¿In what case do I have to use which of them?
In google documentation says:
textMultiLine
Can be combined with text and its variations to allow multiple lines of text in the field. If this flag is not set, the text field will be constrained to a single line.
textLongMessage Text that is the content of a long message.
But I wish use an EditText which will is multiline and with the content of a long message.
You can use multiple tags e.g.