NativeScript Webview newbie questions - webview

I am experimenting with using NativeScript to speed up the process of porting an existing Android app to iOS. The app in question uses a great deal of SVG manipulation in a Cordova webview. To keep things simple I want to port all of my existing Webview side code - in essence the entire existing Cordova www folder and its contents - over to the new NativeScript app. The WebView talks to a custom Cordova plugin which I use to talk with my servers to do such things as get new SVGs to show, keep track of user actions etc.
If I an get through these teething issues I am considering using this component to implement bi-direction communications between by current webview JS code and the, new, NativeScript backend that will replace my current Cordova plugin. Someone here is bound to tell me that I don't need to do that... . However, doing so would mean throwing out the baby with the bathwater and rewriting all of my current Webview ES6/JS/CSS code.
This is pretty much Day 1 for me with NativeScript and I have run into a few issues.
I find that I cannot get rid of the ActionBar even though I have followed the instructions here and set the action bar to hidden.
I can use the following markup in home.component.html
to show external web content. However, what I want to really do is to show the local HTML file that is in the www folder in the following folder hierarchy
app
|
____home
|
____www
|
______ index.html
|
______css
|
______ tpl
|
.....
However, when I use the markup
<Page actionBarHidden="true" >
<WebView src="~/www/index.html"></WebView>
</Page>
I am shown the error message
The webpage at file:///data/data/com.example.myapp/files/app/www/index.html is not available.
I'd be most grateful to anyone who might be able to tell me what I am doing wrong here - and also, how I can get rid of that action bar which is currently showing the app title.

About using local HTML file
Is your local HTML file recognized by Webpack (which is enabled by default in NativeScript)? Try to explicitly add the local HTML file to your webpack.config.js file. This way Webpack will "know" that it will have to bundle this file as well.
new CopyWebpackPlugin([
{ from: { glob: "<path-to-your-custom-file-here>/index.html" } }, // HERE
{ from: { glob: "fonts/**" } },
{ from: { glob: "**/*.jpg" } },
{ from: { glob: "**/*.png" } },
]
Example here
About hiding the ActionBar
NativeScript Core only: Try hiding the action bar directly for the frame that holds the page. See the related documentation here
NativeScript Angular: The page-router-outlet will have an action bar by default (you can hide it by using the Page DI as done here). Otherwise, you could create a router-outlet (instead of page-router-outlet). The router-outler won't have the mobile-specific ActionBar.

