Making sense of web app debug logs on multiple Android and iOS devices

If you’ve ever needed to debug Cordova web apps on iOS and Android it can be quite an awful experience for a web developer. Since working on Postcard web app I’ve found a couple of neat tips to help make sense of those noisy debug logs.

From localhost to native land

Designing and developing in localhost is familiar territory to web developers and so it makes sense to try and get as much work done there as possible. But when you need to use the physical hardware features of a mobile platform the only way to see if things really work is to go native.

For Cordova app development on Android there are a few ways to debug web apps but usually it’s a case of cordova build android then cordova run android --device --debug. Then if you have setup Android SDK’s PATH environment var you can run monitor in command line to open up the Android Device Monitor app to see all the logs.

AndroidDeviceMonitor

For Cordova app development on iOS it’s usually cordova build ios in Terminal and then you just open the project in Xcode to debug the app.

XcodeLogs

Both these options allow you to run and debug multiple devices although you have to tab or switch views to see the other devices logs. Also Android logs are so noisy it’s almost impossible to spot the stuff you want to look at. Ideally I would like to look at all logs at the same time and dial in on the stuff I’m really interested in.

While developing the Postcard app I mocked up the UX flow to perform an Identity Exchange with two devices using our peer to peer Thali Cordova plugin for iOS and Android. Needless to say the Android logs got very busy and I also wanted to be able to get the logs of iOS devices outside of Xcode sessions. Thankfully there are a couple of better ways to debug multiple Android and iOS devices from one Mac –

Debugging Cordova web apps on multiple Android devices using adb and logcat filtering

List android devices attached:

Because I have two android devices attached I want to be able to target both from command line.

Once Cordova has installed the app on device you can use logcat to see the logs in Terminal. However with multiple devices you want to use adb -s to target a device and then use logcat -s to filter out all the noise! With the Postcard app we are using jxcore to run Node.js on mobile so I used ‘jxcore-log:*’ as my filter.

In another Terminal tab or split window in iTerm.

logcat-jxcore

Now that’s much cleaner and stuff doesn’t scroll faster than you can actually read! 😉

Assuming the Android device is already developer enabled you can also inspect the web view and javascript console logs in Chrome: chrome://inspect/#devices

Debugging Cordova web apps on multiple iOS devices using iOS Console

With iOS all you need to do is attach your devices and download iOS Console which is a handy freeware app to view iOS logs on a Mac with filtering. With our iOS Postcard app I have set the filter to ‘jxcore’.

iOSConsole-logs

iOS Console doesn’t need Xcode running and the logs are a lot cleaner than the default Console app.

Also you can inspect the web view and javascript console in Safari once the app is running. In Safari browser go to:
Safari > Preferences > Advanced and turn on “Show Develop menu in menu bar” then select:
Safari > Developer > Device Name

Note: If you are using mobile Safari to test your web app instead of Cordova then you will have to enable “Web Inspector” on the iOS device under Settings > Safari > Advanced

Faster Cordova web app deployment with hotwire script

Building for iOS can be very time consuming. Every time you make changes to a Cordova web app you need to do a cordova build to update the app project. Then you have to go into Xcode to debug on device. But if you don’t need to make changes to native code and you only need to update web elements like HTML, Javascript, image and media files then you can save time by just updating those bits.

I’ve made a Hotwire IPA bash script to replace the ‘www’ web app folder with the updated directory. All you need to do is create an ‘*.ipa’ archive and the hotwire script can quickly update it with all web app changes and deploy to device (without need to jailbreak).

Example usage:

sh hotwire-ipa.sh -f ~/Desktop/app.ipa -d "www" -p ~/Cordova/app/www -b ~/Cordova/app/platforms/ios/www -i

where:
-f is the path to *.ipa archive
-d is the dir to delete inside app
-p is the dir to copy in place
-b is the dir with Cordova build plugins and scripts

Setup and instructions for deploying iOS app using hotwire-ipa over on GitHub.

