I would like to implement check boxes inside flash list control using Flash Pro CS6. I literally follow example provided by Adobe at Work with a CellRenderer. The only code in my .fla file is:
myList.setStyle("cellRenderer", CustomCellRenderer);
myList.addItem({label:"Burger -- $5.95"});
myList.addItem({label:"Fries -- $1.95"});
and the only code in the CustomCellRenderer.as file is (copy-paste from the Adobe example):
package
{
import fl.controls.CheckBox;
import fl.controls.listClasses.ICellRenderer;
import fl.controls.listClasses.ListData;
public class CustomCellRenderer extends CheckBox implements ICellRenderer {
private var _listData:ListData;
private var _data:Object;
public function CustomCellRenderer() {
}
public function set data(d:Object):void {
_data = d;
label = d.label;
}
public function get data():Object {
return _data;
}
public function set listData(ld:ListData):void {
_listData = ld;
}
public function get listData():ListData {
return _listData;
}
}
}
When I test movie I get the following error:
TypeError: Error #1009: Cannot access a property or method of a null object reference.
at fl.controls::CheckBox/drawLayout()
at fl.controls::LabelButton/draw()
at fl.core::UIComponent/drawNow()
at fl.controls::List/drawList()
at fl.controls::List/draw()
at fl.core::UIComponent/callLaterDispatcher()
Any help would be greatly appreciated.
P.S. The author of similar question Display checkbox inside Flash List Control ? (Similar to item rendering in Flex) does not seem to have this problem - his problem is just in multiple selection functionality.
ANSWER (can not post answers for another 8 hour but eager to close the issue) Figured out myself: CheckBox component must be present in the library. Go to menu Window->Components-> Double click CheckBox. Check box will appear on the stage and in the library. Remove check box from the stage. Test movie.
Drag an instance of CheckBox component onto the stage then delete off the stage.
Related
Kind of new Actionscript and I'm just trying to make a simple tamagoci game. I've wrote all the code out but and receiving no compiler errors but for some reason I'm also not receiving any output messages for my mouse event listeners. Here is all my code, I really can't find the problem and any help would be greatly appreciated. Thanks.
package{
import flash.display.MovieClip;
import flash.events.MouseEvent;
public class Main extends MovieClip{
public var feedButton:MovieClip;
public var tamagoci:MovieClip;
public var disButton:MovieClip;
public var dietButton:MovieClip;
public function Main() {
this.init();
}
private function init():void {
this.feedButton.addEventListener(MouseEvent.MOUSE_DOWN, onfeedMouseDownHandler);
this.disButton.addEventListener(MouseEvent.MOUSE_DOWN, ondisMouseDownHandler);
this.dietButton.addEventListener(MouseEvent.MOUSE_DOWN, ondietMouseDownHandler);
}
private function onfeedMouseDownHandler(event:MouseEvent)void{
this.tamagoci.scaleX += 0.1;
this.tamagoci.scaleY += 0.1;
}
private function ondisMouseDownHandler(event:MouseEvent)void{
this.tamagoci.gotoAndPlay(5);
}
private function ondietMouseDownHandler(event:MouseEvent)void{
this.tamagoci.scaleX -= 0.1;
this.tamagoci.scaleY -= 0.1;
}
Are you using Flash Professional?
You're declaring your variable types in your class here;
public var feedButton:MovieClip;
public var tamagoci:MovieClip;
public var disButton:MovieClip;
public var dietButton:MovieClip;
But then in your constructor, all you are doing is running init();
public function Main() {
this.init();
}
So, this could one of a few things. The most likely is that you have declared your variables, but you haven't initialised them. You've created the variables to hold your objects, but according to your code, they're empty. More specifically, a variable or class property that doesn't assign an object to a variable of an object type will contain a default value of null.
You could prove this in your code by simply putting a condition inside your init(); method;
if(tamagoci == null){
trace("I haven't been assigned an object of type class yet!")
