I have an image button and I want to be disabled when the program starts and upon certain condition, it needs to be enabled.
Here is my code,
public Screen( ) { //constructor
ImageButton hints;
ImageButton.ImageButtonStyle hintsstyle = new ImageButton.ImageButtonStyle();
hintsstyle.up = skin.getDrawable("newrightbut");
hintsstyle.down = skin.getDrawable("newrightbut");
hintsstyle.pressedOffsetX = 1;
hints = new ImageButton(hintsstyle);
hints.setPosition(650, 35);
hints.setHeight(70);
hints.setWidth(70);
stage.addActor(hints);
hints.setTouchable(Touchable.disabled);
}
public void update() {
hints.setTouchable(Touchable.enabled);
}
But, the button is not getting disabled when the program starts and I even tested with button.setDisabled(true) method. It also doesn't work. Any idea why? Any help would be great!! Thanks
This issue is 5 months old now but I try to answer regardless.
ImageButton hints is declared within your constructor (So its scope is limited to the constructor).
The only way that you don't get a compilation error calling it from a method outside the constructor is if you have also declared it somewhere else within your class.
Conclusion: you must have declared it somewhere else in your application and any default, it is enabled.
Related
Inside my classes, I invoke this function
MovieClip(root).increaseScore();
which handles the score in the main .as file.
It all works fine during the execution of the level. However when the level is finished and the screen goes to another frame, the game crashes and gives me this error
TypeError: Error #1009: Cannot access a property or method of a null
object reference.
on the line above.
How do I fix this?
Thanks
edit:
This is were I tell it to addScore, this is in the GameController.as file
private function removeBubble(bubble, addScore:Boolean)
{
var delay:Timer = new Timer(200, 1);
delay.addEventListener(TimerEvent.TIMER_COMPLETE, function(e:TimerEvent)
{
if(bubble.parent==mcGameStage)
{
var j:int = bubbleList.indexOf(bubble);
bubbleList.splice(j,1);
if(addScore) bubble.addScore();
mcGameUI.txtScorePlayer.text = String(playerScore);
mcGameStage.removeChild(bubble);
}
e.currentTarget.removeEventListener(e.type, arguments.callee);
checkWin();
});
delay.start();
}
here is the checkWin function:
private function checkWin()
{
if (playerBlue + playerRed + playerYellow + playerOrange + playerPurple + playerGreen == 0)
{
gameWin();
}
}
private function gameWin()
{
while (bubbleList.numChildren > 0)
{
bubbleList.removeChildAt(0);
}
mcGameUI.btnMixBlue.removeEventListener(MouseEvent.CLICK, mixBlue);
mcGameUI.btnMixRed.removeEventListener(MouseEvent.CLICK, mixRed);
mcGameUI.btnMixYellow.removeEventListener(MouseEvent.CLICK, mixYellow);
mcGameUI.btnNeedle.removeEventListener(MouseEvent.CLICK, activateNeedle);
mcGameStage.removeEventListener(Event.ENTER_FRAME,update);
mcGameStage.removeEventListener(MouseEvent.CLICK, checkToHit);
removeEventListener(Event.ADDED_TO_STAGE, gameAddedToStage );
stage.removeEventListener(KeyboardEvent.KEY_DOWN,keyDownHandler);
stage.removeEventListener(KeyboardEvent.KEY_UP,keyUpHandler);
if (mouseCursor != null)
{
mouseCursor.removeEventListener(Event.ENTER_FRAME,followMouse);
mouseCursor = null;
}
gotoAndPlay("level1win");
}
And inside my classes,
public function addScore()
{
root["increaseScore"]();
}
This is what increaseScore does
public function increaseScore()
{
playerScore += 1000;
}
So where is the null object? D:
Also I am very inexperienced using the debugger so I apologize if this could be easily solved with that. I tried it and couldn't figure it out before coming here.
What is OPP method?
What is FrameScript?
Also, the class is MovieClip
thanks :)
Fixing this is done with the help of the debugger!
The error is telling you that something is null and you're trying to access it. That's not good, so let's think what could be null?
1) Your movie clip instance might be null.
2) increaseScore() method of your movie clip instance might try to access something that is null
You didn't post any code that I could analyse at the time I'm writing this answer, so I can't say for sure.
Some possible problems:
Your class is not called MovieClip, but you're just trying to cast your root object to a MovieClip. Thing is, MovieClip's don't have a increaseScore() method. You should instead call the increaseScore() method with
root["increaseScore"]();
This will call the method of your root timeline, but since we are using weak-typing, you might have problems with debugging it later. But I guess that's the price you pay when writing all the code in a frame instead of using OPP approach.
