1 /* 2 * Copyright (C) 2020 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.deskclock.widget 18 19 import android.transition.Fade 20 import android.transition.Transition 21 import android.transition.TransitionManager 22 import android.transition.TransitionSet 23 import android.view.View 24 import android.view.ViewGroup 25 26 import com.android.deskclock.Utils 27 28 /** 29 * Controller that displays empty view and handles animation appropriately. 30 * 31 * @param contentView The view that should be displayed when empty view is hidden. 32 * @param emptyView The view that should be displayed when main view is empty. 33 */ 34 class EmptyViewController( 35 private val mMainLayout: ViewGroup, 36 private val mContentView: View, 37 private val mEmptyView: View 38 ) { 39 private var mEmptyViewTransition: Transition? = null 40 private var mIsEmpty = false 41 42 init { 43 mEmptyViewTransition = if (USE_TRANSITION_FRAMEWORK) { 44 TransitionSet() 45 .setOrdering(TransitionSet.ORDERING_SEQUENTIAL) 46 .addTarget(mContentView) 47 .addTarget(mEmptyView) 48 .addTransition(Fade(Fade.OUT)) 49 .addTransition(Fade(Fade.IN)) 50 .setDuration(ANIMATION_DURATION.toLong()) 51 } else { 52 null 53 } 54 } 55 56 /** 57 * Sets the state for the controller. If it's empty, it will display the empty view. 58 * 59 * @param isEmpty Whether or not the controller should transition into empty state. 60 */ setEmptynull61 fun setEmpty(isEmpty: Boolean) { 62 if (mIsEmpty == isEmpty) { 63 return 64 } 65 mIsEmpty = isEmpty 66 // State changed, perform transition. 67 if (USE_TRANSITION_FRAMEWORK) { 68 TransitionManager.beginDelayedTransition(mMainLayout, mEmptyViewTransition) 69 } 70 mEmptyView.visibility = if (mIsEmpty) View.VISIBLE else View.GONE 71 mContentView.visibility = if (mIsEmpty) View.GONE else View.VISIBLE 72 } 73 74 companion object { 75 private const val ANIMATION_DURATION = 300 76 private val USE_TRANSITION_FRAMEWORK = Utils.isLOrLater 77 } 78 }