Time results for iOS Cordova app:

3m 09s – Each time you update web files you need to execute cordova build ios to stage the updates.
0m 38s – Open in Xcode
8m 10s – Debug from Xcode

Total: 11m 57s

To run the script we need to first create an Archive and export it as an *.ipa archive in Xcode. Once this is done then future updates can be pushed using the script.
2m 53s – Create Archive
2m 13s – Export as .ipa
4m 39s – Deploy to device using hotwire-ipa script with -i switch to install as *.ipa instead of *.app.

Total: 8m 45s (11m 54s if you include initial cordova build ios)

That’s 3 minutes 12 seconds saved the first time if you have already done cordova build ios just to compile the native code, then 7 minutes 18 seconds saved to deploy repeated web app updates.

All times recorded using Postcard web app (using ‘Story_0’ branch) on MacBook 1.2 GHz Intel Core M

Developing a web app that behaves like a native app

Like many developers out there I started out coding for the web. So you might think it would be easier to develop a web app than a native app, right? The short answer is no… but web app development is getting better and the performance gap is closing.

Thoughts on web app vs native app development

Delivering a world-class UX is the main reason to opt for native development. Web app performance has quite some way to go especially on the vast majority of low spec devices. For example even if you get your web app running at a buttery smooth 60fps in iOS Safari, it doesn’t automatically mean you get that sort of performance in an app’s UIWebView.

iOS Tip: Don’t be content testing any web app or web UI framework in Safari and think that it works. A real web app development test is only done by running it inside an embedded WebView.

What you have to be careful off is getting sucked into some web app framework because you can get some decent results pretty quickly, but as soon as you add a little more complexity things can start to break and the speed of development will slow as a result. Whereas while native development might take longer to learn initially, after that you can start building some pretty slick apps just using the standard suite of UI components provided.

Ultimately things are getting better for web app development but probably not enough as to make native app developers want to consider switching. But with all the modern browser javascript speed optimisations and mobile devices becoming ever more powerful it’s worth considering a web app where the ability to share code is most important. After all who wouldn’t rather develop code once that works across mobile and desktop and leverages the extensive web developer knowledge base? So the compelling reason to build a web app is that your code should run on any screen that runs a modern browser.

Postcard app

I’ve been involved with developing the Postcard app which is a web app for demoing a peer to peer web experience using the Thali Cordova plugin. Throughout the design, development and build process of this web app I’ve encountered a number of issues or pain points and thought it would be good to share the golden nuggets I’ve learnt while trying to develop a web app that behaves like a native app!

Postcard app icon

Icons and splashes generator for Cordova web app

With any project I always like to start with design before I jump into development. Design is a time consuming task but some things can be automated like resizing all those app icons and splashscreens across multiple platforms. I wrote a time saving Ruby script to build app icons and splashscreens for iOS and Android with Cordova’s image filenames and sizes. (Usage and instructions are in the gist)

Designing a web app across different screens – live!

Many web apps take advantage of node and there is a great module for designers called BrowserSync.

BrowserSync allows you live preview all your design or code changes across multiple screens. That means you can test your web app in real-time on any browser on Mac or Windows as well as hook up the web app on iPhone, iPad or Android. Also when you interact on one screen for example following a link or scrolling the page this automatically updates everywhere else. This is a must have for any responsive design or adaptive design work!
BrowserSync demo

Polymer 1.0 – a UI kit for web apps

For the UI design side of things I choose Polymer 1.0 due to it’s host of web app elements inspired by a native app’s UI kit. Initially I didn’t like all the custom element names, as this reminded of an Angular wild west of element names but you can quickly learn the Polymer core elements and view the documentation and source behind them. Also there is a benefit to this as it prevents the usual ‘div nest of inception’ meaning that an HTML layout can be understood at a glance.

Getting started developing with Polymer

The trickiest thing is actually getting all the Polymer elements you need to use as these all come separately which of course makes sense later for production. But do yourself a favour and just install all the paper, iron and neon elements for no hassle development.

Should I use Polymer’s ‘on-click’ or ‘on-tap’ event?

