Why Android soft keyboard omits (delete) letters when number or symbol tapped?

Question

I have Android soft keyboard which switch between two languages. Each language has it's own layout (xml). The English language is working but Arabic language has bug. When I enter Arabic letters and immediate after pressing number or symbol remove the letters.

private void handleCharacter(int primaryCode, int[] keyCodes) {
    if (isInputViewShown()) {
        if (mInputView.isShifted()) {
            primaryCode = Character.toUpperCase(primaryCode);
        }
    }
    if (isAlphabet(primaryCode) && mPredictionOn) {
        mComposing.append((char) primaryCode);
        getCurrentInputConnection().setComposingText(mComposing, 1);
        updateShiftKeyState(getCurrentInputEditorInfo());
        updateCandidates();

    }

    getCurrentInputConnection().commitText(
                String.valueOf((char) primaryCode), 1);
}

@Override public void onFinishInput() {
    super.onFinishInput();

    // Clear current composing text and candidates.
    mComposing.setLength(0);
    updateCandidates();

    // We only hide the candidates window when finishing input on
    // a particular editor, to avoid popping the underlying application
    // up and down if the user is entering text into the bottom of
    // its window.
    setCandidatesViewShown(false);

    mCurKeyboard = mQwertyKeyboard;
    if (mInputView != null) {
        mInputView.closing();
    }
}
@Override public void onUpdateSelection(int oldSelStart, int oldSelEnd,
        int newSelStart, int newSelEnd,
        int candidatesStart, int candidatesEnd) {
    super.onUpdateSelection(oldSelStart, oldSelEnd, newSelStart, newSelEnd,
            candidatesStart, candidatesEnd);

    // If the current selection in the text view changes, we should
    // clear whatever candidate text we have.
    if (mComposing.length() > 0 && (newSelStart != candidatesEnd
            || newSelEnd != candidatesEnd)) {
        mComposing.setLength(0);
        updateCandidates();
        InputConnection ic = getCurrentInputConnection();
        if (ic != null) {
            ic.finishComposingText();
        }
    }
}
private void commitTyped(InputConnection inputConnection) {
    if (mComposing.length() > 0) {
        inputConnection.commitText(mComposing, mComposing.length());
        mComposing.setLength(0);
        updateCandidates();
    }
}

/**
 * Helper to update the shift state of our keyboard based on the initial
 * editor state.
 */
private void updateShiftKeyState(EditorInfo attr) {
    if (attr != null 
            && mInputView != null && mQwertyKeyboard == mInputView.getKeyboard()) {
        int caps = 0;
        EditorInfo ei = getCurrentInputEditorInfo();
        if (ei != null && ei.inputType != InputType.TYPE_NULL) {
            caps = getCurrentInputConnection().getCursorCapsMode(attr.inputType);
        }
        mInputView.setShifted(mCapsLock || caps != 0);
    }
}

/**
 * Helper to determine if a given character code is alphabetic.
 */
private boolean isAlphabet(int code) {
    if (Character.isLetter(code)) {
        return true;
    } else {
        return false;
    }
}

Let me know if more code is required. I also checked the related question on stackoverflow regarding this question and it only helped to fix the English language.

The Arabic is RTL, and it works fine when typing English and Arabic, but has problem with numbers and symbols.

Answer 1

I solved the problem by replacing the handlerCharacter method with the following:

private void handleCharacter(int primaryCode, int[] keyCodes) {
    if (isInputViewShown()) {
        if (mInputView.isShifted()) {
            primaryCode = Character.toUpperCase(primaryCode);
        }
    }
    if (isAlphabet(primaryCode) && mPredictionOn) {
        mComposing.append((char) primaryCode);
        getCurrentInputConnection().setComposingText(mComposing, 1);
        updateShiftKeyState(getCurrentInputEditorInfo());
        updateCandidates();
    }
    else {
        mComposing.append((char) primaryCode);
        getCurrentInputConnection().setComposingText(mComposing, 1);
    }

}