The true reason here is said in the error: Cannot access a property or method of a null object reference.
What this means is that MovieClip(root) is null (it doesn't even bother to check if the function is present). The reasons for this might be three:
Your document class is not MovieClip (could be Sprite).
The class you use root in, is not DisplayObject. The property is part of the DislpayObject class and so if you use it on other kind of classes that does not extend it, it won't work.
You are using this piece of code before you have added the instance to the stage (most probable cause). The root property represents the top-most display object in the tree. If you haven't added the child to the tree, it has no roots :) Check out parent - the error should be the same.
In the N+1 video #34 (Progress), there was an example of using CreateBindingSet() for the Android version, which is not typical. But the narrator also mentioned briefly that the same can be done on the Windows platform.
As much as I tried, however, I am unable to get a View's property to be bound to its ModelView on the Windows Phone. I always get a NullReferenceException.
The closest I came was the code below, including suggestions from ReSharper. Here's my FirstView.xaml.cs:
using Cirrious.MvvmCross.Binding.BindingContext;
using Whatever.ViewModels;
namespace Whatever {
// inheriting from IMvxBindingContextOwner was suggested by ReSharper also
public partial class FirstView : BaseView, IMvxBindingContextOwner {
public class MyBindableMediaElement
{
private string _theMediaSource = "whatever";
public string TheMediaSource
{
get
{
return _theMediaSource;
}
set
{
_theMediaSource = value;
}
}
}
public FirstView()
{
InitializeComponent();
_mediaElement = new MyBindableMediaElement(this.theMediaElement);
var set = this.CreateBindingSet<FirstView, FirstViewModel>();
// the corresponding view model has a .SongToPlay property with get/set defined
set.Bind(_mediaElement).For(v => v.TheMediaSource).To(vm => vm.SongToPlay);
set.Apply();
}
public IMvxBindingContext BindingContext { get; set; } // this was suggested by ReSharper
}
I get a NullReferenceException in MvxBaseFluentBindingDescription.cs as soon as the view is created. The exact location is below:
protected static string TargetPropertyName(Expression<Func<TTarget, object>> targetPropertyPath)
{
var parser = MvxBindingSingletonCache.Instance.PropertyExpressionParser; // <----- exception here**
var targetPropertyName = parser.Parse(targetPropertyPath).Print();
return targetPropertyName;
}
I have not seen a working example of creating a binding set on a Windows Phone emulator. Has anyone gotten this to work? Thanks.
I can confirm that the narrator said that remark a little too flippantly without actually thinking about how he might do it...
However, with a little effort, you definitely can get the CreateBindingSet to work in Windows if you want to.
Before you start, do consider some alternatives - in particular, I suspect most people will use either Windows DependencyProperty binding or some hand-crafted code-behind with a PropertyChanged event subscription.
If you do want to add CreateBindingSet code to a Windows project then:
Add the Binding and BindingEx assemblies to your Ui project - the easiest way to do this is using nuget to add the BindingEx package.
In your Setup class, override InitializeLastChance and use this opportunity to create a MvxWindowsBindingBuilder instance and to call DoRegistration on that builder. Both these first two steps are covered in the n=35 Tibet binding video - and it's this second step that will initialise the binding framework and help you get past your current 'NullReferenceException' (for the code, see BindMe.Store/Setup.cs)
In your view, you'll need to implement the IMvxBindingContextOwner interface and you'll need to ensure the binding context gets created. You should be able to do this as simply as BindingContext = new MvxBindingContext();
In your view, you'll need to make sure the binding context is given the same DataContext (view model) as the windows DataContext. For a Phone Page, the easiest way to do this is probably just to add BindingContext.DataContext = this.ViewModel; to the end of your phone page's OnNavigatedTo method. Both steps 3 and 4 could go in your BaseView if you intend to use Mvx Binding in other classes too.
With this done, you should be able to use the CreateBindingSet code - although do make sure that all binding is done after the new MvxBindingContext() has been created.
I've not got a windows machine with me right now so I'm afraid this answer code comes untested - please do post again if it does or doesn't work.
