UIView should be transparent but only shows white - iphone

I have a UIViewController which contains a label and button. I would like the background of the view to be transparent so I set it to clearColor and opaque = NO.
However, the view always displays a white background. How can I fix this?
Thanks.

Once a new view controller is pushed to the top of the stack, whatever is behind it gets hidden so you can adjust the alpha settings for that view but there's nothing to reveal behind it (so you will see white).
You need to use a UIView instead. I'd normally subclass UIView and customise it the way I want, then instantiate and add it as a subview whenever you need to use it:
-(id)initWithFrame:(CGRect)frame
{
if (self = [super initWithFrame:CGRectZero])
{
// Add your label and button here...
}
return self;
}

Sorry, I do not have enough rep to comment on Rog's answer, so I will post 'Another Answer'.
Try this code and see if it turns out well for you:
UIVIew *view = [[UIView alloc] init];
view.alpha = 0; // alpha 1.0 is opaque, alpha 0.5 is translucent and 0 is clear
Honestly, I have not tried that before as I do not require doing so. But when I drag a new UIView from the library, alpha option is in the properties.
Hope this helps.

Related

How to exclude subviews from animation?

I am developing an application in which i am creating small sub views in the same view.
What i want is when i change the value of alpha of the view, the value of alpha for sub view is also getting changed which i do not want.
How to implement the code for changing the value of the view not the small sub views created.
Thanks,
You cannot do that, the alpha is inheritate, so what you have to do is to change the view structure from
YourMainView -> Your SubView
To
ContainerView ->YourMainView
-> Your SubView
So now YourMain View the one that you want to apply the animation, is not the paret view of your current subView, the both views are sibilings, also ContainerView will have a clear background, so it wont affect it will just contain both the views
As suggested already, you should not add YourSubVew as subview of YourMainView.
Make both of your views a subview of an empty and transparent common subview (ContainerView) which has the same size and position that YourMainView currently has.
ContainerView -> YourMainView
-> YourSubView
Make sure to add YourMainView first as subview of ContainerView before you add YourSubView as subview of ContainterView. Otherwise YourMainView may overlap/hide YourSubView.
Doing so you can set both views' alpha independend from each other.
(Omar's answer is quite correct, but his "graphical visualisation" is misleading and it missed the point of the sequence of the subviews.)
Edit:
What you have today is like this:
yourMainView.alpha = 1.0;
...
[yourMainView addSubView:yourSubView];
yourMainView.alpha = 0.1; //probably with animations etc.
What happens is, that yourSubView will "inherit" the alphaValue of its superview.
ANd there is even more to that. Assuming that your subView has an alpha of 0.5, that would effectively become 0.05 when when its superview's alpha is set to 0.1.
Change that code to:
containerView = [[UIView alloc] init]; //you may choose a different init method
//If you use initWithFrame then use the frame of yourMainView.
//However, make sure that ContainterView is of the same size as yourMainView and has the same position.
[containerView addSubView:yourMainView];
yourMainView.alpha = 1.0;
...
[containerView addSubView:yourSubView]; //add it to the container too!
yourMainView.alpha = 0.1; //this will now effect the MainView only.
That is basically all the trick. Views can perfectly well overlap each other without being subviews. Make them subviews only then when they really are subveiws, when they are moved togehter, appear and disappear together, etc.

UIView.setalpha is not working?

