forntoh/android-livedata-validation

DataBinding ViewModel form validation library for Android ♻

Support/Features

• Supports TextView, EditText, AppCompatEditText, TextInputEditText, TextInputLayout and CheckBox
• Combine different types of error messages (String, StringRes, Number...)
• Validation is done in view model using databinding

🔽 Getting started

Download

Gradle:

implementation 'com.forntoh:android-livedata-validation:1.2.0'

Usage

1. Make your ViewModel to extend ValidatorViewModel

class MainViewModel : ValidatorViewModel() {
  ...
  val firstName = MutableLiveData("")
  val lastName = MutableLiveData("")
  ...

2. Initialize the validator in your Fragment/Activity

LiveDataValidator(requireContext()).observe {
    lifecycleOwner(viewLifecycleOwner)
    viewModel(viewModel)
    attachTo(binding.root)
}

3. Override the validate function

Add rules to the validator

/**
 * Add LiveData and Rules to widget
 *
 * @param data    LiveData holding the info to be validated
 * @param viewId  Widget ID on which validation will be applied
 * @param rule    Rules to applied on Widget data
 */
fun <T> addField(data: LiveData<T>, @IdRes viewId: Int, vararg rule: BaseRule)

example

override fun validate() {
    validator
        .addField(firstName, R.id.firstNameEt, NotEmptyRule("First name required"))
        .addField(
            phoneNumber, R.id.phoneNumberEt,
            NumberRule("Must be numbers"),
            NotEmptyRule("Please enter Phone Number"),
            LengthRangeRule.Builder()
                .minLength(3)
                .maxLength(10)
                .error("Please enter valid Phone Number")
                .build()
        )
        .addField(
            email, R.id.emailEtLyt,
            NotEmptyRule("Please enter Email"),
            EmailRule(R.string.error_invalid_email)
        )
        .addField(
            password, R.id.passwordEtLyt,
            NotEmptyRule("Please enter Password"),
            PasswordRule(PasswordPattern.ALPHA_NUMERIC, "Please provide strong Password")
        )
        .addField(
            confirmPassword,
            R.id.confirmPasswordEtLyt,
            NotEmptyRule("Please enter Password"),
            EqualRule(password, "Password and Confirm password must match")
        )
        .addField(haveAcceptTerms, R.id.termsOfUseCB, CheckedRule("Accept terms of use"))
}

4. Bind fields to layout

android:text="@={viewmodel.firstName}"

You can also bind the state of the validation to a button by doing the following

android:enabled="@{viewmodel.validator.isDataValid}"

Available Rules📏:

🔃 FunctionRule 🌟

// NEW in 1.2.0: YOU CAN USE THIS FOR EVERYTHING 🤩🤩
// 
// valueHolder: MutalbeLiveData<String>
.addField(
    valueHolder, R.id.functionTIL,
    FunctionRule("Function returned false") {
        val isCorrect = // Do your validation here
        return@FunctionRule isCorrect
    }
)

✔ CheckedRule (Used with CheckBox only)

// haveAcceptTerms: MutalbeLiveData<Boolean>
addField(haveAcceptTerms, R.id.termsOfUseCB, CheckedRule("Accept terms of use"))

📧 EmailRule

// email: MutalbeLiveData<String>
addField(email, R.id.emailEtLyt, EmailRule("Please enter valid Email"))

⏸ EqualRule

// confirmPassword,password: MutalbeLiveData<String>
addField(confirmPassword, R.id.confirmPasswordEtLyt,
         EqualRule(password, "Password and Confirm password must match"))

🔢 NumberRule

// phoneNumber: MutalbeLiveData<String>
addField(phoneNumber, R.id.phoneNumberEt, NumberRule("Must be numbers"))

🆚 NumberCompareRule

// amount: MutalbeLiveData<String>
// balance: MutalbeLiveData<Number> = MutalbeLiveData(0)
addField(
    amount, R.id.amountTIL,
    NumberCompareRule(Is.GREATER_THAN, balance, "Must be above zero")
)

You can also append multiple error messages

// amount: MutalbeLiveData<String>
// balance: MutalbeLiveData<Number>
//
// R.string.error_amount_more_than = "is more than amount present in"
addField(
    amount, R.id.amountTIL,
    NumberCompareRule(Is.GREATER_THAN, balance,
     /*error args*/ amount, R.string.error_amount_more_than, "Balance:", balance)
)
// Result: XXX is more than amount present in Balance: YYY

🚮 NonEmptyRule

// firstName: MutalbeLiveData<String>
addField(firstName, R.id.firstNameEt, NotEmptyRule("First name required"))

🔑 PasswordRule

// Password can have alphanumeric and symbol characters
addField(password, R.id.passwordEtLyt, PasswordRule("Please provide strong Password"))

// Password should be alphanumeric only eg abc123
addField(password, R.id.passwordEtLyt, PasswordRule(PasswordPattern.ALPHA_NUMERIC,
"Please provide strong Password"))

#️⃣ RegexRule

addField(usernameEditText, RegexRule(RegexRule.USERNAME_PATTERN, "Please enter valid Username"))

addField(usernameEditText, RegexRule("^[a-zA-Z0-9_-]{3,16}",  "Please enter valid Username"))

License

Copyright 2020, Forntoh Thomas

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.