I'm quite new to Android development.
I'm trying to write an app that communicates by Wifi using UDP to an instrument.
The app plots 512 bytes of data it receives over WiFi using AndroidPlot. Transfer rate is satisfactory and communications is fault tolerant.
I would now like to turn my proof of concept into a functional app complete with tabs & swipe navigation.
On one tab I'd have my chart, on another tab I'd have some controls, and another tab with status information. Each tab would need access to the UDP thread.
As I'm new to this I'm having a hard time determining the right architecture to implement.
I feel I've wasted a good bit of time on fragments and pager adapters without really getting the functionality I'm after (the work I've done so far feels as though I'm trying to force something to do what it really isn't meant to do).
Could someone with experience give me a general path to take? Are fragments the answer? Is there a way to support swiped tabs without the additional complication of fragments?
Thanks for any help! Hopefully this isn't too general.
Related
I've been writing an extension that allows the user to issue voice commands to control their browser, and things were going great until I hit a catastrophic problem. It goes like this:
The speech recognition object is in continuous mode, and whenever the onerror: 'no-speech' or onend events fire, it restarts. This way, the extension is constantly waiting to accept input and reacts whenever a command is issued, even after 5 minutes of silence.
After a few days of of development, today I reached the point where I was testing it in practical use, and I found that after a little while (and with no change to anything on my part), my onend event started firing constantly. As in, looking at the console, I would see 18,000 requests being made in the space of three seconds, all being instantly denied, thus triggering onend and restarting the request.
I'm aware that it would be optimal to wait for sound before sending a request, or to have local speech recognition capabilities without the need for a remote server, but the present API does not allow that.
Are my suspicions correct? Am I getting request limited?
Are my suspicions correct? Am I getting request limited?
Yes
I'm aware that it would be optimal to wait for sound before sending a request, or to have local speech recognition capabilities without the need for a remote server, but the present API does not allow that.
To hide the IP source of your request you can use anonymizer networks like Tor, though it will not be fast.
It's naive to assume Google will spend resources to process all audio being recorded on your system. In your application development it is better to rely on API which provides at least some guarantees. It could be either commercial API or open source implementation like CMUSphinx.
With CMUSphinx, you can also properly implement command keyword detection and increase accuracy by specifying the grammar of the commands.
You could also use a Voice Activity Detection (VAD) algorithm to detect when a user is talking. This can be done by either setting a volume threshold or a frequency threshold (Human speech is usually less than 400hz for example). This way, you won't send useless requests to Google unless those conditions are meant. I would not recommend using Tor as this would significantly increase latency. CMUSphinx is probably the best local system option, but if still want to use a web-based service, I would recommend either using a Voice Activity Detection algorithm or finding a different web-based software.
I'm new to mobile development and am looking for a hybrid framework for a few reasons:
Faster development: I don't need learn Objective-c/java or install XCode/Eclipse
Easier to iterate: We're a startup, and need to do a lot of A/B testing as well as iterate quickly. We want to be able to update the app without having to wait for app store approval and for the user to update the app.
Trigger.io solves the latter point - https://trigger.io/reload/ (which is a big plus)
Aside from that, what are the main diffrence between them in terms of (a) learning curve, (2) native UI feel, (3) performance
I originally asked the questions - gonna share my experience so far.
I started with PhonaGap and then switched to Trigger.io. Not necessarily saying that trigger.io is better - my main 2 reasons for switching were:
Trigger.io compiles much faster (seconds vs minutes). When I was using phonegap, I was testing my changes using Ripple stimulator - compiling the code after every small change was simply too time consuming. Making sure that your code runs on Ripple is a headache, and when thing didn't work on the device it took forever to debug. With trigger.io I can easily test every single change on the device.
Trigger.io allows pushing new changes to your release/app store app (instead of waiting for the users to update your app). To me it is one of the key advantages of HTML5 over native.
Some other notes:
Trigger.io provides only mediocre customer support (I have a paid account). Not sure about phonegap
Phonegap has much better opensource support and and way more plugins. With trigger.io if the functionality is not provided by one of their modules, or if you have a bug, you're on your own.
I work for Trigger so I'm going to represent our side of things.
Trigger is particularly focussed on making a good experience for people who don't want to see the native code and just want to write HTML/JS (we do also support native modules, but we hope that the majority of users won't need to write their own).
In terms of learning curve I highly recommend just giving Trigger a try, we have a free trial and you can be running an app in a simulator or on your device in under an hour.
For native UI Trigger has several modules which add native UI components. For example: https://trigger.io/modules/topbar/current/ and https://trigger.io/modules/tabbar/current/. I'm not sure exactly what is available in Phonegap so I can't make a direct comparison. On both platforms however with modern devices its possible to create very nice UIs with just HTML5/CSS.
As for performance both platforms are similar, depending on your app you may run into some limitations with HTML. For example, graphically intensive games are unlikely to work very well. Normal applications, however, are generally not a problem. See https://trigger.io/examples/ for some examples of what can be achieved.
