CDroid

Android's UI framework, faithfully ported to C++ — Android-quality UI on embedded devices with no Android runtime, and a readable mirror of AOSP internals you can actually learn from.

CDroid is a line-by-line C++ port of Android's Java UI SDK — android.widget, android.view, android.text, android.graphics.drawable, android.animation — built on top of Cairo (vector graphics) and targeting embedded systems (runs in as little as 32 MB of RAM). It is neither a wrapper around Android nor merely "Android-inspired": class names, member names, method signatures, and control flow track the AOSP sources closely enough that you can open the Android reference next to the C++ and follow along line by line.

If you can describe a UI in Android XML, you can run that same UI on a set-top box, an in-dash display, or an industrial panel — designed in Android Studio, rendered by Cairo, no JVM in sight.

• Main repository: https://gitee.com/houstudio/cdroid
• Mirror: https://github.com/houstudio/cdroid
• Contact: QQ 1225012331 / WeChat: calfhou

Why does this exist?

Embedded teams keep reinventing UI frameworks, and the results are rarely as good as Android's. CDroid takes the other route: port the real thing, preserve a decade of Android UI engineering, and ship it where Android itself can't run. The guiding rule is fidelity over redesign — translate Android's logic verbatim instead of second-guessing it. (See AGENTS.md.)

Who is it for?

• Embedded engineers who need a polished, animatable, Material-style UI on constrained hardware (32 MB+) where full Android is too heavy.
• Android developers who want to understand how the framework actually works — View measure/layout/draw, Choreographer, input dispatch, text layout, drawables — by reading clean C++ instead of fighting the AOSP build. CDroid is the most readable mirror of AOSP framework internals that exists.
• C++ engineers looking for a substantial, well-architected codebase: real ownership/lifetime challenges, modern features (ConstraintLayout/MotionLayout, RecyclerView, fragments, transitions), and Cairo-based rendering.

Features

• 100+ widgets & 50 drawables, API-compatible with Android — design them in Android Studio / Eclipse.
• Full AndroidX ports: RecyclerView, ConstraintLayout + MotionLayout, FragmentManager + Navigation, Flexbox, CoordinatorLayout, ViewPager2.
• Fragment + Transition framework, including shared-element transitions.
• Binary AXML resources end to end — aapt2-compiled XML + resources.arsc packed into .pak archives, real resource ids in generated R.h, build-time resource overlay.
• android.app services in-process — AlarmManager (suspend-aware delivery, no dedicated thread), dialogs, a minimal PendingIntent.
• In-process accessibility — AccessibilityService + node tree, plus UiAutomation semantic test drivers (--auto-test sweep, --test-script DSL).
• Vector graphics via Cairo — no Bitmap class; Cairo::ImageSurface plays that role.
• Multi-window / multi-layer compositor with damage-region rendering.
• Faithful text stack: spans, StaticLayout/DynamicLayout, minikin line-breaking, fonts.xml family/fallback chain, color emoji (CBDT), KeyCharacterMap, IME.
• Cross-platform backends: DRM, fb, DirectFB, SDL, XCB/Xlib, VNC.

Get involved 👋

CDroid is a large port — there is always more to translate from AOSP, and we'd love your help.

• 🆕 Good First Issues — concrete, self-contained tasks, each pointing to the exact AOSP source to port.
• 📖 Contributing guide — how to build, the fidelity methodology, and how to claim your first task.
• 中文说明见 README.cn.md.

Quick Start

• VM(Ware):https://pan.baidu.com/s/1-v-rLcHxo5W5TXvJ2NUWxA fetchcode：spux (VM Ubuntu User:cdroid password:123456）
• After login pls run git pull to get new version of cdroid
• You'd better remove outXXX and run build.sh to rebuild makefiles after each git pull.

IDE(AndroidStudio/Eclipse)

ScreenShots

View	TextView	Button	ImageView	ImageButton
CompoundButton	ToggleButton	CheckBox	RadioButton	ProgressBar
SeekBar	Chronometer	AnalogClock	ViewGroup	RadioGroup
ScrollView	ViewPager	SimpleMonthView	Switch	RatingBar
NumberPicker	ListView	GridView	RecyclerView	ViewFlipper
ViewAnimator	AdapterViewAnimator	CalendarView	TabLayout	DatePicker
TimePicker	NestedScrollView	HorizontalScrollView	DateTimeView	ViewPager2
YearPickerView	WearableRecyclerView	Toolbar	QRCodeView	CardView

Supported Layouts:

FrameLayout	LinearLayout	RelativeLayout	TableRow	DrawerLayout
TableLayout	AbsoluteLayout	GridLayout	GestureOverlayView	CoordinatorLayout
ConstraintLayout	MotionLayout	FlexboxLayout	SlidingPaneLayout

Supported Drawables:

ColorDrawable	BitmapDrawable	NinePatchDrawable	InsetDrawable
ShapeDrawable	TransitionDrawable	AnimatedVectorDrawable	StateListDrawable
LevelListDrawable	ClipDrawable	AnimatedRotateDrawable	RotateDrawable
GradientDrawable	ScaleDrawable	AnimatedImageDrawable	VectorDrawable
RippleDrawable	AnimationDrawable	AnimatedStateListDrawable	LayerDrawable
BadgeDrawable	PictureDrawable	AnimationScaleListDrawable	AdaptiveIconDrawable

Porting guide:

• 1 A new product porting should be placed to src/porting/xxx(where xxx is you chipset name)
• 2 implement your porting api to xxx directory
• 3 modify build.sh to support your port(you should configure sysroot toolchain...).
• 4 call build.sh --product=xxx
• 5 make you project(SeeAlso Building CDROID)

Building CDROID:

1.install dependencies(Ubuntu 22+):

sudo apt install autoconf libtool build-essential aapt cmake gdb pkg-config zip curl unzip gettext libx11-dev libxcursor-dev libxcb1-dev libxcb-image0-dev libxcb-cursor-dev bison python3 python3-pip python3-lxml python3-pil meson

notes: the "aapt" package ships /usr/bin/aapt2; all Python deps of the build

scripts (lxml + Pillow) come from python3-lxml / python3-pil above -- no pip

install is needed (and bare "pip install" is refused on Ubuntu 23.04+).

2.install vcpkg:

• git clone https://www.github.com/microsoft/vcpkg.git
• cd vcpkg
• ./bootstrap-vcpkg.sh

3.download cdroid source code:

• cd ~
• git clone http://www.gitee.com/houstudio/cdroid.git
  

4. install cdroid supported toolchain's patch

• cp cdroid/scripts/vcpkgpatch4cdroid.tar.gz vcpkg/
• cd vcpkg
• tar -zxvf vcpkgpatch4cdroid.tar.gz

5.install cdroid deplibs:

• ./cdroid_install_libs.sh --triplet=x64-linux-dynamic
  

6.build cdroid:

• cd cdroid
• ./build.sh --build=debug
• cd outX64-Debug
• make -j

7.prepare system and app resource

• No manual copy in the build tree: cdroid.pak / widgetex.pak are generated at the out-root and every app locates them automatically (probe order: the executable's directory and its parents, then cwd, then /usr/share/cdroid and /opt/cdroid).
• An app's own <app>.pak is picked up beside its binary (override the directory with --data).
• For device installs put cdroid.pak / widgetex.pak under /usr/share/cdroid (or /opt/cdroid).

8.build & run samples(in directory outX64-Debug)

• each sample is its own make target, e.g. make buttons then run apps/samples/buttons
• make alarmmanager && apps/samples/alarmmanager (AlarmManager demo)