Develop Reference

R shiny mobile app: prevent PullToRefresh

Context: I am developing a mobile Shiny app using the shinyMobile package, which is a wrapper for the famous framework7 HTML template.
In my app, the user has to make a selection of attributes on a first tab using multiple dropdown lists, and then, on the other tabs, some output is produced. Each tab requires the user to scroll up and down to access all the content and in this process, very often the 'pull to refresh' feature is triggered.
This is really annoying, because the entire attribute selection and output are lost, and the user has to start over from scratch.
What I tried: based on this SO thread which pointed me to this Google developer page, I tried setting the CSS overscroll-behavior property to contain with: body {overscroll-behavior-y: contain;}. PROBLEM: It does not work for me! (tested on Chrome Android)
Minimal reproducible example:
default app, deployed here
library(shiny);library(shinyMobile)
shiny::shinyApp(
ui = f7Page(
f7Card(
h5('try to pull to refresh. normally it should work.')
)
),
server = function(input, output) {}
)
Supposedly fixed app, deployed here
library(shiny);library(shinyMobile)
shiny::shinyApp(
ui = f7Page(
tags$style(type='text/css', '.body{overscroll-behavior-y: contain;}'),
f7Card(
h5('try to pull to refresh. Normally it should not work.')
)
),
server = function(input, output) {}
)
Hope you guys can reproduce my issue and identify what is amiss!!!

You might want to change your css part to: html,body{overscroll-behavior-y: contain;}, see https://stackoverflow.com/a/42509310/3502164.
Then it works for me on my mobile (android chrome).
Reproducible example:
library(shiny)
library(shinyMobile)
app <- shiny::shinyApp(
ui = f7Page(
tags$style(type='text/css', 'html,body{overscroll-behavior-y: contain;}'),
f7Card(
h5('try to pull to refresh. Normally it should not work.')
)
),
server = function(input, output) {}
)
# use host config to access app from mobiles in the same network
shiny::runApp(appDir = app, host = '0.0.0.0')

Android Fotoapparat library

I'm new to Android-Developement and I would like to make a Camera-app. I found this library (this is the Github page).
But I don't know how to implement a library. I followed these steps (method 2) but I'm getting an error in a popup window called 'IDE Fatal Errors'. It says: 'To investigate / fix the problem IDE wants to attach following files to the bug report. We recommend to include all the files providing maximum information. Note: all the data you send will be kept private.' Then I can select a 'diagnostic.txt'. There is a section 'file content' where 'rootsChanged' is written. I can report the whole window to Google.
The following step is to configure the 'Fotoapparat' instance. What is an instance? When I search on Google I only find articles talking about making a library.
I'm sorry if these are stupid question but I am a beginner and I would like to learn more about Android-Development. Thanks in advance for your time and help.

Add this line in your build.gradle(Module: app) file ->
dependecies {
//Your other dependencies...
implementation 'io.fotoapparat:fotoapparat:2.3.3'
}
And start using your code. Library is working fine.
EDIT - >
You need to learn basics of java.
To setup instance of the object you need to create a variable.
Hence in your case:
Fotoapparat yourVariableName = new FotoapparatFotoapparat
.with(context)
.into(cameraView) // view which will draw the camera preview
.previewScaleType(ScaleType.CenterCrop) // we want the preview to fill the view
.photoResolution(ResolutionSelectorsKt.highestResolution()) // we want to have the biggest photo possible
.lensPosition(LensPositionSelectorsKt.back()) // we want back camera
.focusMode(SelectorsKt.firstAvailable( // (optional) use the first focus mode which is supported by device
FocusModeSelectorsKt. continuousFocusPicture(),
FocusModeSelectorsKt.autoFocus(), // in case if continuous focus is not available on device, auto focus will be used
FocusModeSelectorsKt.fixed() // if even auto focus is not available - fixed focus mode will be used
))
.flash(SelectorsKt.firstAvailable( // (optional) similar to how it is done for focus mode, this time for flash
FlashSelectorsKt.autoRedEye(),
FlashSelectorsKt.autoFlash(),
FlashSelectorsKt.torch()
))
.frameProcessor(myFrameProcessor) // (optional) receives each frame from preview stream
.logger(LoggersKt.loggers( // (optional) we want to log camera events in 2 places at once
LoggersKt.logcat(), // ... in logcat
LoggersKt.fileLogger(this) // ... and to file
))
.build();
And start using yourVariableName.

