/* * 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.content.Context; import android.graphics.Path; import android.util.AttributeSet; /** * This base class can be extended to provide motion along a Path to Transitions. * *

* Transitions such as {@link android.transition.ChangeBounds} move Views, typically * in a straight path between the start and end positions. Applications that desire to * have these motions move in a curve can change how Views interpolate in two dimensions * by extending PathMotion and implementing {@link #getPath(float, float, float, float)}. *

*

This may be used in XML as an element inside a transition.

*
 * {@code
 * <changeBounds>
 *     <pathMotion class="my.app.transition.MyPathMotion"/>
 * </changeBounds>
 * }
 * 
*/ public abstract class PathMotion { public PathMotion() {} public PathMotion(Context context, AttributeSet attrs) {} /** * Provide a Path to interpolate between two points (startX, startY) and * (endX, endY). This allows controlled curved motion along two dimensions. * * @param startX The x coordinate of the starting point. * @param startY The y coordinate of the starting point. * @param endX The x coordinate of the ending point. * @param endY The y coordinate of the ending point. * @return A Path along which the points should be interpolated. The returned Path * must start at point (startX, startY), typically using * {@link android.graphics.Path#moveTo(float, float)} and end at (endX, endY). */ public abstract Path getPath(float startX, float startY, float endX, float endY); }