Related

Twitter Card Images not working on Gatsby app

I'm working on a Gatsby app with Netlify CMS (and hosted on Netlify). Trying to get the metadata working so that Twitter cards display correctly with images.
The metadata is generally all right, but the images aren't showing on the Twitter validator or if I try to post to Twitter. The problem is clearly the images themselves, which are hosted on the site using Gatsby and Gatsby Image Sharp to render.
In fact, the validator seems to show no fundamental issues. Simply, the image doesn't show up:
Example relevant metadata:
<meta name="twitter:url" content="https://example.com/" data-react-helmet="true">
<meta name="twitter:image" content="https://example.com/static/12345/c5b20/blah.jpg" data-react-helmet="true">
<meta data-react-helmet="true" name="twitter:title" content="Site title">
<meta data-react-helmet="true" name="twitter:card" content="summary_large_image">
I know the images the issue, because if I replace my image URL (which is the full image URL) with an external URL, it works fine, showing the full card with image.
Any idea what could be causing this? I'm sizing the image down so it loads quickly, and it seems to load just fine directly (eg). (I mean, is there something weird/off about that image?)
NOTE: In a previous version of this question, I referenced Cloudinary and Uploadcare, but have since removed those two in a branch to simplify the problem. (They seem to have been unecessary holdovers from the starter app I used.) You can now see an example page for that branch here and the associated image in the twitter:image tag here. I feed this pre-processed/shrunk image into the header using React Helmet (and Gatsby React Helmet) and using the following code in my GraphQL call to get the image associated with the blogpost in that particular, smaller format:
featuredimage {
childImageSharp {
fixed(width: 480, quality: 75) {
src
}
}
Second Note/thought: Should I be worried about the fact that the pages in production seem to be re-rendering on every reload? Isn't SSR supposed to ensure that doesn't happen? I tested this by including a call to Math.random(), hidden, in the page. You can see the result by running document.getElementsByClassName('document')[0].children[0].innerText, and note that it produces a different number on each page reload. This implies to me that the whole page is being re-rendered by the client. Isn't that wrong? Why would that be happening? Might that relate to some sort of client processing of the images on each request, which might be screwing up the Twitter cards?
Third update: I put together a simpler reproduction here. It's based off of this starter template, with Uploadcare/Cloudinary removed and Twitter card metadata added to the header. Other than that, and removing unnecessary pages, I didn't make any other changes. I used this starter for a repro rather than a vanilla starter app, because I'm unsure whether the issue is caused by the interaction of Netlify CMS and the Gatsby Sharp Image plugin. I might try to put together a second reproduction. For now, the code for this repo is here, and the pages that should show Twitter cards are the blog posts, such as this one.
ACTUALLY, it seems that a super basic reproduction, with Gatsby 3 and no Netlify CMS or anything, has the same issue. Here's the minimal reproduction, with the image taken from src/images using an allImageSharp query and inserted into the metadata for each page. Code here.
FINAL UPDATE
Based on Derek's answer below, I removed the #reach/router stuff, and got the site URL from Netlify build env variables. It appeared that #reach/router only gave this information when JS was running, which excluded the Twitterbot, resulting in an undefined base URL, which broke the Twitter image. Including the URL from Netlify (using process.env.URL in the Gatsby config and pulling that in through a siteMetadata query) fixed the problem!
Update:
I think I might have found the issue. When opening the minimal production with script disabled, the url for twitter:image is invalid:
<meta data-react-helmet="true" name="twitter:image" content="undefined/static/03475800ca60d2a62669c6ad87f5fda0/58026/energy.jpg">
So for some reasons, during build, the hostname is missing, but when JS kicks in, it appears (Might have something to do with the way you get the hostname). Twitter crawlers probably does not have JS enabled & couldn't fetch the image.
Make sure your opengraph images are absolute urls with https:// or http:// protocols. I checked your example link & saw that it was a relative link (/static/etc.)
For Twitter, it seems to demand social cards to be 2:1
Images for this Card support an aspect ratio of 2:1 with minimum dimensions of 300x157 or maximum of 4096x4096 pixels.
https://developer.twitter.com/en/docs/twitter-for-websites/cards/overview/summary-card-with-large-image
If you're using the latest Gatsby image plugin, you can use aspectRatio to crop the image.
Also note that you can skip the twitter:image tag, if your og:image has already satisfied Twitter's card requirement.
SSR does not mean to never run JS in the client, React will render your page on the client side regardless of SSR.
This was solved here: https://github.com/gatsbyjs/gatsby/discussions/32100.
"location and thus origin is not available during gatsby build and thus the generated HTML has undefined there."
I got it working by changing the way I create the image URL inside seo.js from this:
let origin = "";
if (typeof window !== "undefined") {
origin = window.location.origin;
}
const image = origin + imageSrc;
to this:
const imageSrc = thumbnail && thumbnail.childImageSharp.fixed.src;
const image = site.siteMetadata?.siteUrl + imageSrc;
You need to use siteUrl from siteMetadata.
Below is my pageQuery from inside blog-post.js:
export const pageQuery = graphql`
query BlogPostBySlug(
$id: String!
$previousPostId: String
$nextPostId: String
) {
site {
siteMetadata {
title
siteUrl
}
}
markdownRemark(id: { eq: $id }) {
id
excerpt(pruneLength: 160)
html
frontmatter {
title
date(formatString: "MMMM DD, YYYY")
description
thumbnail {
childImageSharp {
fixed(width: 1200) {
...GatsbyImageSharpFixed
}
}
}
}
}
}
`

