KeyCharacterMap
public
class
KeyCharacterMap
extends Object
implements
Parcelable
java.lang.Object | |
↳ | android.view.KeyCharacterMap |
Describes the keys provided by a keyboard device and their associated labels.
Summary
Nested classes | |
---|---|
class |
KeyCharacterMap.KeyData
This class was deprecated
in API level 11.
instead use |
class |
KeyCharacterMap.UnavailableException
Thrown by |
Constants | |
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int |
ALPHA
A keyboard with all the letters, and maybe some numbers. |
int |
BUILT_IN_KEYBOARD
This constant was deprecated
in API level 15.
This constant should no longer be used because there is no
guarantee that a device has a built-in keyboard that can be used for
typing text. There might not be a built-in keyboard, the built-in keyboard
might be a |
int |
COMBINING_ACCENT
|
int |
COMBINING_ACCENT_MASK
Mask the return value from |
int |
FULL
A full PC-style keyboard. |
char |
HEX_INPUT
This private-use character is used to trigger Unicode character input by hex digits. |
int |
MODIFIER_BEHAVIOR_CHORDED
Modifier keys may be chorded with character keys. |
int |
MODIFIER_BEHAVIOR_CHORDED_OR_TOGGLED
Modifier keys may be chorded with character keys or they may toggle into latched or locked states when pressed independently. |
int |
NUMERIC
A numeric (12-key) keyboard. |
char |
PICKER_DIALOG_INPUT
This private-use character is used to bring up a character picker for miscellaneous symbols. |
int |
PREDICTIVE
A keyboard with all the letters, but with more than one letter per key. |
int |
SPECIAL_FUNCTION
A keyboard that is only used to control special functions rather than for typing. |
int |
VIRTUAL_KEYBOARD
The id of a generic virtual keyboard with a full layout that can be used to synthesize key events. |
Inherited constants |
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Fields | |
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public
static
final
Creator<KeyCharacterMap> |
CREATOR
|
Public methods | |
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int
|
describeContents()
Describe the kinds of special objects contained in this Parcelable instance's marshaled representation. |
static
boolean
|
deviceHasKey(int keyCode)
Queries the framework about whether any physical keys exist on any currently attached input devices that are capable of producing the given key code. |
static
boolean[]
|
deviceHasKeys(int[] keyCodes)
Queries the framework about whether any physical keys exist on any currently attached input devices that are capable of producing the given array of key codes. |
boolean
|
equals(Object obj)
Indicates whether some other object is "equal to" this one. |
int
|
get(int keyCode, int metaState)
Gets the Unicode character generated by the specified key and meta key state combination. |
static
int
|
getDeadChar(int accent, int c)
Get the character that is produced by combining the dead key producing accent with the key producing character c. |
char
|
getDisplayLabel(int keyCode)
Gets the primary character for this key. |
KeyEvent[]
|
getEvents(char[] chars)
Get an array of KeyEvent objects that if put into the input stream could plausibly generate the provided sequence of characters. |
boolean
|
getKeyData(int keyCode, KeyCharacterMap.KeyData results)
This method was deprecated
in API level 15.
instead use |
int
|
getKeyboardType()
Gets the keyboard type. |
char
|
getMatch(int keyCode, char[] chars, int metaState)
Gets the first character in the character array that can be generated by the specified key code. |
char
|
getMatch(int keyCode, char[] chars)
Gets the first character in the character array that can be generated by the specified key code. |
int
|
getModifierBehavior()
Gets a constant that describes the behavior of this keyboard's modifier keys
such as |
char
|
getNumber(int keyCode)
Gets the number or symbol associated with the key. |
boolean
|
isPrintingKey(int keyCode)
Returns true if the specified key produces a glyph. |
static
KeyCharacterMap
|
load(int deviceId)
Loads the key character maps for the keyboard with the specified device id. |
void
|
writeToParcel(Parcel out, int flags)
Flatten this object in to a Parcel. |
Protected methods | |
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void
|
finalize()
Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. |
Inherited methods | |
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Constants
ALPHA
public static final int ALPHA
A keyboard with all the letters, and maybe some numbers.
