i wanna build a web base android application with intel XDK! i tried but the output apk file is too large, My files are totaly 2.4MB but the output is 15.6Mb ! What should I do ?
As @HoseinBL indicates, 15.6MB is not that large for a typical APK.
Which Android build are you using? There are actually three available in the current XDK build system. If you're using the one labeled just "Android" the comments above from @Brad Hill and @Tangocoder apply. If you need to use the Canvas API (aka AGI) or the Cordova API you need to build using the "Gold" option. If you only use the Intel XDK API (intel.xdk and appmobi namespaces) you can use the "Lean" option for a slightly smaller APK.
The Crosswalk for Android build will create at minimum a 15MB package, since this option includes a replacement webview that requires a lot of space.
We are in the process of finalizing a 100% Cordova-compatible build (current called "Cordova for Android") that will generate smaller APKs, but it isn't quite ready for prime-time (thus the reason for the "Beta" tag).