URL in CSS no longer works in Vaadin 14.6

After upgrading from Vaadin 14.5 to 14.6 I'm facing problems with CSS that contains URL's that point to content.
For example, the following CSS no longer works:
:host([part="my-part"]) [part="reveal-button"]::before {
content: url("../images/my-image.svg");
}
It fails to "compile" when running the build-frontend goal of the Vaadin Maven plugin with the following error:
ERROR in ../node_modules/#vaadin/flow-frontend/styles/components/my-component.css
Module build failed (from ../node_modules/css-loader/dist/cjs.js):
Error: Can't resolve '../images/my-image.svg' in '<Project Path>\node_modules\#vaadin\flow-frontend\styles\components'
The same error appears in the browser if I try to run the project. This CSS has worked fine in all previous versions of Vaadin 14.
Has anyone encountered anything similar, or have any ideas as to what has changed that might cause this?
With the new custom theme feature the .css loader has changed from raw-loader to css-loader but it shouldn't touch urls outside of frontend/themes/[theme-name] or node_modules
Is the styles/components/my-component.css located in src/main/resources/META-INF/frontend, src/main/resources/META-INF/resources/frontend or src/main/resources/META-INF/resources to be packaged as an add-on jar or compatibility mode?
As in that case the css would end up inside node_modules which might make a difference to the resolving.
As a workaround if you are not building an add-on you should be able to move the css and image to {project_root}/frontend and it should build fine.
Until release of 14.6.2 you can add the raw-loader dependency to a java class with
#NpmPackage(value = "raw-loader", version = "3.1.0")
and then add to webpack.config.js the lines
if(flowDefaults.module.rules[2].test.toString().includes('.css')) {
flowDefaults.module.rules[2].use = [ {loader: 'raw-loader' }];
} else if(flowDefaults.module.rules[1].test.toString().includes('.css')) {
flowDefaults.module.rules[1].use = [ {loader: 'raw-loader' }];
}
Did you change the css structure to follow the new theme structure introduced in 14.6? It is not needed, but it is important context. I think it is at least related to your issue.
The path seems a little weird in your error messages, ending up in a node_modules folder. Could you share where this file is in, and what loads the file to your project?
With the new theme structure, I've used the following css to import images in css:
background: url('./images/fire.png');
And that was placed in a file: frontend/themes/mythemename/mythemefile.css

