UICollectionViewCell selection behavior - iphone

I have a photo gallery in my app. where i can select multiple photos and can delete them. All is going on very well.
I just need to implement apple's default selection behavior as we can see in camera roll.
Right now my selection is like this
I have implemented didSelectItemAtIndexPath method as follows -
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
NSLog(#"Delegate cell %# : SELECTED", [self formatIndexPath:indexPath]);
MyCustomCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];
cell.label.backgroundColor=[UIColor greenColor];
}
- (NSString *)formatIndexPath:(NSIndexPath *)indexPath
{
return [NSString stringWithFormat:#"%ld", (long)indexPath.row+1];
}
And In MyCustomCell.m, I set the frame of label as rectangle as shown in fig (green).
And method setSelected looks like following:
- (void)setSelected:(BOOL)selected
{
UIView *blurView=[[UIView alloc] initWithFrame:CGRectMake(0, 0, 60, 70)];
blurView.backgroundColor=[UIColor whiteColor];
blurView.alpha=0.5;
blurView.opaque=YES;
if (selected) {
self.label.backgroundColor = [UIColor greenColor];
[self.imageThumb addSubview:blurView];
}
}
So, Is it possible to have apple's default selection behavior ??
Any help will be appreciated. Thanks in advance.

In setSelected: of your cell, if selected is YES then add a white UIView with an alpha of 0.5 (or tweak the value to an opacity that looks good to you); if NO, remove that overlay view. Then when you add your checkmark image, make sure to layer it on top of the overlay view with [self.contentView bringSubviewToFront:checkmarkImageView].

Just add an UIView with the desired gray color over the UIImageView.
Set alpha to f.e. 0.5 and hidden = YES;
_blurView.hidden = YES;
_blurView.alpha = 0.5;
Then set hidden = NO if selected.
_blurView.hidden = NO;
You can add the UIView with InterfaceBuilder.
To make it look even better you might use an UIImageView with a nice texture image.

Related

Remove the UITableView Section Border and Background Color with Static Cells ?

I am using UITableView with static cells to make a small form.
I added number of sections in the UITableView but now I have to remove the background color and the border of the section that displays the Login and Forgot Password button.
Check out the screenshot below.
Question 1
How can I remove the background color and the border?
Question 2
Also is there anyway to change the background color of the view. This view inherits from UITableViewController. I believe that I need to change the color of section or the group.
I assigned the identifier to the cell and got to remove the background color.
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
if([cell.reuseIdentifier isEqualToString:#"ButtonsCell"])
{
cell.backgroundColor = [UIColor clearColor];
NSLog(#"login buttons cells found");
}
}
Here is the image:
But the borders are still showing!
SOLUTION
Weird but works!
cell.backgroundView = nil;
I think you want to do a switch cased based on your section within cellForRowAtIndexPath. Then replace the background of that row with a view that's transparent.
switch (section)
{
case BACKGROUND_SECTION:
{
// Only way I could find to get row centered
segmentCell.selectionStyle = UITableViewCellSelectionStyleNone;
[segmentCell setAccessoryType:UITableViewCellAccessoryNone];
// Make the cell background transparent
UIView *backView = [[UIView alloc] initWithFrame:CGRectZero];
backView.backgroundColor = [UIColor clearColor];
segmentCell.backgroundView = backView;
}
}

Custom background image to UITableView, but have tableHeaderView ignore it and remain transparent?

