Scroller

Kotlin |Java

open class Scroller

kotlin.Any
↳	android.widget.Scroller

This class encapsulates scrolling. You can use scrollers (Scroller or OverScroller) to collect the data you need to produce a scrolling animation—for example, in response to a fling gesture. Scrollers track scroll offsets for you over time, but they don't automatically apply those positions to your view. It's your responsibility to get and apply new coordinates at a rate that will make the scrolling animation look smooth.

Here is a simple example:

private Scroller mScroller = new Scroller(context);
  ...
  public void zoomIn() {
      // Revert any animation currently in progress
      mScroller.forceFinished(true);
      // Start scrolling by providing a starting point and
      // the distance to travel
      mScroller.startScroll(0, 0, 100, 0);
      // Invalidate to request a redraw
      invalidate();
  }

To track the changing positions of the x/y coordinates, use computeScrollOffset. The method returns a boolean to indicate whether the scroller is finished. If it isn't, it means that a fling or programmatic pan operation is still in progress. You can use this method to find the current offsets of the x and y coordinates, for example:

if (mScroller.computeScrollOffset()) {
      // Get current x and y positions
      int currX = mScroller.getCurrX();
      int currY = mScroller.getCurrY();
     ...
  }

Summary

Public constructors
`Scroller(context: Context!)` Create a Scroller with the default duration and interpolator.
`Scroller(context: Context!, interpolator: Interpolator!)` Create a Scroller with the specified interpolator.
`Scroller(context: Context!, interpolator: Interpolator!, flywheel: Boolean)` Create a Scroller with the specified interpolator.

Public methods
open Unit	`abortAnimation()` Stops the animation.
open Boolean	`computeScrollOffset()` Call this when you want to know the new location.
open Unit	`extendDuration(extend: Int)` Extend the scroll animation.
open Unit	`fling(startX: Int, startY: Int, velocityX: Int, velocityY: Int, minX: Int, maxX: Int, minY: Int, maxY: Int)` Start scrolling based on a fling gesture.
Unit	`forceFinished(finished: Boolean)` Force the finished field to a particular value.
open Float	`getCurrVelocity()` Returns the current velocity.
Int	`getCurrX()` Returns the current X offset in the scroll.
Int	`getCurrY()` Returns the current Y offset in the scroll.
Int	`getDuration()` Returns how long the scroll event will take, in milliseconds.
Int	`getFinalX()` Returns where the scroll will end.
Int	`getFinalY()` Returns where the scroll will end.
Int	`getStartX()` Returns the start X offset in the scroll.
Int	`getStartY()` Returns the start Y offset in the scroll.
Boolean	`isFinished()` Returns whether the scroller has finished scrolling.
open Unit	`setFinalX(newX: Int)` Sets the final position (X) for this scroller.
open Unit	`setFinalY(newY: Int)` Sets the final position (Y) for this scroller.
Unit	`setFriction(friction: Float)` The amount of friction applied to flings.
open Unit	`startScroll(startX: Int, startY: Int, dx: Int, dy: Int)` Start scrolling by providing a starting point and the distance to travel.
open Unit	`startScroll(startX: Int, startY: Int, dx: Int, dy: Int, duration: Int)` Start scrolling by providing a starting point, the distance to travel, and the duration of the scroll.
open Int	`timePassed()` Returns the time elapsed since the beginning of the scrolling.

Parameters
`startX`	Int: Starting point of the scroll (X)
`startY`	Int: Starting point of the scroll (Y)
`velocityX`	Int: Initial velocity of the fling (X) measured in pixels per second.
`velocityY`	Int: Initial velocity of the fling (Y) measured in pixels per second
`minX`	Int: Minimum X value. The scroller will not scroll past this point.
`maxX`	Int: Maximum X value. The scroller will not scroll past this point.
`minY`	Int: Minimum Y value. The scroller will not scroll past this point.
`maxY`	Int: Maximum Y value. The scroller will not scroll past this point.

Parameters
`startX`	Int: Starting horizontal scroll offset in pixels. Positive numbers will scroll the content to the left.
`startY`	Int: Starting vertical scroll offset in pixels. Positive numbers will scroll the content up.
`dx`	Int: Horizontal distance to travel. Positive numbers will scroll the content to the left.
`dy`	Int: Vertical distance to travel. Positive numbers will scroll the content up.

Scroller

Summary

Public constructors

Scroller

Scroller

Scroller

Public methods

abortAnimation

computeScrollOffset

extendDuration

fling

forceFinished

getCurrVelocity

getCurrX

getCurrY

getDuration

getFinalX

getFinalY

getStartX

getStartY

isFinished

setFinalX

setFinalY

setFriction

startScroll

startScroll

timePassed