An alphabetic keyboard supports text entry directly but may have a condensed
layout with a small form factor. In contrast to a full keyboard
, some
symbols may only be accessible using special on-screen character pickers.
In addition, to improve typing speed and accuracy, the framework provides
special affordances for alphabetic keyboards such as auto-capitalization
and toggled / locked shift and alt keys.
This type of keyboard is generally designed for thumb typing.
Constant Value: 3 (0x00000003)
BUILT_IN_KEYBOARD
public static final int BUILT_IN_KEYBOARD
This constant was deprecated
in API level 15.
This constant should no longer be used because there is no
guarantee that a device has a built-in keyboard that can be used for
typing text. There might not be a built-in keyboard, the built-in keyboard
might be a NUMERIC
or SPECIAL_FUNCTION
keyboard, or there
might be multiple keyboards installed including external keyboards.
When interpreting key presses received from the framework, applications should
use the device id specified in the KeyEvent
received.
When synthesizing key presses for delivery elsewhere or when translating key presses
from unknown keyboards, applications should use the special VIRTUAL_KEYBOARD
device id.
The id of the device's primary built in keyboard is always 0.
Constant Value: 0 (0x00000000)
COMBINING_ACCENT
public static final int COMBINING_ACCENT
Constant Value: -2147483648 (0x80000000)
COMBINING_ACCENT_MASK
public static final int COMBINING_ACCENT_MASK
Mask the return value from get(int, int)
with this value to get
a printable representation of the accent character of a "dead key."
Constant Value: 2147483647 (0x7fffffff)
FULL
public static final int FULL
A full PC-style keyboard.
A full keyboard behaves like a PC keyboard. All symbols are accessed directly by pressing keys on the keyboard without on-screen support or affordances such as auto-capitalization.
This type of keyboard is generally designed for full two hand typing.
Constant Value: 4 (0x00000004)
HEX_INPUT
public static final char HEX_INPUT
This private-use character is used to trigger Unicode character input by hex digits.
Constant Value: 61184 (0x0000ef00)
MODIFIER_BEHAVIOR_CHORDED
public static final int MODIFIER_BEHAVIOR_CHORDED
Modifier keys may be chorded with character keys.
See also:
Constant Value: 0 (0x00000000)
MODIFIER_BEHAVIOR_CHORDED_OR_TOGGLED
public static final int MODIFIER_BEHAVIOR_CHORDED_OR_TOGGLED
Modifier keys may be chorded with character keys or they may toggle into latched or locked states when pressed independently.
See also:
Constant Value: 1 (0x00000001)
NUMERIC
public static final int NUMERIC
A numeric (12-key) keyboard.
A numeric keyboard supports text entry using a multi-tap approach. It may be necessary to tap a key multiple times to generate the desired letter or symbol.
This type of keyboard is generally designed for thumb typing.
Constant Value: 1 (0x00000001)
PICKER_DIALOG_INPUT
public static final char PICKER_DIALOG_INPUT
This private-use character is used to bring up a character picker for miscellaneous symbols.
Constant Value: 61185 (0x0000ef01)
PREDICTIVE
public static final int PREDICTIVE
A keyboard with all the letters, but with more than one letter per key.
This type of keyboard is generally designed for thumb typing.
Constant Value: 2 (0x00000002)
SPECIAL_FUNCTION
public static final int SPECIAL_FUNCTION
A keyboard that is only used to control special functions rather than for typing.
A special function keyboard consists only of non-printing keys such as HOME and POWER that are not actually used for typing.
Constant Value: 5 (0x00000005)
VIRTUAL_KEYBOARD
public static final int VIRTUAL_KEYBOARD
The id of a generic virtual keyboard with a full layout that can be used to
synthesize key events. Typically used with getEvents(char)
.