I have created a bar to appear over the keyboard for next/previous/done like the safari browser. However, the setalpha property of the UIview of the bar doesn't seem to be working. No matter what value I set it to, nothing changes. Here is the code...
here is where the create view is called..
-(void)textFieldDidBeginEditing:(UITextField *)textField{
// Call the createInputAccessoryView method we created earlier.
// By doing that we will prepare the inputAccView.
[self createInputAccessoryView];
// Now add the view as an input accessory view to the selected textfield.
[textField setInputAccessoryView:inputAccView];
// Set the active field. We' ll need that if we want to move properly
// between our textfields.
txtActiveField = textField;
}
here is where i actually create and set its values...
-(void)createInputAccessoryView{
// Create the view that will play the part of the input accessory view.
// Note that the frame width (third value in the CGRectMake method)
// should change accordingly in landscape orientation. But we don’t care
// about that now.
inputAccView = [[UIView alloc] initWithFrame:CGRectMake(10.0, 0.0, 310.0, 40.0)];
// Set the view’s background color. We’ ll set it here to gray. Use any color you want.
[inputAccView setBackgroundColor:[UIColor darkGrayColor]];
// We can play a little with transparency as well using the Alpha property. Normally
// you can leave it unchanged.
[inputAccView setAlpha: 0.1f];
... code for adding buttons and their properties
}
so basically this is all there is to it. but the setAlpha property does nothing, regardless of what I set it to. However, background color works fine. Any ideas?
Thanks
If you want it to look like the prev/next/done bar in Safari etc, create a UIToolbar with the style set to translucent black. This also has the advantage of laying out your buttons nicely, with the correct style, and auto adjusting between landscape and portrait.
Not a direct answer to your question but probably a better way of acheiving what you actually want.
out of utter curiosity try using:
UIView *overlay = [[UIView alloc] initWithFrame:CGRectMake(10.0, 0.0, 310.0, 40.0)];
overlay.backgroundColor = [UIColor blackColor];
overlay.alpha = 0.5f;
[self.view addSubview:overlay];
it's hard to tell what the issue is without being able to see how many views you have and how you've stacked them. check you've defined your "addSubview" and what the hierarchy looks like

Setting the alpha of the table with a transparent subview to a UITableView

I have added a subview over my UITableView using:
TransparentViewController *tvc =
[[TransparentViewController alloc]
initWithNibName:#"TransparentViewController" bundle:nil];
[self.view addSubview:tvc.view];
My Nib has a UIImageView in it that has some text and a transparent background.
When I load the detailView for the table for the first time I show the subview that gives a brief explanation of the information that you can see below the text. Works really well.
What i would like to do is alter the alpha of the underlying table so that it is dimmer but not affect the alpha of the overlay subview. If i use:
[self.view setAlpha:(CGFloat)];
It dims the overlay as well. I seem to be having a mental block.
Changing the alpha affects the subviews as well. Your tvc.view is a subview of self.view, so it is naturally going to be affected.
Why don't you try this: put another view in tvc.view and send this view to this view to the back.
(UIView*) back = [[UIView alloc] initWithFrame:CGFrameMake(...)];
back.backgroundColor = [UIColor grayColor]; // choose a color that you like;
back.alpha = 0.5; // whatever works for you
[tvc.view addSubview:back];
[tvc.view sendSubviewToBack:back];
Set the size and alpha of this new view to something you like. The table view will show through it to a limited extent, which may accomplish what you are trying to do.
Since this is part of our tvc view, it will appear when you show that view and go away when you hide that view.

Light gray background in "bounce area" of a UITableView

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

How can I set the background of UITableView (the tableview style is "Grouped") to use an image?

