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CircularPropagation.javaAPI DocAndroid 5.1 API4516Thu Mar 12 22:22:10 GMT 2015android.transition

CircularPropagation

public class CircularPropagation extends VisibilityPropagation
A propagation that varies with the distance to the epicenter of the Transition or center of the scene if no epicenter exists. When a View is visible in the start of the transition, Views farther from the epicenter will transition sooner than Views closer to the epicenter. When a View is not in the start of the transition or is not visible at the start of the transition, it will transition sooner when closer to the epicenter and later when farther from the epicenter. This is the default TransitionPropagation used with {@link android.transition.Explode}.

Fields Summary
private static final String
TAG
private float
mPropagationSpeed
Constructors Summary
Methods Summary
private static floatdistance(float x1, float y1, float x2, float y2)

        float x = x2 - x1;
        float y = y2 - y1;
        return FloatMath.sqrt((x * x) + (y * y));
public longgetStartDelay(android.view.ViewGroup sceneRoot, Transition transition, TransitionValues startValues, TransitionValues endValues)

        if (startValues == null && endValues == null) {
            return 0;
        }
        int directionMultiplier = 1;
        TransitionValues positionValues;
        if (endValues == null || getViewVisibility(startValues) == View.VISIBLE) {
            positionValues = startValues;
            directionMultiplier = -1;
        } else {
            positionValues = endValues;
        }

        int viewCenterX = getViewX(positionValues);
        int viewCenterY = getViewY(positionValues);

        Rect epicenter = transition.getEpicenter();
        int epicenterX;
        int epicenterY;
        if (epicenter != null) {
            epicenterX = epicenter.centerX();
            epicenterY = epicenter.centerY();
        } else {
            int[] loc = new int[2];
            sceneRoot.getLocationOnScreen(loc);
            epicenterX = Math.round(loc[0] + (sceneRoot.getWidth() / 2)
                    + sceneRoot.getTranslationX());
            epicenterY = Math.round(loc[1] + (sceneRoot.getHeight() / 2)
                    + sceneRoot.getTranslationY());
        }
        float distance = distance(viewCenterX, viewCenterY, epicenterX, epicenterY);
        float maxDistance = distance(0, 0, sceneRoot.getWidth(), sceneRoot.getHeight());
        float distanceFraction = distance/maxDistance;

        long duration = transition.getDuration();
        if (duration < 0) {
            duration = 300;
        }

        return Math.round(duration * directionMultiplier / mPropagationSpeed * distanceFraction);
public voidsetPropagationSpeed(float propagationSpeed)
Sets the speed at which transition propagation happens, relative to the duration of the Transition. A propagationSpeed of 1 means that a View centered farthest from the epicenter and View centered at the epicenter will have a difference in start delay of approximately the duration of the Transition. A speed of 2 means the start delay difference will be approximately half of the duration of the transition. A value of 0 is illegal, but negative values will invert the propagation.

param
propagationSpeed The speed at which propagation occurs, relative to the duration of the transition. A speed of 4 means it works 4 times as fast as the duration of the transition. May not be 0.


                                                                                                                                                                             
        
        if (propagationSpeed == 0) {
            throw new IllegalArgumentException("propagationSpeed may not be 0");
        }
        mPropagationSpeed = propagationSpeed;