Stuck on something and i'm not sure if it's even possible. Is there a way to set the background of a UITableView as a custom image, but NOT let that background apply to the tableHeaderView. I have a header on my table that needs to remain transparent, because I have a parallax type effect (like the path 2 app) implemented with an image behind the transparent table header & the top 1/3rd of the tableview... but i need to get a custom image behind the rest of the table.
I can successfully get close to the background style im looking for that fills in behind each cell, with:
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
However, this is not quite what Im looking for because I would like a radial gradient background view behind the entire tableview on the screen, minus the transparent header... not just the same image for each cell. Also, this approach really hits my tableview's scrolling performance loading a new BG image with each cell.
I know you can use:
UIImageView *tempImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"image.png"]];
[tempImageView setFrame:self.tableView.frame];
self.tableView.backgroundView = tempImageView;
to set the BG image for the tableview, and it is really close to what I'm trying to do, but I neeeeeed that header transparent. Is there any way to use this, but also tell the tableHeaderView to ignore it and be transparent?
Thanks everyone, & happy Halloween!
Yes, you can. I implemented a solution for the parallax effect for a grouped UITableView. You could use the same approach except instead of a black background (example below) you could use your image. Essentially, you have two views behind the tableview (which is clear, header view background clear as well as the table view background itself). These two views you move based on scrolling (UIScrollViewDelegate). Your tableview background image you'll "scroll" 1 for 1 with the table, while your parallax image will "scroll" at a different rate of course. In the below example i think my "_secondParaView" would be your background image for the table.
Firstly, in viewDidLoad, create a view to partially hide your image for the parallax effect, should be the same color as the background you want the tableview to be, in my case blackColor. I placed the view at a fixed offset based on the size of my image, you want the top of this view to line up with the top of the end of 'section 0' header view. It will then "scroll" just as the tableview scrolls. Insert this view below the tableview.
_secondParaView = [[UIView alloc] initWithFrame: CGRectMake(0.0, kTableViewOffset, self.view.frame.size.width, 200.0)];
_secondParaView.backgroundColor = [UIColor colorWithRed: 0.0 green: 0.0 blue: 0.0 alpha: 1.0];
[self.view insertSubview: _secondParaView belowSubview: _tableView];
_headerImageYOffset = -40.0;
_headerImageView = [[UIImageView alloc] initWithImage: [UIImage imageNamed: #"SpaceRedPlanet640x480.png"]];
CGRect headerImageFrame = _headerImageView.frame;
headerImageFrame.origin.y = _headerImageYOffset;
_headerImageView.frame = headerImageFrame;
[self.view insertSubview: _headerImageView belowSubview: _secondParaView];
_tableView.backgroundColor = [UIColor clearColor];
Then implement the two grouped tableview methods for the header view / header view size:
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {
if (section == 0) {
UIView * tableHeaderView = [[UIView alloc] initWithFrame: CGRectMake(0.0, 0.0, self.view.frame.size.width, kTableViewOffset)];
tableHeaderView.backgroundColor = [UIColor clearColor];
return tableHeaderView;
} else
return nil;
}
- (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section {
if (section == 0) {
return kTableViewOffset;
} else
return 2;
}
Just like in the "normal" tableview parallax implementation, make your VC a UIScrollViewDelegate and implement this scrollViewDidScroll like so:
#pragma mark -
#pragma mark UIScrollViewDelegate methods
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
CGFloat scrollOffset = scrollView.contentOffset.y;
CGRect headerImageFrame = _headerImageView.frame;
CGRect underParaFrame = _secondParaView.frame;
if (scrollOffset < 0) {
// Adjust top image proportionally
headerImageFrame.origin.y = _headerImageYOffset - ((scrollOffset / 3));
} else {
// We're scrolling up, return to normal behavior
headerImageFrame.origin.y = _headerImageYOffset - scrollOffset;
}
underParaFrame.origin.y = kTableViewOffset - scrollOffset;
_headerImageView.frame = headerImageFrame;
_secondParaView.frame = underParaFrame;
}
Hope this helps, or at the very least helps someone implement the parallax effect for a grouped tableview. I could find no solution for it.
Is there a reason why you cannot have the tableHeaderView be a container for the image you wish to have the parallax-type effect?
Create a UIView and stick it as the tableHeaderView of the UITableView, and then add your UIImageView (or whatever) to that tableHeaderView. With UIScrollView's delegate methods, you will be able to reposition this UIView however you please within it's parent view in reaction to user scrolling.
See this open source project for a Path inspired parallax UITableView: RBParallaxTableViewController

UITableViewCellSeparatorStyleNone does not hide blue separator line when selecting in UITableView

