I have written drawRect as follows.
-(void)drawRect:(CGRect)rect
{
[super drawRect:rect];
CGContextRef cxt = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(cxt, 2.0);
CGContextSetStrokeColorWithColor(cxt, [UIColor redColor].CGColor);
CGContextMoveToPoint(cxt, 250.0 , 0.0);
CGContextAddLineToPoint(cxt, 250.0, 50.0);
CGContextStrokePath(cxt);
}
It draws red line. But When I set background view to cell line disappears. I have set view as follow.
UIView *view = [[UIView alloc] initWithFrame:cell.frame];
view.backgroundColor = [UIColor grayColor];
cell.backgroundView = view;
What is the problem? How backgrond view hides the line?
Please help
I guess you are in a UITableViewCell?
You should not overwrite drawRect of the cell itself. Instead put your drawing code in a custom backgroundView, or in a custom view within the contentView hierarchy. (depends on your planned result, probably backgroundView is correct for you)
The line is gone, because the backgroundView is a subview of the TableViewCell, so it is on top of the cell itself. (You can see this, if you use [UIColor colorWithWhite:0.0 alpha:0.5] as backgroundColor of your backgroundView.) There are many views on a UITableViewCell, it looks somewhat like this:
UITableViewCell
> BackgroundView
> (EditControl)
> ContentView
> (AccessoryView)
Agree with jaydee3 that you should not override UITableViewCell's drawRect, instead make your custom view class extending from UIView, extend drawRect there and do all the framing and coloring thing there, then set an instance of that view as your cell background view, its much better approach
When u already drawn background of that,u can't set background Color or image again for that cell.It overlays on what u drawn.
I have one UIImageView with a UIButton partially overlapping it. I want the user to see the image and the button as one joined object. When I try to give them drop shadow using QuartzCore:
image.layer.shadowOffset = CGSizeMake(5,5);
button.layer.shadowOffset = CGSizeMake(5,5);
The Button's shadow will partly drop on the image. I want the button shadow to only drop for the part that are outside the image. Something like the union of two rectangles. Help will be appreciated!
Thanks
Leo
Put the UIImageView and the UIButton into a parent view. Set the shadow on the parent view. Make sure the parent view is not opaque and has a transparent background color:
- (void)viewDidLoad {
[super viewDidLoad];
self.shadowView.backgroundColor = [UIColor clearColor];
self.shadowView.opaque = NO;
self.shadowView.layer.shadowOffset = CGSizeMake(5, 5);
self.shadowView.layer.shadowColor = [UIColor blackColor].CGColor;
self.shadowView.layer.shadowOpacity = 1.0;
}
I would like to achieve a similar effect:
http://imageshack.us/m/695/3715/img0419s.png
My initial idea was to create something like presentend in this schema http://imageshack.us/m/9/9227/img0413.png. Ie a ViewController with 2 subviews: a classical one with some information, and a tableView below which should scroll over the previous view.
But I realized that dividing the main view this way couldn't allow my tableview to scroll over the first view.
So I'm asking how this effect is possible. Maybe by setting a transparent header ?
Thanks for your help
Following the teriiehina's advise, here is how I dit it :
In my UITableViewController, I set a 50px contentInset and a transparent color to my tableView.
self.tableView.backgroundColor = [UIColor clearColor];
self.tableView.contentInset = UIEdgeInsetsMake(50,0,0,0);
I added an additional view on the top of the view (same size than the contentInset)
TTView *test = [[TTView alloc] init];
test.frame = CGRectMake(0, 0, 320, 50);
test.backgroundColor = [UIColor grayColor];
[self.view addSubview:test];
Finally, in order to let my tableview scroll over the additional view, I brought it in the front
[self.view bringSubviewToFront:self.tableView];
Now I just have to set a custom color for my cells.
A dirty trick here:
Add the UIView that contains the name first
Add a UIScrollView with clipBounds = NO. That view will contain the message.
That should work for you
I think you can achieve this effect using the contentInset property of the UITableView (which is a UIScrollView subclass) and presenting the tableView at first with a programmatic scroll.
I have a UIView with an alpha of 0.5 which I add as a subview to my primary view in order to gray-out everything else. I want to add an additional UIView to this gray UIView as a subview - the problem is that when I do this, my newly-added subview is also partially transparent.
Is there any way to make a subview "ignore" the alpha value of its superview and be itself fully opaque?
Set the UIView background color alpha not it's alpha directly.