There is a 300ms click delay issue that affects mobile web apps. The good news is that there is a simple fix by using the viewport meta tag with width=device-width property. But the bad news is that this trick only works in Chrome 32+ on Android.

Thankfully Polymer tries to handle this issue for you if you use the on-tap event however it doesn’t appear to currently trigger a click on Mac Safari (using an iframe web app). So if desktop Safari compatibility is more important then you may have to stick with the standard on-click event until this is fixed. Or just incase you already use a ‘fast click’ javascript polyfill it may run into issues due to click delay complications with the iOS 8 web view.

Meet ‘iron-list’ – the UITableView for web app

Polymer’s iron-list element is essential for scrolling large amounts of data on mobile devices. It does this by using a virtual list and recycling (20) cells to handle smooth scrolling of 1000s of items. One note of caution is that this runs fine in Safari browser but there is currently a scrolling issue in iOS 8 WebView beyond a certain number of items. If only UIWebView would behave the same as Safari then development would run so much smoother!

Make it feel like a native app – not a web site!

It’s important to make sure things act like an app and not feel like a website thrown inside a Cordova webview. There are a couple of giveaway indicators that can be fixed, although not everything will behave perfectly.

Disable the scrolling bounce effect

While adding the magical web app meta tags will give you full screen control in the browser it doesn’t get rid of the web page scrolling spring effect common with iOS and Mac. Now while the spring effect provides a wonderful UX in a web browsing context – native app’s don’t spring! To disable this unwanted behaviour the first thing to do is to enable the DisallowOverscroll preference in Cordova’s config.xml.

If you are not using Cordova then you can disable the iOS webview scroll:

It’s always a good idea to do a CSS reset on the html,body and then add the following to disable the bounce effect in the browser:

Disable select copy/paste

Another annoying web behaviour inherited is that everything is selectable on a web page. Again a useful behaviour in a web browsing context but not so much with a web app. Besides not feeling right there is a UX issue if a user taps the ‘wrong way’ instead of activating a button click as expected they end up in a text selection mode. The easiest workaround is setting user-select to none on the ‘body’. NB: If your web app contains form inputs then you can exclude those inputs using the :not() CSS selector but I find it easier to switch everything off by default.

The one problem you still get with iOS UIWebView is that you always get a magnifying glass when doing a long-press and unfortunately there is no simple way of disabling this without hacking UIWebView private APIs.

Prevent scrolling nav bar when editing input

A quirk with web apps on iOS is trying to fix a nav bar so it won’t scroll off the screen when editing an input or textarea that would obscure the soft-keyboard when it pops up. One trick is to position your input as high up the page as possible in order to avoid the issue. But sometimes this isn’t always possible so the other option is to try a hacky workaround discussed on SO which also seems to work pretty well with Polymer:

In Cordova if you want to enable Javascript focus() calls to open the soft-keyboard you can disable the KeyboardDisplayRequiresUserAction preference. Although bear in mind iOS8 now supports focus() calls but I found the input and keyboard can lose connection sometimes.

Problems with web app when running as a native iOS app…

I encountered quite a number of problems when running a web app inside the iOS 8 UIWebView. I have listed the main issues below to watch out for with possible workarounds:

[WebActionDisablingCALayerDelegate setBeingRemoved:]: unrecognized selector sent to instance 0x174009d20
*** WebKit discarded an uncaught exception in the webView:willRemoveScrollingLayer:withContentsLayer:forNode: delegate: -[WebActionDisablingCALayerDelegate setBeingRemoved:]: unrecognized selector sent to instance 0x174009d20

Solution: Add body style for -webkit-transform. This WebView bug occurred when animating an element sliding up from the bottom of the page. It caused the animation to jump and skip frames and seemed to trigger memory warnings.



[46377:7026777] Received memory warning.

Solution: If you’ve tested for memory leaks then try disabling animations. If this solves the issue then try to optimise your script so that expensive business logic is called only after animations are completed.