'LikeView' has no propType 'RCTFBLikeView.onLayout' of native type 'boolean' if you haven't changed this

LikeView has no propType for native prop RCTFBLikeView.onLayout of native type boolean
If you haven't changed this prop yourself, this usually means that your versions of the native code and JavaScript code are out of sync. Updating both should make this error go away.
Not sure why I am getting this error. I'm not using LikeView at all in the android app. I've tried running npm start --reset-cache.
Also iOS version of the app runs no problem. This only occurs for android.
Any suggestions welcomed.
Thanks!

I figured out that the problem is (as RN points out) a mismatch between the native props and the JS ones on the props that every view uses. Namely:
renderToHardwareTextureAndroid
onLayout
accessibilityLiveRegion
accessibilityComponentType
importantForAccessibility
accessibilityLabel
testID
Since I am not using any of the views that the package uses, namely:
FBLikeView
FBLoginButton
FBSendButton
FBShareButton
I tried to set this props as 'native only', so that they are not bound to the JavaScript side. In every component (in the example, FBShareButton.js), I replaced:
const RCTFBShareButton = requireNativeComponent(
'RCTFBShareButton',
ShareButton,
);
with
const RCTFBShareButton = requireNativeComponent(
'RCTFBShareButton',
ShareButton,
{
nativeOnly: {
onChange: true,
onLayout: true,
testID: true,
importantForAccessibility: true,
accessibilityLiveRegion: true,
accessibilityComponentType: true,
accessibilityLabel: true,
renderToHardwareTextureAndroid: true,
}
},
);
I am now going to check if the views are getting rendered properly and edit my post later, but if you just want to be able to compile your app in order to continue development (as it is my case at the moment), that should let you do so.
Edit
I successfully rendered the LoginButton component using the example in the README with my changes.
Edit 2
I made a pull request with my changes to the package. I don't like the solution, but it might raise FB's attention. In the meantime, you can just use my fork. In your package.json, just replace the fbsdk line with this:
"react-native-fbsdk": "git+https://github.com/motius/react-native-fbsdk.git#fix-views"
This other pull request might be a better solution, actually.

Similar to the solution suggested by #martinarroyo, I figured that it has to do with some components that are not synced between the native code and the js code.
If you are not using these components, instead of adding the nativeOnly property in every js file you use it, I commented out the exports from the react-native-fbsdk index.js as follows:
//native components
// exports.LikeView = require('./FBLikeView');
// exports.LoginButton = require('./FBLoginButton');
// exports.SendButton = require('./FBSendButton');
// exports.ShareButton = require('./FBShareButton');
Obviously this is just a workaround but that should get you through that error

You can downgrade react-native-fbsdk to 0.5.1 to avoid this issue until a fix has been merged into a new version.

So after countless experimentation and banging my head on the table, i think the solution was the versioning of the dependency.
Here's a list of things I attempted and the one I think that resolved the issue is marked with an * because I'm not 100% sure if it was this step that resolved it.
removing node_modules folder and reinstalling it.
doing the react-native-git-upgrade as #matt suggested
reinstalled react-native-fbsdk multiple times following the instructions and double checking the code.
changing the buildToolsVersion & targetSdkVersion to 25.
5**. ultimately running react-native uninstall react-native-fbsdk followed by react-native install react-native-fbsdk#0.5.0.
Note* number 5 was attempted throughout the past two days..yet only now it worked...So I don't know what black magic it is that caused it to work just now...
The issue with number 5 is that prior to yesterday the fbsdk dependency version was 0.5.0 and as of yesterday, it was upgraded to 0.6.0. SO I am not sure why even though I reinstalled it yesterday too, it did not fix the bug.
If someone who is more familiar with this can provide an explanation as to why this occurred I would be inclined to learn.

