Create Passcode view in Android

Question

I want to create view in android that reads 4 character pass-code. I want to focus prev element when user press backspace. Is it possible to capture backspace event when selected view is empty?

I Also want to close/hide keyboard after last character is entered. Is it possible?

Answer 1

I have overwritten onKey & onFocusChange functions and used ZeroWidthString("\u200B") to capture Delete Event from Soft Keyboard. Following is the code sniff

@Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
    if(event.getAction() == KeyEvent.ACTION_UP ) {
        TextView tv = (TextView) v;
        if (keyCode == KeyEvent.KEYCODE_DEL){
            if (tv.getText().toString().equalsIgnoreCase(ZeroWidthString))
                moveToPrevField();
            else
                tv.setText(ZeroWidthString);
        }
    }
}

@Override
public void onFocusChange(View v, boolean hasFocus) {
    TextView tv = (TextView) v;
    if (hasFocus) {
        tv.setText(ZeroWidthString);
    }
    else if (tv.getText().toString().equalsIgnoreCase(ZeroWidthString)) {
        tv.setText("");
    }
}