производительность кроссплатформенных мобильных приложений

Question

Есть ли у кого-нибудь опыт работы с этими "кроссплатформенными мобильными приложениями", такими как PhoneGap или Titanium Mobile?

Насколько велика разница в производительности по сравнению с родной Java (для Android) или Objective-C (для iPhone)?

Answer 1

Существуют довольно большие различия в производительности ... но с некоторыми знаниями ... (один вечер чтения) ... вы можете бороться с ними и использовать свои знания в HTML / JS / CSS для быстрого запуска и запуска приложений.

Вот некоторые самородки:

Советы по производительности PhoneGap / Mobile Web

* How Diary.com increased the performance of their PhoneGap app running Sencha: http://www.phonegap.com/2011/06/21/building-the-diary-com-ios-app-using-pg-sencha-touch/
* http://floatlearning.com/2011/03/developing-better-phonegap-apps/
    * http://jslint.com/ - to debug your javascript
    * http://zeptojs.com/ and http://xuijs.com/ - minimal alternative frameworks to jquery and jqtouch

* Disable the accelerometer and location http://blogs.nitobi.com/jesse/2009/10/28/running-jqtouch-in-phonegap/
    * set “EnableAcceleration” to false in PhoneGap.plist
    * set "AutoRotate" to false in PhoneGap.plist

* http://mir.aculo.us/2010/06/04/making-an-ipad-html5-app-making-it-really-fast/
* http://cubiq.org/remove-onclick-delay-on-webkit-for-iphone
    * Demo: http://cubiq.org/dropbox/clickdelay.html 
    * FastClick v TouchStart: http://groups.google.com/group/phonegap/browse_thread/thread/f5f5c78e26513821?pli=1
    * http://forum.jquery.com/topic/ontouch-instead-of-onclick-event

* http://wiki.phonegap.com/w/page/16494809/Performance-tips-for-device/
* http://www.developer.nokia.com/Community/Wiki/JavaScript_Performance_Best_Practices
* http://evolvingwe.com/building-an-iphone-app-part-3-7-dev-tips/
* http://evolvingwe.com/upgrading-to-phonegap1-0/
* VIDEO Performance Tips for Sencha Touch: http://vimeo.com/17882927
    * It covers performance features in Sencha, which are great principles we can reapply. We may even be able to cut code from certain pieces of Sencha to reapply for Skej.
    * It states that we MUST destroy anything that is not visible on the DOM. And that the DOM must be kept as small as possible at all times, with as few listeners as possible. (I.e attach one listener to the parent item of a list, rather than to each list item.)
    * It also has practical CSS3 tips for me to apply... Basically, dont use many of the new transitions and shadows/round corners because the currently use CPU, and not yet GPU. 

* Event Delegation in Sencha Touch: How to design lists with a single listener, and not one on every line. http://www.sencha.com/blog/event-delegation-in-sencha-touch/
* Optimizing DOM Memory Usage in Sencha Touch: Sliding from a List to a Details panel and killing the list, and then sliding from Details to a List and killing the details panel. Minimizing elements on your screen, your DOM. http://www.sencha.com/blog/sencha-touch-optimizing-memory-usage/
    * DESTROY ANYTHING THAT IS NOT VISIBLE ON YOUR DOM!

* Use CSS Animations instead of jQuery

    * http://nyroo.com/l/B7UN5c
    * http://www.ferretarmy.com/css-animation-examples/ 
    * Be careful... these are tricky when they don't leverage the GPU, and bog down the CPU.

Включение новых функций

* Enable Retina Display: http://evolvingwe.com/create-retina-display-images-in-mobile-web-themes-and-phonegap-apps/
* Swipe to delete: http://www.codesta.com/blog/2011/5/23/sencha-touchphonegap-tips-and-tricks.html
* Disable accelerometer and location: http://iamcam.wordpress.com/2009/10/29/phonegap-up-to-speed/
* Cut jQuery and Hand-code: http://cubiq.org/do-you-really-need-jquery-for-mobile-dev
* Display Contact List in Mobile Safari: http://cubiq.org/contact-list-on-webkit-for-iphone
* iScroll4: Create a header, scroll within a fixed size div, pinch and zoom, pull up/down refresh. http://cubiq.org/iscroll-4 (Includes tips on rubber-band effect.)
* PhoneGap's GitHub repo: Includes interesting examples like DatePicker, SMSComposer, ApplicationPreferences, Splashscreen, NetworkActivityIndicator... https://github.com/phonegap/phonegap-plugins

Архитектура

Разработка вашего приложения в Ext JS 4: http://www.sencha.com/learn/architecting-your-app-in-ext-js-4-part-2

Answer 2

Простой способ увидеть для себя приложение Phonegap - просто использовать браузер на обоих телефонах для вашего приложения, отличным демонстрационным приложением будет демо-версия jquery для мобильных устройств, доступная по номеру http://jquerymobile.com/test/

Я считаю, что Titaniumбыстрее за счет необходимости изучать их среду Javascript, потому что он компилируется в нативный код.