What's CCCallBlockN alternative for Cocos2d 3.0 ?
Here is my Cocos2d 2.0 Code:
id calBlock = [CCCallBlockN actionWithBlock:^(CCNode *node){
node.position = orign;
}];
The CCCallBlockN and CCCallBlockND variants have always been superfluous since blocks can reference objects in the local scope:
id someData = (some data however created or obtained);
CCNode* someNode = (some node however created or obtained);
id callBlock = [CCActionCallBlock actionWithBlock:^{
someNode.position = origin;
[someData quickDoSomething];
}];
[someNode runAction:callBlock];
You just need to have a reference like someNode in the outer scope of the block in order to use it inside the block.
You will usually have the desired node reference because after all you're going to run the action on the desired node after creating the action. Only in cases where you create the actions first and run them later would the passed-in node be useful, but I guess that's a rare situation and probably not good style anyway.
Related
I am doing a store query in the controller and then passing the result down to a child component.
// Controller
#tracked comment;
#action
async fetchComment() {
const comment = await this.store.query('note', {
filter: {
listing: this.listing.id,
},
});
if (comment && comment.length > 0) {
this.comment = comment.firstObject;
}
}
// Template
<MyComponent #comment={{this.comment}} />
I want to use the arg to populate a tracked property in the child component.
// Component
#tracked comment = this.args.comment;
I found this does not work but works well as a getter. However with a getter I am unable to set this to null when deleting that record.
I have also tried to set the tracked property in the Constructor but that didnt work either.
I suspect this has something to do with passing in a promise or store object in the args because this works fine with static data.
why your code does not work
this code can not work:
#tracked comment = this.args.comment;
this is because comment on the controller is initially undefined but will later bet set to comment.firstObject when the network request is done and the await in your fetchComment function returns.
Generally everythings on args basically always behaves like its #tracked (while more accurate you would describe it as getters). So this usually will just update fine. But the assignment #tracked comment = this.args.comment; only happens once when you create the component, so you no longer depend on updates on args.
why you can not set this.args.comment to null
If you use a getter or directly always use this.args.comment you can not change this reference. This is because this.args is always readonly. you can change objects on this.args.something, but you never can change the reference or primitive value on this.args.
Sidenote: this is only true if the component was called with <AngleBracket /> syntax. For the older {{curly-component}} syntax this is not true. So this does not depend on the component itself but how the component gets called.
you could notify the controller to remove the reference
one good thing to do is to pass down a deleteComment action to the component that basically does something like this.comment = null on the controller. then you use this.args.comment directly or by a getter and you can call this.args.deleteComment() to set comment on the controller to null, which will update anything that uses this.args.comment or a getter that returns this.args.comment.
this is essentially because in your architecture the controller owns the data (because it loads it). so the controller is also responsible to delete it.
if you use ember-data you can check isDeleted
if its a ember-data model (which it probably is if you call this.store) then it has a isDeleted property. you can use this to check if the record is deleted, since ember-data records dont disappear if they get deleted. which is exactly because of problems like this.
how you use another property to shadow a argument
you could do something like this to shadow an argument in your component:
#tracked commentIsDeleted = false;
get comment() {
return this.commentIsDeleted
? null
: this.args.comment;
}
this way at first this.comment will work like a normal getter, but you can shadow delete it by setting this.commentIsDeleted = true;. From that on this.comment will be null.
I am having an issue with a growing list. Previously I had a normal list, but as it is limited to displaying 100 items, I need to now change this to a growing list, which works fine now and I can get over 100 items loaded when I've put the growing="true" growingThreshold="50" growingScrollToLoad="false" properties on the list.
But now I have an issue with one of the number inputs in the custom list, when entering a number it is not staying set (it has a liveChange event that updates a text component).
I've set a breakpoint in the controller to test and it seems to bug out when I am trying to set the data changes (red arrow on attached image).
Can anyone see the issue with the logic? If any additional code snippets are required I could provide them.
onReceivedQuantityChange: function (oEvent) {
// get model and data
var oModel = this.getOrderModel();
var oData = oModel.getData();
// get item from path
var oItem = this._getOrderItemByPath(oEvent.getSource().getBindingContext(this.MODEL_ORDERS).getPath());
// set received value
oItem._ReceivedValue = oEvent.getParameters().newValue * (oItem.ValuationPrice / oItem.Quantity);
// apply data changes
oModel.setData(oData);
},
Controller code image
onReceivedQuantityChange: function (oEvent) {
var oModel = this.getOrderModel()
var sItemPath = oEvent.getSource().getBindingContext(this.MODEL_ORDERS).getPath()
var iValuationPrice = oModel.getProperty(sItemPath + '/ValuationPrice')
var iQuantity = oModel.getProperty(sItemPath + '/Quantity')
var iNewValue = oEvent.getParameters().newValue
var iReceivedValue = iNewValue * (iValuationPrice / iQuantity)
oModel.setProperty(sItemPath + '/_ReceivedValue', iReceivedValue)
}
If you use setProperty() on the Model you're only chaning the specific Property in DataModel and Sapui5 is able to proceed bindingchanges on this Property only (and not the whole model).