I'm a relative beginner using Google Apps Script and JavaScript, but I've been playing around with bot for days now and I've created a few simple programs and I'd really like to try and get started on my dream project, even if it takes me forever. I'd like some advice on what I should use in terms of making the UI and what database I should use to hold the information (and if this app is even possible).
The App
I'd like to create an online novel management app that utilizes Google Drive as it's source for files. The UI would have a tree that showcases all the google drive files in the novel. When a scene is clicked, the scene opens up for editting.
Questions
Is this app a possibility?
If so, in terms of a UI, what do you think I should use? The google
provided UIbuilder? The HTML service - for example, can I have a
frame on the right that the google doc that needs to be editted
can open up in on the right?
Lastly, what database should I use? The database would have to store
chapter names and positions, as well as scene names, positions,
and the google doc ID that the scene corresponds to. I've got a
handle on ScriptDB and Spreadsheets... And if either of these two
aren't the best option, would some other database work better? And
why?
This app will, hopefully, be able to give an overview of a novel in tree form, allow you to open a particular scene and edit it, create new scenes, and also change the order in which the scenes are displayed. And then when the person finishes their novel, the app will compile all the scenes into one novel (also in google Drive).
Any insight or suggestions would be greatly appreciated!
Having a look at the questions you recently posted I think I have a pretty good idea of what you are trying to do and it looks like an exciting project... I can only encourage you to start it as soon as you can even if you're not comfortable with all the tools you will need to use, the best learning method is probably to work on something important to you.
Now your 3 questions : 1 - This is perfectly doable in the GAS environment and shouldn't be too hard to go through.
2 - the GUI builder is an easy way to start with UI but it lacks a number of features and tools that you will be needing (tree for example ) and is not so easy to expand if you ever need to. Depending on your knowledge in html, the choice is mainly between UiApp and html service... I would choose UiApp because I'm not good at all in html (but that's not relevant here ;-) but both are capable of building what you want, are easily expandable and not too hard to debug. The advantage could go to html service if you are going to look for 'nice looking features' because it opens the door to 3rd party tools... but again, this is a matter of personal choice.
3 - A recent post from Mogsdad showed that spreadsheet are faster than scriptDb for data storage and manipulation. I find it also easier since I can have a global view on data in the spreadsheet when debugging. Of course Spreadsheet must be considered as a container and data manipulated at array level to benefit from maximum performance. I use that in a lot of database application with full satisfaction.
Sorry for these "general considerations" that don't comply to sto standards ;-)
Yes, it seems that all of the things you are requesting are not too ridiculous. I recommend sticking to Google services because they are all easily integrated. To start off, you may want to use the UI builder/UI services. There may be a point in this project where you may want some functionality that the UiApp doesn't provide. At that point, you might want to switch over to HtmlService.
My answer is the same for the databases question. You might want to use a spreadsheet for your database so that you will be able to easily edit it by hand if you need to. You may not have the performance that another database would give you, but it will be fairly easy to test and mess around with your spreadsheet "database."
You could start out with getting the basics down. There's a serious amount of data out there. I would suggest you research on an "as-needed" basis. Design some work-/dataflow patterns for your app, for which you could try to use the Fluid UI extension for Chrome. Have a look at this from Mozilla on the designing of apps.
When you've gone through this you might want to have a look at Phonegap and the basics of web development and how you could combine the two.
There's also several ways of using/storing data. You could try WebSQL though it they no longer develop it. You could look at IndexedDB. You could try to use cookies.
Seriously, have a look around. You might also like the books of Wrox. They're very informative and have great work with reading demo's. Though the books are huge ;)
I opened this matrix multiplication benchmarks and my browser (Firefox 7.0.1) froze until the benchmarks finished (I opened the page in an old Asus EeePC 1000H).
I heard that web workers were invented to separate processing from displaying the web pages. Is it possible to make use of the Web Workers API to make WebGL not stall the whole web browser ?
For the sake of clarity: the benchmark that you linked to does not use WebGL at all. (I should know, I wrote it.) And in the case of that particular benchmark you absolutely could run it in a Web Worker now and it would be perfectly fine.
(Fun fact - Web Workers didn't support TypedArrays when the benchmark was built, and since most of the matrix libraries rely on that it was impractical to run it in a Worker at that time. That has since been fixed.)
Anyway, to answer your original question: No, WebGL cannot run in a worker. The core blocker to this is that in order to get a WebGL context you need to call getContext on a canvas element. Web Workers explicitly disallow DOM access (which is a good thing, BTW!) and as such you'll never be able to access WebGL from a worker.
But that's not as bad as you might think. For one, consider that most all 3D rendering is actually happening in a different thread anyway. Specifically, a whole bunch of threads running on your GPU. The only part the browser has in it is to tell your graphics driver "Hey! Start rendering some triangles using this data!" and then it moves on without waiting for the triangles to actually be rendered. As such, while the draw commands must be executed from the main process, the time it spends blocking that process is (usually) very little.
