringWithFormat:#"image%d: ready to upload.",indexPath.row];
cell.detailTextLabel.text = [NSString stringWithFormat:#"1.3MB to folder %#", [destinations objectAtIndex:indexPath.row]];
//[[cell imageView] setImage:[UIImage imageWithCGImage:[asset thumbnail]]];
return cell;
}
There are a couple of issues with your code sample:
The image retrieval is happening asynchronously, so when you try to update the image, you want to make sure the cell is still visible (and not reused for another NSIndexPath).
In this case, the retrieval from the ALAssetsLibrary will probably be so fast that this isn't critical, but it's a good pattern to familiarize yourself with, because if you're ever retrieving images over the Internet, this issue becomes increasingly important.
Because cells are being reused, if you don't find the image immediately and have to update it asynchronously, make sure you reset the UIImageView before initiating the asynchronous process. Otherwise, you'll see a "flickering" of replacing old images with new ones.
You are using UITableViewCell for your cell. The problem with that is that it will layout the cell based upon the size of the image present by the time cellForRowAtIndexPath finishes.
There are two easy solutions to this. First, you could initialize the cell's imageView to be a placeholder image of the correct size. (I usually have an image called placeholder.png that is all white or all transparent that I add to my project, which is what I used below.) This will ensure that cell will be laid out properly, so that when you asynchronously set the image later, the cell will be laid out properly already.
Second, you could alternatively use a custom cell whose layout is fixed in advance, bypassing this annoyance with the standard UITableViewCell, whose layout is contingent upon the initial image used.
I'd suggest using a NSCache to hold the thumbnails images. That will save you from having to constantly re-retrieve the thumbnail images as you get them from your ALAssetsLibrary as you scroll back and forth. Unfortunately, iOS 7 broke some of the wonderful NSCache memory-pressure logic, so I'd suggest a cache that will respond to memory pressure and purge itself if necessary.
Anyway, putting that all together, you get something like:
#interface ViewController ()
#property (nonatomic, strong) NSMutableArray *assetGroups;
#property (nonatomic, strong) ALAssetsLibrary *library;
#property (nonatomic, strong) ThumbnailCache *imageCache;
#end
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
self.imageCache = [[ThumbnailCache alloc] init];
self.assetGroups = [NSMutableArray array];
self.library = [[ALAssetsLibrary alloc] init];
[self.library enumerateGroupsWithTypes:ALAssetsGroupAll usingBlock:^(ALAssetsGroup *group, BOOL *stop) {
if (!group) {
[self.tableView reloadData];
return;
}
CustomAssetGroup *assetGroup = [[CustomAssetGroup alloc] init];
assetGroup.name = [group valueForProperty:ALAssetsGroupPropertyName];
assetGroup.assetURLs = [NSMutableArray array];
[group enumerateAssetsUsingBlock:^(ALAsset *result, NSUInteger index, BOOL *stop) {
if (result) {
[assetGroup.assetURLs addObject:[result valueForProperty:ALAssetPropertyAssetURL]];
}
}];
[self.assetGroups addObject:assetGroup];
} failureBlock:^(NSError *error) {
NSLog(#"%s: enumerateGroupsWithTypes error: %#", __PRETTY_FUNCTION__, error);
}];
}
#pragma mark - UITableViewDataSource
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return self.assetGroups.count;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
CustomAssetGroup *group = self.assetGroups[section];
return [group.assetURLs count];
}
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
{
CustomAssetGroup *group = self.assetGroups[section];
return group.name;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
// note, these following three lines are unnecessary if you use cell prototype in Interface Builder
if (!cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}
CustomAssetGroup *group = self.assetGroups[indexPath.section];
NSURL *url = group.assetURLs[indexPath.row];
NSString *key = [url absoluteString];
UIImage *image = [self.imageCache objectForKey:key];
if (image) {
cell.imageView.image = image;
} else {
UIImage *placeholderImage = [UIImage imageNamed:#"placeholder.png"];
cell.imageView.image = placeholderImage; // initialize this to a placeholder image of the right size
[self.library assetForURL:url resultBlock:^(ALAsset *asset) {
UIImage *image = [UIImage imageWithCGImage:asset.thumbnail]; // note, use thumbnail, not fullResolutionImage or anything like that
[self.imageCache setObject:image forKey:key];
// see if the cell is still visible, and if so, update it
// note, do _not_ use `cell` when updating the cell image, but rather `updateCell` as shown below
UITableViewCell *updateCell = (id)[tableView cellForRowAtIndexPath:indexPath]; // not to be confused with similarly named table view controller method ... this one checks to see if cell is still visible
if (updateCell) {
[UIView transitionWithView:updateCell.imageView duration:0.1 options:UIViewAnimationOptionTransitionCrossDissolve animations:^{
updateCell.imageView.image = image;
updateCell.textLabel.text = asset.defaultRepresentation.filename;
} completion:nil];
}
} failureBlock:^(NSError *error) {
NSLog(#"%s: assetForURL error: %#", __PRETTY_FUNCTION__, error);
}];
}
return cell;
}
#end
The above uses the following classes:
/** Thumbnail cache
*
* This cache optimizes retrieval of old thumbnails. This purges itself
* upon memory pressure and sets a default countLimit.
