I do not understand how best to do the implementation of the task in InputFilter ?
There is an EditText field. It is necessary to enter the time in the 24-hour format.
I need to make the colon between the numbers of hours and minutes always always stand , like this:
"__:__" -> "1_:__" -> "12:__" -> "12:3_" -> "12:34"
And the removal to go in this order:
"12:34" -> "12:3_" -> "12:__" -> "1_:__" -> "__:__"
Now I enter these numbers and substitute ":" myself.
I found solutions here, like checking in TextWatcher add a colon programmatically, upon reaching the line length = 2, but I don’t need it. It is necessary that the colon always stands in EditText and when entering the first 2 numbers, the pointer jumped over this colon and I could add the remaining 2 numbers. And you could also delete numbers without deleting the colon.
As I understand it, you need to initially write two spaces in the EditText , a colon and two more spaces so that the colon is in the center (the text is aligned inside the input field), then somehow enter and replace the space with a number when entering text.
Now I have an InputFilter implementation with input numbers from "00:00" to "29:59":
timeFilter = new InputFilter() { // фильтр ввода. позволяет вводить от 00:00 до 23:59 @Override public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) { if (source.length() > 1 && !doneOnce) { source = source.subSequence(source.length() - 1, source.length()); if (source.charAt(0) >= '0' && source.charAt(0) <= '2') { // первый символ может быть 0,1,2 doneOnce = true; //флаг первого символа в editText return source; } else { return ""; //остальные символы будут зануляться } } if (source.length() == 0) { return null;// deleting, keep original editing } String result = ""; result += dest.toString().substring(0, dstart); result += source.toString().substring(start, end); result += dest.toString().substring(dend, dest.length()); if (result.length() > 5) { // если в поле 5 символов( 1 2 : 4 5 ) return "";// не разрешать добавлять символы } boolean allowEdit = true; char c; if (result.length() > 0) { c = result.charAt(0); allowEdit &= (c >= '0' && c <= '2'); } if (result.length() > 1) { c = result.charAt(1); if (result.charAt(0) == '0' || result.charAt(0) == '1') allowEdit &= (c >= '0' && c <= '9'); else allowEdit &= (c >= '0' && c <= '3'); } if (result.length() > 2) { c = result.charAt(2); allowEdit &= (c == ':'); } if (result.length() > 3) { c = result.charAt(3); allowEdit &= (c >= '0' && c <= '5'); } if (result.length() > 4) { c = result.charAt(4); allowEdit &= (c >= '0' && c <= '9'); } return allowEdit ? null : ""; } }; 