Objective-C
UIView *view;
...
view.backgroundColor = [[UIColor blackColor] colorWithAlphaComponent:.6];
It's not the same as:
view.backgroundColor = [UIColor blackColor];
view.alpha = .6;
Swift
view.backgroundColor = UIColor.black.withAlphaComponent(0.6)
No, not really. What you want is to take your overlay view, and make it just have a clear background color. As a subview of that new overlay place your view that will grey things out. And as a sibling view to that put your view you want to be opaque.
[OpaqueView] [DimmingView]
| |
[OverlayView]
Don't put it inside the semi-transparent view. Make it a sibling to semi-transparent view and put it over it using z-ordering.
This will only work if you have any image on the background.
Instead of reducing the alpha of UIView, add an UIImageView on that view and then reduce the alpha of the UIImageView.
now add your subviews on the UIView.
your subviews will not take the alpha property anymore.. :)
No, any view will inherit the opacity of its parent.
Apple's iPhone apps such as Music and Contants use a search bar in a UITableView. When you scroll down so that the search bar moves down, the empty space above the scroll view's contents has a light gray background color (see screenshot).
(Notice that the search bar has a slightly darker edge line at its top. This is not there for the default UISearchBar, but subclassing should take care of that.)
I tried setting the background color of the UITableView, but that affects the rows as well. Does anyone know how to achieve this effect? Am I going to have to override implement drawRect: or is there a built in way?
Setting transparencies is bad for performance. What you want is the gray area above the search bar, but it should still be white beyond the end of the list.
You can add a subview to your UITableView that lives above the content instead.
CGRect frame = self.list.bounds;
frame.origin.y = -frame.size.height;
UIView* grayView = [[UIView alloc] initWithFrame:frame];
grayView.backgroundColor = [UIColor grayColor];
[self.listView addSubview:grayView];
[grayView release];
You could add more fancy stuff to the view if you like, perhaps a fade, or a divider line without subclassing UISearchBar.
This is one of my very favorite tricks.
UIView *topview = [[[UIView alloc] initWithFrame:CGRectMake(0,-480,320,480)] autorelease];
topview.backgroundColor = [UIColor colorWithRed:226.0/255.0 green:231.0/255.0 blue:238.0/255.0 alpha:1];
[self.tableView addSubview:topview];
Basically you're creating a big view the size of the screen and placing it "above" the content area. You'll never be able to scroll up past it.
And don't worry about the memory impact of a UIView that's 320x480 pixels, it won't consume any significant memory because the CALayer doesn't have any meaningful content.
NOTE: Why is this answer relevant when the "accepted" answer is so much simpler? Why not just set the backgroundView on the table view? It's because, in the case of the Contacts app as shown in the original question, the area "above" the table view has a different background color (light blue) than the area "below" the table view (white). This technique allows you to have two different colors above and below the table view, which cannot be accomplished by a simple background.
EDIT 1/2018: As Tom in the comments pointed out, this answer is quite old and assumes that all iOS devices have the same screen size (seems crazy but it was the case in 2009 when I answered this). The concept I present here still works, but you should use UIScreen.main.bounds to figure out the actual screen size, or you could get into some fancy auto layout stuff (suggestions welcome). I don't recommend using tableView.bounds as in another answer, because typically in viewDidLoad the size of your views is not necessarily the size that they will become after the controller resizes them. Sometimes they start out as 0x0!
To extend on HusseinB's suggestion:
Swift 3
let bgView = UIView()
bgView.backgroundColor = UIColor.white
self.tableView.backgroundView = bgView
Objective C
UIView *bgView = [UIView new];
bgView.backgroundColor = [UIColor whiteColor];
[self.tableView setBackgroundView:bgView];
As of iOS 7, you can tinker this by changing the tableview background view.
[self.tableView setBackgroundView:view];
make the view's background colour the same as your parent view colour.
This code works in Swift fot UITableView:
var frame = self.tableView.bounds
frame.origin.y = -frame.size.height
frame.size.height = frame.size.height
frame.size.width = UIScreen.mainScreen().bounds.size.width
let blueView = UIView(frame: frame)
blueView.backgroundColor = UIColor.headerBlueColor()
self.tableView.addSubview(blueView)
In Swift (tested on iOS9)
let backView = UIView(frame: self.tableView.bounds)
backView.backgroundColor = UIColor.clearColor() // or whatever color
self.tableView.backgroundView = backView
EASIEST SOLUTION
The easiest way to create different colors in the bottom and in the top of a bouncing area of a table view is to set the key tableHeaderBackgroundColor of the table view. Doing this way you set the top color. I'm not sure, but maybe there is another key for the footer, take a look. If you don't find anything, you just have to set the background of the table view with the color that you want to show in the bottom. Above you can see an example code:
self.table.setValue(UIColor.blue , forKey: "tableHeaderBackgroundColor")
Hope it help you. If yes, let other people know about this easy way giving an up in the answer :)
I've only found one way to do this. You have to set the backgroundColor of the UITableView to be transparent, set the backgroundColor of the cell's contentView to whatever colour you want the actual cells to be, then crucially you have to get the light grey colour to appear behind the UITableView. That last step you can do by either setting the backgroundColour of the UIWindow, or of whatever is containing or your tableViewController.