}
So it could be 1 of these 3 things:
1: If you have written your own classes for these class properties/variables, then you need to instantiate them with the new keyword. The general syntax is;
variable_name = new ClassName(parameter_1, parameter_2);
If you are using classes you have written yourself, you have to create an instance of the object, assign it to a variable, and then add it to the stage using addChild();. For example, lets say you've written your own Tamagoci class;
tamagoci = new Tamagoci();
tamagoci.x = 100; // set the x location
tamagoci.y = 200; // set the y location
addChild(tamagoci);
Notice the use of Tamagoci. This is just an example, but this is the class name, which shouldn't be confused with variable/property name. It could just have easily been;
tamagoci = new MovieClip();
But then, this is just an empty MovieClip. It needs a property to display on the screen. A Shape, A Bitmap, or another container class object like MovieClip or Sprite (container classes allow you to nest display objects inside them). But on a basic level, it must contain a visual component to appear on the stage.
2:
Have you made Main your document class? This is the class which will get automatically called when your Flash movie plays. To set this, click on your stage, and in the properties dialogue box on the right, under PUBLISH, type in the name of your class, which is "Main".
3:
If you have created MovieClips in your library in Flash Professional, then you need to go to your library, right click the MovieClips, and select properties. From there, you need to make sure Export for Actionscript is ticked.
Now, if you click on your MovieClips on the stage, then open the Properties tab in the top right of Flash Professional's default layout, then right at the top should be a text field, and if you hover over it, Instance name will pop up as a tool tip. This is where you name your stage objects. Once that is done, you have access to them in your timeline.
If this is how you've done this, then you don't need to declare the variables in your main class, as they are already declared on your stage by Flash Professional and instantiated automatically.
I'm dabbling with game design and trying to create some characters for the game. Right now I've just created a single MovieClip that contains a rectangle. The MovieClip symbol extends a class that I've created in Flash Builder that implements the logic of a monster. I can then drag an instance of this monster symbol from the library to the stage and the code works when I run the simulation. So far, so good.
Now I want to create several monsters, all slightly different:
public class Monster extends MovieClip
{
public var isFriendly:Boolean = true;
public var strength:int = 10;
public var catchPhrase:String = "Booyah!";
public function Monster()
{
}
}
One way to do this is to write a new class for each monster that extends Monster and sets the properties I want in the constructor (I'd also have to create a unique symbol in the library for each of these variations too). However, this seems to be overkill if my monsters only differ by their property values.
Looking at the Flash Professional use interface, I see that at the very bottom of the Properties panel is a section that looks like a small table headed by 'Properties/Value'. Can I use this to somehow set the properties of my classes from within the Flash Professional UI? I can't find any info on how this is used.
Okay, I figured it out. The key is converting my symbol into a flash Component.
First I edited my ActionScript class to export the properties I wanted to set (including the Inspectable tag):
public class Monster
{
private var _catchPhrase:String;
public function Monster()
{
}
public function get catchPhrase():String
{
return _catchPhrase;
}
[Inspectable(name = "catchPhrase", type = String, defaultValue = "Booyah!")]
public function set catchPhrase(value:String):void
{
_catchPhrase = value;
}
}
Then I right clicked on the Monster symbol in my library and selected 'Component Definition...'. This brought up the Component Definition dialog. I then entered the name of my ActionScript class in the Class field and clicked the checkmark to validate it. Flash then automatically generated the properties I needed.
I also found this tutorial helpful:
http://redbjarne.wordpress.com/actionscript-3-0-custom-components-from-hell/
I have a custom Flex Toggleswitch component that changes the text values of the switch.
package skins
{
import spark.skins.mobile.ToggleSwitchSkin;
public class MyToggleSwitchSkin extends ToggleSwitchSkin
{
public function MyToggleSwitchSkin()
{
super();
selectedLabel="Serviceable";
unselectedLabel="Fault";
}
}
}
If I add the control using the MXML tag, it works fine. However, when I add the component using action script, it does not.
import skins.MyToggleSwitchSkin;
public function addToggle():void {
var myCustomToggle:MyToggleSwitchSkin = new MyToggleSwitchSkin();
hgroup.addElement(myCustomToggle);
}
The control dsiplays but will not activate.
Any ideas what I have missed?
Without seeing your MXML Code, it's tough to compare your two approaches, but I believe #al_Birdy addressed the problem. You've created a custom ToggleSwitchSkin; not a custom ToggleSwitch.
Modify your addToggle() method like this:
public function addToggle():void {
var myCustomToggle:MyToggleSwitch = new MyToggleSwitch();
myCustomToggle.setStyle('skinClass',skins.MyToggleSwitchSkin);
hgroup.addElement(myCustomToggle);
}
I suspect you'll have better luck.
