mirror of https://github.com/KokaKiwi/BarInsta
69 lines
2.1 KiB
Kotlin
69 lines
2.1 KiB
Kotlin
/*
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* Copyright 2017 Google Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package awais.instagrabber.utils
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import android.util.Log
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import androidx.annotation.MainThread
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import androidx.lifecycle.LifecycleOwner
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import androidx.lifecycle.MutableLiveData
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import androidx.lifecycle.Observer
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import awais.instagrabber.utils.extensions.TAG
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import java.util.concurrent.atomic.AtomicBoolean
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/**
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* A lifecycle-aware observable that sends only new updates after subscription, used for events like
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* navigation and Snackbar messages.
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*
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*
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* This avoids a common problem with events: on configuration change (like rotation) an update
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* can be emitted if the observer is active. This LiveData only calls the observable if there's an
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* explicit call to setValue() or call().
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*
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*
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* Note that only one observer is going to be notified of changes.
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*/
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class SingleLiveEvent<T> : MutableLiveData<T>() {
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private val pending = AtomicBoolean(false)
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@MainThread
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override fun observe(owner: LifecycleOwner, observer: Observer<in T>) {
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if (hasActiveObservers()) {
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Log.w(TAG, "Multiple observers registered but only one will be notified of changes.")
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}
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// Observe the internal MutableLiveData
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super.observe(owner, { t ->
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if (pending.compareAndSet(true, false)) {
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observer.onChanged(t)
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}
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})
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}
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@MainThread
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override fun setValue(t: T?) {
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pending.set(true)
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super.setValue(t)
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}
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/**
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* Used for cases where T is Void, to make calls cleaner.
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*/
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@MainThread
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fun call() {
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value = null
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}
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}
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