Printing from a Xamarin.Forms app

I'm all new to Xamarin and I'm currently working on a sample or a "prove of concept" app using Xamarin.Forms.
I'm supposed to perform a print task from this app though I'm not at this point sure what to print yet (the screen, content of a label, a file etc.).
Either way, what is the easiest way to print from a Xamarin.Forms app?
(current target is primarily Android 4.4+).
I hope this isn't too complicated :)
EDIT:
Ok let me just update this post as the original text might be a bit ambitious/vague.
I have a Xamarin.Forms project (+ an Android part) and I have some HTML available in the XF part of the project that I need to get into a WebView and print it.
From what I understand, the thing with the WebView has to be done on the Android part of the project due to the fact that this is where the printing will be handled.
I was hoping this could be done from code since I don't really need to display the WebView, just print it's content.
The Android part of the project has only the MainActivity and no layouts or XAML files.
I don't know where to add the WebView or how to access it (other than DependecyService seems to be a buzz word here) so I'm kinda stuck here.
I'm thinking that this task should be rather trivial to someone with a little more Xamarin experience than me.
Every platform XF supports has it's own mechanism for printing. XF does not provide any abstractions for printing in a cross-platform manner. You will need to write printing logic for each layer and expose it to XF using DependencyService (or some other DI engine).
Here is a good example, of course, using dependency service:
https://codemilltech.com/xamarin-forms-e-z-print/
I so wanted to do this but it was too hard. Finally built it into Forms9Patch - a MIT licensed open source project.
Verifying that Printing is available
Before printing, you should verify that printing is available on your device. To do so, call:
if (Forms9Patch.PrintService.CanPrint)
{
// do the printing here
}
Print the contents of a Xamarin.Forms.WebView
using Forms9Patch;
...
var myWebView = new Xamarin.Forms.WebView
myWebView.Source = new HtmlWebViewSource
{
Html = "some HTML text here"
};
...
myWebView.Print("my_print_job_name");
Note that your WebView does not have to be attached to a Layout. This allows you to Print without having to display the WebView in your app’s UI.
Printing an HTML string
using Forms9Patch;
...
var myHtmlString = #"
<!DOCTYPE html>
<html>
<body>
<h1>Convert to PNG</h1>
<p>This html will be converted to a PNG, PDF, or print.</p>
</body>
</html>
";
...
myHtmlString.Print("my_print_job_name");
PLEASE NOTE: iOS sometimes places the page breaks in weird places. I have a StackOverflow Bounty on why this happens and how to fix it.
Using EmbeddedResource as a source for a Xamarin.Forms.WebView
This is sort of an experimental feature I’ve built that I’ve found it useful. As such the documentation is sparse. It allow you to put HTML content in a folder in your app’s EmbeddedResources folder and then use it as a source for a WebView. A much nicer solution than using platform specific approach provided by Xamarin. It also supports putting all of the HTML content into a zip file. Please take a look at the source code to see how it works.
You can handle the printing of lists/ invoices .. with the xfinium pdf component from xamarin componentstore. With that you create your _pdffile and then call the following method which starts the adobereader from where you can select a printer (in my case google cloudprint)
public void printPdfToCloud(string _pdffile)
{
try
{
var saveto = System.IO.Path.Combine(Android.OS.Environment.ExternalStorageDirectory.ToString(), "YourApp/"+_pdffile);
string file_path = saveto;
if (System.IO.File.Exists(file_path))
{
Android.Net.Uri pdfFile = Android.Net.Uri.FromFile(new Java.IO.File(file_path));
Intent pdfIntent = new Intent(Intent.ActionView);
pdfIntent.SetPackage("com.adobe.reader");
pdfIntent.SetDataAndType(pdfFile, "application/pdf");
pdfIntent.SetFlags(ActivityFlags.NoHistory);
StartActivity(pdfIntent);
}else
{
// give a note that the file does not exist
}
}
catch (Exception E)
{
// Do some Error dialog
}
}

Use local json file with Cordova/ionic/Angular. Works in browser, but not on device?

