I have a problem with TextField that is hiding under the keyboard, I've found the answers for the similar question here, but they are not helping me in my case. I have a LazyColumn with the list of different composables in it, and when I have not enough elements in the window for scroll to be activated, focusing on TextField is not lifting up focused TextField above keyboard. Keyboard just hides it.
My code:
val listState = rememberLazyListState()
typealias ComposableType = #Composable (Int) -> Unit
val uiList = listOf<ComposableType>( {IconButton}, {Text}, {CustomTextField(listState,it)}, {CustomTextField(listState,it)})
LazyColumn() {
itemsIndexed(uiList) { index, ui ->
ui.invoke(index)
}
}
val scope = rememberCoroutineScope()
#Composable
CustomTextField(scrollState: LazyListState, position: Int) {
OutlinedTextField(
modifier = Modifier.onFocusEvent { focusState ->
if (focusState.isFocused) {
scope.launch {
scrollState.animateScrollToItem(position)
}
}
)
}
So, for example if i have 10 CustomTextFields in my uiList, scroll works when one of TextField is focused. But when there are only 2 TextFields in the uiList, focusing on either of them does not lift up them above keyboard.
Also I tried using RelocationRequester() and used Column with scroll instead of LazyColumn, none of it helped.
It's a combination of things...
You need to add this in your activity's declaration in Android.xml
android:windowSoftInputMode="adjustResize"
Use BringIntoViewRequester as modifier in your TextField as you mentioned.
.bringIntoViewRequester(yourBringIntoViewRequester)
The steps above worked for me when the component gain focus programatically (using FocusRequester). However, when the user taps on the TextField, it didn't work for me. So I implemented a workaround (which I'm not very proud of): when the TextField gain focus, I wait a bit to use the RelocationRequester. So I added this modifier to my TextField.
.onFocusEvent {
if (it.isFocused) {
coroutineScope.launch {
delay(200)
yourBringIntoViewRequester.bringIntoView()
}
}
}
These three things worked for me.
You need to add this in your activity's declaration in AndroidManifest.xml
android:windowSoftInputMode="adjustResize"
You have to set wrapContentHeight().navigationBarsWithImePadding() to the modifier of parent composable
Column(modifier = Modifier.wrapContentHeight().navigationBarsWithImePadding()){}
This solution worked for me.
Add this to your activity in manifest file
android:windowSoftInputMode="adjustResize"
And in the column for example use :
Column (horizontalAlignment = Alignment.CenterHorizontally,
modifier = Modifier
.fillMaxWidth()
.wrapContentHeight()
.navigationBarsPadding().imePadding()
.verticalScroll(rememberScrollState())
.fillMaxHeight()
.padding(top = 20.dp))
works for me , happy coding ..
I have NSOutlineViews with floating group rows as a heading. My headers are semi-transparent so scrolled content can just be seen underneath:
In Big Sur, the headers look like this:
They have an underline below them, and all transparency is removed - so it looks as though a background is being added somewhere.
I am subclassing NSTableRowView and NSOutlineView to stop any drawing:
override func draw(_ dirtyRect: NSRect) {}
I am disabling 'Group Style' on the NSTableRowView too:
override var isGroupRowStyle: Bool { get { false } set {} }
Can anyone tell me where the line and background may be coming from? Thank you.
EDIT
Further investigation shows the background and line rendering is part of the NSScrollView floating content view (_NSScrollViewFloatingSubviewsContainerView). There don't seem to be any options associated with this.
The following extreme hack works currently for me to change the background of the floating header in a NSTableView, and to remove the underline:
extension YourViewController: NSTableViewDelegate {
func tableView(_ tableView: NSTableView, didAdd rowView: NSTableRowView, forRow row: Int) {
if row == 0, rowView.isGroupRowStyle {
DispatchQueue.main.async {
if let scroll = tableView.enclosingScrollView {
for sub in scroll.subviews {
if sub.className.contains("Float"),
let effect = sub.subviews.first?.subviews.first?.subviews.first as? NSVisualEffectView,
let line = sub.subviews.first?.subviews.first?.subviews.last {
effect.material = .menu
line.isHidden = true
}
}
}
}
}
}
}
When row 0 is added, the sub views of the .enclosingScrollView of the tableview are being iterated (after giving the tableview some time to render the floating header by calling the rest of the code async) until we encounter the views we want to change.