Using Cordova, is there a way to reference native icons?

I'm using Cordova 3.5 to build an app which contains a menu with pretty standard items in the list (home, contacts, etc.), and I want to use the native menu icons whenever possible. I believe those icons are already on the device as part of the OS, but I don't know if Cordova gives me a way to reference them.
I suppose I'd need to write a Javascript function to choose the right file name based on the platform, e.g.:
// this is pseudocode
var icon = '';
if (platform === 'android') {
icon = 'some/path/home.png';
} else {
icon = 'other/path/icon.home.png';
// or maybe a function such as the following exists:
// icon = cordova.getNativeIcon('icon.home.png');
}
$('.selector').css('background-image', icon);
Alternatively, I may be able to make do by referencing the files in CSS, e.g.:
.android .home-icon {
background-image: url('some/path/home.png');
}
.ios .home-icon {
background-image: url('other/path/icon.home.png');
}
So, how do folks handle this sort of thing in Cordova? Is there a function I can use to access native icons? Are folks just copying them into their projects? What's the best practice?

If you're working with Cordova, then you'll be working inside a web view provided by the host OS and you won't have direct access to any artwork. I've found that using icon fonts and CSS "themes" to work well enough, but that approach will replicate artwork already provided. There's extra work involved with theming for iOS 6 vs iOS 7 or 8, for example, but it's not as bad as it sounds.
IBM does have an article on partitioning your view between native and web controls, but it sounds a bit cumbersome. More details here: https://www.ibm.com/developerworks/community/blogs/worklight/entry/ios_combining_native_and_web_controls_in_cordova_based_applications

Same Titanium code base for Android & Iphone

I have been trying to create a single codebase for both Iphone & Android for a intermediate level app. ( 4 tabs, multiple windows, maps etc.) using itanium 2.1 API.
However, I have found that things on Android platform dont work as smoothly or willingly as on Iphone epsecially tableviews & UI elemnts. The UI responsiveness on Android is also sluggish.
The kitchen sink examples are pretty straightforward. I am looking at an enterprise ready app which has to be maintained for atleast next couple of years.
Has anybody worked on similar lines with platform quirks and been successful in creating fully functional iOS & Android apps from SAME codebase?

I'm having a lot of success using the compile-time CommonJS mechanism for having a root view that then has os-specific capabilities.
For instance, my os-independent view might be ui/MyView.js :
var createAddButton = require("ui/MyView.AddButton");
var MyView = function() {
var self = Ti.UI.createWindow();
createAddButton(self, function() { alert('ADD!'); });
return self;
};
module.exports = MyView;
Then, I create os-specific functions to handle it:
iphone/ui/MyView.AddButton.js
module.exports = function(view, addHandler) {
var addButton = Titanium.UI.createButton({
systemButton: Titanium.UI.iPhone.SystemButton.ADD
});
addButton.addEventListener("click", addHandler);
view.rightNavButton = addButton;
};
android/ui/MyView.AddButton.js
module.exports = function(view, addHandler) {
view.activity.onCreateOptionsMenu = function(e){
var menuItem = e.menu.add({ title: "Add" });
menuItem.addEventListener("click", addHandler);
};
};
The CommonJS system they have implemented will pick the appropriate version of MyView.AddButton.js so that the button is added to the right place. It allows for the majority of the view to be the same, but the os-specific things to be separated properly.

Titanium is not meant for 1 codebase for all. You do need to rewrite stuff for every OS. However, some app developers claim to have reused 95% of its code. So only 5% of the code is OS specific. But I am sure their code is full with if-elses.
What I recommend doing, to be able to maintain it properly, without thousands of if-else constructions, is build a single backend core, and write code specifically for UI related matters per OS. This way, you have some UI related code for Android, UI related code for iOS and 1 core working for both.
Since Android and iOS differ a lot, writing a single codebase will make sure you can never use OS specific features (like android hardware menu button, or iOS NavigationGroup), and will let the UI look non-intuitive.