Tableview Images doesn't load, but at times appears when i scroll the page or else appears when i click on a cell.
NB: I am using SDWebImage for lazy loading purposes.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
MyTableViewCell *c = [tableView dequeueReusableCellWithIdentifier:#"cell"];
if (c == nil)
{
c = [[MyTableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle
reuseIdentifier:#"cell"];
}
[c.imageView1 setImageWithURL:[NSURL URLWithString:#"http://www.worldweatheronline.com/images/wsymbols01_png_64/wsymbol_0008_clear_sky_night.png"] placeholderImage:[UIImage imageNamed:#"pl.png"]];
Better use SDWebImage+ActivityIndicator, it will show you the activity indicator when the image is downloading.
Dowload link - SDWebImage+ActivityIndicator
Replace as this method- [c.imageView1 setImageWithURL:[NSURL URLWithString:temp1] placeholderImage:[UIImage imageNamed:#"emptypic"] usingActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
Related
In my app I load cell's photo right in cellforrowatindexpath, but it takes main thread for a long period, and when I scroll, my app stops for a while.
What should I do? If I add async thread it would call it every time I scroll and there could be 2 or more equal photo loading requests, and this is not good... Is there any idea without spaghetti coding?
Try SDWebImage framework
https://github.com/rs/SDWebImage
Sample Code
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *MyIdentifier = #"MyIdentifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:MyIdentifier];
if (cell == nil)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:MyIdentifier];
}
// Here we use the new provided sd_setImageWithURL: method to load the web image
[cell.imageView sd_setImageWithURL:[NSURL URLWithString:#"Get each url from array and set it here using indexpath.row"]
placeholderImage:[UIImage imageNamed:#"placeholder.png"]];
cell.textLabel.text = #"My Text";
return cell;
}
It supports variety of features like caching etc.
I feed a UITableView with a list of names and images from a JSON. "SDWebImage" handles images download. It works OK apart from the fact that the images move to the left when the user selects a row or when scrolls the table view.
Two screen captures to show the issue.
Interface Builder setup
Implementation is pretty standard:
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return array.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell"];
if (cell == nil ) {
cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:#"Cell"];
}
cell.textLabel.text = [[array objectAtIndex:indexPath.row]objectForKey:#"marca"];
cell.textLabel.lineBreakMode = NSLineBreakByWordWrapping;
[cell.imageView setImageWithURL:[NSURL URLWithString:[[array objectAtIndex:indexPath.row]objectForKey:#"photoUrl"]]placeholderImage:[UIImage imageNamed:#"placeholder.png"] ];
return cell;
}
What can I do to stop images moving?
I've just had a similar issue on an app and found it was because I was re-using UITableViewCells default imageView IBOutlet.
After creating my a new IBOutlet, called something other than imageView, and hooking it up it resolved the issue.
Requirement : To Display upto 9 Datapoints in a single Custom TableViewCell with 2 UILabels,4 UIButtons and 3 UIImages.
Problem Statement:Scrolling with the Custom UITableViewCell is not smooth with these UIImages and UIButtons added as subviews. There are approximately 500 rows in the UITableView.
If the problem is in number of view on one cell.
Try to set shouldRasterize property of cell's layer to YES.
yourCell.layer.shouldRasterize = YES;
yourCell.layer.rasterizationScale = [UIScreen mainScreen].scale;
But remember that all animated views such as UIActivityIndicatorView will force the cell to redraw it's content on each frame.
I use this Library which is just perfect
SDWebImage
You just need to #import <SDWebImage/UIImageView+WebCache.h> to your project, and you can define also the placeholder when image is being downloaded with just this code:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *MyIdentifier = #"MyIdentifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:MyIdentifier];
if (cell == nil)
{
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:MyIdentifier] autorelease];
}
// Here we use the new provided setImageWithURL: method to load the web image
[cell.imageView setImageWithURL:[NSURL URLWithString:#"http://www.domain.com/path/to/image.jpg"]
placeholderImage:[UIImage imageNamed:#"placeholder.png"]];
cell.textLabel.text = #"My Text";
return cell;
}
It also cache downloaded images and gives you great performance.
