1 /* 2 * Copyright (C) 2018 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.launcher3.uioverrides; 18 19 import android.animation.ValueAnimator; 20 21 import com.android.launcher3.Launcher; 22 import com.android.launcher3.LauncherState; 23 import com.android.launcher3.LauncherStateManager; 24 import com.android.launcher3.anim.AnimatorSetBuilder; 25 import com.android.quickstep.OverviewInteractionState; 26 27 public class BackButtonAlphaHandler implements LauncherStateManager.StateHandler { 28 29 private static final String TAG = "BackButtonAlphaHandler"; 30 31 private final Launcher mLauncher; 32 private final OverviewInteractionState mOverviewInteractionState; 33 BackButtonAlphaHandler(Launcher launcher)34 public BackButtonAlphaHandler(Launcher launcher) { 35 mLauncher = launcher; 36 mOverviewInteractionState = OverviewInteractionState.getInstance(mLauncher); 37 } 38 39 @Override setState(LauncherState state)40 public void setState(LauncherState state) { 41 UiFactory.onLauncherStateOrFocusChanged(mLauncher); 42 } 43 44 @Override setStateWithAnimation(LauncherState toState, AnimatorSetBuilder builder, LauncherStateManager.AnimationConfig config)45 public void setStateWithAnimation(LauncherState toState, 46 AnimatorSetBuilder builder, LauncherStateManager.AnimationConfig config) { 47 if (!config.playNonAtomicComponent()) { 48 return; 49 } 50 float fromAlpha = mOverviewInteractionState.getBackButtonAlpha(); 51 float toAlpha = toState.hideBackButton ? 0 : 1; 52 if (Float.compare(fromAlpha, toAlpha) != 0) { 53 ValueAnimator anim = ValueAnimator.ofFloat(fromAlpha, toAlpha); 54 anim.setDuration(config.duration); 55 anim.addUpdateListener(valueAnimator -> { 56 final float alpha = (float) valueAnimator.getAnimatedValue(); 57 mOverviewInteractionState.setBackButtonAlpha(alpha, false); 58 }); 59 builder.play(anim); 60 } 61 } 62 } 63