Message from debugger: failed to send the k packet

Solution: Keep app awake! In the app delegate enable setIdleTimerDisabled:

iOS Tip: When testing web apps on iOS it can take so long to build and debug on device that the screen locks and the deploy fails. Use the setIdleTimerDisabled to keep the app alive for debugging!


Developing a peer to peer web for iOS

To establish peer to peer (p2p) communication on iOS devices there is an API for that known as the Multipeer Connectivity framework. There are a couple of things to bear in mind about this framework:

  • Discovers and connects with iOS devices but will not discover devices on other platforms like Android
  • Maximum number of 7 invitees (client peers)
  • Will raise a prompt for user acceptance of a peer connection request

Intro to Thali project for iOS

Thali is an experimental open source p2p project that promises to enable p2p web to run on mobile devices. This is quite a big undertaking so to make life easier to begin with we can start to look at the iOS to iOS p2p connectivity story which is documented as Thali “Story -1”.
The spec will use the TCP internet standard to transport data across peers therefore all mobile devices will run a Node.js layer. In order to run Node.js on iOS we use a Cordova plugin which runs JXCore. This will then connect with a native TCP bridge which will relay the data over the iOS Multipeer Connectivity framework. The flow is illustrated in the diagram below:
Thali flow for iOS

How to build Thali demo for iOS

If you like playing with bleeding edge code you can build the “Story -1” iOS dev branch. (NB: You will need two iOS devices with Bluetooth 4.0 support.)

To run this build script in Terminal you will need Node.js. If you haven’t already got Node.js installed you can get Node.js with NVM for Mac OS X.

Install the Cordova package:

Build Thali “Story -1” demo for iOS:

How all the parts work inside the Xcode project…

There are three main parts or layers in the Thali iOS project:

  1. Cordova

    • All demo UI code is handled by “thali_main.js” script.
  2. JXCore

    • UI actions will trigger a call to functions in “app.js” script which is responsible for running all our Node.js code and calling the native methods as documented in the Thali common API.
  3. Native Plugins

    • All native methods called from JXCore are registered in “THEAppContext.m” defineJavaScriptExtensions method

What about Android p2p?

More info about Thali for Android is available on Dr Jukka’s blog.

What about iOS and Android p2p?

More info about future Thali development including iOS and Android p2p interoperability is documented on Thali stories.

Unity3D Leaderboard demo using BitRave Azure plugin

This is a quick Unity3D game developer tutorial showing how to save, update and query high scores stored in the Cloud using a Mobile Service and the BitRave Azure plugin.

Watch how to create a Leaderboard in the cloud using the Unity3D BitRave plugin.

  1. To save scores in the Leaderboard table you will need to create a Mobile Service.

    If you don’t have an Azure account there is a special Cloud GameDev Offer for game developers.

  2. Get the BitRave plugin with Leaderboard scripts on my GitHub fork.

    There are two new scripts I’ve added for the Leaderboard demo:

    Unity3D BitRave Fork with Leaderboard script demo
  3. Create new Unity project.

    Unity3D BitRave Fork with Leaderboard script demo
  4. Copy contents of the BitRave Universal Plugin Assets folder into your Unity3D project’s Assets folder.

    Unity3D BitRave Fork with Leaderboard script demo
  5. Import JSON.NET dependancy from Unity Asset Store.

    Unity3D BitRave Fork with Leaderboard script demo
  6. Open the TestAzure scene.

    Unity3D BitRave Fork with Leaderboard script demo

    Select Main Camera and remove Script in the Inspector panel. (This will be replaced later.)

    Unity3D BitRave Fork with Leaderboard script demo
  7. Create ‘Leaderboard’ table in Azure Mobile Services.

    Unity3D BitRave Fork with Leaderboard script demo
  8. Open AzureUILeaderboard.cs script and replace Azure Mobile Service connection strings.

    Unity3D BitRave Fork with Leaderboard script demo
  9. Drag & drop AzureUILeaderboard.cs script to attach it to the Main Camera.

    Unity3D BitRave Fork with Leaderboard script demo
  10. Now you’re ready to play in Unity Editor add post some high scores!

