Convert unicode value to KeyEvent constant in OnKeyboardActionListener.onKey

Question

I am new to Android development and currently programming an Input Method Editor (IME) for the Google Android operating system (API level 11 == version 3.0).

(The following code is simplified to point out the problem.)

I am able to send characters to the underlying application via:

@Override
public final void onKey(final int primaryCode, final int[] keyCodes) {    
    this.getCurrentInputConnection().commitText(String.valueOf((char) primaryCode), 1);
}

Now I want to send special key combinations (e.g. SHIFT + A). The Java code to reach this goal is the following (for the special case of SHIFT + A):

@Override
public final void onKey(final int primaryCode, final int[] keyCodes) {
        long eventTime = SystemClock.uptimeMillis();    
        this.sendDownKeyEvent(KeyEvent.KEYCODE_SHIFT_LEFT);

        KeyEvent keyEvent = new KeyEvent(
            eventTime,
            eventTime,
            KeyEvent.ACTION_DOWN,
            KeyEvent.KEYCODE_A, // ToDo: How to convert primaryCode to the corresponding KeyEvent constant?
            KeyEvent.META_SHIFT_ON
        );
        this.getCurrentInputConnection().sendKeyEvent(keyEvent);
}

public final void sendDownKeyEvent(final int keyEventCode) {
    InputConnection ic = this.getCurrentInputConnection();
    if (ic != null) {
        long eventTime = SystemClock.uptimeMillis();
        ic.sendKeyEvent(
            new KeyEvent(
                eventTime, eventTime,
                KeyEvent.ACTION_DOWN, keyEventCode, 0, 0, 0, 0,
                KeyEvent.FLAG_SOFT_KEYBOARD | KeyEvent.FLAG_KEEP_TOUCH_MODE
            )
        );
    }
}

The comment in the previous code sample shows my problem. To send key combinations via a KeyEvent object I have to convert the variable primaryCode (which contains the unicode code of the pressed key) to a constant of the class KeyEvent.

Does a convenient method for this case exist already or do I have to write it by myself? In general: Is the above solution to send combinations of keys elegant or do better approaches exist? (It isn't easy to find examples for Android IMEs on the Internet...)

Thank you in advance!

Answer 1

A little late it seems. I found the following solution to the same issue, translating a primaryCodeinto a sequence of KeyEvents.

The solution involves loading a KeyCharacterMap and using its KeyCharacterMap.getEvents() method to get a KeyEvent list that can reproduce the character.

//This snippet tries to translate the glyph 'primaryCode' into key events

//retrieve the keycharacter map from a keyEvent (build yourself a default event if needed)
KeyCharacterMap myMap=KeyCharacterMap.load(event.getDeviceId()); 

//event list to reproduce glyph
KeyEvent evs[]=null;

//put the primariCode into an array
char chars[]=new char[1];
chars[0]=primaryCode;

// retrieve the key events that could have produced this glyph
evs=myMap.getEvents(chars);

if (evs != null){
    // we can reproduce this glyph with this key event array
    for (int i=0; i< evs.length;i++) MySendKeyEventHelperMethod(evs[i]);
}
else { /* could not find a way to reproduce this glyph */ }