Of course, this kind of code is an example of 'bad practice', and will stop working as soon as Apple changes the implementation of the sticky header, but I don't expect anything to crash due to all specific conditions.
In the meanwhile it's probably the best idea to file a Feedback with a request to make the floating header of NSTableView and NSOutlineView adjustable.
Xcode 10.1, Swift 4.2, macOS 10.14.2
I am trying to make a simple to do list app for macOS where there are a series of NSTableView rows and inside each one is an NSTextField. Each field is a to-do item. I want the NSTableView rows to expand to fit the size of the text within each NSTextField.
I have all of the following working:
Setting the text in the NSTextField makes the NSTableView row expand as needed. Auto layout constraints are set in my storyboard.
Using tableView.reloadData(forRowIndexes: ..., columnIndexes: ...) sets the text and resizes the table row correctly.
But doing tableView.reloadData() always resets every NSTextField to a single line of text as shown here:
Interestingly, if you click into the NSTextField after reloading the whole table, the field resizes to fit its content again:
I believe I have set all the appropriate auto layout constraints on my NSTextField and I'm using a custom subclass for it as well (from a helpful answer here):
class FancyField: NSTextField{
override var intrinsicContentSize: NSSize {
// Guard the cell exists and wraps
guard let cell = self.cell, cell.wraps else {return super.intrinsicContentSize}
// Use intrinsic width to jibe with autolayout
let width = super.intrinsicContentSize.width
// Set the frame height to a reasonable number
self.frame.size.height = 150.0
// Calcuate height
let height = cell.cellSize(forBounds: self.frame).height
return NSMakeSize(width, height)
}
override func textDidChange(_ notification: Notification) {
super.textDidChange(notification)
super.invalidateIntrinsicContentSize()
}
}
⭐️Here is a sample project: https://d.pr/f/90CTEh
I'm at a loss as to what else I can try. Any ideas?
I think there is some basic problems with the constraints in interface builder. Resizing the window makes everything wonky. Also you should call validateEditing() in the textDidChange(forBounds:) in your FancyField class.
I created a sample project, that does what you want on Github
Write a comment if you have any problems with it.
Thinking a little about it, thought i would add the meat of the code here. Only thing that really needs to work, is the update on the NSTextField when the "Tasks" is being updated. Following is the code required for the NSTextField.
public class DynamicTextField: NSTextField {
public override var intrinsicContentSize: NSSize {
if cell!.wraps {
let fictionalBounds = NSRect(x: bounds.minX, y: bounds.minY, width: bounds.width, height: CGFloat.greatestFiniteMagnitude)
return cell!.cellSize(forBounds: fictionalBounds)
} else {
return super.intrinsicContentSize
}
}
public override func textDidChange(_ notification: Notification) {
super.textDidChange(notification)
if cell!.wraps {
validatingEditing()
invalidateIntrinsicContentSize()
}
}
}
Hope it helps.
Short version:
I am having a problem with auto layout top layout guide when used in conjunction with custom transition and UINavigationController in iOS7. Specifically, the constraint between the top layout guide and the text view is not being honored. Has anyone encountered this issue?
Long version:
I have a scene which has unambiguously define constraints (i.e. top, bottom, left and right) that renders a view like so:
But when I use this with a custom transition on the navigation controller, the top constraint to the top layout guide seems off and it renders is as follows, as if the top layout guide was at the top of the screen, rather than at the bottom of the navigation controller:
It would appear that the "top layout guide" with the navigation controller is getting confused when employing the custom transition. The rest of the constraints are being applied correctly. And if I rotate the device and rotate it again, everything is suddenly rendered correctly, so it does not appear to be not a matter that the constraints are not defined properly. Likewise, when I turn off my custom transition, the views render correctly.
