# WindowId

Added in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  
Summary: [Nested Classes](https://developer.android.com/reference/android/view/WindowId#nestedclasses) \| [Inherited Constants](https://developer.android.com/reference/android/view/WindowId#inhconstants) \| [Fields](https://developer.android.com/reference/android/view/WindowId#lfields) \| [Methods](https://developer.android.com/reference/android/view/WindowId#pubmethods) \| [Inherited Methods](https://developer.android.com/reference/android/view/WindowId#inhmethods)  

# WindowId

*** ** * ** ***

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


`
public


class
WindowId
`


`

extends `[Object](https://developer.android.com/reference/java/lang/Object)`


`

`


implements

`[Parcelable](https://developer.android.com/reference/android/os/Parcelable)`


`

|---|-----------------------|
| [java.lang.Object](https://developer.android.com/reference/java/lang/Object) ||
| ↳ | android.view.WindowId |

<br />

*** ** * ** ***

Safe identifier for a window. This currently allows you to retrieve and observe
the input focus state of the window. Most applications will
not use this, instead relying on the simpler (and more efficient) methods available
on [View](https://developer.android.com/reference/android/view/View). This classes is useful when window input interactions need to be
done across processes: the class itself is a Parcelable that can be passed to other
processes for them to interact with your window, and it provides a limited safe API
that doesn't allow the other process to negatively harm your window.

## Summary

|                                                                                                                 ### Nested classes                                                                                                                 ||
|----------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| ` class` | [WindowId.FocusObserver](https://developer.android.com/reference/android/view/WindowId.FocusObserver) Subclass for observing changes to the focus state of an [WindowId](https://developer.android.com/reference/android/view/WindowId). |

|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  ### Inherited constants                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| From interface [android.os.Parcelable](https://developer.android.com/reference/android/os/Parcelable) |-------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `int` | [CONTENTS_FILE_DESCRIPTOR](https://developer.android.com/reference/android/os/Parcelable#CONTENTS_FILE_DESCRIPTOR) Descriptor bit used with [describeContents()](https://developer.android.com/reference/android/os/Parcelable#describeContents()): indicates that the Parcelable object's flattened representation includes a file descriptor.                                                                                                                                            | | `int` | [PARCELABLE_WRITE_RETURN_VALUE](https://developer.android.com/reference/android/os/Parcelable#PARCELABLE_WRITE_RETURN_VALUE) Flag for use with [writeToParcel(Parcel, int)](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 `[Creator](https://developer.android.com/reference/android/os/Parcelable.Creator)`<`[WindowId](https://developer.android.com/reference/android/view/WindowId)`>` | [CREATOR](https://developer.android.com/reference/android/view/WindowId#CREATOR) |

|                                                                                                                                                                                               ### Public methods                                                                                                                                                                                                ||
|-----------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| ` int`                                                                | ` `[describeContents](https://developer.android.com/reference/android/view/WindowId#describeContents())`() ` Describe the kinds of special objects contained in this Parcelable instance's marshaled representation.                                                                                                                     |
| ` boolean`                                                            | ` `[equals](https://developer.android.com/reference/android/view/WindowId#equals(java.lang.Object))`(`[Object](https://developer.android.com/reference/java/lang/Object)` otherObj) ` Comparison operator on two IntentSender objects, such that true is returned then they both represent the same operation from the same package.     |
| ` int`                                                                | ` `[hashCode](https://developer.android.com/reference/android/view/WindowId#hashCode())`() ` Returns a hash code value for the object.                                                                                                                                                                                                   |
| ` boolean`                                                            | ` `[isFocused](https://developer.android.com/reference/android/view/WindowId#isFocused())`() ` Retrieve the current focus state of the associated window.                                                                                                                                                                                |
| ` void`                                                               | ` `[registerFocusObserver](https://developer.android.com/reference/android/view/WindowId#registerFocusObserver(android.view.WindowId.FocusObserver))`(`[WindowId.FocusObserver](https://developer.android.com/reference/android/view/WindowId.FocusObserver)` observer) ` Start monitoring for changes in the focus state of the window. |
| ` `[String](https://developer.android.com/reference/java/lang/String) | ` `[toString](https://developer.android.com/reference/android/view/WindowId#toString())`() ` Returns a string representation of the object.                                                                                                                                                                                              |
| ` void`                                                               | ` `[unregisterFocusObserver](https://developer.android.com/reference/android/view/WindowId#unregisterFocusObserver(android.view.WindowId.FocusObserver))`(`[WindowId.FocusObserver](https://developer.android.com/reference/android/view/WindowId.FocusObserver)` observer) ` Stop monitoring changes in the focus state of the window.  |
| ` void`                                                               | ` `[writeToParcel](https://developer.android.com/reference/android/view/WindowId#writeToParcel(android.os.Parcel,%20int))`(`[Parcel](https://developer.android.com/reference/android/os/Parcel)` out, int flags) ` Flatten this object in to a Parcel.                                                                                   |

