EdgeEffectCompat

public EdgeEffectCompat(Context context)

Construct a new EdgeEffect themed using the given context.

Note: On platform versions that do not support EdgeEffect, all operations on the newly constructed object will be mocked/no-ops.

public static @NonNull EdgeEffect create(@NonNull Context context, @Nullable AttributeSet attrs)

Constructs and returns a new EdgeEffect themed using the given context, allowing support for the view attributes.

public boolean draw(Canvas canvas)

Draw into the provided canvas. Assumes that the canvas has been rotated accordingly and the size has been set. The effect will be drawn the full width of X=0 to X=width, beginning from Y=0 and extending to some factor <1.f of height.

public void finish()

Immediately finish the current animation. After this call isFinished will return true.

public static float getDistance(@NonNull EdgeEffect edgeEffect)

Returns the pull distance needed to be released to remove the showing effect. It is determined by the onPulldeltaDistance and any animating values, including from onAbsorb and onRelease. This can be used in conjunction with onPullDistance to release the currently showing effect. On API level 30 and earlier, this will return 0.

public boolean isFinished()

Reports if this EdgeEffectCompat's animation is finished. If this method returns false after a call to draw the host widget should schedule another drawing pass to continue the animation.

public boolean onAbsorb(int velocity)

Call when the effect absorbs an impact at the given velocity. Used when a fling reaches the scroll boundary.

When using a Scroller or OverScroller, the method getCurrVelocity will provide a reasonable approximation to use here.

public boolean onPull(float deltaDistance)

A view should call this when content is pulled away from an edge by the user. This will update the state of the current visual effect and its associated animation. The host view should always invalidate if this method returns true and draw the results accordingly.

public boolean onPull(float deltaDistance, float displacement)

A view should call this when content is pulled away from an edge by the user. This will update the state of the current visual effect and its associated animation. The host view should always invalidate if this method returns true and draw the results accordingly. Views using EdgeEffect should favor onPull when the displacement of the pull point is known.

public static void onPull(
    @NonNull EdgeEffect edgeEffect,
    float deltaDistance,
    float displacement
)

A view should call this when content is pulled away from an edge by the user. This will update the state of the current visual effect and its associated animation. The host view should always invalidate after call this method and draw the results accordingly.

public static float onPullDistance(
    @NonNull EdgeEffect edgeEffect,
    float deltaDistance,
    float displacement
)

A view should call this when content is pulled away from an edge by the user. This will update the state of the current visual effect and its associated animation. The host view should always invalidate after this and draw the results accordingly. This works similarly to onPull, but returns the amount of deltaDistance that has been consumed. For API level 31 and above, if the getDistance is currently 0 and deltaDistance is negative, this function will return 0 and the drawn value will remain unchanged. For API level 30 and below, this will consume all of the provided value and return deltaDistance. This method can be used to reverse the effect from a pull or absorb and partially consume some of a motion:

    if (deltaY < 0 && EdgeEffectCompat.getDistance(edgeEffect) != 0) {
        float displacement = x / getWidth();
        float dist = deltaY / getHeight();
        float consumed = EdgeEffectCompat.onPullDistance(edgeEffect, dist, displacement);
        deltaY -= consumed * getHeight();
        if (edgeEffect.getDistance() == 0f) edgeEffect.onRelease();
    }

public boolean onRelease()

Call when the object is released after being pulled. This will begin the "decay" phase of the effect. After calling this method the host view should invalidate if this method returns true and thereby draw the results accordingly.

public void setSize(int width, int height)

Set the size of this edge effect in pixels.