Before describing the problem, let me first point out that this is a distinct issue from this question.
The Problem
This screenshot was taken with a break set at tableView:didSelectRowAtIndexPath:, and as you can see in the simulator (far right of the image), there's a single-pixel blue line at the bottom of the selected cell. This is not the design asked for by the client, nor is it how this app used to behave: there should be no separator, even on selection.
How I Got Here
I'd initially designed this table view using custom UITableViewCell classes with corresponding nib (.xib) files and had no trouble with selections: the separator was hidden as desired. Predictably, scrolling was sluggish due to all the overhead from the view hierarchy, so I reworked the custom cells to use Loren Brichter's fast scrolling solution. Now scrolling is much faster, but I can't get rid of the separator for the life of me.
What I've tried
At the time of the screenshot above...
the table view has "Separator [None]" in IB.
the UIViewController that contains the table view has this line in viewDid Load: self.tableView.separatorStyle = UITableViewCellSeparatorStyleNone;
As you can see in the screenshot, I inserted some unused lines to prove that separatorStyle is set as desired. Other testing confirms that tableView and self.tableView are equivalent pointers at that same breakpoint.
I've also tried setting tableView.separatorColor to black and to clear, all with the same result: the cells look right until a selection is made.
Manjunath: Here's the code I'm using to draw alternate backgrounds depending on whether the cell's been touched or not. You can see the difference—which is less subtle when animated—in the screenshot.
if(self.highlighted) {
textColor = [UIColor blackColor];
UIImage *bg = [UIImage imageNamed:#"image-cell-background_highlighted.png"];
[bg drawAtPoint:CGPointMake(0.0, 1.0)];
}
else {
UIImage *bg = [UIImage imageNamed:#"image-cell-background.png"];
[bg drawAtPoint:CGPointMake(0.0, 0.0)];
}
This gets called in UIImageCell.m in drawContentView:, a method inherited from Mr. Brichter's ABTableViewCell super class.
Chris,
Delving into ABTableViewCell, I see:
- (void)setFrame:(CGRect)f
{
[super setFrame:f];
CGRect b = [self bounds];
b.size.height -= 1; // leave room for the seperator line
[contentView setFrame:b];
}
Since the height of the cell is one pixel shorter than the actual cell, when the cell gets selected, that one-pixel line will bleed through in the color of the selection color. It may look like it's the separator, but it is actually the selection color.
To test, try to change that line above to be two pixels or more shorter to see what happens.
Update:
By making this change to the FastScrollingExample project's -rootViewController:
- (void)viewDidLoad
{
self.title = #"Fast Scrolling Example";
self.tableView.separatorStyle = UITableViewCellSeparatorStyleNone;
[super viewDidLoad];
}
and commenting out:
// if(self.selected)
// {
// backgroundColor = [UIColor clearColor];
// textColor = [UIColor whiteColor];
// }
//
in -drawContentView to mimic what would happen if you didn't have the selection color showing through, then I get a screen shot like this:
alt text http://files.me.com/mahboud/7k656q
Look familiar?
How would you get around this? If you don't need to select cells, then disable cell selection. Otherwise, if you are selecting cells, then you should make the rect larger so the default selection color doesn't show through when you paint with your own selection color in -drawConentRect.
Try this:
[cell setSelectionStyle:UITableViewCellSelectionStyleNone];
// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = NSLocalizedString(#"Cell",#"");
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (nil == cell)
{
cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease];
}
[cell setSelectionStyle:UITableViewCellSelectionStyleNone];
return cell;
}

How can I set the background color of a cell in UITableView on iphone?