I can confirm it works almost perfectly; the only problem is, there are no defaults register, so one has to do the full binding like:
set.Bind(PageText).For(c => c.Text).To(vm => vm.Contents.PageText).OneTime();
to fix this, instead of registering MvxWindowsBindingBuilder, I am registering the following class. Note: I have just created this class, and needs testing.
public class UpdatedMvxWindowsBindingBuilder : MvxWindowsBindingBuilder
{
protected override void FillDefaultBindingNames(IMvxBindingNameRegistry registry)
{
base.FillDefaultBindingNames(registry);
registry.AddOrOverwrite(typeof(Button), "Command");
registry.AddOrOverwrite(typeof(HyperlinkButton), "Command");
//registry.AddOrOverwrite(typeof(UIBarButtonItem), "Clicked");
//registry.AddOrOverwrite(typeof(UISearchBar), "Text");
//registry.AddOrOverwrite(typeof(UITextField), "Text");
registry.AddOrOverwrite(typeof(TextBlock), "Text");
//registry.AddOrOverwrite(typeof(UILabel), "Text");
//registry.AddOrOverwrite(typeof(MvxCollectionViewSource), "ItemsSource");
//registry.AddOrOverwrite(typeof(MvxTableViewSource), "ItemsSource");
//registry.AddOrOverwrite(typeof(MvxImageView), "ImageUrl");
//registry.AddOrOverwrite(typeof(UIImageView), "Image");
//registry.AddOrOverwrite(typeof(UIDatePicker), "Date");
//registry.AddOrOverwrite(typeof(UISlider), "Value");
//registry.AddOrOverwrite(typeof(UISwitch), "On");
//registry.AddOrOverwrite(typeof(UIProgressView), "Progress");
//registry.AddOrOverwrite(typeof(IMvxImageHelper<UIImage>), "ImageUrl");
//registry.AddOrOverwrite(typeof(MvxImageViewLoader), "ImageUrl");
//if (_fillBindingNamesAction != null)
// _fillBindingNamesAction(registry);
}
}
This is a skeleton from Touch binding, and so far I have only updated three controls to test out (Button, HyperButton and TextBlock)
I have an issue with a function I use to delete an instance and replace it with another. Basically, it keeps the item in memory no matter what. Inside the object I have weak listeners and I null everything after it gets removed, but the function I run to check if it is still active tells me that it is (just an Event.ENTER_FRAME tracing some text, with a weak link).
Even when I removed everything from the instances I am loading, it still seems to stay in memory, according to my trace it still is. How do I completely delete something from memory more thoroughly than nulling it out after removing it from the stage? Am I not seeing something?
This is the function:
private function loadArea(inputArea:String)
{
//This is for a checker to make sure that areas only get loaded once.
currentRoom = inputArea;
//If the area currently loaded is not null, make it null now.
if(selectedArea != null) selectedArea = null;
//Null any data inside of the reference used to create the name of the new area.
areaReference = null;
//Grab the class using the input.
areaReference = getDefinitionByName(inputArea + "Area") as Class;
//Null the sprite used to house the class
areaSprite = null;
//Set the holder as a new instance of the desired class.
areaSprite = new areaReference() as Sprite;
//If the selected area is still not null for some reason,
if(selectedArea != null)
{
//Remove the area from the container...
areaContainer.removeChild(selectedArea);
//...and nullify it.
selectedArea = null;
}
//Set the current area as the newly created instance.
selectedArea = areaSprite;
//If the area is not the "Game", load in the assets one way,
if(inputArea != "Game") selectedArea.construct(areaAssets);
//otherwise do it another way.
else selectedArea.construct(newScreenData,apiServer,cdnServer,areaAssets);
//This is for a checker that fades out the screen, which it needs to fade back in soon.
newScreenData = null;
//While the container for areas has any areas inside of it, remove them.
while(areaContainer.numChildren) areaContainer.removeChildAt(0);
//...then add the new instance area to the container.
areaContainer.addChild(selectedArea);
//...then let all the parts of the game know that a new area has been laoded in.
Global.echoEvent.echo("gameBootUp","playAreaIn");
}
The memory is actually released when Garbage Collector will find and erase an orphaned instance of yours. Before that, your memory usage will state there is an instance in memory. There is no way to force garbage collection, calling System.gc() only "instructs" Flash to run it, it might not obey. So, you have done what you had to, let it be.
Removing all references including stage and nulling an object is all it takes to free up memory.
If the object is not being released then you are missing something or doing something incorrectly or out of sequence.
Carefully go through your code, making sure you identify where objects are being referenced so you can remove them.
Looking at your example code:
if(selectedArea != null) selectedArea = null;
Here you are making sure that the selectedArea is null.
But immediately after you are testing selectedArea again
(you know it is null so this block is never used)
if(selectedArea != null){
//Remove the area from the container...
areaContainer.removeChild(selectedArea);
//...and nullify it.
selectedArea = null;
}
In every language its VERY DIFFICULT to "clear" memory... even HTML. That being said... try to reduce your memory footprint.
