1 /* 2 * Copyright 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 @file:Suppress("NOTHING_TO_INLINE") 18 19 package androidx.preference 20 21 /** 22 * Returns the preference with `key`. 23 * 24 * @throws NullPointerException if no preference is found with that key. 25 */ 26 inline operator fun PreferenceGroup.get(key: CharSequence): Preference = findPreference(key) 27 28 /** 29 * Returns the preference at `index`. 30 * 31 * @throws IndexOutOfBoundsException if index is less than 0 or greater than or equal to the count. 32 */ 33 operator fun PreferenceGroup.get(index: Int): Preference = getPreference(index) 34 ?: throw IndexOutOfBoundsException("Index: $index, Size: $preferenceCount") 35 36 /** Returns `true` if `preference` is found in this preference group. */ 37 operator fun PreferenceGroup.contains(preference: Preference): Boolean { 38 for (index in 0 until preferenceCount) { 39 if (getPreference(index) == preference) { 40 return true 41 } 42 } 43 return false 44 } 45 46 /** Adds `preference` to this preference group. */ 47 inline operator fun PreferenceGroup.plusAssign(preference: Preference) { 48 addPreference(preference) 49 } 50 51 /** Removes `preference` from this preference group. */ 52 inline operator fun PreferenceGroup.minusAssign(preference: Preference) { 53 removePreference(preference) 54 } 55 56 /** Returns the number of preferences in this preference group. */ 57 inline val PreferenceGroup.size: Int get() = preferenceCount 58 59 /** Returns true if this preference group contains no preferences. */ 60 inline fun PreferenceGroup.isEmpty(): Boolean = size == 0 61 62 /** Returns true if this preference group contains one or more preferences. */ 63 inline fun PreferenceGroup.isNotEmpty(): Boolean = size != 0 64 65 /** Performs the given action on each preference in this preference group. */ 66 inline fun PreferenceGroup.forEach(action: (preference: Preference) -> Unit) { 67 for (index in 0 until preferenceCount) { 68 action(get(index)) 69 } 70 } 71 72 /** Performs the given action on each preference in this preference group, providing its sequential index. */ 73 inline fun PreferenceGroup.forEachIndexed(action: (index: Int, preference: Preference) -> Unit) { 74 for (index in 0 until preferenceCount) { 75 action(index, get(index)) 76 } 77 } 78 79 /** Returns a [MutableIterator] over the preferences in this preference group. */ 80 operator fun PreferenceGroup.iterator() = object : MutableIterator<Preference> { 81 private var index = 0 82 override fun hasNext() = index < size 83 override fun next() = getPreference(index++) ?: throw IndexOutOfBoundsException() 84 override fun remove() { 85 removePreference(getPreference(--index)) 86 } 87 } 88 89 /** Returns a [Sequence] over the preferences in this preference group. */ 90 val PreferenceGroup.children: Sequence<Preference> 91 get() = object : Sequence<Preference> { 92 override fun iterator() = this@children.iterator() 93 } 94