*/
#interface ThumbnailCache : NSCache
// nothing needed here
#end
#implementation ThumbnailCache
/** Initialize cell
*
* Add observer for UIApplicationDidReceiveMemoryWarningNotification, so it purges itself under memory pressure
*/
- (instancetype)init
{
self = [super init];
if (self) {
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(removeAllObjects) name:UIApplicationDidReceiveMemoryWarningNotification object:nil];
self.countLimit = 50;
};
return self;
}
/** Dealloc
*
* Remove observer before removing cache
*/
- (void)dealloc
{
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIApplicationDidReceiveMemoryWarningNotification object:nil];
}
#end
and
/** Custom AssetGroup object
*
* This is my model object for keeping track of the name of the group and list of asset URLs.
*/
#interface CustomAssetGroup : NSObject
#property (nonatomic, copy) NSString *name;
#property (nonatomic, strong) NSMutableArray *assetURLs;
#end
#implementation CustomAssetGroup
// nothing needed here
#end
You have to explore all the code base related to the save and retrieve functionality.
However, here are some good tips.
Save the ALAsset Url instead of saving the entire ALAsset as a string.
Retrieve the ALAsset Url from the database and convert it to NSUrlString.
Use ALAsset Library to load the image or thumbnail back.
Hope this will help you.
I have a little problem, I use this class for load some image asincronusly
#import <UIKit/UIKit.h>
#interface AsyncImageView : UIView {
NSURLConnection* connection;
NSMutableData* data;
}
- (void)loadImageFromURL:(NSURL*)url;
- (UIImage*) image;
#end
#import "AsyncImageView.h"
#implementation AsyncImageView
- (void)dealloc {
[connection cancel]; //in case the URL is still downloading
}
- (void)loadImageFromURL:(NSURL*)url {
//in case we are downloading a 2nd image
NSURLRequest* request = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0];
connection = [[NSURLConnection alloc] initWithRequest:request delegate:self]; //notice how delegate set to self object
}
//the URL connection calls this repeatedly as data arrives
- (void)connection:(NSURLConnection *)theConnection didReceiveData:(NSData *)incrementalData {
if (data==nil) { data = [[NSMutableData alloc] initWithCapacity:2048]; }
[data appendData:incrementalData];
}
//the URL connection calls this once all the data has downloaded
- (void)connectionDidFinishLoading:(NSURLConnection*)theConnection {
//so self data now has the complete image
connection=nil;
if ([[self subviews] count]>0) {
//then this must be another image, the old one is still in subviews
[[[self subviews] objectAtIndex:0] removeFromSuperview]; //so remove it (releases it also)
}
//make an image view for the image
UIImageView* imageView = [[UIImageView alloc] initWithImage:[UIImage imageWithData:data]];
imageView.contentMode = UIViewContentModeScaleAspectFit;
[self addSubview:imageView];
imageView.frame = self.bounds;
[imageView setNeedsLayout];
[self setNeedsLayout];
data=nil;
}
- (UIImage*) image {
UIImageView* iv = [[self subviews] objectAtIndex:0];
return [iv image];
}
#end
and this for load the image
AsyncImageView *asyncImage = [[AsyncImageView alloc] initWithFrame:frame];
asyncImage.tag = 999;
NSURL *url = [NSURL URLWithString:indirizzoImmagine];
[asyncImage loadImageFromURL:url];
[self.view addSubView:asyncImage]
with this code all work but when I try to put asyncImage on [cell.imageview setImage:async.image]; the app crash, I think that I need to change the subclass in uiimageview but nothing...the same error
Terminating app due to uncaught exception 'NSRangeException', reason: '* -[__NSArrayI objectAtIndex:]: index 0 beyond bounds for empty array'
How can I geto only the image?
