To add the library to your project:

• add these lines to your root project's build.gradle file

allprojects {
  repositories {
    ...
    maven { url 'https://jitpack.io' }
  }
}

• add these lines to the dependencies block in your module's build.gradle file

dependencies {
        compile 'com.github.thenixan:android-regexp-formatter:v0.0.+'
}

Library allows you to validate the input of the Android's default implementation of EditText via the TextWatcher interface. All you have to do is the create an instance of the RegExpFormatter class using it's constructor by passing it the regular expression of the valid input.

For example you want your users to enter some kind of code that look like 123-456. It means it's valid only if it consists of two blocks of three digits divided by - sign. Regular expression for that input is \d{3}-\d{3}.

Declare your formatter as the Acitivty's variable:

val regExpFormatter = RegExpFormatter("\\d{3}-\\d{3}")

After the setContentView you should set your regExpFormatter as the TextWatcher for the target EditText:

(findViewById(R.id.test_edit) as (EditText)).addTextChangedListener(regExpFormatter)

Optionally you can provide inputType for the EditText to set the proper keyboard type:

(findViewById(R.id.test_edit) as (EditText)).setRawInputType(regExpFormatter.inputType)

Also you can check if the input is correct or not:

if (regExpFormatter.check((findViewById(R.id.test_edit) as (EditText)).text.toString())) {
    // Do something
}

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Possible formatting variants:

• \d+ – at least one digit
• \w* - unlimited length of characters
• [A-Z0-9]{2,4} - two, three or four capital letters or digits

---

Examples:

Mask: asd\d{3}asd Input: 000 Result: asd000asd

Mask: asd\w{3} Input: www Result: asdwww

Mask: asdw\w{3} Input: www Result: asdwww

Mask: asdw\w{3} Input: asd Result: asd

Mask: \d{2}12\d{2,4} Input: 9999 Result: 991299

Mask: \d{1,2}test Input: 1t2 Result: 1test