android.widget.Scroller
This class encapsulates scrolling. The duration of the scroll
can be passed in the constructor and specifies the maximum time that
the scrolling animation should take. Past this time, the scrolling is
automatically moved to its final stage and computeScrollOffset()
will always return false to indicate that scrolling is over.
Summary
Public Constructors
Public Methods
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void |
abortAnimation() |
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boolean |
computeScrollOffset() |
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void |
extendDuration(int extend) |
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void |
fling(int startX, int startY, int velocityX, int velocityY, int minX, int maxX, int minY, int maxY) |
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final |
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void |
forceFinished(boolean finished) |
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final |
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int |
getCurrX() |
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final |
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int |
getCurrY() |
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final |
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int |
getDuration() |
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final |
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int |
getFinalX() |
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final |
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int |
getFinalY() |
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final |
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boolean |
isFinished() |
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void |
setFinalX(int newX) |
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void |
setFinalY(int newY) |
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void |
startScroll(int startX, int startY, int dx, int dy) |
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void |
startScroll(int startX, int startY, int dx, int dy, int duration) |
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int |
timePassed() |
clone,
equals,
finalize,
getClass,
hashCode,
notify,
notifyAll,
toString,
wait,
wait,
wait
Details
Public Constructors
public
Scroller(Context context)
Create a Scroller with the default duration and interpolator.
public
Scroller(Context context, Interpolator interpolator)
Create a Scroller with the specified interpolator. If the interpolator is
null, the default (viscous) interpolator will be used.
Public Methods
public
void
abortAnimation()
public
boolean
computeScrollOffset()
Call this when you want to know the new location. If it returns true,
the animation is not yet finished. loc will be altered to provide the
new location.
public
void
extendDuration(int extend)
Extend the scroll animation. This allows a running animation to
scroll further and longer, when used with setFinalX() or setFinalY().
Parameters
extend
| Additional time to scroll in milliseconds.
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public
void
fling(int startX, int startY, int velocityX, int velocityY, int minX, int maxX, int minY, int maxY)
Start scrolling based on a fling gesture. The distance travelled will
depend on the initial velocity of the fling.
Parameters
startX
| Starting point of the scroll (X) |
startY
| Starting point of the scroll (Y) |
velocityX
| Initial velocity of the fling (X) measured in pixels per
second. |
velocityY
| Initial velocity of the fling (Y) measured in pixels per
second |
minX
| Minimum X value. The scroller will not scroll past this
point. |
maxX
| Maximum X value. The scroller will not scroll past this
point. |
minY
| Minimum Y value. The scroller will not scroll past this
point. |
maxY
| Maximum Y value. The scroller will not scroll past this
point.
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public
final
void
forceFinished(boolean finished)
Force the finished field to a particular value.
Parameters
finished
| The new finished value.
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public
final
int
getCurrX()
Returns the current X offset in the scroll.
Returns
- The new X offset as an absolute distance from the origin.
public
final
int
getCurrY()
Returns the current Y offset in the scroll.
Returns
- The new Y offset as an absolute distance from the origin.
public
final
int
getDuration()
Returns how long the scroll event will take, in milliseconds.
Returns
- The duration of the scroll in milliseconds.
public
final
int
getFinalX()
Returns where the scroll will end. Valid only for "fling" scrolls.
Returns
- The final X offset as an absolute distance from the origin.
public
final
int
getFinalY()
Returns where the scroll will end. Valid only for "fling" scrolls.
Returns
- The final Y offset as an absolute distance from the origin.
public
final
boolean
isFinished()
Returns whether the scroller has finished scrolling.
Returns
- True if the scroller has finished scrolling, false otherwise.
public
void
setFinalX(int newX)
public
void
setFinalY(int newY)
public
void
startScroll(int startX, int startY, int dx, int dy)
Start scrolling by providing a starting point and the distance to travel.
The scroll will use the default value of 250 milliseconds for the
duration.
Parameters
startX
| Starting horizontal scroll offset in pixels. Positive
numbers will scroll the content to the left. |
startY
| Starting vertical scroll offset in pixels. Positive numbers
will scroll the content up. |
dx
| Horizontal distance to travel. Positive numbers will scroll the
content to the left. |
dy
| Vertical distance to travel. Positive numbers will scroll the
content up.
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public
void
startScroll(int startX, int startY, int dx, int dy, int duration)
Start scrolling by providing a starting point and the distance to travel.
Parameters
startX
| Starting horizontal scroll offset in pixels. Positive
numbers will scroll the content to the left. |
startY
| Starting vertical scroll offset in pixels. Positive numbers
will scroll the content up. |
dx
| Horizontal distance to travel. Positive numbers will scroll the
content to the left. |
dy
| Vertical distance to travel. Positive numbers will scroll the
content up. |
duration
| Duration of the scroll in milliseconds.
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