Constant Value: -1 (0xffffffff)
Fields
Public methods
describeContents
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)
,
the return value of this method must include the
CONTENTS_FILE_DESCRIPTOR
bit.
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 |
deviceHasKey
public static boolean deviceHasKey (int keyCode)
Queries the framework about whether any physical keys exist on any currently attached input devices that are capable of producing the given key code.
Parameters | |
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keyCode |
int : The key code to query. |
Returns | |
---|---|
boolean |
True if at least one attached keyboard supports the specified key code. |
deviceHasKeys
public static boolean[] deviceHasKeys (int[] keyCodes)
Queries the framework about whether any physical keys exist on any currently attached input devices that are capable of producing the given array of key codes.
Parameters | |
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keyCodes |
int : The array of key codes to query. |
Returns | |
---|---|
boolean[] |
A new array of the same size as the key codes array whose elements are set to true if at least one attached keyboard supports the corresponding key code at the same index in the key codes array. |
equals
public boolean equals (Object obj)
Indicates whether some other object is "equal to" this one.
The equals
method implements an equivalence relation
on non-null object references:
- It is reflexive: for any non-null reference value
x
,x.equals(x)
should returntrue
. - It is symmetric: for any non-null reference values
x
andy
,x.equals(y)
should returntrue
if and only ify.equals(x)
returnstrue
. - It is transitive: for any non-null reference values
x
,y
, andz
, ifx.equals(y)
returnstrue
andy.equals(z)
returnstrue
, thenx.equals(z)
should returntrue
. - It is consistent: for any non-null reference values
x
andy
, multiple invocations ofx.equals(y)
consistently returntrue
or consistently returnfalse
, provided no information used inequals
comparisons on the objects is modified. - For any non-null reference value
x
,x.equals(null)
should returnfalse
.
An equivalence relation partitions the elements it operates on into equivalence classes; all the members of an equivalence class are equal to each other. Members of an equivalence class are substitutable for each other, at least for some purposes.
Parameters | |
---|---|
obj |
Object : the reference object with which to compare. |
Returns | |
---|---|
boolean |
true if this object is the same as the obj
argument; false otherwise. |
get
public int get (int keyCode, int metaState)
Gets the Unicode character generated by the specified key and meta key state combination.
Returns the Unicode character that the specified key would produce
when the specified meta bits (see MetaKeyKeyListener
)
were active.
Returns 0 if the key is not one that is used to type Unicode characters.
If the return value has bit COMBINING_ACCENT
set, the
key is a "dead key" that should be combined with another to
actually produce a character -- see getDeadChar(int, int)
--
after masking with COMBINING_ACCENT_MASK
.
Parameters | |
---|---|
keyCode |
int : The key code. |
metaState |
int : The meta key modifier state. |
Returns | |
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int |
The associated character or combining accent, or 0 if none. |
getDeadChar
public static int getDeadChar (int accent, int c)
Get the character that is produced by combining the dead key producing accent with the key producing character c. For example, getDeadChar('`', 'e') returns è. getDeadChar('^', ' ') returns '^' and getDeadChar('^', '^') returns '^'.
Parameters | |
---|---|
accent |
int : The accent character. eg. '`' |
c |
int : The basic character. |
Returns | |
---|---|
int |
The combined character, or 0 if the characters cannot be combined. |
getDisplayLabel
public char getDisplayLabel (int keyCode)
Gets the primary character for this key. In other words, the label that is physically printed on it.
Parameters | |
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keyCode |
int : The key code. |
Returns | |
---|---|
char |
The display label character, or 0 if none (eg. for non-printing keys). |
getEvents
public KeyEvent[] getEvents (char[] chars)
Get an array of KeyEvent objects that if put into the input stream could plausibly generate the provided sequence of characters. It is not guaranteed that the sequence is the only way to generate these events or that it is optimal.
This function is primarily offered for instrumentation and testing purposes.
