问题
I have included api, before everything were working perfect in polymer 1.7, after upgraded to polymer ^2.0 google map does not renders. here is my code in main app page written polymer class base:
<iron-pages role="main" selected="[[page]]" attr-for-selected="name" selected-attribute="visible" fallback-selection="404">
<jj-maps name="maps" user="{{user}}" sprof="{{sprof}}"></jj-maps>
<jj-list name="list" > Jobs </jj-list>
<jj-infos name="infos"> infos </jj-infos>
<jj-contacts name="contacts" > Contacts </jj-contacts>
<jj-messages name="messages"> Messages </jj-messages>
<jj-404 name="404" > 404 </jj-404>
</iron-pages>
at jj-maps.html code sample is :
<link rel="import" href="../bower_components/polymer/polymer.html">
<link rel="import" href="../bower_components/google-map/google-map.html">
<link rel="import" href="../bower_components/google-map/google-map-marker.html">
style codes in template tag:
<dom-module id="jj-maps">
<template>
<style include="iron-flex iron-flex-alignment">
:host {
.....
google-map, #mapResults {
margin-top: 10px;
position: relative;
height: 100vh;
width: 100vh%;
z-index: 1;
}
....
<div id="mapResults">
<google-map
id="map"
map="{{map}}"
latitude="[[latitude]]"
longitude="[[longitude]]"
zoom="10"
api-key="[[myApiKey]]"
on-google-map-ready= '_mapLoaded'
additional-map-options='{"gestureHandling" : "greedy"}'
>
<google-map-marker map="{{map}}" slot="marker" latitude="{{latitude}}" longitude="{{longitude}}"
title="You are here !" icon="./src/image/gpslocc.png" draggable="true">
</google-map-marker>
<template is="dom-repeat" items="{{sprof}}" as="item">
<google-map-marker map="[[map]]" slot="marker" latitude="[[item.myLat]]" longitude="[[item.myLng]]" animation="DROP" click-events title="{{item.prof}}" icon="{{calculateIconType(item.isFree)}}" on-google-map-marker-click='showUserDetail' userid="[[item.uid]]" isFree="{{item.isFree}}" >
</google-map-marker>
</template>
<paper-fab icon="maps:my-location" on-tap="updateCurrentPosition"></paper-fab>
</google-map>
</div>
</template>
this code works perfect in previous polymer. And Another point when I bower install the dependencies as bower install --save GoogleWebComponents/google-map
bower asks me for two as :
- Unable to find a suitable version for polymer, please choose one by typing one of the numbers below:
I chose : 7) polymer#^2.0.0 which resolved to 2.0.1 and is required by myApp
- Unable to find a suitable version for webcomponentsjs, please choose one by typing one of the numbers below:
I chose : 2) webcomponentsjs#^1.0.0 which resolved to 1.0.1 and is required by myApp
Sorry in advance that I ve written detailed codes. Meanwhile I have tried many options but could not able to render map in my jj-maps elements (class base template, even I have tried legacy template (as same as polymer 1.7 ver)
Here is is console warning :
dom-module.html:24 dom-module google-map has style outside template
dom-module google-map-marker has style outside template
Maps are not rendering...
So, how to solve ? Thanks in advance. (previous polymer ver. working at jobijoy.com
回答1:
I'm having exactly same issue. Tried to add slot="marker" to google-map-marker as someone suggested Polymer 2.0 issue in github but doesn't work for me. It looks like the google-map component's size is set to 0 by 0 thus does not display at all. Since the google components are not updated to be compatible with Polymer 2.0. I've manually updated my local google-map.html and google-map-marker.html files under bower_component folder and moved the style tags into the template tags. The warnings are gone and the map displays now. I guess we have to wait for the update of the google components for things to work properly. I hope this helps.
回答2:
slot="marker"
should solve the issue.
Unfortunately the example in the code does not insert this important line.
Here is the without slot="markers" current code example:
<google-map latitude="37.77493" longitude="-122.41942" fit-to-markers>
<google-map-marker latitude="37.779" longitude="-122.3892" draggable="true" title="Go Giants!">
</google-map-marker>
<google-map-marker latitude="37.777" longitude="-122.38911">
</google-map-marker>
</google-map>
And below the suggested corrected example that should be inside the code:
<google-map latitude="37.77493" longitude="-122.41942" fit-to-markers>
<google-map-marker slot="markers" latitude="37.779" longitude="-122.3892" draggable="true" title="Go Giants!">
</google-map-marker>
<google-map-marker slot="markers" latitude="37.777" longitude="-122.38911">
</google-map-marker>
</google-map>
What is happening?
google-map does not know when markers are inserted or updated because without the attribute slot="markers" they are inserted outside the slot where they should be inserted in.
Several consequences can happen from this issue: the map can be viewed, but not respond to important events, like fit-to-markers.
In these turbulent moves from original without-slots version to the current slotted version (and soon moving to polymer 3.0 version) of the excellent google-map webcomponent, there is a high chance that the busy developers simply forgot to add this important slot="markers" attribute in the example that shows how to add each new google-map-marker webcomponent inside google-map.
This only complements the already correct above answer. If anyone needed more explanation, I offer these, If I am correct, of course (please correct me if I made wrong conclusions).
You can detect this flaw inspecting your google-map element. Without the slot="markers" correction, open google-map; inside it, open iron-selector; and finally inside it open the element <slot id="markers" name="markers"><slot>. If you do not use the suggested correction, this slot will be empty. If you use this suggested correction, this slot will contain references to each google-map-marker. And so the google-map element will be able to handle several events that rely on detecting when each marker is inserted or updated.
Sorry for the long answer.
来源：https://stackoverflow.com/questions/44607665/how-to-include-google-map-in-polymer2-0-as-it-was-working-in-polymer-1-7