Java tutorial
/* * Copyright (C) 2017 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.graphics.drawable; import static android.support.annotation.RestrictTo.Scope.LIBRARY_GROUP; import android.content.Context; import android.content.res.Resources; import android.content.res.Resources.NotFoundException; import android.content.res.Resources.Theme; import android.content.res.XmlResourceParser; import android.os.Build; import android.support.annotation.RestrictTo; import android.support.v4.view.animation.FastOutLinearInInterpolator; import android.support.v4.view.animation.FastOutSlowInInterpolator; import android.support.v4.view.animation.LinearOutSlowInInterpolator; import android.util.AttributeSet; import android.util.Xml; import android.view.animation.AccelerateDecelerateInterpolator; import android.view.animation.AccelerateInterpolator; import android.view.animation.AnimationUtils; import android.view.animation.AnticipateInterpolator; import android.view.animation.AnticipateOvershootInterpolator; import android.view.animation.BounceInterpolator; import android.view.animation.CycleInterpolator; import android.view.animation.DecelerateInterpolator; import android.view.animation.Interpolator; import android.view.animation.LinearInterpolator; import android.view.animation.OvershootInterpolator; import org.xmlpull.v1.XmlPullParser; import org.xmlpull.v1.XmlPullParserException; import java.io.IOException; /** * Defines common utilities for working with animations. * @hide */ @RestrictTo(LIBRARY_GROUP) public class AnimationUtilsCompat { /** * Loads an {@link Interpolator} object from a resource * * @param context Application context used to access resources * @param id The resource id of the animation to load * @return The animation object reference by the specified id */ public static Interpolator loadInterpolator(Context context, int id) throws NotFoundException { // From API 21, we added path Interpolator . if (Build.VERSION.SDK_INT >= 21) { return AnimationUtils.loadInterpolator(context, id); } XmlResourceParser parser = null; try { // Special treatment for the interpolator introduced at API 21. if (id == AndroidResources.FAST_OUT_LINEAR_IN) { return new FastOutLinearInInterpolator(); } else if (id == AndroidResources.FAST_OUT_SLOW_IN) { return new FastOutSlowInInterpolator(); } else if (id == AndroidResources.LINEAR_OUT_SLOW_IN) { return new LinearOutSlowInInterpolator(); } parser = context.getResources().getAnimation(id); return createInterpolatorFromXml(context, context.getResources(), context.getTheme(), parser); } catch (XmlPullParserException ex) { NotFoundException rnf = new NotFoundException( "Can't load animation resource ID #0x" + Integer.toHexString(id)); rnf.initCause(ex); throw rnf; } catch (IOException ex) { NotFoundException rnf = new NotFoundException( "Can't load animation resource ID #0x" + Integer.toHexString(id)); rnf.initCause(ex); throw rnf; } finally { if (parser != null) parser.close(); } } private static Interpolator createInterpolatorFromXml(Context context, Resources res, Theme theme, XmlPullParser parser) throws XmlPullParserException, IOException { Interpolator interpolator = null; // Make sure we are on a start tag. int type; int depth = parser.getDepth(); while (((type = parser.next()) != XmlPullParser.END_TAG || parser.getDepth() > depth) && type != XmlPullParser.END_DOCUMENT) { if (type != XmlPullParser.START_TAG) { continue; } AttributeSet attrs = Xml.asAttributeSet(parser); String name = parser.getName(); if (name.equals("linearInterpolator")) { interpolator = new LinearInterpolator(); } else if (name.equals("accelerateInterpolator")) { interpolator = new AccelerateInterpolator(context, attrs); } else if (name.equals("decelerateInterpolator")) { interpolator = new DecelerateInterpolator(context, attrs); } else if (name.equals("accelerateDecelerateInterpolator")) { interpolator = new AccelerateDecelerateInterpolator(); } else if (name.equals("cycleInterpolator")) { interpolator = new CycleInterpolator(context, attrs); } else if (name.equals("anticipateInterpolator")) { interpolator = new AnticipateInterpolator(context, attrs); } else if (name.equals("overshootInterpolator")) { interpolator = new OvershootInterpolator(context, attrs); } else if (name.equals("anticipateOvershootInterpolator")) { interpolator = new AnticipateOvershootInterpolator(context, attrs); } else if (name.equals("bounceInterpolator")) { interpolator = new BounceInterpolator(); } else if (name.equals("pathInterpolator")) { interpolator = new PathInterpolatorCompat(context, attrs, parser); } else { throw new RuntimeException("Unknown interpolator name: " + parser.getName()); } } return interpolator; } }