Correct Null:
1. remove all event listeners
2. remove all children
3. remove all mapped/referenced methods/parameters
4. set the class object to null
In most cases this is all you need to do, the WAY you do it will determine if the object gets cleared. Consider the following situation.
You have a custom sprite class (MEMORY FOOTPRINT #1) that has a mapped property (mapping happen when one class object references another). Once you map/reference one object to another = MEMORY FOOTPRINT #2. Adding events = MEMORY FOOTPRINT #3, etc and so on.
Custom Sprite
import flash.display.Sprite;
class CustomSprite extends Sprite{
private var _mappedProperty:Object;
public function addMapping(map:Object):void{
_mappedProperty = map;
}
public function finalize():void{
_mappedProperty = null;
}
}
Assuming we're using CustomSprite in many other methods, lets look at some common ways of removing the ojbect.
INCORRECT - in this situation [objToRemove] was not set to null to free its memory:
var objToRemove:CustomSprite = new CustomSprite;
function doSomething(referenceObj:CustomSprite):void{
var methodObj:CustomSprite = referenceObj;
//CRAZY LINES OF CODE
methodObj = null; //frees memory from [doSomething::methodObj]
referenceObj = null; //frees memory from [doSomething::referenceObj]
//objToRemove is not cleared and will remain in memory
}
INCORRECT - in this situation [objToRemove] has a reference object so it will not clean until the reference is removed:
var objToRemove:CustomSprite = new CustomSprite;
var mappedObject:Sprite = new Sprite;
objToRemove.addMapping(mappedObject);
objToRemove.addEventListener(Event.ENTER_FRAME,onEnterFrame);
//CRAZY LINES OF CODE
//remove all children
while(objToRemove.numChildren > 0){
objToRemove.removeChildAt(0);
}
//remove all event listeners
objToRemove.removeEventListener(Event.ENTER_FRAME,onEnterFrame);
//this will NOT work
objToRemove = null;
//reason is objToRemove has a reference object of [mappedObject]
//[mappedObject] is not a child so it needs to be removed manually
//from WHITIN the CustomSprite class using [CustomSprite::finalize()]
Ok... breath... the correct way is actually simple.
CORRECT - here we are using [Dynamic] objects rather than [Static] class objects, this is considered Object Mapping:
//think of this as a global list of objects
var objPool:Dictionary = new Dictionary;
//create a pool reference
objPool['poolObj'] = new CustomSprite;
//CRAZY LINES OF CODE;
//do the normal [null] process
//both of these will work
objPool['poolObj'] = null;
//or
delete objPool['poolObj'];
SUPER ADVANCED CORRECT - no example provided, I have to get back to work lol...
1. Take a ByteArray clone of the class
2. User a Loader to construct the ByteArray as the class, rather than using "new"
3. When finished... unload/remove the loader
4. EVERYTHING will clear... thats how a Loader works!
(Not getting into why and how... too long of an explanation)
Although this works flawlessly... its not generally accepted or suggested in a work environment.
I am using a s:TextInput in Flex 4.5. It shows it's prompt text if the underlying text value is null or empty String. Does anybody know if I can make either don't show the prompt on empty String or even show a different prompt?
I already found a way by extending the TextInput class and overriding some of the methods but I am still hoping anyone here knows an easier way ;-)
Ok, so based on the comments, here it is:
You store the current prompt value in a private variable, like so:
private var _inputPrompt:String = "";
Then you create a getter, so the value is accessible from outside of this class:
public function get inputPrompt():String
{
return _inputPrompt;
}
Now you can bind inputPrompt anywhere you need it, however, the problem is the getter won't be recalled once the private value changes. You can fix this very easily: Create an update method, for example like so:
public function updateInputPrompt(value:String):void
{
_inputPrompt = value;
}
Ok, nothing fancy so far. I'm guessing this is the point where you are right now. In order to "force" the getter to be recalled, you have to bind it to an event, like so:
[Bindable(event="inputPromptUpdated")]
public function get inputPrompt():String
{
return _inputPrompt;
}
Finally, you can simply dispatch this event when the value is update (i.e. in the updateInputPrompt method):
public function updateInputPrompt(value:String):void
{
_inputPrompt = value;
dispatchEvent("inputPromptUpdated"); // For binding
}
This way, the getter will be recalled every time you dispatch that event.
Hope this helps. Have a great day, and a great weekend!