How can I set the background color of a cell in UITableView?
Thanks.
I know this is an old post, but I am sure some people are still looking for help. You can use this to set the background color of an individiual cell, which works at first:
-(UITableViewCell*)tableView:(UITableView*)tableView cellForRowAtIndexPath:(NSIndexPath*)indexPath {
[cell setBackgroundColor:[UIColor lightGrayColor]];
However, once you start scrolling, the iphone will reuse cells, which jumbles different background colors (if you are trying to alternate them). You need to invoke the tableView:willDisplayCell:forRowAtIndexPath. This way, the background color gets set before the reuse identfier is loaded. You can do it like this:
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
cell.backgroundColor = ([indexPath row]%2)?[UIColor lightGrayColor]:[UIColor whiteColor];
}
The last line is just a condensed if/else statement. Good luck!
Update
Apparently the existing UITableViewCell framework makes it very difficult to change the background color of a cell and have it work well through all its state changes (editing mode, etc.).
A solution has been posted at this SO question, and it's being billed on several forums as "the only solution approved by Apple engineers." It involves subclassing UITableViewCell and adding a custom view for the subclassed cell's backgroundView property.
Original post - this solution doesn't work fully, but may still be useful in some situations
If you already have the UITableViewCell object, just alter its contentView's backgroundColor property.
If you need to create UITableViewCells with a custom background color, the process is a bit longer. First, you'll want to create a data source for your UITableView - this can be any object that implements the UITableViewDataSource protocol.
In that object, you need to implement the tableView:cellForRowAtIndexPath: method, which returns a UITableViewCell when given an NSIndexPath for the location of the cell within the table. When you create that cell, you'll want to change the backgroundColor property of its contentView.
Don't forget to set the dataSource property of the UITableView to your data source object.
For more info, you can read these API docs:
UITableViewDataSource - tableView:cellForRowAtIndexPath
UITableViewCell - contentView
UIView - backgroundColor
UITableView - dataSource
Note that registration as an Apple developer is required for all three of these links.
The backgroundView is all the way on the bottom. It's the one that shows the rounded corners and the edges. What you want is the contentView which is on top of the backgroundView. It covers the usually white area of the cell.
The version I wrote will work in iPhone 3.0 or higher and fallback to a white background otherwise.
In your viewDidLoad method of the UITableViewController we add the following:
self.view.backgroundColor=[UIColor clearColor];
// Also consider adding this line below:
//self.tableView.separatorColor=[UIColor clearColor];
When you are creating your cells (in my code this is my tableView:cellForRowAtIndexPath:) add the following code:
cell.backgroundColor=[UIColor colorWithPatternImage:[UIImage imageNamed:#"code_bg.png"]];
float version = [[[UIDevice currentDevice] systemVersion] floatValue];
if (version >= 3.0)
{
[[cell textLabel] setBackgroundColor:[UIColor clearColor]];
}
This works perfectly for me:
NSEnumerator *enumerator = [cell.subviews objectEnumerator];
id anObject;
while (anObject = [enumerator nextObject]) {
if( [anObject isKindOfClass: [ UIView class] ] )
((UIView*)anObject).backgroundColor = [UIColor lightGrayColor];
}
You may set the backgroundColor of the backgroundView. If the backgroundView does not exists, you can create one for it.
if (!tableView.backgroundView) {
tableView.backgroundView = [[UIView alloc] initWithFrame:tableView.bounds];
}
tableView.backgroundView.backgroundColor = [UIColor theMostFancyColorInTheUniverse];
If you want to set the background of a cell to an image then use this code:
// Assign our own background image for the cell
UIImage *background = [UIImage imageNamed:#"image.png"];
UIImageView *cellBackgroundView = [[UIImageView alloc] initWithImage:background];
cellBackgroundView.image = background;
cell.backgroundView = cellBackgroundView;

After moving a UITableView row, then selecting it, it only turns blue at the edges