Having said that, _autolayoutTrace is reporting that the UILayoutGuide objects suffer from AMBIGUOUS LAYOUT, when I run:
(lldb) po [[UIWindow keyWindow] _autolayoutTrace]
But those layout guides are always reported as ambiguous whenever I look at them even though I've ensured that there are no missing constraints (I've done the customary selecting of view controller and choosing "Add missing constraints for view controller" or selecting all of the controls and doing the same for them).
In terms of how precisely I'm doing the transition, I've specified an object that conforms to UIViewControllerAnimatedTransitioning in the animationControllerForOperation method:
- (id<UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController
animationControllerForOperation:(UINavigationControllerOperation)operation
fromViewController:(UIViewController*)fromVC
toViewController:(UIViewController*)toVC
{
if (operation == UINavigationControllerOperationPush)
return [[PushAnimator alloc] init];
return nil;
}
And
#implementation PushAnimator
- (NSTimeInterval)transitionDuration:(id <UIViewControllerContextTransitioning>)transitionContext
{
return 0.5;
}
- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
UIViewController* toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIViewController* fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
[[transitionContext containerView] addSubview:toViewController.view];
CGFloat width = fromViewController.view.frame.size.width;
toViewController.view.transform = CGAffineTransformMakeTranslation(width, 0);
[UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
fromViewController.view.transform = CGAffineTransformMakeTranslation(-width / 2.0, 0);
toViewController.view.transform = CGAffineTransformIdentity;
} completion:^(BOOL finished) {
fromViewController.view.transform = CGAffineTransformIdentity;
[transitionContext completeTransition:![transitionContext transitionWasCancelled]];
}];
}
#end
I've also done a rendition of the above, setting the frame of the view rather than the transform, with the same result.
I've also tried manually make sure that the constraints are re-applied by calling layoutIfNeeded. I've also tried setNeedsUpdateConstraints, setNeedsLayout, etc.
Bottom line, has anyone successfully married custom transition of navigation controller with constraints that use top layout guide?
Managed to fix my issue by adding this line:
toViewController.view.frame = [transitionContext finalFrameForViewController:toViewController];
To:
- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext fromVC:(UIViewController *)fromVC toVC:(UIViewController *)toVC fromView:(UIView *)fromView toView:(UIView *)toView {
// Add the toView to the container
UIView* containerView = [transitionContext containerView];
[containerView addSubview:toView];
[containerView sendSubviewToBack:toView];
// animate
toVC.view.frame = [transitionContext finalFrameForViewController:toVC];
NSTimeInterval duration = [self transitionDuration:transitionContext];
[UIView animateWithDuration:duration animations:^{
fromView.alpha = 0.0;
} completion:^(BOOL finished) {
if ([transitionContext transitionWasCancelled]) {
fromView.alpha = 1.0;
} else {
// reset from- view to its original state
[fromView removeFromSuperview];
fromView.alpha = 1.0;
}
[transitionContext completeTransition:![transitionContext transitionWasCancelled]];
}];
}
From Apple's Documentation for [finalFrameForViewController] : https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIViewControllerContextTransitioning_protocol/#//apple_ref/occ/intfm/UIViewControllerContextTransitioning/finalFrameForViewController:
I solved this by fixing the height constraint of the topLayoutGuide. Adjusting edgesForExtendedLayout wasn't an option for me, as I needed the destination view to underlap the navigation bar, but also to be able to layout subviews using topLayoutGuide.
Directly inspecting the constraints in play shows that iOS adds a height constraint to the topLayoutGuide with value equal to the height of the navigation bar of the navigation controller. Except, in iOS 7, using a custom animation transition leaves the constraint with a height of 0. They fixed this in iOS 8.
This is the solution I came up with to correct the constraint (it's in Swift but the equivalent should work in Obj-C). I've tested that it works on iOS 7 and 8.
func animateTransition(transitionContext: UIViewControllerContextTransitioning) {
let fromView = transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey)!.view
let destinationVC = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey)!
destinationVC.view.frame = transitionContext.finalFrameForViewController(destinationVC)
let container = transitionContext.containerView()
container.addSubview(destinationVC.view)
// Custom transitions break topLayoutGuide in iOS 7, fix its constraint
if let navController = destinationVC.navigationController {
for constraint in destinationVC.view.constraints() as [NSLayoutConstraint] {
if constraint.firstItem === destinationVC.topLayoutGuide
&& constraint.firstAttribute == .Height
&& constraint.secondItem == nil
&& constraint.constant == 0 {
constraint.constant = navController.navigationBar.frame.height
}
}
}
// Perform your transition animation here ...