Using AS3 / Flash CS4
Alright thanks to everyone who is reading this. My problem specifically I am designing a user interface with controls on it. 5 buttons rotate left, rotate right, zoom in, zoom out, and auto rotate. The interface in itself works fine, I can trace out button clicks, toggle the auto rotate button etc...
My program reads an xml file. Loads some images, fills an array with links for each image, and when the image is clicked a loader loads a swf from a URL and displays it on screen. No problem.
Now I originally had the zoom controls user interface in the runtime_loaded.fla library, and the mouse listeners in the same linked document class. The interface works with the movieClip in runtime_loaded.swf when it is in the same code.
Now to practice good coding, I decided to remove the UI from the runtime_loaded.fla and add it to the Main.fla. This is essential because the main is going to handle possible 100's of images/objects that each have their own unique swf to link too. If I decide to change out the look of the interface but leave the function calls the same, I could essentially put in as many as I want into the main.fla instead of the runtime_loaded.fla which I would have to do for every single object.
THE FILE STRUCTURE
Main.fla <- interface in the library. 5 mouse event functions. Inside each function calls
a property of loaded_swf (loaded_swf.rotateLeft, loaded_swf.rotateRight) etc...
Runtime_loaded.fla <- links specificObject.as in properties (AS3/CS4)
specificObject.as <- has 5 public static functions{ rotateRight, rotateLeft, zoomIn, zoomOut, toggleAutoRotate }
THE CODE
//showFlashBox
function showFlashBox(temp_string:String):void {
if(!flash_box_on){
var temp_top:uint = numChildren;
addChildAt(FlashBoxContainer,temp_top);
newXButton.addEventListener(MouseEvent.CLICK, flashBoxXClick);
1. addChild(new_loader);
2. var url:URLRequest = new URLRequest(temp_string);
new_loader.x = 0;
new_loader.y = 0;
new_loader.load(url);
3. new_loader.contentLoaderInfo.addEventListener(Event.COMPLETE, gotSwf);
flash_box_on = true;
}
}
function gotSwf(e:Event){
4. //loaded_swf = e.target.content;
trace(e.target.content);
5. new_zoom_controls.button_minus.addEventListener(MouseEvent.CLICK, zoomOutFunction);
new_zoom_controls.button_plus.addEventListener(MouseEvent.CLICK, zoomInFunction);
new_zoom_controls.button_left.addEventListener(MouseEvent.CLICK, rotateLeftFunction);
new_zoom_controls.button_right.addEventListener(MouseEvent.CLICK, rotateRightFunction);
new_zoom_controls.button_rotate.addEventListener(MouseEvent.CLICK, toggleRotateFunction);
function rotateRightFunction(e:MouseEvent){
6. //loaded_swf.rotateRight();
}
function rotateLeftFunction(e:MouseEvent){
//loaded_swf.rotateLeft();
}
function zoomInFunction(e:MouseEvent){
//loaded_swf.zoomIn();
}
function zoomOutFunction(e:MouseEvent){
//loaded_swf.zoomOut();
}
function toggleRotateFunction(e:MouseEvent){
//loaded_swf.toggleAutoRotate();
if(new_zoom_controls.button_rotate.currentFrame == 1){
new_zoom_controls.button_rotate.gotoAndStop(2);
}
else new_zoom_controls.button_rotate.gotoAndStop(1);
}
new_loader.contentLoaderInfo.removeEventListener(Event.COMPLETE, gotSwf);
}
If you follow steps 1-6 you see my steps of loading the .swf, mouse event listeners and click handlers, then the object call of the var loaded_swf:Object;
public static function rotateLeft():void
{
object.yaw(animation_turning_speed);
}
public static function rotateRight():void
{
object.yaw(-animation_turning_speed);
}
if I run the main.fla and try to click the buttons. This happens.
ReferenceError: Error #1069: Property rotateRight not found on
ThreedsKU39web and there is no default value. at MethodInfo-82()
ReferenceError: Error #1069: Property rotateLeft not found on
ThreedsKU39web and there is no default value. at MethodInfo-83()
I actually stumbled upon the answer before I finished submitting this as I went through the code to copy it. But after spending a few hours of frustrating moments on this last night, I will post it to ensure the next guy doesn't meet the same demise.
The answer was in the function of the runtime-loaded swf class.
public static function rotateRight():void
{
object.yaw(-animation_turning_speed);
}
It turns out it only needs to be public function instead of public static.
Mainly human error as after the file was working, I attempted to copy the code over to all my other object files, and somehow static got back in there and messed it up. So for future reference when loading in the external swf, public function should do the trick. *Note that many of my variables were returning errors until being declared as public static though.