What is the right way to call play on an audio element in AngularDart?
I know that I can use #ViewChild('audio') annotation to get ElementRef, but ElementRef is deprecated.
<div class="audio-controls">
<material-fab raised (trigger)="onPlay()">
<material-icon icon="play_arrow" ></material-icon>
</material-fab>
</div>
<audio><source src="audio.ogg"></audio>
class AudioComponent {
void onPlay() {
//??
}
}
I just started learning AngualDart. I see now that this is wrong approach. I should use AudioContext to play audio or eventually, as a last resort, create AudioElement inside AudioComponent. AudioElement doesn't have to be added to a DOM tree (?).
Template should be used to define interface not logic (audio tag).
Related
From here :
https://github.com/dart-lang/angular_components_example/blob/master/example/app_layout_example/lib/app_layout_example.html
I want to split this template in two templates:
one for sidebar <material-drawer>, named for example sidebar_component.{dart,html}
one other for <div class="material-content">, named for example app_component.{dart,html}
Question:
How to reach <material-drawer> from sidebar_component, with <material-button icon class="material-drawer-button" (trigger)="drawer.toggle()"> into app_component?
Components are encapsulated on purpose. So there isn't a super easy way to reach into the encapsulation of one component from the other.
What you can do is create a passthrough from one component to the other.
<side-bar #sidebar></side-bar>
<app-component (openSideBar)="sidebar.toggle()"></app-component>
sidebar_component
#Component()
class SidebarComponent {
#ViewChild(MaterialPersistentDrawerDirective)
MaterialPersistentDrawerDirective drawer;
void toggle() => drawer.toggle();
}
app_component.dart
#Component()
class AppComponent {
final _openSideBar = StreamController<void>();
#Output()
Stream<void> openSideBar => _openSideBar.stream;
// This is getting called by the trigger of the button click
void onButtonClick() => _openSideBar.add();
}
I would say that for me passing all of these events feels like a bit of a smell. The components themselves are breaking encapsulation and so I wouldn't architect the app exactly like that.
I would probably have the contents of the drawer be a component, and perhaps the header and body depending on how complex they got. To have something more like this:
<material-drawer #drawer>
<side-bar *deferredContent></side-bar>
</material-drawer>
<div class="material-content">
<app-header class="material-header shadow" (triggerDrawer)="drawer.toggle()">
</app-header>
<router-outlet></router-outlet>
</div>
I find it better to keep the app-layout logic in the same components if possible and encapsulate the pieces of that. You could also pass the drawer as an input, but then you are making those highly coupled which I tend to try not to do.
I have a custom button component done in Polymer Dart:
<div id="buttonDiv">
<my-button id="traceButton"
mode="icon" faicon="fa-comment-o"
toolTip="Print a simple comment"
disabled="false" on-click="{{ traceSomething }}">
</my-button>
</div>
I'm trying to copy/paste this button somewhere else. So a user defines it somwhere, and I basically move it by way of getting $['buttonDiv'].children then inserting it somewhere else. The problem is that {{ traceSomething }} is now irrelevant since it's not part of the new parent. I get errors saying that the parent object, which is another polymer component doesn't have an instance getter "traceSomething".
My question is, is there a way to remove "traceSomething" before I insert it somwhere else? I tried removing the "onClick" event listeners, but the buttons still wants to call that function upon click. Also, I've tried adding a preventDefault, etc, like in: In Dart, if I listen to a click event with two listeners, how do I know which happens first?
But, no luck.
I'm not sure what you mean by copy/past. Do you clone the element, or do you just append it to some other elements children.
Anyway, I don't think you can remove the event listener if it was added declaratively. If you add it imperatively it is easy to remove and readd later.
import 'dart:async';
...
StreamSubscription subsc;
#override
attached() {
super.attached();
subscr = onClick.listen((e) => (this.parentNode as ShadowRoot).host.traceSomething(e));
}
#override
detached() {
super.detached();
if(subscr != null) {
subscr.cancel();
}
}
See also https://stackoverflow.com/a/22168745/217408 about accessing the parent of a Polymer element (for Dart Polymer <= 0.16.x)
Say I have a AngularDart component that adds a div and an iframe to that div as it's template.
I have the element passed for the outer component in the components constructor
#Component(
selector: "input-html",
templateUrl: "packages/myproject/components/inputs/html.html",
useShadowDom: false
)
class HtmlComponent implements ShadowRootAware {
HtmlComponent(NgModel ngModel, Element element):super(ngModel, element){
}
}
I have shadowdom turned off because I'm using Bootstrap for styling and want the elements easily accessible for the bootstrap css.
My template code is along the lines of
<div>
<iframe id="my-iframe"></iframe>
</div>
It's more complicated than that, there's a bunch of buttons etc, as I'm porting a javascript html editor to angulardart.
My problem is, I need to get the iframe element, but whenever I query element.querySelector("#my-iframe") or even window.document.querySelector("#my-iframe") the object is null. I believe this is because the template hasn't been added to the DOM yet.
I need the iframe object because I need to set the iframe content for the HTML editor to work. There's a few other areas of my project that I wanted to get the template dom objects but couldn't either.
I've tried onShadowRoot, which worked in AngularDart 0.14 but no longer works in 1.0. I've tried ScopeAware and querying for the iframe when the scope is set, but that didn't work (ScopeAware fires before shadowroot event).