}
I struggled with the exact same problem. Putting this in the viewDidLoad of my toViewController really helped me out:
self.edgesForExtendedLayout = UIRectEdgeNone;
This did not solve all my issues and I'm still looking for a better approach, but this certainly made it a bit easier.
Just put the following code toviewDidLoad
self.extendedLayoutIncludesOpaqueBars = YES;
FYI, I ended up employing a variation of Alex's answer, programmatically changing the top layout guide's height constraint constant in the animateTransition method. I'm only posting this to share the Objective-C rendition (and eliminate the constant == 0 test).
CGFloat navigationBarHeight = toViewController.navigationController.navigationBar.frame.size.height;
for (NSLayoutConstraint *constraint in toViewController.view.constraints) {
if (constraint.firstItem == toViewController.topLayoutGuide
&& constraint.firstAttribute == NSLayoutAttributeHeight
&& constraint.secondItem == nil
&& constraint.constant < navigationBarHeight) {
constraint.constant += navigationBarHeight;
}
}
Thanks, Alex.
As #Rob mentioned, topLayoutGuide is not reliable when using custom transitions in UINavigationController. I worked around this by using my own layout guide. You can see the code in action in this demo project. Highlights:
A category for custom layout guides:
#implementation UIViewController (hp_layoutGuideFix)
- (BOOL)hp_usesTopLayoutGuideInConstraints
{
return NO;
}
- (id<UILayoutSupport>)hp_topLayoutGuide
{
id<UILayoutSupport> object = objc_getAssociatedObject(self, #selector(hp_topLayoutGuide));
return object ? : self.topLayoutGuide;
}
- (void)setHp_topLayoutGuide:(id<UILayoutSupport>)hp_topLayoutGuide
{
HPLayoutSupport *object = objc_getAssociatedObject(self, #selector(hp_topLayoutGuide));
if (object != nil && self.hp_usesTopLayoutGuideInConstraints)
{
[object removeFromSuperview];
}
HPLayoutSupport *layoutGuide = [[HPLayoutSupport alloc] initWithLength:hp_topLayoutGuide.length];
if (self.hp_usesTopLayoutGuideInConstraints)
{
[self.view addSubview:layoutGuide];
}
objc_setAssociatedObject(self, #selector(hp_topLayoutGuide), layoutGuide, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
#end
HPLayoutSupport is the class that will act as a layout guide. It has to be a UIView subclass to avoid crashes (I wonder why this isn't part of the UILayoutSupport interface).
#implementation HPLayoutSupport {
CGFloat _length;
}
- (id)initWithLength:(CGFloat)length
{
self = [super init];
if (self)
{
self.translatesAutoresizingMaskIntoConstraints = NO;
self.userInteractionEnabled = NO;
_length = length;
}
return self;
}
- (CGSize)intrinsicContentSize
{
return CGSizeMake(1, _length);
}
- (CGFloat)length
{
return _length;
}
#end
The UINavigationControllerDelegate is the one responsible for "fixing" the layout guide before the transition:
- (id <UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController
animationControllerForOperation:(UINavigationControllerOperation)operation
fromViewController:(UIViewController *)fromVC
toViewController:(UIViewController *)toVC
{
toVC.hp_topLayoutGuide = fromVC.hp_topLayoutGuide;
id <UIViewControllerAnimatedTransitioning> animator;
// Initialise animator
return animator;
}
Finally, the UIViewController uses hp_topLayoutGuide instead of topLayoutGuide in the constraints, and indicates this by overriding hp_usesTopLayoutGuideInConstraints:
- (void)updateViewConstraints
{
[super updateViewConstraints];
id<UILayoutSupport> topLayoutGuide = self.hp_topLayoutGuide;
// Example constraint
NSDictionary *views = NSDictionaryOfVariableBindings(_imageView, _dateLabel, topLayoutGuide);
NSArray *constraints = [NSLayoutConstraint constraintsWithVisualFormat:#"V:|[topLayoutGuide][_imageView(240)]-8-[_dateLabel]" options:NSLayoutFormatAlignAllCenterX metrics:nil views:views];
[self.view addConstraints:constraints];
}
- (BOOL)hp_usesTopLayoutGuideInConstraints
{
return YES;
}
Hope it helps.