It may fail to map characters to key codes. In particular, the key character
map for the built-in keyboard
device id may be empty.
Consider using the key character map associated with the
virtual keyboard
device id instead.
For robust text entry, do not use this function. Instead construct a
KeyEvent
with action code KeyEvent#ACTION_MULTIPLE
that contains
the desired string using KeyEvent#KeyEvent(long, String, int, int)
.
Parameters | |
---|---|
chars |
char : The sequence of characters to generate. |
Returns | |
---|---|
KeyEvent[] |
An array of KeyEvent objects, or null if the given char array
can not be generated using the current key character map. |
Throws | |
---|---|
|
java.lang.IllegalArgumentException IllegalArgumentException} if the passed array of characters is null. |
getKeyData
public boolean getKeyData (int keyCode, KeyCharacterMap.KeyData results)
This method was deprecated
in API level 15.
instead use KeyCharacterMap#getDisplayLabel(int)
,
KeyCharacterMap#getNumber(int)
or KeyCharacterMap#get(int, int)
.
Get the character conversion data for a given key code.
Parameters | |
---|---|
keyCode |
int : The keyCode to query. |
results |
KeyCharacterMap.KeyData : A KeyData instance that will be filled with the results. |
Returns | |
---|---|
boolean |
True if the key was mapped. If the key was not mapped, results is not modified. |
getKeyboardType
public int getKeyboardType ()
Gets the keyboard type.
Returns NUMERIC
, PREDICTIVE
, ALPHA
, FULL
or SPECIAL_FUNCTION
.
Different keyboard types have different semantics. Refer to the documentation associated with the keyboard type constants for details.
Returns | |
---|---|
int |
The keyboard type. |
getMatch
public char getMatch (int keyCode, char[] chars, int metaState)
Gets the first character in the character array that can be generated by the specified key code. If there are multiple choices, prefers the one that would be generated with the specified meta key modifier state.
Parameters | |
---|---|
keyCode |
int : The key code. |
chars |
char : The array of matching characters to consider. |
metaState |
int : The preferred meta key modifier state. |
Returns | |
---|---|
char |
The matching associated character, or 0 if none. |
Throws | |
---|---|
|
java.lang.IllegalArgumentException IllegalArgumentException} if the passed array of characters is null. |
getMatch
public char getMatch (int keyCode, char[] chars)
Gets the first character in the character array that can be generated by the specified key code.
This is a convenience function that returns the same value as
getMatch(keyCode, chars, 0)
.
Parameters | |
---|---|
keyCode |
int : The keycode. |
chars |
char : The array of matching characters to consider. |
Returns | |
---|---|
char |
The matching associated character, or 0 if none. |
Throws | |
---|---|
|
java.lang.IllegalArgumentException IllegalArgumentException} if the passed array of characters is null. |
getModifierBehavior
public int getModifierBehavior ()
Gets a constant that describes the behavior of this keyboard's modifier keys
such as KeyEvent#KEYCODE_SHIFT_LEFT
.
Currently there are two behaviors that may be combined:
- Chorded behavior: When the modifier key is pressed together with one or more character keys, the keyboard inserts the modified keys and then resets the modifier state when the modifier key is released.
- Toggled behavior: When the modifier key is pressed and released on its own it first toggles into a latched state. When latched, the modifier will apply to next character key that is pressed and will then reset itself to the initial state. If the modifier is already latched and the modifier key is pressed and release on its own again, then it toggles into a locked state. When locked, the modifier will apply to all subsequent character keys that are pressed until unlocked by pressing the modifier key on its own one more time to reset it to the initial state. Toggled behavior is useful for small profile keyboards designed for thumb typing.
This function currently returns MODIFIER_BEHAVIOR_CHORDED
when the
keyboard type
is FULL
or SPECIAL_FUNCTION
and
MODIFIER_BEHAVIOR_CHORDED_OR_TOGGLED
otherwise.