I have a UITableView with reorderable rows and I'm using the standard UITableViewCell.text property to display text. When I tap Edit, move a row, tap Done, then tap the row, the built-in UILabel turns completely white (text and background) and opaque, and the blue shade to the cell doesn't show behind it. What gives? Is there something I should be doing that I'm not? I have a hacky fix, but I want the real McCoy.
Here is how to reproduce it:
Starting with the standard "Navigation-Based Application" template in the iPhone OS 2.2.1 SDK:
Open RootViewController.m
Uncomment viewDidLoad, and enable the Edit button:
- (void)viewDidLoad {
[super viewDidLoad];
// Uncomment the following line to display an Edit button in the navigation bar for this view controller.
self.navigationItem.rightBarButtonItem = self.editButtonItem;
}
Specify that the table has a few cells:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return 4;
}
In tableView:cellForRowAtIndexPath:, add a line to set the text property of a cell, and therefore to use the built-in UILabel subview:
// Set up the cell...
cell.text = #"Test";
To enable reordering, uncomment tableView:moveRowAtIndexPath:toIndexPath:. The default implementation is blank, which is fine in this case since the template doesn't include a data model.
Configure the project for the Simulator, OS 2.2.1, Build and Go. When the app comes up, tap Edit, then slide any row to a new position, tap Done, and then tap each row one at a time. Usually a tap will select a row, turn it blue, and turn its text white. But a tap on the row that you just moved does that and leaves the UILabel's background color as white. The result is a confusing white open space with blue strips on the edges. Oddly enough, after the first bogus tap, another tap appears to correct the problem.
So far I have found a hack that fixes it, but I'm not happy with it. It works by ensuring that the built-in UILabel is non-opaque and that it has no background color, immediately upon selection.
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
// hacky bugfix: when a row is reordered and then selected, the UILabel displays all crappy
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
for (UIView *view in cell.contentView.subviews) {
if ([[view class] isSubclassOfClass:[UILabel class]]) {
((UILabel *) view).backgroundColor = nil;
view.opaque = NO;
}
}
// regular stuff: only flash the selection, don't leave it blue forever
[tableView deselectRowAtIndexPath:indexPath animated:YES];
}
This appears to work, but I don't expect it to be a good idea forever. What is the Right Way to fix this?
This looks like a bug in UITableView's rendering, and you should file a Radar bug report on it. It's like the cells don't get refreshed properly after the move.
One way to work around this for now is to not use the built-in label, but roll your own in the cell:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease];
CGRect frame = cell.contentView.bounds;
frame.origin.x = frame.origin.x + 10.0f;
UILabel *textLabel = [[UILabel alloc] initWithFrame:frame];
[textLabel setAutoresizingMask:UIViewAutoresizingFlexibleRightMargin];
textLabel.tag = 1;
textLabel.textAlignment = UITextAlignmentLeft;
textLabel.backgroundColor = [UIColor clearColor];
textLabel.textColor = [UIColor blackColor];
textLabel.font = [UIFont boldSystemFontOfSize:20.0];
textLabel.numberOfLines = 1;
textLabel.highlightedTextColor = [UIColor whiteColor];
[cell.contentView addSubview:textLabel];
[textLabel release];
}
UILabel *textLabel = (UILabel *)[cell viewWithTag:1];
textLabel.text = #"Test";
return cell;
}
I tried this, and it doesn't exhibit the same sort of white blank rectangle you see with the built-in label. However, adding another non-opaque view to the table cell might not be the best for overall rendering performance.
I don't know how major of a glitch this is, because Apple doesn't want you to persist a selection highlight on a table row (they've been enforcing this lately during the review process). You're supposed to place a checkmark or move on to the next level in the navigation hierarchy with a selection, at which point this white box would only be on the screen for a fraction of a second.
The trick in the solution from Brad appears to be:
textLabel.backgroundColor = [UIColor clearColor];
If you leave the background as the default you still get the problem even when you roll your own cells UITableViewCells.
The reason I left it as the default is because the documentation says it is less computationally costly to use opaque backgrounds. Ideally I wouldn't want to use [UIColor clearColor] to fix this bug.
Maybe a completely custom painted cell would somehow fix it. I haven't tried those before though.
Does anyone else have a solution for this?
Thanks for the info, I was searching how to erase the background color from a UILabel.
I used the following line:
textLabel.backgroundColor = [UIColor clearColor];
and worked perfectly!!!
thanks
Alejandra :)
Selections aren't meant to be shown for extended periods! (We got knocked on this for several of our apps)
??? That means Apple would not approve their own Calendar app on iPhone! When you go to edit the start and end times of the event, the start time is selected indefinitely, it only changes once the user taps to the next field.