Java tutorial
/* * 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.animation.AnimatorListenerAdapter; import android.animation.ObjectAnimator; import android.animation.ValueAnimator; import android.support.v4.view.ViewCompat; import android.util.Log; import android.view.View; import android.view.ViewGroup; /** * This transition tracks changes to the visibility of target views in the * start and end scenes and fades views in or out when they become visible * or non-visible. Visibility is determined by both the * {@link View#setVisibility(int)} state of the view as well as whether it * is parented in the current view hierarchy. * * <p>The ability of this transition to fade out a particular view, and the * way that that fading operation takes place, is based on * the situation of the view in the view hierarchy. For example, if a view was * simply removed from its parent, then the view will be added into a {@link * android.view.ViewGroupOverlay} while fading. If a visible view is * changed to be {@link View#GONE} or {@link View#INVISIBLE}, then the * visibility will be changed to {@link View#VISIBLE} for the duration of * the animation. However, if a view is in a hierarchy which is also altering * its visibility, the situation can be more complicated. In general, if a * view that is no longer in the hierarchy in the end scene still has a * parent (so its parent hierarchy was removed, but it was not removed from * its parent), then it will be left alone to avoid side-effects from * improperly removing it from its parent. The only exception to this is if * the previous {@link android.transition.Scene} was * {@link ScenePort#getSceneForLayout(ViewGroup, int, android.content.Context) * created from a layout resource file}, then it is considered safe to un-parent * the starting scene view in order to fade it out.</p> * * <p>A Fade transition can be described in a resource file by using the * tag <code>fade</code>, along with the standard * attributes of {@link android.R.styleable#Fade} and * {@link android.R.styleable#Transition}.</p> */ class FadePort extends VisibilityPort { /** * Fading mode used in {@link #FadePort(int)} to make the transition * operate on targets that are appearing. Maybe be combined with * {@link #OUT} to fade both in and out. */ public static final int IN = 0x1; /** * Fading mode used in {@link #FadePort(int)} to make the transition * operate on targets that are disappearing. Maybe be combined with * {@link #IN} to fade both in and out. */ public static final int OUT = 0x2; private static final String LOG_TAG = "Fade"; private static final String PROPNAME_SCREEN_X = "android:fade:screenX"; private static final String PROPNAME_SCREEN_Y = "android:fade:screenY"; private static boolean DBG = TransitionPort.DBG && false; private int mFadingMode; /** * Constructs a Fade transition that will fade targets in and out. */ public FadePort() { this(IN | OUT); } /** * Constructs a Fade transition that will fade targets in * and/or out, according to the value of fadingMode. * * @param fadingMode The behavior of this transition, a combination of * {@link #IN} and {@link #OUT}. */ public FadePort(int fadingMode) { mFadingMode = fadingMode; } /** * Utility method to handle creating and running the Animator. */ private Animator createAnimation(View view, float startAlpha, float endAlpha, AnimatorListenerAdapter listener) { if (startAlpha == endAlpha) { // run listener if we're noop'ing the animation, to get the end-state results now if (listener != null) { listener.onAnimationEnd(null); } return null; } final ObjectAnimator anim = ObjectAnimator.ofFloat(view, "alpha", startAlpha, endAlpha); if (DBG) { Log.d(LOG_TAG, "Created animator " + anim); } if (listener != null) { anim.addListener(listener); } return anim; } private void captureValues(TransitionValues transitionValues) { int[] loc = new int[2]; transitionValues.view.getLocationOnScreen(loc); transitionValues.values.put(PROPNAME_SCREEN_X, loc[0]); transitionValues.values.put(PROPNAME_SCREEN_Y, loc[1]); } @Override public void captureStartValues(TransitionValues transitionValues) { super.captureStartValues(transitionValues); captureValues(transitionValues); } @Override public Animator onAppear(ViewGroup sceneRoot, TransitionValues startValues, int startVisibility, TransitionValues endValues, int endVisibility) { if ((mFadingMode & IN) != IN || endValues == null) { return null; } final View endView = endValues.view; if (DBG) { View startView = (startValues != null) ? startValues.view : null; Log.d(LOG_TAG, "Fade.onAppear: startView, startVis, endView, endVis = " + startView + ", " + startVisibility + ", " + endView + ", " + endVisibility); } endView.setAlpha(0); TransitionListener transitionListener = new TransitionListenerAdapter() { boolean mCanceled = false; float mPausedAlpha; @Override public void onTransitionCancel(TransitionPort transition) { endView.setAlpha(1); mCanceled = true; } @Override public void onTransitionEnd(TransitionPort transition) { if (!mCanceled) { endView.setAlpha(1); } } @Override public void onTransitionPause(TransitionPort transition) { mPausedAlpha = endView.getAlpha(); endView.setAlpha(1); } @Override public void onTransitionResume(TransitionPort transition) { endView.setAlpha(mPausedAlpha); } }; addListener(transitionListener); return