In AsyncImageView class synthesize imageCache using following code you can get the image
[imageView.imageCache imageForKey:str_ImgUrl];
Here imageView is the object of AsyncImageView.
I am calling .NET webservice hosted locally from my iPhone app (iOS5) like this:
(IBAction)btnCallService:(id)sender {
[XYZActivity startAnimating];
// So I could show activity on my main UI thread.
[self performSelector: #selector(CallXYZSService)
withObject: nil
afterDelay: 0];
}
(void) CallXYZSService
{
NSURL *url = [NSURL URLWithString: #"http://localwinhost/JSON_Service.asmx/GetFunction1"];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:url cachePolicy:1 timeoutInterval:30];
NSData *requestData = [NSData dataWithBytes:[jsonRequest UTF8String] length:[jsonRequest length]];
[request setHTTPMethod:#"POST"];
[request setValue:#"application/x-www-form-urlencoded" forHTTPHeaderField:#"Content-Type"];
[request setValue:#"close" forHTTPHeaderField:#"Connection"];
[request setValue:[NSString stringWithFormat:#"%d", [requestData length]] forHTTPHeaderField:#"Content-Length"];
[request setHTTPBody: requestData];
//[req setHTTPBody: [postStr dataUsingEncoding:NSUTF8StringEncoding]];
myConn = [[NSURLConnection alloc] initWithRequest:request delegate:self];
if (myConn) {
webData = [NSMutableData data];
}
else
{
NSLog(#"Connection Failed");
}
}
}
-(void) connection:(NSURLConnection *)connection
didReceiveResponse:(NSURLResponse *) response{
[webData setLength: 0];
}
-(void) connection:(NSURLConnection *)connection
didReceiveData:(NSData *) data {
[webData appendData:data];
}
-(void) connection:(NSURLConnection *)connection
didFailWithError:(NSError *) error {
NSLog(#"Service Failed");
}
Now my problem is sometimes it calls the service and I recive data , and sometimes it doesn'tand nothing happens.... not even timeout error...
What I am doing wrong here , I am calling my webservice asynch ... issue is it even doesn't go to any other delegate methods , just prepare the request , init the connection and then nothing happens....
Is it has something to do with previous connections to the webservice ? As for testing I am calling 2,3 different functions on same service on same server ... but these are happening on different viewcontrollers ...so I init new connection and set my connection to nil in connectionDidFinishLoading method.
Can any one plz help me here, how to make sure that I always get response back from service either valid response or some error.... or timeout....
If I test the same service on MAC in Safari , it always get called without any issue...!!!
Thanks,
Maverick
I have changed the code as below
I have changed the code as below NSString *jsonRequest_NE = [NSString stringWithFormat:#"ID=%#&Password=%#",strID,strPwd];
NSString *jsonRequest = [jsonRequest_NE stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSLog(#"Request: %#", jsonRequest);
NSString *myURL = #"http://localwinhost/JSON_Service.asmx/GetFunction1";
NSString *fixedURL = [myURL stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
but still the same beahviour, sometime it works sometimes it just doesn't.....
I have searched alot...but still could't find proper solution...
any one plz help me hereeeeeeeeeeee !!!
Make sure you don't have any non-UFT8 characters in your jsonRequest variable.
Let me know how you managed it.
I have been struggling with this piece of code for a while and I just don't know why it happens that when running in the device ... the app crashes with an EXC_BAD_ACCESS Error but when running in the simulator it runs fine.
The scenario: A subclass of NSOperation that makes an async connection with NSURLConnection and gets custom data. When finished, it calls the block with the downloaded data.