In the future, the function may also take into account global keyboard
accessibility settings, other user preferences, or new device capabilities.
Returns | |
---|---|
int |
The modifier behavior for this keyboard. |
getNumber
public char getNumber (int keyCode)
Gets the number or symbol associated with the key.
The character value is returned, not the numeric value. If the key is not a number, but is a symbol, the symbol is retuned.
This method is intended to to support dial pads and other numeric or symbolic entry on keyboards where certain keys serve dual function as alphabetic and symbolic keys. This method returns the number or symbol associated with the key independent of whether the user has pressed the required modifier.
For example, on one particular keyboard the keys on the top QWERTY row generate
numbers when ALT is pressed such that ALT-Q maps to '1'. So for that keyboard
when getNumber(int)
is called with KeyEvent#KEYCODE_Q
it returns '1'
so that the user can type numbers without pressing ALT when it makes sense.
Parameters | |
---|---|
keyCode |
int : The key code. |
Returns | |
---|---|
char |
The associated numeric or symbolic character, or 0 if none. |
isPrintingKey
public boolean isPrintingKey (int keyCode)
Returns true if the specified key produces a glyph.
Parameters | |
---|---|
keyCode |
int : The key code. |
Returns | |
---|---|
boolean |
True if the key is a printing key. |
load
public static KeyCharacterMap load (int deviceId)
Loads the key character maps for the keyboard with the specified device id.
Parameters | |
---|---|
deviceId |
int : The device id of the keyboard. |
Returns | |
---|---|
KeyCharacterMap |
The associated key character map. |
Throws | |
---|---|
|
android.view.KeyCharacterMap.UnavailableException UnavailableException} if the key character map could not be loaded because it was malformed or the default key character map is missing from the system. |
writeToParcel
public void writeToParcel (Parcel out, int flags)
Flatten this object in to a Parcel.
Parameters | |
---|---|
out |
Parcel : The Parcel in which the object should be written.
This value cannot be null . |
flags |
int : Additional flags about how the object should be written.
May be 0 or Parcelable.PARCELABLE_WRITE_RETURN_VALUE .
Value is either 0 or a combination of Parcelable.PARCELABLE_WRITE_RETURN_VALUE , and android.os.Parcelable.PARCELABLE_ELIDE_DUPLICATES |
Protected methods
finalize
protected void finalize ()
Called by the garbage collector on an object when garbage collection
determines that there are no more references to the object.
A subclass overrides the finalize
method to dispose of
system resources or to perform other cleanup.
The general contract of finalize
is that it is invoked
if and when the Java virtual
machine has determined that there is no longer any
means by which this object can be accessed by any thread that has
not yet died, except as a result of an action taken by the
finalization of some other object or class which is ready to be
finalized. The finalize
method may take any action, including
making this object available again to other threads; the usual purpose
of finalize
, however, is to perform cleanup actions before
the object is irrevocably discarded. For example, the finalize method
for an object that represents an input/output connection might perform
explicit I/O transactions to break the connection before the object is
permanently discarded.
The finalize
method of class Object
performs no
special action; it simply returns normally. Subclasses of
Object
may override this definition.
The Java programming language does not guarantee which thread will
invoke the finalize
method for any given object. It is
guaranteed, however, that the thread that invokes finalize will not
be holding any user-visible synchronization locks when finalize is
invoked. If an uncaught exception is thrown by the finalize method,
the exception is ignored and finalization of that object terminates.
After the finalize
method has been invoked for an object, no
further action is taken until the Java virtual machine has again
determined that there is no longer any means by which this object can
be accessed by any thread that has not yet died, including possible
actions by other objects or classes which are ready to be finalized,
at which point the object may be discarded.
The finalize
method is never invoked more than once by a Java
virtual machine for any given object.
Any exception thrown by the finalize
method causes
the finalization of this object to be halted, but is otherwise
ignored.
Throws | |
---|---|
Throwable |
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Last updated 2024-04-11 UTC.