me.everything.android.ui.overscroll

Class OverScrollBounceEffectDecoratorBase

java.lang.Object

me.everything.android.ui.overscroll.OverScrollBounceEffectDecoratorBase

All Implemented Interfaces:

android.view.View.OnTouchListener, IOverScrollDecor

Direct Known Subclasses:

HorizontalOverScrollBounceEffectDecorator, VerticalOverScrollBounceEffectDecorator

public abstract class OverScrollBounceEffectDecoratorBase
extends java.lang.Object
implements IOverScrollDecor, android.view.View.OnTouchListener

A standalone view decorator adding over-scroll with a smooth bounce-back effect to (potentially) any view - provided that an appropriate IOverScrollDecoratorAdapter implementation exists / can be written for that view type (e.g. RecyclerViewOverScrollDecorAdapter).

Design-wise, being a standalone class, this decorator powerfully provides the ability to add the over-scroll effect over any view without adjusting the view's implementation. In essence, this eliminates the need to repeatedly implement the effect per each view type (list-view, recycler-view, image-view, etc.). Therefore, using it is highly recommended compared to other more intrusive solutions.

Note that this class is abstract, having HorizontalOverScrollBounceEffectDecorator and VerticalOverScrollBounceEffectDecorator providing concrete implementations that are view-orientation specific.

Implementation Notes

At it's core, the class simply registers itself as a touch-listener over the decorated view and intercepts touch events as needed.

Internally, it delegates the over-scrolling calculations onto 3 state-based classes:

1. Idle state - monitors view state and touch events to intercept over-scrolling initiation (in which case it hands control over to the Over-scrolling state).
2. Over-scrolling state - handles motion events to apply the over-scroll effect as users interact with the view.
3. Bounce-back state - runs the bounce-back animation, all-the-while blocking all touch events till the animation completes (in which case it hands control back to the idle state).

See Also:

RecyclerViewOverScrollDecorAdapter, IOverScrollDecoratorAdapter

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	OverScrollBounceEffectDecoratorBase.AnimationAttributes
protected class	OverScrollBounceEffectDecoratorBase.BounceBackState When entered, starts the bounce-back animation.
protected static interface	OverScrollBounceEffectDecoratorBase.IDecoratorState Interface of decorator-state delegation classes.
protected class	OverScrollBounceEffectDecoratorBase.IdleState Idle state: monitors move events, trying to figure out whether over-scrolling should be initiated (i.e.
protected static class	OverScrollBounceEffectDecoratorBase.MotionAttributes Motion attributes: keeps data describing current motion event.
protected class	OverScrollBounceEffectDecoratorBase.OverScrollingState Handles the actual over-scrolling: thus translating the view according to configuration and user interactions, dynamically.
protected static class	OverScrollBounceEffectDecoratorBase.OverScrollStartAttributes

Field Summary

Fields

Modifier and Type	Field and Description
static float	DEFAULT_DECELERATE_FACTOR
static float	DEFAULT_TOUCH_DRAG_MOVE_RATIO_BCK
static float	DEFAULT_TOUCH_DRAG_MOVE_RATIO_FWD
protected static int	MAX_BOUNCE_BACK_DURATION_MS
protected OverScrollBounceEffectDecoratorBase.BounceBackState	mBounceBackState
protected OverScrollBounceEffectDecoratorBase.IDecoratorState	mCurrentState
protected OverScrollBounceEffectDecoratorBase.IdleState	mIdleState
protected static int	MIN_BOUNCE_BACK_DURATION_MS
protected OverScrollBounceEffectDecoratorBase.OverScrollingState	mOverScrollingState
protected OverScrollBounceEffectDecoratorBase.OverScrollStartAttributes	mStartAttr
protected IOverScrollStateListener	mStateListener
protected IOverScrollUpdateListener	mUpdateListener
protected float	mVelocity When in over-scroll mode, keep track of dragging velocity to provide a smooth slow-down for the bounce-back effect.
protected IOverScrollDecoratorAdapter	mViewAdapter
static java.lang.String	TAG

Constructor Summary

Constructors

Constructor and Description
OverScrollBounceEffectDecoratorBase(IOverScrollDecoratorAdapter viewAdapter, float decelerateFactor, float touchDragRatioFwd, float touchDragRatioBck)

Method Summary

Modifier and Type	Method and Description
protected void	attach()
protected abstract OverScrollBounceEffectDecoratorBase.AnimationAttributes	createAnimationAttributes()
protected abstract OverScrollBounceEffectDecoratorBase.MotionAttributes	createMotionAttributes()
void	detach() Detach the decorator from its associated view, thus disabling it entirely.
int	getCurrentState() Get the current decorator's runtime state, i.e.
android.view.View	getView()
protected void	issueStateTransition(OverScrollBounceEffectDecoratorBase.IDecoratorState state)
boolean	onTouch(android.view.View v, android.view.MotionEvent event)
void	setOverScrollStateListener(IOverScrollStateListener listener)
void	setOverScrollUpdateListener(IOverScrollUpdateListener listener)
protected abstract void	translateView(android.view.View view, float offset)
protected abstract void	translateViewAndEvent(android.view.View view, float offset, android.view.MotionEvent event)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

