/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.transition;
import android.graphics.Rect;
import android.transition.Slide.GravityFlag;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
/**
* A <code>TransitionPropagation</code> that propagates based on the distance to the side
* and, orthogonally, the distance to epicenter. If the transitioning View is visible in
* the start of the transition, then it will transition sooner when closer to the side and
* later when farther. If the view is not visible in the start of the transition, then
* it will transition later when closer to the side and sooner when farther from the edge.
* This is the default TransitionPropagation used with {@link android.transition.Slide}.
*/
public class SidePropagation extends VisibilityPropagation {
private static final String TAG = "SlidePropagation";
private float mPropagationSpeed = 3.0f;
private int mSide = Gravity.BOTTOM;
/**
* Sets the side that is used to calculate the transition propagation. If the transitioning
* View is visible in the start of the transition, then it will transition sooner when
* closer to the side and later when farther. If the view is not visible in the start of
* the transition, then it will transition later when closer to the side and sooner when
* farther from the edge. The default is {@link Gravity#BOTTOM}.
*
* @param side The side that is used to calculate the transition propagation. Must be one of
* {@link Gravity#LEFT}, {@link Gravity#TOP}, {@link Gravity#RIGHT},
* {@link Gravity#BOTTOM}, {@link Gravity#START}, or {@link Gravity#END}.
*/
public void setSide(@GravityFlag int side) {
mSide = side;
}
/**
* Sets the speed at which transition propagation happens, relative to the duration of the
* Transition. A <code>propagationSpeed</code> of 1 means that a View centered at the side
* set in {@link #setSide(int)} and View centered at the opposite edge 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.
*/
public void setPropagationSpeed(float propagationSpeed) {
if (propagationSpeed == 0) {
throw new IllegalArgumentException("propagationSpeed may not be 0");
}
mPropagationSpeed = propagationSpeed;
}
@Override
public long getStartDelay(ViewGroup sceneRoot, Transition transition,
TransitionValues startValues, TransitionValues endValues) {
if (startValues == null && endValues == null) {
return 0;
}
int directionMultiplier = 1;
Rect epicenter = transition.getEpicenter();
TransitionValues positionValues;
if (endValues == null || getViewVisibility(startValues) == View.VISIBLE) {
positionValues = startValues;
directionMultiplier = -1;
} else {
positionValues = endValues;
}
int viewCenterX = getViewX(positionValues);
int viewCenterY = getViewY(positionValues);
int[] loc = new int[2];
sceneRoot.getLocationOnScreen(loc);
int left = loc[0] + Math.round(sceneRoot.getTranslationX());
int top = loc[1] + Math.round(sceneRoot.getTranslationY());
int right = left + sceneRoot.getWidth();
int bottom = top + sceneRoot.getHeight();
int epicenterX;
int epicenterY;
if (epicenter != null) {
epicenterX = epicenter.centerX();
epicenterY = epicenter.centerY();
} else {
epicenterX = (left + right) / 2;
epicenterY = (top + bottom) / 2;
}
float distance = distance(sceneRoot, viewCenterX, viewCenterY, epicenterX, epicenterY,
left, top, right, bottom);
float maxDistance = getMaxDistance(sceneRoot);
float distanceFraction = distance/maxDistance;
long duration = transition.getDuration();
if (duration < 0) {
duration = 300;
}
return Math.round(duration * directionMultiplier / mPropagationSpeed * distanceFraction);
}
private int distance(View sceneRoot, int viewX, int viewY, int epicenterX, int epicenterY,
int left, int top, int right, int bottom) {
final int side;
if (mSide == Gravity.START) {
final boolean isRtl = sceneRoot.getLayoutDirection() == View.LAYOUT_DIRECTION_RTL;
side = isRtl ? Gravity.RIGHT : Gravity.LEFT;
} else if (mSide == Gravity.END) {
final boolean isRtl = sceneRoot.getLayoutDirection() == View.LAYOUT_DIRECTION_RTL;
side = isRtl ? Gravity.LEFT : Gravity.RIGHT;
} else {
side = mSide;
}
int distance = 0;
switch (side) {
case Gravity.LEFT:
distance = right - viewX + Math.abs(epicenterY - viewY);
break;
case Gravity.TOP:
distance = bottom - viewY + Math.abs(epicenterX - viewX);
break;
case Gravity.RIGHT:
distance = viewX - left + Math.abs(epicenterY - viewY);
break;
case Gravity.BOTTOM:
distance = viewY - top + Math.abs(epicenterX - viewX);
break;
}
return distance;
}
private int getMaxDistance(ViewGroup sceneRoot) {
switch (mSide) {
case Gravity.LEFT:
case Gravity.RIGHT:
case Gravity.START:
case Gravity.END:
return sceneRoot.getWidth();
default:
return sceneRoot.getHeight();
}
}
}