59 lines
1.8 KiB
Kotlin
59 lines
1.8 KiB
Kotlin
/*
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* Copyright (c) 2019 Hemanth Savarala.
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*
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* Licensed under the GNU General Public License v3
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*
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* This is free software: you can redistribute it and/or modify it under
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* the terms of the GNU General Public License as published by
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* the Free Software Foundation either version 3 of the License, or (at your option) any later version.
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*
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* This software is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
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* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*/
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package code.name.monkey.retromusic.misc
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import com.google.android.material.appbar.AppBarLayout
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import kotlin.math.abs
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/**
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* @author Hemanth S (h4h13).
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* https://stackoverflow.com/a/33891727
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*/
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abstract class AppBarStateChangeListener : AppBarLayout.OnOffsetChangedListener {
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private var mCurrentState = State.IDLE
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override fun onOffsetChanged(appBarLayout: AppBarLayout, i: Int) {
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when {
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i == 0 -> {
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if (mCurrentState != State.EXPANDED) {
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onStateChanged(appBarLayout, State.EXPANDED)
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}
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mCurrentState = State.EXPANDED
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}
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abs(i) >= appBarLayout.totalScrollRange -> {
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if (mCurrentState != State.COLLAPSED) {
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onStateChanged(appBarLayout, State.COLLAPSED)
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}
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mCurrentState = State.COLLAPSED
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}
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else -> {
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if (mCurrentState != State.IDLE) {
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onStateChanged(appBarLayout, State.IDLE)
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}
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mCurrentState = State.IDLE
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}
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}
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}
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abstract fun onStateChanged(appBarLayout: AppBarLayout, state: State)
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enum class State {
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EXPANDED,
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COLLAPSED,
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IDLE
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}
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} |