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James Yang
James Yang

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Why you can't type Chinese or Japanese in Android SSH terminals — and how to fix it

#ssh #vibecoding #terminal #ime

A deep dive into TYPE_NULL, InputConnection, and commitText() — and why switching keyboards never helps.

If you've ever opened an SSH client on Android, switched to a Chinese, Japanese, or Korean keyboard, and watched your carefully-composed text simply not appear in the shell — you're not imagining it, and it's not your keyboard's fault. It's a bug in how most terminal apps handle text input, and once you understand it, the fix is obvious.

This post explains the root cause, why it affects far more languages than just Chinese, why changing your IME doesn't help, and how to implement it correctly.

The symptom

You SSH into a server that fully supports UTF-8. You tap the terminal, your keyboard pops up, you switch to Pinyin, you type nihao, the candidate bar shows 你好 — and when you tap it, nothing reaches the terminal. English works fine. The keyboard clearly works in every other app. But in this one, non-English text evaporates.

Two layers of Android text input

To see why, you need to know that Android has two completely different input paths, and a terminal has to deal with both:

  1. Hardware / raw key events — KeyEvents delivered to View.onKeyDown(). This is how a terminal gets Ctrl, Alt, Esc, Tab, arrow keys, function keys — the control keys a shell needs.
  2. The input method (IME) framework — the on-screen keyboard talks to your app through an InputConnection. This is how text is entered, including everything that needs composition: 
   pinyin:   nihao → [candidate bar] → 你好   → commitText("你好")
   japanese: nihongo → にほんご → 日本語        → commitText("日本語")
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The IME never sends a KeyEvent for 你好 — there is no "你好 key." It sends the finished text through InputConnection.commitText(), after showing you a live preview via setComposingText().

The root cause: terminals that behave like a keyboard, not a text field

Terminal apps lean heavily on path #1 because they must — a shell is useless without Ctrl-C, Tab, and Esc. So many implementations take a shortcut and treat the terminal as a keyboard device rather than a real text editor. That shortcut shows up in one of two ways:

Failure mode A: declaring TYPE_NULL 

@Override
public InputConnection onCreateInputConnection(EditorInfo outAttrs) {
    outAttrs.inputType = InputType.TYPE_NULL; // "just give me raw key events"
    return new BaseInputConnection(this, false);
}
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TYPE_NULL tells the IME: this field doesn't accept composed text; send me key events instead. Modern IMEs respond by falling back to a Latin-only, no-composition mode. The Chinese/Japanese candidate machinery is disabled at the source. You can still switch to the Chinese keyboard visually, but it can't compose — so nothing meaningful gets committed.

Failure mode B: ignoring commitText()

Even with a non-null input type, some terminals only wire up KeyEvent handling and never properly handle the InputConnection callbacks. The IME calls commitText("你好"), the app… does nothing with it. The text is dropped on the floor.

Either way, the observable result is identical: English (which arrives as key events) works; anything that arrives via commitText() doesn't.

Why switching keyboards doesn't help

This is the part that trips everyone up. People try Gboard, then Sogou, then Baidu, then iFlytek — same result — and conclude their phone is broken.

But the bug is in the app's InputConnection, not the keyboard. No IME can deliver composed text to a field that declared TYPE_NULL or that throws away commitText(). The keyboard is doing its job correctly; the app refuses to listen.

It's not a "Chinese" problem — it's an IME problem

Because the real issue is the IME text path, the blast radius is huge. Anything that isn't a direct ASCII keypress is affected:

Category Languages Why
Composition + candidate conversion Chinese (Pinyin/Zhuyin), Japanese (kana→kanji) Rely entirely on composing text + candidates
Composition Korean (Hangul), Hindi/Bengali/Tamil, transliteration IMEs Build characters via composition
Non-ASCII Unicode commit Russian, Greek, Arabic, Persian, Hebrew, Thai, Vietnamese, accented French/German/Spanish No candidates, but still delivered via commitText()
Works everywhere English / ASCII Arrives as key events

If you build "Chinese input" and stop there, you've solved a sliver of the actual problem. The correct framing is full Android IME / Unicode input.

