/*
* Copyright (C) 2016 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.support.transition;
import android.animation.Animator;
import android.annotation.TargetApi;
import android.support.annotation.RequiresApi;
import android.view.View;
import android.view.ViewGroup;
/**
* This transition tracks changes to the visibility of target views in the
* start and end scenes. Visibility is determined not just by the
* {@link View#setVisibility(int)} state of views, but also whether
* views exist in the current view hierarchy. The class is intended to be a
* utility for subclasses such as {@link FadePort}, which use this visibility
* information to determine the specific animations to run when visibility
* changes occur. Subclasses should implement one or both of the methods
* {@link #onAppear(ViewGroup, TransitionValues, int, TransitionValues, int)},
* {@link #onDisappear(ViewGroup, TransitionValues, int, TransitionValues, int)},
*/
@RequiresApi(14)
@TargetApi(14)
abstract class VisibilityPort extends TransitionPort {
private static final String PROPNAME_VISIBILITY = "android:visibility:visibility";
private static final String PROPNAME_PARENT = "android:visibility:parent";
private static final String[] sTransitionProperties = {
PROPNAME_VISIBILITY,
PROPNAME_PARENT,
};
@Override
public String[] getTransitionProperties() {
return sTransitionProperties;
}
private void captureValues(TransitionValues transitionValues) {
int visibility = transitionValues.view.getVisibility();
transitionValues.values.put(PROPNAME_VISIBILITY, visibility);
transitionValues.values.put(PROPNAME_PARENT, transitionValues.view.getParent());
}
@Override
public void captureStartValues(TransitionValues transitionValues) {
captureValues(transitionValues);
}
@Override
public void captureEndValues(TransitionValues transitionValues) {
captureValues(transitionValues);
}
/**
* Returns whether the view is 'visible' according to the given values
* object. This is determined by testing the same properties in the values
* object that are used to determine whether the object is appearing or
* disappearing in the {@link
* TransitionPort#createAnimator(ViewGroup, TransitionValues, TransitionValues)}
* method. This method can be called by, for example, subclasses that want
* to know whether the object is visible in the same way that Visibility
* determines it for the actual animation.
*
* @param values The TransitionValues object that holds the information by
* which visibility is determined.
* @return True if the view reference by <code>values</code> is visible,
* false otherwise.
*/
public boolean isVisible(TransitionValues values) {
if (values == null) {
return false;
}
int visibility = (Integer) values.values.get(PROPNAME_VISIBILITY);
View parent = (View) values.values.get(PROPNAME_PARENT);
return visibility == View.VISIBLE && parent != null;
}
private VisibilityInfo getVisibilityChangeInfo(TransitionValues startValues,
TransitionValues endValues) {
final VisibilityInfo visInfo = new VisibilityInfo();
visInfo.visibilityChange = false;
visInfo.fadeIn = false;
if (startValues != null) {
visInfo.startVisibility = (Integer) startValues.values.get(PROPNAME_VISIBILITY);
visInfo.startParent = (ViewGroup) startValues.values.get(PROPNAME_PARENT);
} else {
visInfo.startVisibility = -1;
visInfo.startParent = null;
}
if (endValues != null) {
visInfo.endVisibility = (Integer) endValues.values.get(PROPNAME_VISIBILITY);
visInfo.endParent = (ViewGroup) endValues.values.get(PROPNAME_PARENT);
} else {
visInfo.endVisibility = -1;
visInfo.endParent = null;
}
if (startValues != null && endValues != null) {
if (visInfo.startVisibility == visInfo.endVisibility &&
visInfo.startParent == visInfo.endParent) {
return visInfo;
} else {
if (visInfo.startVisibility != visInfo.endVisibility) {
if (visInfo.startVisibility == View.VISIBLE) {
visInfo.fadeIn = false;
visInfo.visibilityChange = true;
} else if (visInfo.endVisibility == View.VISIBLE) {
visInfo.fadeIn = true;
visInfo.visibilityChange = true;
}
// no visibilityChange if going between INVISIBLE and GONE
} else if (visInfo.startParent != visInfo.endParent) {
if (visInfo.endParent == null) {
visInfo.fadeIn = false;
visInfo.visibilityChange = true;
} else if (visInfo.startParent == null) {
visInfo.fadeIn = true;
visInfo.visibilityChange = true;
}
}
}
}
if (startValues == null) {
visInfo.fadeIn = true;
visInfo.visibilityChange = true;
} else if (endValues == null) {
visInfo.fadeIn = false;
visInfo.visibilityChange = true;
}
return visInfo;
}
@Override
public Animator createAnimator(ViewGroup sceneRoot, TransitionValues startValues,
TransitionValues endValues) {
VisibilityInfo visInfo = getVisibilityChangeInfo(startValues, endValues);
if (visInfo.visibilityChange) {
// Only transition views that are either targets of this transition
// or whose parent hierarchies remain stable between scenes
boolean isTarget = false;
if (mTargets.size() > 0 || mTargetIds.size() > 0) {
View startView = startValues != null ? startValues.view : null;
View endView = endValues != null ? endValues.view : null;
int startId = startView != null ? startView.getId() : -1;
int endId = endView != null ? endView.getId() : -1;
isTarget = isValidTarget(startView, startId) || isValidTarget(endView, endId);
}
if (isTarget || ((visInfo.startParent != null || visInfo.endParent != null))) {
if (visInfo.fadeIn) {
return onAppear(sceneRoot, startValues, visInfo.startVisibility,
endValues, visInfo.endVisibility);
} else {
return onDisappear(sceneRoot, startValues, visInfo.startVisibility,
endValues, visInfo.endVisibility
);
}
}
}
return null;
}
/**
* The default implementation of this method does nothing. Subclasses
* should override if they need to create an Animator when targets appear.
* The method should only be called by the Visibility class; it is
* not intended to be called from external classes.
*
* @param sceneRoot The root of the transition hierarchy
* @param startValues The target values in the start scene
* @param startVisibility The target visibility in the start scene
* @param endValues The target values in the end scene
* @param endVisibility The target visibility in the end scene
* @return An Animator to be started at the appropriate time in the
* overall transition for this scene change. A null value means no animation
* should be run.
*/
public Animator onAppear(ViewGroup sceneRoot,
TransitionValues startValues, int startVisibility,
TransitionValues endValues, int endVisibility) {
return null;
}
/**
* The default implementation of this method does nothing. Subclasses
* should override if they need to create an Animator when targets disappear.
* The method should only be called by the Visibility class; it is
* not intended to be called from external classes.
*
* @param sceneRoot The root of the transition hierarchy
* @param startValues The target values in the start scene
* @param startVisibility The target visibility in the start scene
* @param endValues The target values in the end scene
* @param endVisibility The target visibility in the end scene
* @return An Animator to be started at the appropriate time in the
* overall transition for this scene change. A null value means no animation
* should be run.
*/
public Animator onDisappear(ViewGroup sceneRoot,
TransitionValues startValues, int startVisibility,
TransitionValues endValues, int endVisibility) {
return null;
}
private static class VisibilityInfo {
boolean visibilityChange;
boolean fadeIn;
int startVisibility;
int endVisibility;
ViewGroup startParent;
ViewGroup endParent;
VisibilityInfo() {
}
}
}