How to check if a string follow mm/DD/yyyy format?-CodePudding

Good day. I have an android app where I allow the user to input their birthday into the edit texts.

Edit text has the following attributes:

<com.google.android.material.textfield.TextInputLayout
                style="@style/CustomOutlinedBox"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                app:boxBackgroundColor="@color/white"
                android:hint="Birthday MM/DD/YYYY">
                <com.google.android.material.textfield.TextInputEditText
                    android:id="@ id/et_new_member_birthday"
                    android:textColor="@color/black"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:textSize="16sp"
                    android:inputType="date"/>
            </com.google.android.material.textfield.TextInputLayout>

How can I check if their input follows the mm/DD/yyyy format?

Editted: I tried adding the following block, unfortunately, it crashed my app.

private fun isDateValid(date: String): Boolean {
        val format = "MM/dd/yyyy"
        return try {
            val formatter = DateTimeFormatter.ofPattern(format)
            val convertedDate = LocalDate.parse(date, formatter)
            Toast.makeText(this, "Date is $convertedDate", Toast.LENGTH_SHORT).show()


            true
        } catch (e: ParseException) {
            Toast.makeText(this, "Error parsing date.", Toast.LENGTH_LONG).show()
            false
        }
    }

And I'm calling this method via Activity:

val etBirthday = binding.etNewMemberBirthday.text.toString()

...

TextUtils.isEmpty(etBirthday) || isDateValid(etBirthday)->{
                showErrorSnackBar(binding.root, "Please input a valid date.", true)
                false
            }
...

CodePudding user response：

You can simply use built in date picker dialog when ever user will click on edit text open date picker dialog user can easily select date and it can be of any pattern.


    et_new_member_birthday.setOnClickListener {
                val c = Calendar.getInstance()
                val year = c.get(Calendar.YEAR)
                val month = c.get(Calendar.MONTH)
                val day = c.get(Calendar.DAY_OF_MONTH)
    
                val dpd = DatePickerDialog(
                    mActivity,
                    R.style.DateDialogTheme,
                    { _, year, monthOfYear, dayOfMonth ->
                        val cal = Calendar.getInstance()
    
                        cal.set(Calendar.YEAR, year)
                        cal.set(Calendar.MONTH, monthOfYear)
                        cal.set(Calendar.DAY_OF_MONTH, dayOfMonth)
    
                        val pattern = "MM/dd/yyyy"
                        val simpleDateFormat = SimpleDateFormat(pattern)
                        val date = simpleDateFormat.format(cal.time)
                        et_new_member_birthday.setText(date)
                        
                    },
                    year,
                    month,
                    day
                )
                dpd.show()
    }