I'm attempting to use a JSON object living in a data.json file to be the dataset for a quick prototype I'm working on. This lives in a my_project/www/data/ directory. I have an Angular service that goes and grabs the data within this file using $http, does some stuff to it, and then it's used throughout my app.
I'm using Cordova and Ionic. When using ionic serve on my computer, everything looks perfect in the browser. However, when using ionic view (http://view.ionic.io/) and opening the app on my iPad, I see a:
{"data":null,"status":0,"config":{"method":"GET","transformRequest":[null],"transformResponse":[null],"url":"../data/items.json","headers":{"Accept":"application/json,test/plain,*/*}},"statusText":""}
for a response. I would think that if it were a relative URL issue, that it would also not work in the browser, but that is not the case.
Here's what I'm doing:
config.xml has this line:
<access origin="*" subdomains="true"/>
My service that preforms the simple request is doing:
return $http.get("../data/data.json").then(function (response) {
return response.data;
});
And finally, in my controller, I ask for the service to preform the request:
myService.goGetData().then(onComplete, onError);
In my browser, onComplete() is invoked and on the iPad, onError() is invoked.
Any guidance?
On your local developer machine you're actually running a webserver when you run ionic serve. So a path like ../../data.json will work because it is totally valid in the context of the webserver that has complete filesystem access.
If, however, you try to do the same thing on your device, you're probably going to run into an issue because the device has security policies in place that don't allow ajax to traverse up outside of the root. It is not a dynamic webserver so it can't load files up the tree. Instead you'd use something like the cordova file plugin to grab the file contents from the filesystem. If you prefer, you can use ngCordova to make interacting with the plugin a bit less painful.
I am 99% sure this is what is happening but you can test my theory by pointing your $http call to some dummy .json data hosted on a publicly available server to see if it works. Here is some dummy json data.
Just gonna leave this here because I had the same problem as the original question author. Simply removing any starting slashes from the json file path in the $http.get function solved this problem for me, now loading the json data works both in the browser emulator and on my android device. The root of the $http call url seems to always be the index.html folder no matter where your controller or service is located. So use a path relative from that folder and it should work. like $http.get("data/data.json")
So this is an example json file. save it as data.json
[
{
"Name" : "Sabba",
"City" : "London",
"Country" : "UK"
},
{
"Name" : "Tom",
"City" : "NY",
"Country" : "USA"
}
]
And this this is what a example controller looks like
var app = angular.module('myApp', ['ionic']);
app.controller('ExhibitionTabCtrl', ['$scope', '$http', function($scope,$http) {
$http.get("your/path/from/index/data.json")
.success(function (response)
{
$scope.names = response;
});
}]);
Then in your template make sure you are you are referencing your controller.
<ion-content class="padding" ng-controller="ExhibitionTabCtrl">
You should then be able to use the a expression to get the data
{{ names }}
Hope this helps :)
I was also looking for this and found this question, since there is no real answer to the problem I kept my search on the Internet and found this answer at the Ionic Forum from ozexpert:
var url = "";
if(ionic.Platform.isAndroid()){
url = "/android_asset/www/";
}
I've used it to load a 3D model and its textures.
update: ionic 2 beta (version date 10 Aug 2016)
You must add prefix to local url like this: prefix + 'your/local/resource'.
prefix by platform:
ios = '../www/'
android = '../www/'
browser = ''
we can create an urlResolver provider to do this job.
notice: only change url in *.ts code to access local resource, don's do this with remote url or in html code.
Have fun and good luck with beta version.
An Starter Ioner
It is possible to access local resources using $http.get.
If the json file is located in www/js/data.json. You can access using
js/data.json
Do not use ../js/data.json. Using that only works in the local browser. Use js/data.json will work on both local browser and iOS device for Cordova.

How to add launch image to a Sencha Touch 2 app?

The iOS guideline requires launch image for all apps. To my understanding, that's a "default.png" file located in the root folder of your app.
I packaged my app using Sencha CMD v3 and I don't see any launch image while loading.
There are some default launch images located in root/webapp/resources/loading/ folder but they are not showed in my app. Any idea?
The "startupImage" seems only appliable to the app added to the home screen, anyway, here is a part of my app.js:
startupImage: {
'320x460': 'resources/startup/320x460.jpg',
'640x920': 'resources/startup/640x920.png',
'768x1004': 'resources/startup/768x1004.png',
'748x1024': 'resources/startup/748x1024.png',
'1536x2008': 'resources/startup/1536x2008.png',
'1496x2048': 'resources/startup/1496x2048.png'
}
Added related posts:
[2.1] Splash screen is white on startup on Android and iOS
I have this at the beginning of my application - I'm not packaging it for iOS, but this seems like what you may need:
Ext.require([
'Ext.XTemplate',
'Ext.Panel',
'Ext.Button',
'Ext.List'
]);
// Main application entry point
Ext.application({
phoneStartupScreen: 'images/sencha_logo.png',
name: 'Analytics',
// setup our MVC items
Here is a handy-dandy link to the api doc on this:
http://docs.sencha.com/touch/2-0/#!/api/Ext.app.Application-cfg-phoneStartupScreen
For launch image you need to modify the index.html in your app directory. In here you will find a div with id appLoadingIndicator inside body tag. In my application I have replaced the content of #appLoadingIndicator with an img tag which refers to my splash image.
<div id="appLoadingIndicator">
<img src="resources/images/splash.png" />
</div>
For customizing the css you might want to remove the default embedded styles in index.html present in style tag inside the head tag which are applied to #appLoadingIndicator.
Now add your custom css and you will have your splash image ready.

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