If you get the data out of the model by getData() you are only getting a reference to this Object. If you change something on this Object, you don't have to set it back by setData() (it is already there because you used the reference of this Object).
But Sapui5 need to know that there was a specific change in datamodel and this is done by using setProperty()
As the question states, is there any downside in referencing the service directly in the template as such :
[disabled]="stateService.selectedClient == null || stateService.currentStep == 1"
In my opinion this doesn't seem like good practice and I'd much rather keep a "selectedClient" object in whatever component needs to use it. How can I get the state and store it into local variables, while observing the changes:
example: I want to move from step1 to step2 by changing "currentStep" in the "stateService", however I want the component that keeps "currentStep" ALSO as a local variable to reflect the change in the state?
Is it good practice to reference services in html templates in Angular
2?
I'd generally avoid it. It seems to bring more chaos than good.
Cons:
Coming from OOP background, this approach looks like it breaks the Law of Demeter, but more importantly,
It's no longer MVC, where your controller (Angular2's Component) acts like a mediator between the view and the services.
Like Ced said, what if a call to a service's member is costly and we need to refer to it multiple times in the view?
At the moment my editor of choice (VS Code) does not fully support Angular2 templates; referencing too many things outside of its own Component's scope in a template makes refactoring not fun anymore.
Pros:
Sometimes it looks more elegant (because it saves you 2 lines of code), but trust me, it's not.
How can I get the state and store it into local variables, while
observing the changes
Madhu Ranjan has a good answer to this. I'll just try to make it more complete here for your particular example:
In your StateService, define:
currentStep : Subject<number> = new Subject<number>();
selectedClient: Subject<Client> = new Subject<Client>();
changeStep(nextStep: number){
this.currentStep.next(nextStep);
}
selectClient(client: Client) {
this.selectedClient.next(client);
}
In your Component:
currentStep: number;
constructor(stateService : StateService){
stateService.currentStep.combineLatest(
stateService.selectedClient,
(currStep, client) => {
if (client == null) {
// I'm assuming you are not showing any step here, replace it with your logic
return -1;
}
return currStep;
})
.subscribe(val => {
this.currentStep = val;
});
}
You may try below,
stateService
currentStep : Subject<number> = new Subject<number>();
somestepChangeMethod(){
this.currentStep.next(<set step here to depending on your logic>);
}
component
// use this in template
currentStep: number;
constructor(stateService : stateServiceClass){
stateService.currentStep.subscribe(val => {
this.currentStep = val;
});
}
Hope this helps!!
It is probably not a good idea to expose your subject inside of your state service. Something like this would be better.
StateService
private currentStep: Subject<number> = new Subject<number>();
changeStep(value: number) {
this.currentStep.next(value);
}
get theCurrentStep(): Observable<number> {
this.currentStep.asObservable();
}
Component
currentStep: number;
constructor(private stateService: StateService) {
this.currentStep = this.stateService.theCurrentStep;
}
Template
[disabled]="(currentStep | async) == 1" // Not sure if this part would work
I have an EmberData snapshot which I'd like decorate with a few additional attributes before handing over to the UI for presentation. This decoration will be setting "properties" of the Ember-Data record not actual attributes. It looks like this:
let foo = Ember.computed.oneWay(this.get('store').find('activity'));
foo.map(item => {
item.set('foobar', 'baz');
return item;
}
I would then hope that foo would be the beneficiary of the promised record (it is) and the setting of the foobar property would be localized to the foo property (it's not, it seems to be globally scoped to the record's properties).
As for me this is expected behavior.
1) OneWay means only you are not bind set method on foo. It used to work between properties of objects, but this.get('store').find('activity') is a just promise.
2) foo is store.find() result of DS.RecordArray type (assuming promise is resolved). So you are iterating on records returned and set foobar property on them.
Achieving your goal, you could decorate activity record by component (Ember 2.0 way) for UI presentation.
So far the only way I've been able to do this is using Ember's ObjectProxy like so:
const FooDecorator = Ember.ObjectProxy.extend({
foobar: 'baz'
});
let foo = Ember.computed(function() {
return this.get('store').find('activity').map(item => {
FooDecorator.create({content: item});
});
}
This works but I thought I'd been hearing things about Object proxies not being a welcome part of Ember 2.0 roadmap so not sure if this approach is best. I'll keep this open for a few days before closing.
So I'm using ui-router and stateparams to nest child states, and it works well. I'm now trying to find a way to dictate a css class what state level the app is at. main.route1.section1 would be 3 levels.
Here's some non-working code to help show:
<div ng-class="{findState().currentCount}"></div>
app.run(function($rootScope, $state, $stateParams) {
$rootScope.$state = $state;
$rootScope.$stateParams = $stateParams;
$rootScope.findState = function() {
var currentName = $state.current.name;
var currentMatch = currentName.match(/./g);
$rootScope.currentCount = currentMatch.length;
};
});
I'm basically looking for a way to take $state.current.name which say equals main.route1.section1 and split it at the dot and count how many are in the array and return that number to the mg-class. Unless you have a better idea... like a regex filter?
Take a look of the object $state.$current (instead of $state.current). In particular, the property path : it's an array representing the state hierarchy of the current state.
So what you are looking for is : $state.$current.path.length