So, assuming you have a view controller that is derived from UITableViewController, insert these lines in the -(void)viewDidLoad method:-
// sets the background of the table to be transparent
self.tableView.backgroundColor = [UIColor colorWithWhite:1.0 alpha:0.0];
// assuming we are inside a navigation or tab controller, set the background
self.parentViewController.view.backgroundColor = [UIColor lightGrayColor];
Then inside the part of tableView:cellForRowAtIndexPath: that creates new cells, add:-
// set an opaque background for the cells
cell.contentView.backgroundColor = [UIColor whiteColor];
I just encountered this issue myself and found a solution.
Cause
I used Spark Inspector to examine the layout of the table view - which really helped.
Thing is, that in this scenario the UITableView has 3 subviews:
UITableViewWrapperView
UIView - With backgroundColor set to light gray color
UISearchBar
While you swipe the tableview content downwards, the second subview height is dynamically increasing to fill the space between the UITableViewWrapperView and the UITableView frame origin.
Solution
Setting the backgroundColor or backgroundView property won't effect the 2nd subview.
What you need to do is find the second view and change its color, like so:
if (_tableView.subviews.count > 1) {
_tableView.subviews[1].backgroundColor = THE_TARGET_COLOR;
}
In my case I needed all views to be white so I used the following which is less prone to future changes of UITableView view hierarchy by Apple:
for (UIView *subview in _tableView.subviews) {
subview.backgroundColor = [UIColor whiteColor];
}
I will give you the best way to do this.
First set the background color of the table view to the one you want in interface builder.
Then respond to the UITableView delegate tableView:willDisplayCell:ForIndexPath: method
like this
- (void)tableView:(UITableView*)tableView willDisplayCell:(UITableViewCelll*)cell forIndexPath:(NSINdexPath*)indexPath
{
[cell setBackgroundColor:[UIColor whiteColor]];
}
Another Method is :
in ViewDidLoad method (or anywhere you like) set the tableView background color to clear color like this:
self.tableView.backgroundColor = [UIColor clearColor];
and then set the superview color to white
self.tableView.superview.backgroundColor = [UIColor whiteColor];
I don't think you want to override drawRect. Most likely what you're seeing is the background colour of another view or the window, which lies "behind" (i.e. is a superview of) the table view. There's usually a fairly complex layers of UIViews in Apple's UI widgets. Explore the view hierarchy in GDB, look at [myView superview] and then [someSuperView subviews] and try manipulating their BG colours in the debugger to see if you can find which one it is. However, if you implement a fix this way, be warned that it may not be future compatible.
You might also try setting the BG colour of one of the views behind the tableview in Interface Builder (or of the window itself).
If you are using a tableviewcell, you can set the view background to be opaque white. Then use
self.tableView.backgroundColor = [UIColor grayColor];
in the view did load method.
I'm sure that that is [UITableView backgroundColor].
You have affected rows, because rows have backgroundColor == clear (or semi-transparent).
So, If you'll make rows non-trasparent, all will work fine.
This will be solution.
I followed the tip outlined by Peylow, for a UITableView, by simply adding a subview. My only change from the code was to grab a color a bit closer to the one used in Apple apps, plus I got it a bit closer to Apple's look of having a line above the UISearchbar by reducing the frame origin y coordinate by one pixel:
frame.origin.y = -frame.size.height - 1
For anyone who's wondering how to do the same for the bottom bounce area:
First add a subview with your desired background color to your table view's background view:
self.bottomView = [[UIView alloc] initWithFrame:CGRectOffset(self.tableView.frame, 0, self.tableView.frame.size.height)];
self.bottomView.backgroundColor = whateverColorYouLike;
[self.tableView.backgroundView addSubview:self.bottomView];
And then in your table view's delegate:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
CGRect frame = self.bottomView.frame;
frame.origin.y = self.tableView.contentSize.height - self.tableView.contentOffset.y;
self.bottomView.frame = frame;
}
In my case the solution was to create a headerview for the table and assign a color, it solved the black background in bounce area in my apps when in dark mode. I did the same to its tableFooterView.
table.tableHeaderView = UIView()
table.tableHeaderView!.backgroundColor = UIColor.white