I have a movie clip with an external class attached.
here is the MC code (I've shorten it only for the relevant part...)
package {
//all the imports here...
public class mc_masterChapter extends MovieClip {
public function mc_masterChapter() {
trace (picFile,strChapTitle);
}
//Properties
public var picFile:String;
public var strChapTitle:String;
}
}
In the main class file I'm adding this object to stage using addChild:
var masterChapter:mc_masterChapter = new mc_masterChapter;
masterChapter.picFile = "pic_Chap1.jpg";
masterChapter.strChapTitle = "ABCD:
addChildAt(masterChapter,1);
now, the trace in the MC class code gives nulls to both parametes but if i put a trace inside the MC timeline (instead of the attached class code), it gives the right value!
how can I access the values from the MC class itself without getting nuls?
Thank you.
It works! Let me explain:
var masterChapter:mc_masterChapter = new mc_masterChapter; // Calls class constuctor
// so calls trace() too!
// You will get null null
masterChapter.picFile = "pic_Chap1.jpg"; // Assign the variables
masterChapter.strChapTitle = "ABCD"; // so they can be read
trace(masterChapter.picFile, masterChapter.strChapTitle); // Should trace pic_Chap1.jpg ABCD
If you add the following method to your class:
public function test():void {
trace(picFile, strChapTitle);
}
Then call masterChapter.test() it will successfully trace those two properties. So yes, the class can read its properties.
Make the var you use in your main class public static vars.
OK!
I solved the mystery.
I put two traces. one in the main MC class saying "hey, I'm inside the MC - the picFile="
and one in the put Function saying "I'm putting this file into picFile:"
well this is what I've got:
hey, I'm inside the MC - the picFile=null
I'm putting this file into picFile:image.jpg
got it!?! at the moment I asked him to give birth to an instance of the MC (even before putting it on stage - just defining the object (with this line:)
var masterChapter:mc_masterChapter = new mc_masterChapter;
it allready run the class, so of course that in this stage the parameters were not defined allready and were null.
the definition code came right after that line (in the main.as)
masterChapter.pic="pic_Chap1.jpg";
so what I did, was to move all the code from the main class of the MC object to a public function inside the same package called init(). Then I called this function manually from the parent main class.
By that I can decide when to call it (after I declare all the parameters of course).
That's it.
god is hiding in the small details : )
tnx for all the helpers.
Possibly a better solution would be to use a getter/setter pair, so you can know at the exact moment the properties are set:
protected var _picFile:String:
public function get picFile():String {
return _picFile;
}
public function set picFile(value:String):void {
if (value != _picFile) {
_picFile=value;
trace('picFile set to', _picFile);
}
}
How do I access Stage Class properties in Costum Class?
Class:
package {
import Main;
import flash.events.*;
import flash.display.Sprite;
import flash.display.Stage;
public class Run extends Sprite {
var obj:a1_spr;
public function Run() {
runAssets();
}
private function runAssets():void {
obj = new a1_spr()
addChild(obj);
obj.x = stage.stageWidth/2;
}
}
}
Output:
TypeError: Error #1009: Cannot access a property or method of a null object reference.
To expand on what Joel said, and put it into context:
Every display object has a .stage property, but that property is null until you add you display object onto the display list. So during construction, you will never be able to access it, (because it gets added afterwards)
The event ADDED_TO_STAGE gets fired when you add your object to the stage, ltting you know that the .stage property is now populated. After that happens you can access the stage from anywhere in you object.
Hope that clarifies things for you.
this.addEventListener(Event.ADDED_TO_STAGE, handleAdedToStage)
private function handleAddedToStage(event:Event):void
{
this.runAssets()
}
private function runAssets():void
{
obj = new a1_spr();
addChild(obj);
obj.x = this.stage.stageWidth/2;
}
You aren't going to have access to the stage in the constructor (unless you inject the stage into the class). Sprite has a stage property.
when flash compiles the fla assets with your .as files, there's no stage. so the code is initiated as preparation for your documentclass, you have to listen to if there's a stage so it can be rendered.
that's why you listen to ADDED_TO_STAGE , to check it's actually in the display list.
This problem occurs for all display objects, since they must be added to the display list when there's an actual stage.
get used to add that listener, and check for a stage. specially when working in a team and your doing your own components in a larger project.