    Unity3D BitRave Fork with Leaderboard script demo
    Unity3D BitRave Fork with Leaderboard script demo

In this demo project you can submit new scores, return list of all scores and update them. You can also query to show only high scores or get list of a user’s scores.

Check it out!

Karma Labs on Azure Mobile Services and BitRave plugin in their Unity3D game development.

If you are also looking to handle user identity with Mobile Services and configure build settings for iOS and Android development I touch on this in my first getting started with BitRave Azure plugin tutorial.

Share your Unity3D #GameDev with @deadlyfingers

Unity3D game dev with Azure Mobile Services using BitRave plugin

This quick-start tutorial is for Unity3D game developers who would like to get a cloud backend that runs across multiple platforms (including the Unity Editor for quick testing). One of the big advantages for game devs using Unity3D is that it supports so many platforms. It’s fair to say more people own more than one device that connects to the internet and a lot of them can run apps and games. While the platforms and ecosystems may differ as a gamer I would like to play the same game across any device (and on any platform) and expect things to sync. Azure Mobile Services is a ‘Backend as a Service’ which supports multi-platform app development. In Unity the BitRave plugin for Azure Mobile Services is designed to just work on any platform that Unity supports.

Watch getting started with Unity BitRave Azure plugin running on iOS and Android

  1. To kick off with create a Mobile Service in Azure management portal. If you don’t have an Azure account yet game developers can register for the Cloud GameDev Offer.

    NB: A Mobile Service will only take a minute to setup and just a couple of minutes more to become active and ready to use.

  2. Download BitRave plugin.

  3. Create new Unity3D project.

  4. Copy BitRave’s AzureMobileServicesUniversalPlugin/Assets into Unity3D project’s ‘Assets’ folder.

  5. Get JSON.NET Unity asset to enable cross platform support.

  6. Open TestAzure Scene.

  7. Open AzureUI.cs script and replace the connection strings with your own Mobile Service URL & API Key.

  8. The BitRave demo uses Authentication with Facebook. You will need to create a Facebook app for your Mobile Service and copy & paste the App Id and App Secret into your Mobile Service’s IDENTITY Facebook section. Then generate the Facebook Access Token under Facebook’s Tools > Access Tokens.

    Copy the Access Token and paste into AzureUI.cs script’s Access Token value.

    NB: Remember to save changes.

  9. In Unity select the Main Camera and remove the Script in the Inspector panel.

    Reattach the AzureUI.cs script. (Drag & drop the script onto the Camera.)

  10. Add the demo TodoItem table (in Azure Mobile Service’s get started section).

  11. Run in Unity Editor and connect to Mobile Service.

    Once logged in you can add a TodoItem.

    You can query or list all items.

    Items can be selected to updated.

  12. In Unity Build Settings switch platform to build for iOS. I’ve selected Development Build and Symlink Unity Libraries for smaller/faster builds.

    To run on the iOS Simulator edit Player Settings and under Target iOS Version menu select Simulator SDK

  13. Open Xcode project to build & run. Rotate iOS simulator to landscape to display UI.

    Connect to Mobile Services by logging in to add some items.

  14. In Unity Build Settings switch platform to build for Android. I’ve selected Development Build and Google Android Project.

    Edit Player Settings to change the Bundle Identifier. (This is in reverse domain name notation – for example net.deadlyfingers.DemoApp)

  15. Import Android project into Android Studio.

    Edit the AndroidManifest.xml and change the installLocation attribute to auto.

    Build & run app. (I find the Nexus 7 tablet API 21 ARM emulator works best with Unity builds.)

    Rotate Android emulator to landscape to display UI.

    Connect to Mobile Services by logging in to add some items.

One more thing to todo!

You can also record the userId by adding one line of code on the server-side.

TodoItem-Insert-userId

Edit TodoItem table Script > Insert

Score bonus points!

Check out my Leaderboard BitRave tutorial showing how to save, update and query high scores stored in the Cloud using a Mobile Service.

Share your Unity3D #GameDev with @deadlyfingers