How to render UITableViewCell - iphone

Question

I create UITabBar template. Then I add to firstViewController a tableView. Make connections (UITableViewDataSource and UITableViewDelegate).
In didselect method I need to render selected UITableViewCell and animate it to one of UITabBars.
If I render UITableViewCell row = 0 - it's ok, But if I render UITableViewCell row > 0 (1,2,...) I get black rectangle.
I can render UITableViewCell contentView, but it will render without background.
How can I get snapshot of UITableViewCell with a background?
#import <UIKit/UIKit.h>
#interface AppDelegate : UIResponder <UIApplicationDelegate, UITabBarControllerDelegate>
#property (strong, nonatomic) UIWindow *window;
#property (strong, nonatomic) UITabBarController *tabBarController;
#end
#import "AppDelegate.h"
#import "FirstViewController.h"
#import "SecondViewController.h"
#implementation AppDelegate
#synthesize window = _window;
#synthesize tabBarController = _tabBarController;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions: (NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
UIViewController *viewController1 = [[FirstViewController alloc] initWithNibName:#"FirstViewController" bundle:nil];
UIViewController *viewController2 = [[SecondViewController alloc] initWithNibName:#"SecondViewController" bundle:nil];
self.tabBarController = [[UITabBarController alloc] init];
self.tabBarController.viewControllers = [NSArray arrayWithObjects:viewController1, viewController2, nil];
self.window.rootViewController = self.tabBarController;
[self.window makeKeyAndVisible];
return YES;
}
#import <UIKit/UIKit.h>
#interface FirstViewController : UIViewController <UITableViewDelegate, UITableViewDataSource>
#property (nonatomic, strong) IBOutlet UITableView *tableViewAnimation;
#property (nonatomic, retain) UIImageView *thumbnail;
- (UIImage*)screenshotFromView:(UIView *)view;
#end
#import "FirstViewController.h"
#import <QuartzCore/QuartzCore.h>
#implementation FirstViewController
#synthesize tableViewAnimation = _tableViewAnimation;
#synthesize thumbnail = _thumbnail;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
self.title = NSLocalizedString(#"First", #"First");
self.tabBarItem.image = [UIImage imageNamed:#"first"];
}
return self;
}
#pragma mark - UITableView DataSource
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
NSUInteger count = 10;
return count;
}
// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *goodsListCellIdentifier = #"ListOfGoodsIndetifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:goodsListCellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:goodsListCellIdentifier];
cell.textLabel.backgroundColor = [UIColor clearColor];
}
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
cell.textLabel.text = #"detalied view";
return cell;
}
#pragma mark - UITableView Delegate
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
cell.backgroundColor = [UIColor redColor];
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [_tableViewAnimation cellForRowAtIndexPath:indexPath];
CGRect imageViewFrame = cell.frame;
imageViewFrame.origin.y = 64.0 + tableView.frame.origin.y + imageViewFrame.origin.y - tableView.contentOffset.y;
// imageViewFrame.size.width = cell.contentView.frame.size.width;
UIImageView *imageView = [[UIImageView alloc] initWithFrame:imageViewFrame];
imageView.image = [self screenshotFromView:cell];
[self.tabBarController.view addSubview:imageView];
self.thumbnail = imageView;
self.thumbnail.hidden = NO;
self.view.userInteractionEnabled = NO;
[UIView animateWithDuration:1.0
animations:^{
CGRect tabBarFrame = self.tabBarController.tabBar.frame;
CGFloat xoffset = tabBarFrame.size.width / 2;
[_thumbnail setCenter:CGPointMake(xoffset * 0.5, tabBarFrame.origin.y + 25.0)];
[_thumbnail setTransform:CGAffineTransformMakeScale(0.1, 0.1)];
[_thumbnail setAlpha:0.4];
}
completion:^(BOOL finished){
[self.thumbnail removeFromSuperview];
self.thumbnail = nil;
self.view.userInteractionEnabled = YES;
}];
}
- (UIImage*)screenshotFromView:(UIView *)view {
// Create a graphics context with the target size
// On iOS 4 and later, use UIGraphicsBeginImageContextWithOptions to take the scale into consideration
// On iOS prior to 4, fall back to use UIGraphicsBeginImageContext
CGSize imageSize = view.bounds.size;
UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0);
CGContextRef context = UIGraphicsGetCurrentContext();
// -renderInContext: renders in the coordinate space of the layer,
// so we must first apply the layer's geometry to the graphics context
CGContextSaveGState(context);
// Center the context around the window's anchor point
CGContextTranslateCTM(context, [view center].x, [view center].y);
// Apply the window's transform about the anchor point
CGContextConcatCTM(context, [view transform]);
// Offset by the portion of the bounds left of and above the anchor point
CGContextTranslateCTM(context, -[view bounds].size.width * [[view layer] anchorPoint].x, -[view bounds].size.height * [[view layer] anchorPoint].y);
// Render the layer hierarchy to the current context
[[view layer] renderInContext:context];
// Restore the context
CGContextRestoreGState(context);
// Retrieve the screenshot image
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
#end

Answer 1

The background is probably not rendered automatically by the cell but by the table instead.
Note that background is rendered depending on cell state (background / selected background).
You can take cell.backgroundView and render it before you render the cell.
[((UITableViewCell*) view).backgroundView.layer renderInContext:context]
But that's only a guess.
Maybe it's something simpler. When you tap a cell, selection animation is started. renderInContext ignores animations. Maybe there is a problem?

Answer 2

Just comment next lines:
// Center the context around the window's anchor point
// CGContextTranslateCTM(context, [view center].x, [view center].y);
// Apply the window's transform about the anchor point
// CGContextConcatCTM(context, [view transform]);
// Offset by the portion of the bounds left of and above the anchor point
// CGContextTranslateCTM(context, -[view bounds].size.width * [[view layer] anchorPoint].x, -[view bounds].size.height * [[view layer] anchorPoint].y);