i found way. First uncheck "Extend Edges" property of controller. after that navigation bar getting dark color. Add a view to controller and set top and bottom LayoutConstraint -100. Then make view's clipsubview property no (for navigaionbar transculent effect). My english bad sory for that. :)
I had the same problem, ended up implementing my own topLayout guide view and making constraints to it rather then to topLayoutGuide. Not ideal. Only posting it here in case someone is stuck and looking for quick hacky solution http://www.github.com/stringcode86/SCTopLayoutGuide
Here's the simple solution I'm using that's working great for me: during the setup phase of - (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext, manually set your "from" and "to" viewController.view.frame.origin.y = navigationController.navigationBar.frame.size.height. It'll make your auto layout views position themselves vertically as you expect.
Minus the pseudo-code (e.g. you probably have your own way of determining if a device is running iOS7), this is what my method looks like:
- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
UIViewController *fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
UIView *container = [transitionContext containerView];
CGAffineTransform destinationTransform;
UIViewController *targetVC;
CGFloat adjustmentForIOS7AutoLayoutBug = 0.0f;
// We're doing a view controller POP
if(self.isViewControllerPop)
{
targetVC = fromViewController;
[container insertSubview:toViewController.view belowSubview:fromViewController.view];
// Only need this auto layout hack in iOS7; it's fixed in iOS8
if(_device_is_running_iOS7_)
{
adjustmentForIOS7AutoLayoutBug = toViewController.navigationController.navigationBar.frame.size.height;
[toViewController.view setFrameOriginY:adjustmentForIOS7AutoLayoutBug];
}
destinationTransform = CGAffineTransformMakeTranslation(fromViewController.view.bounds.size.width,adjustmentForIOS7AutoLayoutBug);
}
// We're doing a view controller PUSH
else
{
targetVC = toViewController;
[container addSubview:toViewController.view];
// Only need this auto layout hack in iOS7; it's fixed in iOS8
if(_device_is_running_iOS7_)
{
adjustmentForIOS7AutoLayoutBug = toViewController.navigationController.navigationBar.frame.size.height;
}
toViewController.view.transform = CGAffineTransformMakeTranslation(toViewController.view.bounds.size.width,adjustmentForIOS7AutoLayoutBug);
destinationTransform = CGAffineTransformMakeTranslation(0.0f,adjustmentForIOS7AutoLayoutBug);
}
[UIView animateWithDuration:_animation_duration_
delay:_animation_delay_if_you_need_one_
options:([transitionContext isInteractive] ? UIViewAnimationOptionCurveLinear : UIViewAnimationOptionCurveEaseOut)
animations:^(void)
{
targetVC.view.transform = destinationTransform;
}
completion:^(BOOL finished)
{
[transitionContext completeTransition:([transitionContext transitionWasCancelled] ? NO : YES)];
}];
}
A couple of bonus things about this example:
For view controller pushes, this custom transition slides the pushed toViewController.view on top of the unmoving fromViewController.view. For pops, fromViewController.view slides off to the right and reveals an unmoving toViewController.view under it. All in all, it's just a subtle twist on the stock iOS7+ view controller transition.
The [UIView animateWithDuration:...] completion block shows the correct way to handle completed & cancelled custom transitions. This tiny tidbit was a classic head-slap moment; hope it helps somebody else out there.
Lastly, I'd like to point out that as far as I can tell, this is an iOS7-only issue that has been fixed in iOS8: my custom view controller transition that is broken in iOS7 works just fine in iOS8 without modification. That being said, you should verify that this is what you're seeing too, and if so, only run the fix on devices running iOS7.x. As you can see in the code example above, the y-adjustment value is 0.0f unless the device is running iOS7.x.
