MobileZX

MobileZX is a 48k ZX Spectrum emulator for mobile devices with support for J2ME MIDP2.0. It is oriented to devices such as PDAs and mobile phones.

Platform:unknown; License: GNU General Public   (GPL)

Reference：https://mobilezx.sourceforge.net/

Opie: Open Palmtop Intergrated Environment

The Open Palmtop Integrated Environment is an Open Source based graphical user environment for PDAs and other form-factor devices running Linux. It is included in various embedded Linux distributions such as Ångström, OpenZaurus, Familiar and OpenSIMpad.

GPE: the GPE Palmtop Environment

The GPE Palmtop Environment provides a Free Software GUI environment for palmtop/handheld computers running on Linux and other Unix-like operating systems. The components and infrastructure provided by the environment make it possible to use your GNU/Linux handheld for standard tasks such as Personal Information Management (PIM), network access and multimedia. Moreover, the environment defines standards for program design and interaction based on the C programming language and other common standards such as SQL and XML.

Pocky

Poky is an open source platform build tool and offers over 500 pre-configured packages to build into a system. As a software development environment for the creation of Linux devices, it enables you to design, develop, build, debug, and test a complete software stack using Linux, the X Window System and GNOME Mobile based application frameworks for both x86 and ARM based platforms.

Qt

Qt is a cross-platform application and UI framework. Using Qt, you can write web-enabled applications once and deploy them across desktop, mobile and embedded operating systems without rewriting the source code.

Features：

Intuitive C++ class library
Portability across desktop and embedded operating systems
Integrated development tools
with cross-platform IDE
High runtime performance and small footprint on embedded

Platform: Cross Platform; License: GNU LGPL 2.1、GNU GPL3, with Qt special exception、Commercial Developer License

Reference: https://qt.nokia.com/