BackEvent
public
final
class
BackEvent
extends Object
java.lang.Object | |
↳ | android.window.BackEvent |
Object used to report back gesture progress. Holds information about the touch event, swipe direction and the animation progress that predictive back animations should seek to.
Summary
Constants | |
---|---|
int |
EDGE_LEFT
Indicates that the edge swipe starts from the left edge of the screen |
int |
EDGE_NONE
Indicates that the back event was not triggered by an edge swipe back gesture. |
int |
EDGE_RIGHT
Indicates that the edge swipe starts from the right edge of the screen |
Public constructors | |
---|---|
BackEvent(float touchX, float touchY, float progress, int swipeEdge)
Creates a new |
|
BackEvent(float touchX, float touchY, float progress, int swipeEdge, long frameTimeMillis)
Creates a new |
Public methods | |
---|---|
boolean
|
equals(Object other)
Indicates whether some other object is "equal to" this one. |
long
|
getFrameTimeMillis()
Returns the frameTime of the BackEvent in milliseconds. |
float
|
getProgress()
Returns a value between 0 and 1 on how far along the back gesture is. |
int
|
getSwipeEdge()
Returns the screen edge that the swipe starts from. |
float
|
getTouchX()
Returns the absolute X location of the touch point, or NaN if the event is from a button press. |
float
|
getTouchY()
Returns the absolute Y location of the touch point, or NaN if the event is from a button press. |
String
|
toString()
Returns a string representation of the object. |
Inherited methods | |
---|---|
Constants
EDGE_LEFT
public static final int EDGE_LEFT
Indicates that the edge swipe starts from the left edge of the screen
Constant Value: 0 (0x00000000)
EDGE_NONE
public static final int EDGE_NONE
Indicates that the back event was not triggered by an edge swipe back gesture. This applies to cases like using the back button in 3-button navigation or pressing a hardware back button.
Constant Value: 2 (0x00000002)
EDGE_RIGHT
public static final int EDGE_RIGHT
Indicates that the edge swipe starts from the right edge of the screen
Constant Value: 1 (0x00000001)
Public constructors
BackEvent
public BackEvent (float touchX, float touchY, float progress, int swipeEdge)
Creates a new BackEvent
instance with a frame time of 0.
Parameters | |
---|---|
touchX |
float : Absolute X location of the touch point of this event. |
touchY |
float : Absolute Y location of the touch point of this event. |
progress |
float : Value between 0 and 1 on how far along the back gesture is. |
swipeEdge |
int : Indicates which edge the swipe starts from.
Value is EDGE_LEFT , EDGE_RIGHT , or EDGE_NONE |
BackEvent
public BackEvent (float touchX, float touchY, float progress, int swipeEdge, long frameTimeMillis)
Creates a new BackEvent
instance.
Parameters | |
---|---|
touchX |
float : Absolute X location of the touch point of this event. |
touchY |
float : Absolute Y location of the touch point of this event. |
progress |
float : Value between 0 and 1 on how far along the back gesture is. |
swipeEdge |
int : Indicates which edge the swipe starts from.
Value is EDGE_LEFT , EDGE_RIGHT , or EDGE_NONE |
frameTimeMillis |
long : frame time of the back event. |
Public methods
equals
public boolean equals (Object other)
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 | |
---|---|
other |
Object : the reference object with which to compare. |
Returns | |
---|---|
boolean |
true if this object is the same as the obj
argument; false otherwise. |
getFrameTimeMillis
public long getFrameTimeMillis ()
Returns the frameTime of the BackEvent in milliseconds. Useful for calculating velocity.
Returns | |
---|---|
long |
getProgress
public float getProgress ()
Returns a value between 0 and 1 on how far along the back gesture is. This value is driven by the horizontal location of the touch point, and should be used as the fraction to seek the predictive back animation with. Specifically,
- The progress is 0 when the touch is at the starting edge of the screen (left or right), and animation should seek to its start state.
- The progress is approximately 1 when the touch is at the opposite side of the screen, and animation should seek to its end state. Exact end value may vary depending on screen size.
Returns | |
---|---|
float |
Value is between 0 and 1 inclusive |
getSwipeEdge
public int getSwipeEdge ()
Returns the screen edge that the swipe starts from.
Returns | |
---|---|
int |
Value is EDGE_LEFT , EDGE_RIGHT , or EDGE_NONE |
getTouchX
public float getTouchX ()
Returns the absolute X location of the touch point, or NaN if the event is from a button press.
Returns | |
---|---|
float |
getTouchY
public float getTouchY ()
Returns the absolute Y location of the touch point, or NaN if the event is from a button press.
Returns | |
---|---|
float |
toString
public String toString ()
Returns a string representation of the object.
Returns | |
---|---|
String |
a string representation of the object. |