I ran into this same issue but without using a UINavigationController and just positioning a view off of the topLayoutGuide. The layout would be correct when first displayed, a transition would take place to another view, and then upon exiting and returning to the first view, the layout would be broken as that topLayoutGuide would no longer be there.
I solved this problem by capturing the safe area insets prior to the transition and then reimplementing them, not by adjusting my constraints, but by setting them on the viewController's additionalSafeAreaInsets.
I found this solution to work well as I don't have to adjust any of my layout code and search through constraints and I can just reimplementing the space that was there previously. This could be more difficult if you are actually using the additionalSafeAreaInsets property.
Example
I added a variable to my transitionManager to capture the safe insets that exist when the transitionManager is created.
class MyTransitionManager: NSObject, UIViewControllerAnimatedTransitioning, UIViewControllerTransitioningDelegate {
private var presenting = true
private var container:UIView?
private var safeInsets:UIEdgeInsets?
...
Then during the entering transition I save those insets.
let toView = viewControllers.to.view
let fromView = viewControllers.from.view
if #available(iOS 11.0, *) {
safeInsets = toView.safeAreaInsets
}
In the case of the iPhone X this looks something like UIEdgeInsets(top: 44.0, left: 0.0, bottom: 34.0, right: 0.0)
Now when exiting, the insets on that same view we transitioned from in the entrance will be .zero so we add our captured insets to the additionalSafeAreaInsets on the viewController, which will set them on our view for us as well as update the layout. Once our animation is done, we reset the additionalSafeAreaInsets back to .zero.
if #available(iOS 11.0, *) {
if safeInsets != nil {
viewControllers.to.additionalSafeAreaInsets = safeInsets!
}
}
...then in the animation completion block
if #available(iOS 11.0, *) {
if self.safeInsets != nil {
viewControllers.to.additionalSafeAreaInsets = .zero
}
}
transitionContext.completeTransition(true)
try :
self.edgesforextendedlayout=UIRectEdgeNone
Or just set navigationbar opaque and set background image or backgroundcolor to navigationbar
In storyboard add another vertical constraint to main view's top. I have the same problem too but adding that constraint help me to avoid manual constraints. See screenshot here link
Other solution is to calculate toVC frame... something like this:
float y = toVC.navigationController.navigationBar.frame.origin.y + toVC.navigationController.navigationBar.frame.size.height;
toVC.view.frame = CGRectMake(0, y, toVC.view.frame.size.width, toVC.view.frame.size.height - y);
Let me know if you have found a better solution. I have been struggling with this issue as well and I came up with previous ideas.
I embed SVG graphics in my Flex application using
package MyUI
{
public class Assets
{
[Embed(source="/assets/pic.svg"]
[Bindable]
public static var svgPic:Class;
}
}
and then extending the Tree class with some of my own code, setting the icon upon adding a node to the data provider:
public class MyTree extends Tree
{
public function MyTree()
{
// ...
this.iconField = "svgIcon";
// ...
this.dataProvider = new ArrayCollection;
this.dataProvider.addItem({ /* ... */ svgIcon: MyUI.Assets.svgPic /* ... */ });
// ...
}
}
Now I have two things I want to do:
use the SVG graphics in multiple places in the app, scaling them to the appropriate size for each appearance, i. e. scale them to a proper icon size when using them in the tree
change the size of the icon at runtime, e. g. display a slightly larger icon for selected items or let an icon "pulse" as a response to some event
I read the Flex documentation on the 9-slice scaling properties in the Embed tag, but I think that's not what I want.
Edit:
I unsuccessfully checked the "similar questions" suggested by SO, among others this one:
Flex: Modify an embedded icon and use it in a button?
Subclass mx.controls.treeClasses.TreeItemRenderer and make it resize the icon to your desired dimensions, or create your own item renderer implementation by using the same interfaces as TreeItemRenderer. Set a custom item renderer with the itemRenderer property:
exampleTree.itemRenderer = new ClassFactory( ExampleCustomItemRendererClass );
The answer to this question might point you in the right direction, without knowing more about the trouble you're having:
Flex: Modify an embedded icon and use it in a button?
Hope it helps!