| ### Inherited methods |
|-----------------------|---|
| From class ` `[java.lang.Object](https://developer.android.com/reference/java/lang/Object)` ` |--------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | ` `[Object](https://developer.android.com/reference/java/lang/Object)          | ` `[clone](https://developer.android.com/reference/java/lang/Object#clone())`() ` Creates and returns a copy of this object.                                                                                                                                                        | | ` boolean`                                                                     | ` `[equals](https://developer.android.com/reference/java/lang/Object#equals(java.lang.Object))`(`[Object](https://developer.android.com/reference/java/lang/Object)` obj) ` Indicates whether some other object is "equal to" this one.                                             | | ` void`                                                                        | ` `[finalize](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 `[Class](https://developer.android.com/reference/java/lang/Class)`<?>` | ` `[getClass](https://developer.android.com/reference/java/lang/Object#getClass())`() ` Returns the runtime class of this `Object`.                                                                                                                                                 | | ` int`                                                                         | ` `[hashCode](https://developer.android.com/reference/java/lang/Object#hashCode())`() ` Returns a hash code value for the object.                                                                                                                                                   | | ` final void`                                                                  | ` `[notify](https://developer.android.com/reference/java/lang/Object#notify())`() ` Wakes up a single thread that is waiting on this object's monitor.                                                                                                                              | | ` final void`                                                                  | ` `[notifyAll](https://developer.android.com/reference/java/lang/Object#notifyAll())`() ` Wakes up all threads that are waiting on this object's monitor.                                                                                                                           | | ` `[String](https://developer.android.com/reference/java/lang/String)          | ` `[toString](https://developer.android.com/reference/java/lang/Object#toString())`() ` Returns a string representation of the object.                                                                                                                                              | | ` final void`                                                                  | ` `[wait](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`                                                                  | ` `[wait](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`                                                                  | ` `[wait](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 ` `[android.os.Parcelable](https://developer.android.com/reference/android/os/Parcelable)` ` |------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | ` abstract int`  | ` `[describeContents](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` | ` `[writeToParcel](https://developer.android.com/reference/android/os/Parcelable#writeToParcel(android.os.Parcel,%20int))`(`[Parcel](https://developer.android.com/reference/android/os/Parcel)` dest, int flags) ` Flatten this object in to a Parcel. | ||

## Fields

### CREATOR

Added in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  

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

<br />

<br />

## Public methods

### describeContents

Added in [API level 18](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 [writeToParcel(android.os.Parcel, int)](https://developer.android.com/reference/android/os/Parcelable#writeToParcel(android.os.Parcel,%20int)),
the return value of this method must include the
[CONTENTS_FILE_DESCRIPTOR](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 [CONTENTS_FILE_DESCRIPTOR](https://developer.android.com/reference/android/os/Parcelable#CONTENTS_FILE_DESCRIPTOR) <br /> |

### equals

Added in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  

```
public boolean equals (Object otherObj)
```

Comparison operator on two IntentSender objects, such that true
is returned then they both represent the same operation from the
same package.

<br />

|                       Parameters                       ||
|------------|--------------------------------------------|
| `otherObj` | `Object`: This value may be `null`. <br /> |

|                                           Returns                                           ||
|-----------|----------------------------------------------------------------------------------|
| `boolean` | `true` if this object is the same as the obj argument; `false` otherwise. <br /> |

### hashCode

Added in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  

```
public int hashCode ()
```

Returns a hash code value for the object. This method is
supported for the benefit of hash tables such as those provided by
[HashMap](https://developer.android.com/reference/java/util/HashMap).


The general contract of `hashCode` is:

- Whenever it is invoked on the same object more than once during an execution of a Java application, the `hashCode` method must consistently return the same integer, provided no information used in `equals` comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
- If two objects are equal according to the [equals](https://developer.android.com/reference/java/lang/Object#equals(java.lang.Object)) method, then calling the `hashCode` method on each of the two objects must produce the same integer result.
- It is *not* required that if two objects are unequal according to the [equals](https://developer.android.com/reference/java/lang/Object#equals(java.lang.Object)) method, then calling the `hashCode` method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.

<br />

<br />

|                     Returns                      ||
|-------|-------------------------------------------|
| `int` | a hash code value for this object. <br /> |

### isFocused

Added in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  

```
public boolean isFocused ()
```

Retrieve the current focus state of the associated window.

<br />

|      Returns      ||
|-----------|--------|
| `boolean` | <br /> |

### registerFocusObserver

Added in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  

```
public void registerFocusObserver (WindowId.FocusObserver observer)
```

Start monitoring for changes in the focus state of the window.

<br />

|                 Parameters                  ||
|------------|---------------------------------|
| `observer` | `WindowId.FocusObserver` <br /> |

### toString

Added in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  

```
public String toString ()
```

Returns a string representation of the object.

<br />

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

### unregisterFocusObserver

Added in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  

```
public void unregisterFocusObserver (WindowId.FocusObserver observer)
```

Stop monitoring changes in the focus state of the window.

<br />

|                 Parameters                  ||
|------------|---------------------------------|
| `observer` | `WindowId.FocusObserver` <br /> |

### writeToParcel

Added in [API level 18](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  

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

Flatten this object in to a Parcel.

<br />

|                                                                                                                                                                                                                                 Parameters                                                                                                                                                                                                                                  ||
|---------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| `out`   | `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 [Parcelable.PARCELABLE_WRITE_RETURN_VALUE](https://developer.android.com/reference/android/os/Parcelable#PARCELABLE_WRITE_RETURN_VALUE). Value is either `0` or a combination of [Parcelable.PARCELABLE_WRITE_RETURN_VALUE](https://developer.android.com/reference/android/os/Parcelable#PARCELABLE_WRITE_RETURN_VALUE), and android.os.Parcelable.PARCELABLE_ELIDE_DUPLICATES <br /> |