How to fix it

The terminal has to serve both input paths at once: keep raw key events for control keys, and implement the InputConnection contract for text.

1. Declare a real text input type (not TYPE_NULL):

@Override
public InputConnection onCreateInputConnection(EditorInfo outAttrs) {
    // A real editable text field, so IMEs enable composition for CJK & friends.
    // NO_SUGGESTIONS avoids autocorrect meddling with commands.
    outAttrs.inputType = InputType.TYPE_CLASS_TEXT
            | InputType.TYPE_TEXT_FLAG_NO_SUGGESTIONS;
    outAttrs.imeOptions = EditorInfo.IME_FLAG_NO_FULLSCREEN
            | EditorInfo.IME_FLAG_NO_EXTRACT_UI;
    return new TerminalInputConnection(this, /* fullEditor = */ true);
}
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A subtle trap: don't reach for TYPE_TEXT_VARIATION_VISIBLE_PASSWORD to "stabilize" the keyboard. Password variations make many CJK IMEs force a Latin-only layout — and on some OEM skins (e.g. MIUI) put the field into a secure mode. NO_SUGGESTIONS alone is enough to stop autocorrect.

2. Handle composing text — but keep it local. The composing (preedit) string is not final; the remote shell has no concept of "text being composed." So draw it yourself at the cursor and only send text on commit:

@Override
public boolean setComposingText(CharSequence text, int newCursorPosition) {
    boolean r = super.setComposingText(text, newCursorPosition);
    updatePreeditOverlay();  // draw the in-progress "nihao"/"にほん" near the cursor
    return r;                // do NOT send to the remote yet
}

@Override
public boolean commitText(CharSequence text, int newCursorPosition) {
    super.commitText(text, newCursorPosition);
    sendToTerminal(getEditable());  // now it's final → send it
    getEditable().clear();
    clearPreeditOverlay();
    return true;
}
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3. Encode by Unicode code point, not char. Java strings are UTF-16; emoji and many CJK extension characters are surrogate pairs. Iterate code points so you don't split them:

void sendToTerminal(CharSequence text) {
    int n = text.length();
    for (int i = 0; i < n; i++) {
        char c = text.charAt(i);
        int cp;
        if (Character.isHighSurrogate(c) && i + 1 < n) {
            cp = Character.toCodePoint(c, text.charAt(++i));
        } else {
            cp = c;
        }
        writeCodePointAsUtf8(cp);  // → SSH
    }
}
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4. Leave the key-event path intact. Ctrl, Alt, Esc, Tab, arrows, Ctrl-C etc. still flow through onKeyDown()/your key handler. The two paths coexist: control keys via KeyEvent, text via InputConnection.

That's the whole fix. The moment the app declares itself a real text field and honors commitText(), every IME — Gboard, Sogou, Baidu, a Hindi or Arabic keyboard — starts working, because you're finally speaking the protocol they've been speaking all along.

One honest caveat: input vs. display

Getting the bytes in is solved by the above. Displaying complex scripts is a separate, older terminal-emulator limitation: CJK wide characters and combining marks are fine, but right-to-left scripts (Arabic, Hebrew) and complex Indic ligatures are typically rendered cell-by-cell, left-to-right, without bidi reordering — in almost every terminal emulator, not just Android ones. So Arabic input reaches your server correctly; it may just look simplified in the terminal view. Worth stating plainly so you're not surprised.

Wrapping up

"I can't type Chinese in my SSH client" is really "this terminal declared TYPE_NULL / ignores commitText()." It's an app bug, not a keyboard problem, and it quietly breaks a dozen writing systems, not one. The fix is to implement Android's InputConnection contract properly while keeping the raw key-event path for control keys.

I hit this exact wall doing "vibe coding" from my phone — running Claude Code and Codex over SSH — so I built *VibeTerm*, an open-source (GPL-3.0) Android SSH terminal with the IME implementation described above, plus tmux-backed reconnection, split-screen, and lock-screen approval for AI agents. (Disclosure: I'm the author.) If you've been fighting this bug, I'd love your feedback.

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