TextWatcher.kt

textWatcher(object : TextWatcher {
                        private val mArray_pos: IntArray = intArrayOf(3)
                        private var mBeforeTextChanged: CharSequence = ""
                        private val mAppentText: String = "-"

                        override fun afterTextChanged(s: Editable) {
                            for (i in mArray_pos.indices) {
                                if (mBeforeTextChanged.length - mAppentText.length * i == mArray_pos[i] - 1 && s.length - mAppentText.length * i == mArray_pos[i]) {
                                    s.append(mAppentText)

                                    break
                                }

                                if (mBeforeTextChanged.length - mAppentText.length * i == mArray_pos[i] && s.length - mAppentText.length * i == mArray_pos[i] + 1) {
                                    val idx_start = mArray_pos[i] + mAppentText.length * i
                                    val idx_end = Math.min(idx_start + mAppentText.length, s.length)

                                    val sub = s.toString().substring(idx_start, idx_end)

                                    if (sub != mAppentText) {
                                        s.insert(s.length - 1, mAppentText)
                                    }

                                    break
                                }

                                if (mAppentText.length > 1 &&
                                    mBeforeTextChanged.length - mAppentText.length * i == mArray_pos[i] + mAppentText.length &&
                                    s.length - mAppentText.length * i == mArray_pos[i] + mAppentText.length - 1
                                ) {
                                    val idx_start = mArray_pos[i] + mAppentText.length * i
                                    val idx_end = Math.min(idx_start + mAppentText.length, s.length)

                                    s.delete(idx_start, idx_end)

                                    break
                                }

                                if (s.toString().isNotBlank() && s.toString().length == 7) {
                                    viewModel.setStateProp(claimCode = s.toString())
                                }
                            }
                        }

                        override fun beforeTextChanged(
                            s: CharSequence, start: Int,
                            count: Int, after: Int
                        ) {
                            mBeforeTextChanged = s.toString()
                        }

                        override fun onTextChanged(
                            s: CharSequence, start: Int,
                            before: Int, count: Int
                        ) {
                        }
                    })