Here is the .h file:
#interface FileDownloader : NSOperation <NSURLConnectionDataDelegate>
typedef void (^CompletionBlockForFile)(NSData *);
- (id)initWithCompletionBlock:(CompletionBlockForFile)block;
#end
and the .m file:
#interface FileDownloader ()
#property (strong, nonatomic) CompletionBlockForFile completionBlock;
#property (strong, nonatomic) NSMutableData *downloadedData;
- (void)downloadFileWithCompletionBlock:(CompletionBlockForFile)block;
#end
#implementation FileDownloader
#synthesize downloadedData = _downloadedData;
#synthesize completionBlock = _completionBlock;
- (id)initWithCompletionBlock:(CompletionBlockForFile)block
{
self = [super init];
if (self) {
_completionBlock = block;
}
return self;
}
- (void)main
{
if (self.isCancelled) return;
if (_completionBlock) {
[self downloadFileWithCompletionBlock:_completionBlock];
}
}
- (void)downloadFileWithCompletionBlock:(CompletionBlockForFile)block
{
NSURL *url = [NSURL URLWithString:#"http://www.google.com"];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
dispatch_async(dispatch_get_main_queue(), ^{
NSURLConnection *connection = [NSURLConnection connectionWithRequest:request delegate:self];
[connection start];
});
}
... delegate methods of NSURLConnection
#end
And Finally, the method that adds the operation object to the queue at the MainViewController Class:
- (void)viewDidLoad
{
[super viewDidLoad];
NSOperationQueue *queue = [[NSOperationQueue alloc] init];
FileDownloader *fileDownloader = [[FileDownloader alloc] initWithCompletionBlock:^(NSData *data){ // <----- HERE IS THE EXC_BAD_ACCES ERROR JUST WHEN RUNNING IN THE DEVICE !!! :S
NSLog(#"%#", data);
}];
[queue addOperation:fileDownloader];
}
Can anybody explain me what am I doing wrong? And is it correct to put strong for the block var in the property? Why not assign? Or weak ?
Thanks in advance :)
Blocks should be copied and not retained.
Change
#property (**strong**, nonatomic) CompletionBlockForFile completionBlock;
to
#property (**copy**, nonatomic) CompletionBlockForFile completionBlock;
and it should work
I'm trying to set up a Tab Bar Application as my root controller, and one of the tabs to be a Navigation setup. On my Root View Controller of the Navigation View, I have one child level that is a subclass of the UIViewController called IntervalViewController.
I have this in my Root View Controller (IntervalSetupViewController.m):
#import "IntervalSetupViewController.h"
#import "IntervalViewController.h"
#implementation IntervalSetupViewController
#synthesize controllers; // My Array for the Table View Cells
- (void)viewDidLoad {
self.title = #"Interval Setup";
NSMutableArray *array = [[NSMutableArray alloc] init];
// Interval List Setup
IntervalViewController *newInterval = [[IntervalViewController alloc]
initWithStyle:UITableViewStylePlain];
newInterval.title = #"Interval 1";
[array addObject:newInterval];
[newInterval release];
self.controllers = array;
[array release];
[super viewDidLoad];
}
- (void)viewDidUnload {
self.controllers = nil;
[super viewDidUnload];
}
- (void)dealloc {
[controllers release];
[super dealloc];
}
#pragma mark -
#pragma mark Table Data Source Methods
- (NSInteger)tableView:(UITableView *)table numberOfRowsInSection:(NSInteger)section {
return [self.controllers count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *IntervalCell = #"IntervalCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:IntervalCell];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:IntervalCell] autorelease];
}
// Configure the cell
NSUInteger row = [indexPath row];
IntervalViewController *newController = [controllers objectAtIndex:row];
cell.textLabel.text = newController.title;
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
return cell;
}
#pragma mark Table View Delegate Methods
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
NSUInteger row = [indexPath row];
IntervalViewController *nextController = [self.controllers objectAtIndex:row];
[self.navigationController pushViewController:nextController animated:YES];
}
#end
This is the error screen from the console:
* -[IntervalViewController initWithStyle:]: unrecognized selector sent to instance 0x3b33e60
* Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[IntervalViewController initWithStyle:]: unrecognized selector sent to instance 0x3b33e60'
I assume that I am passing an invalid argument to my initWithStyle method, but I thought UITableViewStylePlain was a valid parameter. Am I setting this up right? I was following the example in APress Beginning iPhone Development 3 book and trying to modify it a little to what I wanted to do, but I'm new to coding. Thanks!
initWithStyle is used to initialize a UITableViewController not a UIViewController