How can I set the background of UITableView (the tableview style is "Grouped") to use an image?
In newer versions of the SDK, you'll need to set tableView.backgroundView if you want it to be transparent, try something like this:
tableView.backgroundColor = [UIColor clearColor];
tableView.opaque = NO;
tableView.backgroundView = nil;
We need to do something about that plain background. We're going to use a PNG image and display it behind the UITableView.
Prepare a PNG image. It should be either 320x460 (if you have the status bar visible in your app) or 320x480 (if you hide it).
Drag it into XCode into the Resources folder and add to your project
Load the NIB file containing your UITableView into Interface Builder
Open the library (Tools> Library), switch to the Media tab, and drag the image to the View, create a new UIImageView.
Use the inspector to move and resize the image so it's at X=0, Y=0, Width=320, Height=480
Put the UIImageView behind the UITableView (Layout > Send to Back)
Save, Build and Go!
Disappointingly, you won't be able to see your background. The UITableView's background is blocking us from seeing the UIImageView. There are three changes you need to make:
In the Attributes Inspector, make sure the UITableView's "opaque" checkbox is unchecked!
Set the UITableView's background color to transparent:
tableView.backgroundColor = [UIColor clearColor];
I hope this helps and solves your problem. It has worked for me and I have yet to find a more elegant way to display a background image for a UITableView.
The advantage of my solution, in comparison with setting a background image directly on the UITableView, is that you can indent the table's content. I often wanted to do this to just show two or three table cells at the bottom of the screen.
[tableView setBackgroundColor:[UIColor colorWithPatternImage:[UIImage imageNamed:#"whatever.png"]]];
tableView.backgroundView = nil;
is enough. No need to set background color as Clear Color.
One way would be to make the table view transparent (set the view's background to 0% opacity) and place a UIImageView behind the UITableView. Remember that transparent tables and table cells will not perform as well as opaque ones.
In UI Builder the Background color has an "Other" choice.
This brings up a color picker.
The color picker has an opacity setting.
If you set the Opacity of the COLOR to 0 it works, can't speak to performance.
What I've found is that you have to use a "plain" styled table with a transparent background and then recreate the look of the rounded-corner cells by setting each cell's backgroundView to a UIImageView with a image that simulates the rounded look. This means that the top, bottom, and middle cells need different background images.
However, this does not address what happens when the user taps the cell and it goes "highlighted" - it will look squared off then. You can get around this by setting the highlighted image for your faked tablecell background image. You will also want to create your own disclosure accessory view (ImageView) with a white highlighted version. Then you can create a cell like this one I'm using (below). After I alloc one of these cells I then set the backgroundView and accessoryView to my UIImageViews.
#import "ClearBackRoundedTableCell.h"
#implementation ClearBackRoundedTableCell
- (id)initWithReuseIdentifier:(NSString *)reuseIdentifier
{
if (self = [super initWithStyle:UITableViewCellStyleDefault reuseIdentifier:reuseIdentifier]) {
}
return self;
}
- (void)setHighlighted:(BOOL)highlighted animated:(BOOL)animated
{
if( [[self.accessoryView class] isSubclassOfClass:[UIImageView class]] )
((UIImageView *)self.accessoryView).highlighted = highlighted;
if( [[self.backgroundView class] isSubclassOfClass:[UIImageView class]] )
((UIImageView *)self.backgroundView).highlighted = highlighted;
self.textLabel.highlighted = highlighted;
}
#end
One note if you go this route: the cells in a grouped table are typically 300 px wide (in portrait mode) but your plain table here would need to be 302 wide to allow for the grey line on each side of the table, which is normally outside of the "content" of the table cell.
After spending a while with color picker, I found out that you need to specify opaque background not for the table view cell xib, but for the Table View where the cells will be located, which is another xib. From what I have seen, table view cell background attributes have no visual effect.
try this one
UIView *backView = [[[UIView alloc] initWithFrame:CGRectZero] autorelease];
backView.backgroundColor = [UIColor clearColor];
cell.backgroundView = backView;
It worked for me in grouped tableview.
Make UITableview background as clear color.
Programmatically you can do it like this if your image is added into your resources:
self.tableView.backgroundColor = [UIColor clearColor];
self.tableView.opaque = NO;
UIImage *backroundImage = [UIImage imageNamed:#"my_backround"];
UIImageView *backroundImageView = [[UIImageView alloc] initWithImage:backroundImage];
Else you can do it in Interface Builder with this style :
You may need to configure the header files interface from UITableViewController to UIViewController and add <UITableViewDataSource,UITableViewDelegate> ,also don't forget to set the attributes of the tableview to not be opaque and reconnect the tableviews datasource and delegate outlets to the viewcontroller.