Added in [API level 27](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) Summary: [Inherited Constants](https://developer.android.com/reference/android/service/autofill/LuhnChecksumValidator#inhconstants) \| [Fields](https://developer.android.com/reference/android/service/autofill/LuhnChecksumValidator#lfields) \| [Ctors](https://developer.android.com/reference/android/service/autofill/LuhnChecksumValidator#pubctors) \| [Methods](https://developer.android.com/reference/android/service/autofill/LuhnChecksumValidator#pubmethods) \| [Inherited Methods](https://developer.android.com/reference/android/service/autofill/LuhnChecksumValidator#inhmethods)

# LuhnChecksumValidator

*** ** * ** ***

[Kotlin](https://developer.android.com/reference/kotlin/android/service/autofill/LuhnChecksumValidator "View this page in Kotlin") \|Java


`
public

final

class
LuhnChecksumValidator
`


`

extends https://developer.android.com/reference/java/lang/Object


`

`


implements

https://developer.android.com/reference/android/os/Parcelable,

https://developer.android.com/reference/android/service/autofill/Validator


`

|---|---|
| [java.lang.Object](https://developer.android.com/reference/java/lang/Object) ||
| ↳ | android.service.autofill.LuhnChecksumValidator |

<br />

*** ** * ** ***

Validator that returns `true` if the number created by concatenating all given fields
pass a Luhn algorithm checksum. All non-digits are ignored.

See `https://developer.android.com/reference/android/service/autofill/SaveInfo.Builder#setValidator(android.service.autofill.Validator)` for examples.

## Summary

| ### Inherited constants |
|---|
| From interface `https://developer.android.com/reference/android/os/Parcelable` |---|---| | `int` | `https://developer.android.com/reference/android/os/Parcelable#CONTENTS_FILE_DESCRIPTOR` Descriptor bit used with `https://developer.android.com/reference/android/os/Parcelable#describeContents()`: indicates that the Parcelable object's flattened representation includes a file descriptor. | | `int` | `https://developer.android.com/reference/android/os/Parcelable#PARCELABLE_WRITE_RETURN_VALUE` Flag for use with `https://developer.android.com/reference/android/os/Parcelable#writeToParcel(android.os.Parcel,%20int)`: the object being written is a return value, that is the result of a function such as "`Parcelable someFunction()`", "`void someFunction(out Parcelable)`", or "`void someFunction(inout Parcelable)`". | |

| ### Fields ||
|---|---|
| ` public static final https://developer.android.com/reference/android/os/Parcelable.Creator<https://developer.android.com/reference/android/service/autofill/LuhnChecksumValidator>` | `https://developer.android.com/reference/android/service/autofill/LuhnChecksumValidator#CREATOR` |

| ### Public constructors ||
|---|---|
| ` https://developer.android.com/reference/android/service/autofill/LuhnChecksumValidator#LuhnChecksumValidator(android.view.autofill.AutofillId[])(https://developer.android.com/reference/android/view/autofill/AutofillId ids) ` Default constructor. |

| ### Public methods ||
|---|---|
| ` int` | ` https://developer.android.com/reference/android/service/autofill/LuhnChecksumValidator#describeContents()() ` Describe the kinds of special objects contained in this Parcelable instance's marshaled representation. |
| ` https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/android/service/autofill/LuhnChecksumValidator#toString()() ` Returns a string representation of the object. |
| ` void` | ` https://developer.android.com/reference/android/service/autofill/LuhnChecksumValidator#writeToParcel(android.os.Parcel,%20int)(https://developer.android.com/reference/android/os/Parcel parcel, int flags) ` Flatten this object in to a Parcel. |

| ### Inherited methods |
|---|---|
| From class ` https://developer.android.com/reference/java/lang/Object ` |---|---| | ` https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/Object#clone()() ` Creates and returns a copy of this object. | | ` boolean` | ` https://developer.android.com/reference/java/lang/Object#equals(java.lang.Object)(https://developer.android.com/reference/java/lang/Object obj) ` Indicates whether some other object is "equal to" this one. | | ` void` | ` https://developer.android.com/reference/java/lang/Object#finalize()() ` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. | | ` final https://developer.android.com/reference/java/lang/Class<?>` | ` https://developer.android.com/reference/java/lang/Object#getClass()() ` Returns the runtime class of this `Object`. | | ` int` | ` https://developer.android.com/reference/java/lang/Object#hashCode()() ` Returns a hash code value for the object. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#notify()() ` Wakes up a single thread that is waiting on this object's monitor. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#notifyAll()() ` Wakes up all threads that are waiting on this object's monitor. | | ` https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/java/lang/Object#toString()() ` Returns a string representation of the object. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#wait(long,%20int)(long timeoutMillis, int nanos) ` Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*, or until a certain amount of real time has elapsed. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#wait(long)(long timeoutMillis) ` Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*, or until a certain amount of real time has elapsed. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#wait()() ` Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*. | ||
| From interface ` https://developer.android.com/reference/android/os/Parcelable ` |---|---| | ` abstract int` | ` https://developer.android.com/reference/android/os/Parcelable#describeContents()() ` Describe the kinds of special objects contained in this Parcelable instance's marshaled representation. | | ` abstract void` | ` https://developer.android.com/reference/android/os/Parcelable#writeToParcel(android.os.Parcel,%20int)(https://developer.android.com/reference/android/os/Parcel dest, int flags) ` Flatten this object in to a Parcel. | ||

## Fields

### CREATOR

Added in [API level 27](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static final Creator<LuhnChecksumValidator> CREATOR
```

<br />

<br />

## Public constructors

### LuhnChecksumValidator

Added in [API level 27](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public LuhnChecksumValidator (AutofillId... ids)
```

Default constructor.

<br />

| Parameters ||
|---|---|
| `ids` | `AutofillId`: id of fields that comprises the number to be checked. This value cannot be `null`. <br /> |

## Public methods

### describeContents

Added in [API level 27](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public int describeContents ()
```

Describe the kinds of special objects contained in this Parcelable
instance's marshaled representation. For example, if the object will
include a file descriptor in the output of `https://developer.android.com/reference/android/os/Parcelable#writeToParcel(android.os.Parcel,%20int)`,
the return value of this method must include the
`https://developer.android.com/reference/android/os/Parcelable#CONTENTS_FILE_DESCRIPTOR` bit.

<br />

| Returns ||
|---|---|
| `int` | a bitmask indicating the set of special object types marshaled by this Parcelable object instance. Value is either `0` or - `https://developer.android.com/reference/android/os/Parcelable#CONTENTS_FILE_DESCRIPTOR` |

### toString

Added in [API level 27](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public String toString ()
```

Returns a string representation of the object.

<br />

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/String` | a string representation of the object. <br /> |

### writeToParcel

Added in [API level 27](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public void writeToParcel (Parcel parcel, 
                int flags)
```

Flatten this object in to a Parcel.

<br />

| Parameters ||
|---|---|
| `parcel` | `Parcel`: The Parcel in which the object should be written. This value cannot be `null`. <br /> |
| `flags` | `int`: Additional flags about how the object should be written. May be 0 or `https://developer.android.com/reference/android/os/Parcelable#PARCELABLE_WRITE_RETURN_VALUE`. Value is either `0` or a combination of the following: - `https://developer.android.com/reference/android/os/Parcelable#PARCELABLE_WRITE_RETURN_VALUE` |