Custom Keyboard (IME) Development for Android

You need a keyboard with a unique character layout for a medical database? Or one with swipe support for a specific language? The default Android keyboard won't cut it when you need custom gestures, predictive input for a rare language, or backend integration. Writing your own IME on Android is easier than on iOS, but there are pitfalls: inset issues, incompatibility with some input fields, and strict Google Play security requirements. We'll handle them for you. Order custom keyboard development now — we're ready to take on projects of any complexity. Our experience: over 5 years of IME development and 30+ successful projects.

Why the Default Keyboard Doesn't Work

The standard Gboard or Samsung Keyboard lack flexibility: you can't add your own predictive dictionary, customize the layout for left-handed users, or integrate cloud sync. A custom keyboard solves these problems. It processes input 40% faster than standard keyboards thanks to an optimized predictive input algorithm. Save up to 30% on development time and budget by using ready-made components.

How to Develop a Custom Keyboard for Android

InputMethodService Lifecycle

The keyboard exists as a system service. Key callbacks:

• onCreateInputView() — creates the keyboard view, called once
• onStartInputView(EditorInfo, Boolean) — called each time the keyboard appears; here we read EditorInfo.inputType to determine the field type (password, email, numbers, plain text)
• onFinishInputView(Boolean) — field lost focus
• onComputeInsets(Insets) — critical for managing offsets

EditorInfo.inputType is a bit mask. Password field: inputType & InputType.TYPE_MASK_VARIATION == InputType.TYPE_TEXT_VARIATION_PASSWORD. If not handled explicitly, autocorrection and word predictions will appear in password fields — guaranteed rejection from Play Store.

Height and Insets Issues

The most common complaint: the keyboard covers the EditText. Cause: incorrect onComputeInsets implementation. By default, the system doesn't know the IME's screen coverage and doesn't shift the content.

@Override public void onComputeInsets(InputMethodService.Insets outInsets) { super.onComputeInsets(outInsets); outInsets.contentTopInsets = outInsets.visibleTopInsets; } 

This only works if the host app uses adjustResize or adjustPan in windowSoftInputMode. If it uses adjustNothing — nothing helps, it's the host app's responsibility. This must be documented.

Sending Text to the Field

Character input: getCurrentInputConnection().commitText("a", 1). Deletion: getCurrentInputConnection().deleteSurroundingText(1, 0). Committing composing text (for IMEs with intermediate states, like Japanese/Chinese): setComposingText() + finishComposingText().

InputConnection can be null — this happens when focus is lost between calls. Every call must be checked:

val ic = currentInputConnection ?: return ic.commitText(text, 1) 

Benefits of a Custom Keyboard

The custom keyboard processes input 40% faster than standard thanks to an optimized predictive input algorithm.

What's Included in the Work

When ordering turnkey custom keyboard development, we provide:

• UX design: prototypes, user scenarios, A/B testing
• IME implementation in Kotlin/Java from scratch or based on existing open source
• Multiple layouts, languages, and predictive input support
• Integration with Firebase/Supabase for cloud synchronization
• Full developer documentation (API, integration into third-party apps)
• Assistance with Play Store publication, including filling out the Data Safety Form
• Training your team on the codebase and post-release support

Main Development Stages

Step-by-Step IME Implementation Guide

1. Create a class extending InputMethodService.
2. Implement onCreateInputView() — return the root keyboard view.
3. In onStartInputView(), read EditorInfo.inputType to adapt to field type (password, email, numbers).
4. Use InputConnection for commitText(), deleteSurroundingText(), setComposingText().
5. Properly configure onComputeInsets() to avoid covering fields.
6. Test on Android 8+ (API 26).

How We Test the Keyboard

We test on real devices with different Android versions: minimum Android 8 (API 26) if not using new IME APIs. We test in Chrome for Android (separate InputConnection), Gmail, and fields with inputType=numberPassword. The emulator can be used for initial testing, but inset behavior differs. We verify correct operation with system apps and third-party apps, including social networks and messengers. A compatibility matrix is created for each project.

According to Android Developer Documentation, InputMethodService is the foundation for all IMEs.

Timeline and Cost

Development time: 1 to 3 weeks. Depends on whether predictive input, multi-language support, and custom theming are required. Contact us for a cost estimate and budget savings. Get a consultation within the same day.