TAG

public static final java.lang.String TAG

See Also:

Constant Field Values

DEFAULT_TOUCH_DRAG_MOVE_RATIO_FWD

public static final float DEFAULT_TOUCH_DRAG_MOVE_RATIO_FWD

See Also:

Constant Field Values

DEFAULT_TOUCH_DRAG_MOVE_RATIO_BCK

public static final float DEFAULT_TOUCH_DRAG_MOVE_RATIO_BCK

See Also:

Constant Field Values

DEFAULT_DECELERATE_FACTOR

public static final float DEFAULT_DECELERATE_FACTOR

See Also:

Constant Field Values

MAX_BOUNCE_BACK_DURATION_MS

protected static final int MAX_BOUNCE_BACK_DURATION_MS

See Also:

Constant Field Values

MIN_BOUNCE_BACK_DURATION_MS

protected static final int MIN_BOUNCE_BACK_DURATION_MS

See Also:

Constant Field Values

mStartAttr

protected final OverScrollBounceEffectDecoratorBase.OverScrollStartAttributes mStartAttr

mViewAdapter

protected final IOverScrollDecoratorAdapter mViewAdapter

mIdleState

protected final OverScrollBounceEffectDecoratorBase.IdleState mIdleState

mOverScrollingState

protected final OverScrollBounceEffectDecoratorBase.OverScrollingState mOverScrollingState

mBounceBackState

protected final OverScrollBounceEffectDecoratorBase.BounceBackState mBounceBackState

mCurrentState

protected OverScrollBounceEffectDecoratorBase.IDecoratorState mCurrentState

mStateListener

protected IOverScrollStateListener mStateListener

mUpdateListener

protected IOverScrollUpdateListener mUpdateListener

mVelocity

protected float mVelocity

When in over-scroll mode, keep track of dragging velocity to provide a smooth slow-down for the bounce-back effect.

Constructor Detail

OverScrollBounceEffectDecoratorBase

public OverScrollBounceEffectDecoratorBase(IOverScrollDecoratorAdapter viewAdapter,
                                           float decelerateFactor,
                                           float touchDragRatioFwd,
                                           float touchDragRatioBck)

Method Detail

onTouch

public boolean onTouch(android.view.View v,
                       android.view.MotionEvent event)

Specified by:

onTouch in interface android.view.View.OnTouchListener

setOverScrollStateListener

public void setOverScrollStateListener(IOverScrollStateListener listener)

Specified by:

setOverScrollStateListener in interface IOverScrollDecor

setOverScrollUpdateListener

public void setOverScrollUpdateListener(IOverScrollUpdateListener listener)

Specified by:

setOverScrollUpdateListener in interface IOverScrollDecor

getCurrentState

public int getCurrentState()

Description copied from interface: IOverScrollDecor

Get the current decorator's runtime state, i.e. one of the values specified by IOverScrollState.

Specified by:

getCurrentState in interface IOverScrollDecor

Returns:

The state.

getView

public android.view.View getView()

Specified by:

getView in interface IOverScrollDecor

issueStateTransition

protected void issueStateTransition(OverScrollBounceEffectDecoratorBase.IDecoratorState state)

attach

protected void attach()

detach

public void detach()

Description copied from interface: IOverScrollDecor

Detach the decorator from its associated view, thus disabling it entirely.

It is best to call this only when over-scroll isn't currently in-effect - i.e. verify that getCurrentState()==IOverScrollState.STATE_IDLE as a precondition, or otherwise use a state listener previously installed using IOverScrollDecor.setOverScrollStateListener(IOverScrollStateListener).

Note: Upon detachment completion, the view in question will return to the default Android over-scroll configuration (i.e. View.OVER_SCROLL_ALWAYS mode). This can be overridden by calling View.setOverScrollMode(mode) immediately thereafter.

Specified by:

detach in interface IOverScrollDecor

createMotionAttributes

protected abstract OverScrollBounceEffectDecoratorBase.MotionAttributes createMotionAttributes()

createAnimationAttributes

protected abstract OverScrollBounceEffectDecoratorBase.AnimationAttributes createAnimationAttributes()

translateView

protected abstract void translateView(android.view.View view,
                                      float offset)

translateViewAndEvent

protected abstract void translateViewAndEvent(android.view.View view,
                                              float offset,
                                              android.view.MotionEvent event)