Hope it will help you!
I am facing a weird issue and I am sure I am doing something wrong. In my UITableViewController class I have a function as follows:
-(void)EERefreshView
{
NSLog(#"App delegate requested the view be refreshed");
[self loadEventsFromDB];
for(int a=0;a<eventsList.count;a++)
{
DB_EEEvent *event = (DB_EEEvent*)eventsList[a];
UITableViewCell *cell =
[self.tableView dequeueReusableCellWithIdentifier:#"Cell"];
//NSLog(#"CellID %#", cell.reuseIdentifier);
//get references to the UI components
UILabel *lblTitle = (UILabel*)[cell.contentView viewWithTag:5];
UILabel *lblDate = (UILabel*) [cell.contentView viewWithTag:6];
UIImageView *imgEvent = (UIImageView*)[cell.contentView viewWithTag:7];
//set values
lblTitle.text = event.name;
lblDate.text = [NSString stringWithFormat:#"%# - %#",
event.startdate,event.enddate];
AppDelegate *del = [AppDelegate sharedAppDelegate]; //need this to get the BaseURL
// Here we use the new provided setImageWithURL: method to load the web image
NSString * imageURL =[[NSString alloc] initWithFormat:#"http://%#%#",del.api.BaseURL,event.logo];
NSString* webStringURL = [imageURL stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSURL *url = [NSURL URLWithString:webStringURL];
[imgEvent setImageWithURL:url placeholderImage:[UIImage imageNamed:#"placeholder.png"] completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType) {
//do somethign when image call completes
}];
[eventsListCells addObject:cell];
if(a == selectedEvent)
{
}
}
dispatch_async(dispatch_get_main_queue(), ^{
[tblEventsList reloadData];
});
}
This function loads an array with UITableViewCell objects which is then used later on by
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
// Configure the cell data
NSLog(#"IndexPathRow: %d", indexPath.row);
UITableViewCell *cell = (UITableViewCell*)eventsListCells[indexPath.row];
return cell;
}
However when the cell is loaded lblTitle and lblDate have no text displaying in them. But when I tap on a cell it then displays the text in the labels. So this means that the data is there but its not being refresh when initially created. I suspect this might have something to do with threads but I am not an expert on the subject and would appreciate any help that I can get.
I see what is bothering you and why you created this method, but you don't need it. The only reason why you need back thread is your image loading so that should be thrown in bkg. thread and the rest of the code should be in -
(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath.
U really don't need to pre create cells, and U cant cause they are reusable. For example if you have 50 elements in eventsList and room for only 5 cell on your screen you cant create 50 cells cause the code will create only 5+1 and reuse them as they appear on the screen, so every element of your eventsList will use one of those 5 cells and on the other side every cell will be a host for 10 different elements from your eventsList array. So as you can see your code doesn't make much sense...
The second function you mentioned in your question is the function that is called to populate the table with data. When you call [tblEventsList reloadData]; your app just calls the (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath method. So this method needs to be outputting data back to the table. A very simple example is below. Also, make sure your table delegate and data source are set.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView
dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc]
initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:CellIdentifier];
}
// Configure the cell.
cell.textLabel.text = [self.your_data_source objectAtIndex:[indexPath row]];
return cell;
}
I'm trying to display a UITableView with a list of artists who read from Last.fm API. I store all the artists in an array, then I show a table with your name and your picture.
Initially the photos look good, but when I do scroll the images are very small.
This is the initial appearance:
This is the appearance after scrolling, with the problem:
This is my code for create the cells:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"TopArtistCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
JSCArtist *artist = self.artists[indexPath.row];
cell.textLabel.text = [artist name];
[cell.imageView setImageWithURL:[NSURL URLWithString:[[artist photo] thumbnail]] placeholderImage: [UIImage imageNamed:#"default_photo.jpeg"]];
return cell;
}
The default imageView for a UITableView acts a little odd. I would just create a custom UITableViewCell subclass and do your own layout.