I have a hack that's messy that works, by using ng-show="init()" and in that init method I have
bool _initDone = false;
bool init() {
if(_initDone == false) {
iframe = element.querySelector("#my-iframe")
_initDone = true;
}
return true;
}
Which works, but it's messy and I don't like that solution and obviously isn't the correct way to do it.
Anyone know how I can achieve this in AngularDart 1.0?
I think onShadowRoot is the right place for the code to query the element. If it really doesn't work wrap it in a Future to add it as a task at the end of the event queue to delay it a bit more.
onShadowRoot() {
new Future(() {
querySelector(...);
});
}
I'm trying to attach an event handler to the keyDown event in a canvas element. Here is a simplified version of my code.
class CanvasFun{
CanvasElement canvas;
CanvasFun(this.canvas){
print("Game is loading!");
this.canvas.onKeyDown.listen(handleInput);
}
void handleInput(e)
{
//breakpoint is never hit
print(e.keyCode);
}
}
I've removed some of the drawing code. In my main function I simply query the canvas element and pass it to my CanvasFun constructor.
I've also tried doing it this way:
void main() {
var canvas = query("#Game");
canvas.onKeyDown.listen(handleInput);
var canvasFun = new CanvasFun(canvas);
}
void handleInput(e)
{
print(e.keyCode);
}
The reason why the event is not firing is because the focus is on the document (or some other element like an input, for example). And in fact, canvas element even when focused does not fire an event. Some elements do, like input elements.
The solution is to listen to key down events from the document or window:
window.onKeyDown.listen(handleInput);
document.onKeyDown.listen(handleInput); // You already noticed this worked.
John McCutchan has written a nice Dart package to help handle keyboard input. You can read more about it here: http://dartgamedevs.org/blog/2012/12/11/keyboard-input/
Note that this library helps you handle input "correctly". You do not want to do any "work" in the input handling, instead you simply want to register that a key was pressed. You can check the state of any key presses inside of your requestAnimationFrame callback.
Hope that helps!
There exists a workaround to get the canvas-element accept KeyboardEvents:
Problems handling KeyboardEvents on DartFlash
Once you add the tabindex-attribute to your canvas-element, it can get the focus and then it will receive KeyboardEvents.
It looks like I can get it to work if I register the event on the document rather than the canvas element.
document.onKeyDown.listen(handleInput);
I have a page made of custom components. In that page I have a button. If I click the button I have to call another page (page.mxml consisting of custom components). Then click event handler is written in Action-script, in a separate file.
How to make a object of an MXML class, in ActionScript? How to display the object (i.e. the page)?
My code:
page1.mxml
<comp:BackgroundButton x="947" y="12" width="61" height="22"
paddingLeft="2" paddingRight="2" label="logout" id="logout"
click="controllers.AdminSession.logout()"
/>
This page1.mxml has to call page2.mxml using ActionScript code in another class:
static public function logout():void {
var startPage:StartSplashPage = new StartSplashPage();
}
Your Actionscript class needs a reference to the display list in order to add your component to the stage. MXML is simply declarative actionscript, so there is no difference between creating your instance in Actionscript or using the MXML notation.
your function:
static public function logout():void {
var startPage:StartSplashPage = new StartSplashPage();
}
could be changed to:
static public function logout():StartSplashPage {
return new StartSplashPage();
}
or:
static public function logout():void {
var startPage:StartSplashPage = new StartSplashPage();
myReferenceToDisplayListObject.addChild( startPage );
}
If your actionscript does not have a reference to the display list, than you cannot add the custom component to the display list. Adding an MXML based custom component is no different than adding ANY other DisplayObject to the display list:
var mySprite:Sprite = new Sprite();
addChild(mySprite)
is the same as:
var startPage:StartSplashPage = new StartSplashPage();
myReferenceToDisplayListObject.addChild( startPage );
Both the Sprite and the StartSplashPage are extensions of DisplayObject at their core.
You reference MVC in the comments to another answer. Without knowing the specific framework you've implemented, or providing us with more code in terms of the context you are trying to perform this action in, it is difficult to give a more specific answer.
I assume that you are on a page with a set of components and want to replace this set of components on the page with a different set of components. My apologies in advance if this is not what you are trying to do.
You can do this using ViewStacks and switching the selected index on selection -- this can be done either by databinding or by firing an event in controllers.AdminSession.logout() and listening for that event in the Main Page and switching the selectedIndex of the view stack in the handler function.
MainPage.mxml
<mx:ViewStack>
<views:Page1...>
...
<comp:BackgroundButton x="947" y="12" width="61" height="22"
paddingLeft="2" paddingRight="2" label="logout" id="logout"
click="controllers.AdminSession.logout()"/>
</views:Page1...>
<views:Page2 ...>
...
<comp:Comp1 .../>
<comp:Comp2 .../>
</views:Page2>
I think you may use state to do you work.
You may take a look at http://blog.flexexamples.com/2007/10/05/creating-view-states-in-a-flex-application/#more-221
Edit:
I am not sure I fully understand your case.
As I know, you may make a new state in page1.mxml, and name it, eg. secondPageState, and then put the custom component page2.mxml in the secondPageState.
In the controller, you need an import statement to import the page1 component and make a public var for the page1 component, eg. firstPage.
Then, the code will similar to:
public function logout():voild
{
firstPage.currentState = "secondPageState";
}
Another solution:
If you don't like the change state solution, you may try to use the addchild, to add the custom component to your application.