createAnimation(endView, 0, 1, null); } @Override public Animator onDisappear(ViewGroup sceneRoot, TransitionValues startValues, int startVisibility, TransitionValues endValues, int endVisibility) { if ((mFadingMode & OUT) != OUT) { return null; } View view = null; View startView = (startValues != null) ? startValues.view : null; View endView = (endValues != null) ? endValues.view : null; if (DBG) { Log.d(LOG_TAG, "Fade.onDisappear: startView, startVis, endView, endVis = " + startView + ", " + startVisibility + ", " + endView + ", " + endVisibility); } View overlayView = null; View viewToKeep = null; if (endView == null || endView.getParent() == null) { if (endView != null) { // endView was removed from its parent - add it to the overlay view = overlayView = endView; } else if (startView != null) { // endView does not exist. Use startView only under certain // conditions, because placing a view in an overlay necessitates // it being removed from its current parent if (startView.getParent() == null) { // no parent - safe to use view = overlayView = startView; } else if (startView.getParent() instanceof View && startView.getParent().getParent() == null) { View startParent = (View) startView.getParent(); int id = startParent.getId(); if (id != View.NO_ID && sceneRoot.findViewById(id) != null && mCanRemoveViews) { // no parent, but its parent is unparented but the parent // hierarchy has been replaced by a new hierarchy with the same id // and it is safe to un-parent startView view = overlayView = startView; } } } } else { // visibility change if (endVisibility == View.INVISIBLE) { view = endView; viewToKeep = view; } else { // Becoming GONE if (startView == endView) { view = endView; viewToKeep = view; } else { view = startView; overlayView = view; } } } final int finalVisibility = endVisibility; // TODO: add automatic facility to Visibility superclass for keeping views around if (overlayView != null) { // TODO: Need to do this for general case of adding to overlay int screenX = (Integer) startValues.values.get(PROPNAME_SCREEN_X); int screenY = (Integer) startValues.values.get(PROPNAME_SCREEN_Y); int[] loc = new int[2]; sceneRoot.getLocationOnScreen(loc); ViewCompat.offsetLeftAndRight(overlayView, (screenX - loc[0]) - overlayView.getLeft()); ViewCompat.offsetTopAndBottom(overlayView, (screenY - loc[1]) - overlayView.getTop()); ViewGroupOverlay.createFrom(sceneRoot).add(overlayView); // sceneRoot.getOverlay().add(overlayView); // TODO: add automatic facility to Visibility superclass for keeping views around final float startAlpha = 1; float endAlpha = 0; final View finalView = view; final View finalOverlayView = overlayView; final View finalViewToKeep = viewToKeep; final ViewGroup finalSceneRoot = sceneRoot; final AnimatorListenerAdapter endListener = new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { finalView.setAlpha(startAlpha); // TODO: restore view offset from overlay repositioning if (finalViewToKeep != null) { finalViewToKeep.setVisibility(finalVisibility); } if (finalOverlayView != null) { ViewGroupOverlay.createFrom(finalSceneRoot).remove(finalOverlayView); // finalSceneRoot.getOverlay().remove(finalOverlayView); } } // // @Override // public void onAnimationPause(Animator animation) { // if (finalOverlayView != null) { // finalSceneRoot.getOverlay().remove(finalOverlayView); // } // } // // @Override // public void onAnimationResume(Animator animation) { // if (finalOverlayView != null) { // finalSceneRoot.getOverlay().add(finalOverlayView); // } // } }; return createAnimation(view, startAlpha, endAlpha, endListener); } if (viewToKeep != null) { // TODO: find a different way to do this, like just changing the view to be // VISIBLE for the duration of the transition viewToKeep.setVisibility((View.VISIBLE)); // TODO: add automatic facility to Visibility superclass for keeping views around final float startAlpha = 1; float endAlpha = 0; final View finalView = view; final View finalOverlayView = overlayView; final View finalViewToKeep = viewToKeep; final ViewGroup finalSceneRoot = sceneRoot; final AnimatorListenerAdapter endListener = new AnimatorListenerAdapter() { boolean mCanceled = false; float mPausedAlpha = -1; // @Override // public void onAnimationPause(Animator animation) { // if (finalViewToKeep != null && !mCanceled) { // finalViewToKeep.setVisibility(finalVisibility); // } // mPausedAlpha = finalView.getAlpha(); // finalView.setAlpha(startAlpha); // } // // @Override // public void onAnimationResume(Animator animation) { // if (finalViewToKeep != null && !mCanceled) { // finalViewToKeep.setVisibility(View.VISIBLE); // } // finalView.setAlpha(mPausedAlpha); // } @Override public void onAnimationCancel(Animator animation) { mCanceled = true; if (mPausedAlpha >= 0) { finalView.setAlpha(mPausedAlpha); } } @Override public void onAnimationEnd(Animator animation) { if (!mCanceled) { finalView.setAlpha(startAlpha); } // TODO: restore view offset from overlay repositioning if (finalViewToKeep != null && !mCanceled) { finalViewToKeep.setVisibility(finalVisibility); } if (finalOverlayView != null) { ViewGroupOverlay.createFrom(finalSceneRoot).add(finalOverlayView); // finalSceneRoot.getOverlay().remove(finalOverlayView); } } }; return createAnimation(view, startAlpha, endAlpha, endListener); } return null; } }