imgui-mirror/examples/example_android_vulkan/README.md

Android Vulkan + Dear ImGui Example

A standalone Android application that renders Dear ImGui using the Vulkan graphics API via NativeActivity. No Java/Kotlin code required — pure C++.

Features

• Pure native — NativeActivity with android_native_app_glue, no Java layer
• Vulkan rendering — Instance, Device, Swapchain, RenderPass all managed via ImGui helpers
• Touch input — imgui_impl_android.h handles multi-touch natively
• Orientation handling — Swapchain auto-rebuilds on rotation
• Modular code — Clean separation into vulkan_helper.h, menu.h, and main.cpp

Requirements

Requirement	Version
Android Studio	2024.x+
Android NDK	29.0.x
CMake	3.22.1
Min SDK	26 (Android 8.0)
Target SDK	36
ABI	arm64-v8a

Project Structure

app/src/main/
├── AndroidManifest.xml          ← NativeActivity config
└── cpp/
    ├── CMakeLists.txt           ← Build config (links imgui + vulkan)
    ├── main.cpp                 ← Entry point: lifecycle (Init, MainLoopStep, Shutdown)
    ├── vulkan_helper.h          ← vkh:: namespace — Vulkan setup, rendering, cleanup
    └── menu.h                   ← menu:: namespace — Your ImGui UI (edit this!)

ImGui sources are referenced from the parent imgui directory (../../../../../../).

Build & Run

# Build
./gradlew assembleDebug

# Build + install on connected device
./gradlew installDebug

# View logs
adb logcat -s ImGuiVulkan

Customizing the UI

Edit menu.h — the menu::Draw() function is called every frame:

namespace menu
{
    inline void Draw()
    {
        ImGui::Begin("My App");
        ImGui::Text("Hello!");
        // Add your widgets here...
        ImGui::End();
    }
}

All ImGui widgets work out of the box: windows, buttons, sliders, checkboxes, color pickers, popups, combo boxes, etc.

How It Works

1. android_main() — NativeActivity entry point, runs the event + render loop
2. Init() — Called on APP_CMD_INIT_WINDOW:
   • Creates VkInstance, VkDevice, VkQueue
   • Creates VkSurfaceKHR from ANativeWindow
   • Sets up swapchain, render pass, framebuffers via ImGui_ImplVulkanH_Window
   • Initializes Dear ImGui with imgui_impl_android + imgui_impl_vulkan
3. MainLoopStep() — Called every frame:
   • Checks for orientation/size changes → rebuilds swapchain if needed
   • Calls ImGui_ImplVulkan_NewFrame() + ImGui_ImplAndroid_NewFrame()
   • Calls menu::Draw() for your UI
   • Records Vulkan command buffer + presents
4. Shutdown() — Called on APP_CMD_TERM_WINDOW, cleans up everything

Key Files Reference

File	What to modify
menu.h	UI widgets — add buttons, sliders, windows
vulkan_helper.h	Vulkan settings (present mode, min image count)
main.cpp	App lifecycle, ImGui style/scaling
AndroidManifest.xml	App name, permissions, orientation

License

This example uses Dear ImGui which is licensed under the MIT License.