I want to overlay an image over a button. the button has a background image. If i want to overlay a semi transparent image over the button, suppose i overlay a red color image, which is semi transparent. Can any one suggest how to do that? Suggest some documentation.
UIImageView *overlay = [[UIImageView alloc] initWithImage:...];
[overlay setAlpha:0.5];
UIButton *button = [[UIButton alloc] initWithType:UIButtonTypeRoundedRect];
[button setBackgroundImage:...];
[button addSubview:overlay];
[overlay release];
UIButton also has an image property as well as a backgroundImage property, although I'm unsure how transparency would work with it.
http://developer.apple.com/iphone/library/documentation/uikit/reference/UIButton_Class/UIButton/UIButton.html
Following dc answer, note that changing the button alpha will affect also the overlay transparency, so check that button alpha is 1.0f (default value).
Note also that you should release the overlay variable after adding it as subview to button, otherwise, you'll get a memory leak.
Related
Is it possible to have a custom UIButton that has an image covering only half of it?
I imagine it would be something like this:
UIButton *someButton = [UIButton buttonWithType:UIButtonTypeCustom];
[someButton setBackgroundImage:[UIImage imageNamed:#"buttonPicture"]];
/* Then there must be some property I can set that prevents the button from stretching the image?? */
.
.
.
I want to have a 50x100px button which only has a 50x50px image on the top half, and to be transparent on the bottom half.
I know how to create a custom button and everything. Im just woondering what the property is that controls the stretching of the backgroundImage.
Thanks!
Use
[someButton setImage:[UIImage imageNamed:#"buttonPicture"] forState: UIControlStateNormal];
someButton.imageEdgeInsets = UIEdgeInsetsMake(-50, 0, 0, 0);
I think you could:
create your button image as a 50x100px image (same size as the button);
make this image be half transparent (PNG with alpha),
instead of trying to assign the button a smaller image covering only half of it and prevent stretching.
I'm making customized navigation bar by using UIView and UIButtons instead of UINavigationBar.
But my UIButtons on the navigation bar doesn't response sensitively.
I have to tap almost center of the UIButton to tap.
It doesn't respond if I tap edge of the UIButton.
But buttons on normal UINavigationBar can be tapped by tapping edge of the button.
Even by tapping outside of the button, it can be tapped.
Shutter button or Option button on the camera app also can be tapped by tapping edge or outside of buttons.
How can I implement those easily tappable buttons to my app?
Use an image and create a custom button. Set the button so the image does not scale to the size of the button's view, but instead will just Center. Expand the button's size so it is larger than the image on each side. Apple does this as well with things like tab buttons.
UIButton has an imageEdgeInsets property specially for this purpose. Just make a UIButton frame as big as you need for touchable area and than scale image inside it appropriately, using imageEdgeInsets.
Disclaimer: This code has not been tested, but it gives you an idea of how it could be done.
You make a button (in this case 40px x 40px), and then add a background image to it which is smaller, hence gives the impression of that the image is very "clickable".
// This image is 20px x 20px (Just an example)
UIImage* backgroundImage = UIImage imageNamed:#"backgroundImage.png"]
// Custom button, remember to add a target method
UIButton* customButton = [UIButton buttonWithType:UIButtonTypeCustom];
customButton.frame = CGRectMake(0.0, 0.0, 40.0, 40.0);
customButton.contentMode = UIViewContentModeCenter;
[customButton setImage:backgroundImage forState:UIControlStateNormal];
UIBarButtonItem* customBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:customButton];
self.navigationItem.rightBarButtonItem = customBarButtonItem;
[customBarButtonItem release];
I would like to create something like this:
I would like to place an UITextField with an UIButton into one grey frame, and I would like the button's border to be contained by this grey frame.
Please somebody show me some sample code for this!
Thx!
1. Use a UIImageView of required rect. Set the background image to the gradient gray colour image.
UIImageView*myImageView=[[UIImageView alloc] initWithFrame:yourFrame];
[myImageView setImage:[UIImage imageNamed:#"grayBackground.png"];
[self.view addSubview:myImageView];
2. Use a round rect. UITextField make it a subview of the image view. Use a place holder as "Write a reply..." make it a subview to your imageview.
UITextField*myField=[[UITextField alloc] initWithFrame:yourRect];
[myField setBorderStyle:UITextBorderStyleRoundedRect];
[myField setPlaceholder:#"Write a reply..."];
[myImageView addSubview:myField];
3. Use a UIButton with type Custom and the send image as its background image, make it a subview to your imageview.
UIButton*myButton=[UIButton buttonWithType:UIButtonTypeCustom];
[myButton setFrame:yourRect]
[myButton setBackgroundImage:[UIImage imageNamed:#"sendImage.png"] forState:UIControlStateNormal];
[myImageView addSubView:myButton];
Simple way is to create title bar with grey background and delete the title.and place textfield and button which u want to place it.configure the size and button outside the title bar and drag it to the title bar..u'll get like the image which u have got.
I have a UIToolbar that I've customized with my own background image. Consequently, the built-in UIBarButtonItem appearance doesn't work for me, so I'm using images that are already prepared to show in the bar. I create a custom button item with this method:
+ (UIBarButtonItem *)customWithImage:(UIImage *)image enabled:(BOOL)enabled target:(id)target action:(SEL)selector {
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
//I've tried different values for the frame here, but no luck
button.frame = CGRectMake(0, 0, 44, 44);
button.enabled = enabled;
button.showsTouchWhenHighlighted = YES;
[button addTarget:target action:selector forControlEvents:UIControlEventTouchUpInside];
[button setImage:image forState:UIControlStateNormal];
UIBarButtonItem *it = [[[UIBarButtonItem alloc] initWithCustomView:button] autorelease];
//Tried changing this, to no avail
it.width = 32.f;
return it;
I have one button on the left and one on the right and I'm trying to make it so that if you tap on the far left or far right of the UIToolbar, the corresponding button is tapped. However, with these custom buttons, the hit targets do not extend all the way to the edges of the UIToolbar, but are inset from the sides:
http://skitch.com/andpoul/d1p8g/hit-targets
Any help greatly appreciated!
UIBarButtonItem.width might be ignored if you're using a custom view (it probably just uses the width of the view).
A lame hack is to make the toolbar wider (so it sticks outside the screen) and add transparent edges to the background image to compensate. This brings the buttons closer to the edge of the screen.
An alternative is just to use a UIImageView with UIButton subviews.
I think the only way you will have to go is to make buttons wider (change image by adding some from left for one and right for another) and adjust size...
UIImageView *navBarImageView = [[UIImageView alloc] initWithImage:navBarImage];
[navBarImageView setFrame:CGRectMake(0, 0, 320, 44)];
self.navigationItem.titleView = navBarImageView;
[navBarImageView release];
I am trying to add an image to my navigationBar, but when I used the code as listed above, it places the image into the navigationBar but leaves a grey gap to the left and right of the image. The image was created at 320x44, I'm not sure why it is resizing it despite the fact that I am setting the frame.
That's... probably not how you want to do that—it's not what the titleView is for. The usual way to do a custom navigation-bar background is to create a category on UINavigationBar, like so:
#implementation UINavigationBar(MyCustomBackground)
- (void)drawRect:(CGRect)r
{
[[UIImage imageNamed:#"my-navigation-background.png"] drawInRect:self.bounds];
}
#end
Throw that in a .m file in your project and you should see all of your navigation bars use "my-navigation-background.png" as their background.