Of course, that's not what's going to eat up a bunch of your time if you were coding a realtime game. You've got animations, physics, AI, collision detection, pathfinding... there's a lot of non-graphical tasks involved that will eat your CPU alive if you let them. In some case (animation), it's usually just gobs and gobs of matrix math, just like the benchmark you linked to! Fortunately for us, however, that type of processing CAN be done in a Worker, and all we need to communicate back to the main thread is the data required to render the scene.
Yes, this introduces some challenges in terms of synchronization and data transfer, but on the whole it will be vastly preferable to locking up your browser while we try and simulate those 500 boxes colliding.
Yes, on Firefox!
https://hacks.mozilla.org/2016/01/webgl-off-the-main-thread/
We’re happy to announce WebGL in Web Workers in Firefox 44+! Using the new OffscreenCanvas API you can now create a WebGL context off of the main thread.
By default you can't use WebGL in a Web Worker as Toji explained.
You can check out WebGLWorker which is a library that lets you do WebGL stuff in a Web Worker, by transparently proxying commands to the main thread.
Here is a nice blog post that explains how it works.
I'm not a Web Developer, and I don't know a lot about the web application frameworks out there.
Recently, however, I got into Wt. It's a web framework written in C++ (that's why I got into it), but what impressed me the most is the idea it's based on.
Its API is different from any web framework I ever heard of (CppCMS, Yii, Django, Pylons, Zope, Drupals, Java Servlets, Struts ...): a new Application object gets created for any user session, and it stays alive until the session expires (only at this point the Application object gets destroied). This Application object works like a desktop window: you put Widgets in it (widgets like forms, links, labels ...); when the user clicks on a link (when the HTTP server receives a new GET/POST request) a function gets called on the object tight to the user session (in a nice Signal/Slot way), which can remove/add/change the widgets, thus changing the page the user will see.
As I said, I'm not very skilled with web frameworks, I develop almost only desktop applications; maybe for this reason I think this paradigm behind Wt is great.
I'd like to know what are the pros and cons of this framework API in respect to the other ones, and if there are other frameworks (also in other languages) based on the same concepts.
Wt is a great framework for its intended range of applications.
Wt is great for :
web apps tightly coupled to a session, i.e.
made to be accessed only by users that are logged in (except the landing page)
display a lot of user-dependent content (so not for a wiki)
relying heavily on state
web apps that need to have a lot of controls/buttons and user input.
For exemple, I plan to write a browser MMORPG. Pages will all be having a state tied to a user, and there will be a lot of buttons. Wt is perfect for that. I used to be a Ruby on Rails developper, and switching to Wt for this kind of app was a great moment. It's increadibly cumbersome to design forms with traditional frameworks that try to enforce pure REST.
Wt would also be perfect for a control interface on some process. For example, an interface allowing your customers to configure their adword campain, etc.
Of course, using Wt is not perfect regarding control and separation, but it allows extremely fast development when you need only the "classic" features (buttons, editors, etc.)
So as a rule of thumb, if you are trying to put a desktop application on the web (which is a great idea, removing the need to deploy and update on your customers' machines), Wt is a good candidate.
Also, if you are interfacing with an existing C++ codebase, Wt has an advantage.
I think this is generally bad idea.
Web application is very different from GUI one and there are many reasons:
99% of the web is about the content rather then about iteration.
You go to web to get or share content rather then to do some real time interaction
like drawing a picture, working with spreadsheet or anything else.
Web is content driven rather then "event driven" interactive application.
This has strong impact on how do you create most of web - you bring information
to user rather then interact with him.
The server and client programming is very different
There are some web GUI applications like e-Mail, Chats clients but to perform well
they require very good separation between the client side written
in high quality Java Script and the high quality server side backend that is used
over AJAX for content retrieval.
Hiding this separation like Wt does or (other known frameworks) lead to crappy
software and generally brings more problems then solutions in long run.
Because it should be very clear separation between server side and client side jobs
as some require real time response and some don't.
When you try to solve all this in one wait for problems. Note, there are client-server
solutions for GUI (see X-Server as example) but unlike web they designed for this
and rather work more like IPC rather then client-server solitions.
The web is stateless most of the time.
Or to be more correct the state usually keeps quite small amount of data.
Creation of instant session object is nice idea until you need to...
Scale up save state in long terms then this model becomes not so good, of course
this not "forced" model by Wt but it is general concept that fits certain concept
and some does not.
Bottom Line
If you want to design good GUI like web application. Start learning JavaScript and use good GUI JavaScript frameworks that fit well to GUI even driven design. Then combine them with some server side API using some interaction RPC model like Json-RPC, XML-RPC and other
AJAX tools.
This is the way to do things right for highly interactive applications.
If your application is more content oriented then most of server side web
frameworks do great job - concentrate on server side with its great tools suitable
for the job.
All in one solution? It just does not work...
Disclosure: I'm developer of CppCMS and I think Wt just goes in wrong way.
ASP.NET is similar; it has the same goal to make web development look like desktop application development.