Remove child element's attribute from Polymer js - polymer

Question

I've a custom element which, among other things, has a core-input and a paper button in it.
When the element is created, the input is disabled, and I want to enable it when I tap the button.
I've tried several ways and can't access the input's attribute.
<paper-input-decorator label="Nombre de usuario" floatingLabel>
<input id="usernameinput" value="{{UserName}}" is="core-input" disabled />
</paper-input-decorator>
<paper-button raised id="edprobutton" on-tap="{{edbutTapped}}">EDITAR</paper-button>
What should I write in
edbutTapped: function () {
},
EDIT
So, I've learned that the problem was that my username input element was inside a repeat template, and that's bad for what I was trying to do. Now I'm trying to bind a single json object to my element, with no luck so far.
What I have right now:
In my Index page:
<profile-page id="profpage" isProfile="true" entity="{{profEntity}}"></profile-page>
<script>
$(document).ready(function () {
var maintemplate = document.querySelector('#fulltemplate');
$.getJSON('api/userProfile.json', function (data) {
var jsonString = JSON.stringify(data);
alert(jsonString);
maintemplate.profEntity = jsonString;
});
}
</script>
In my element's page:
<polymer-element name="profile-page" attributes="isprofile entity">
<template>
<style>
[...]
</style>
<div flex vertical layout>
<core-label class="namepro">{{entity.Name}}</core-label>
<core-label class="subpro">{{entity.CompanyPosition}}</core-label>
<core-label class="subpro">{{entity.OrgUnitName}}</core-label>
</div>
</template>
</polymer-element>
And my JSON looks like this:
{"Name": "Sara Alvarez","CompanyPosition": "Desarrollo","OrgUnitName": "N-Adviser"}
I'm asuming I need to "update" my element somehow after changing its entity attribute?

Answer 1

Try the following
<script>
Polymer({
edbutTapped: function () {
this.$.usernameinput.disabled = false;
}
});
</script>
The this.$ allows you to access controls defined in an elements and the usernameinput is the id you assigned to the input.
This can go below the closing tag of the element you are defining.

Answer 2

'disabled' is conditional-attribute.
So this will be the correct use of it:
<input id="usernameinput" value="{{UserName}}" is="core-input" disabled?="{{isDisabled}}" />
In the prototype:
//first disable the field, can be done in ready callback:
ready: function () {
this.isDisabled = 'true';
}
//set idDisabled to 'false' i.e. enable the input
edbutTapped: function () {
this.isDisabled = 'false';
},

Answer 3

OK this is going to be a long answer (hence why I am not entering this as an edit of my original answer). I've just done something which is functionally the same.
The first thing is this code;
$.getJSON('api/userProfile.json', function (data) {
var jsonString = JSON.stringify(data);
alert(jsonString);
maintemplate.profEntity = jsonString;
});
Polymer has a control called core-ajax - this as it's name suggests makes an ajax call. The other really nice thing is that it can be made to execute when the URL changes. This is the code from the project I've got.
<core-ajax id="ajax"
auto=true
method="POST"
url="/RoutingMapHandler.php?Command=retrieve&Id=all"
response="{{response}}"
handleas="json"
on-core-error="{{handleError}}"
on-core-response="{{handleResponse}}">
</core-ajax>
The auto is the bit which tells it to fire when the URL changes. The description of auto from the polymer documentation is as follows;
With auto set to true, the element performs a request whenever its
url, params or body properties are changed.
you don't need the on-core-response but the on-core-error might be more useful. For my code response contains the JSON returned.
So for your code - it would be something like this
<core-ajax id="ajax"
auto=true
method="POST"
url="/api/userProfile.json"
response="{{jsonString}}"
handleas="json"
on-core-error="{{handleError}}" >
</core-ajax>
Now we have the data coming into your project we need to handle this. This is done by making use of Polymer's data-binding.
Lets detour to the element you are creating. Cannot see anything wrong with the following line.
<polymer-element name="profile-page" attributes="isprofile entity">
We have an element called 'profile-page' with two properties 'isprofile' and 'entity'.
Only because my Javascript leaves a bit to be desired I would pass each property as a seperate entity making that line
<polymer-element name="profile-page" attributes="isprofile name companyposition OrgUnitName">
Then at the bottom of your element define a script tag
<script>
Polymer({
name: "",
companyposition: "",
OrgUnitName: ""
});
</script>
Now back to the calling (profile-page). The following code (from my project) has the following;
<template repeat="{{m in response.data}}">
<map-list-element mapname="{{m.mapName}}" recordid="{{m.Id}}" on-show-settings="{{showSettings}}">
</map-list-element>
</template>
Here we repeat the following each element. In your case you only have one entry and it is stored in jsonString so your template is something like this
<template repeat="{{u in jsonString}}">
<profile-page name="{{u.name}} companyposition="{{u.companyposition}}" OrgUnitName="{{u.OrgUnitName}}">
</profile-page>
</template>
Now we get to the issue you have. Return to your profie-page element. Nothing wrong with the line
on-tap="{{edbutTapped}}"
This calls a function called edbutTapped. Taking the code I gave you earlier
<script>
Polymer({
edbutTapped: function () {
this.$.usernameinput.disabled = false;
}
});
</script>
The only thing to change here is add the following code
created: function() {
this.$.usernameinput.disabled = true;
},
This is inserted after the Polymer({ line. I cannot see in your revised code where the usernameinput is defined but I am assuming you have not posted it and it is defined in the element.
And you should be working, but remember to keep your case consistent and to be honest I've not been - certain parts of Polymer are case sensitive - that catches me out all the time :)