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Diffstat (limited to 'taler-kotlin-common/src/main/java/net/taler/common/CombinedLiveData.kt')
-rw-r--r-- | taler-kotlin-common/src/main/java/net/taler/common/CombinedLiveData.kt | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/taler-kotlin-common/src/main/java/net/taler/common/CombinedLiveData.kt b/taler-kotlin-common/src/main/java/net/taler/common/CombinedLiveData.kt new file mode 100644 index 0000000..4e7016b --- /dev/null +++ b/taler-kotlin-common/src/main/java/net/taler/common/CombinedLiveData.kt @@ -0,0 +1,51 @@ +/* + * This file is part of GNU Taler + * (C) 2020 Taler Systems S.A. + * + * GNU Taler is free software; you can redistribute it and/or modify it under the + * terms of the GNU General Public License as published by the Free Software + * Foundation; either version 3, or (at your option) any later version. + * + * GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY + * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR + * A PARTICULAR PURPOSE. See the GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along with + * GNU Taler; see the file COPYING. If not, see <http://www.gnu.org/licenses/> + */ + +package net.taler.common + +import androidx.lifecycle.LiveData +import androidx.lifecycle.MediatorLiveData +import androidx.lifecycle.Observer + +class CombinedLiveData<T, K, S>( + source1: LiveData<T>, + source2: LiveData<K>, + private val combine: (data1: T?, data2: K?) -> S +) : MediatorLiveData<S>() { + + private var data1: T? = null + private var data2: K? = null + + init { + super.addSource(source1) { t -> + data1 = t + value = combine(data1, data2) + } + super.addSource(source2) { k -> + data2 = k + value = combine(data1, data2) + } + } + + override fun <S : Any?> addSource(source: LiveData<S>, onChanged: Observer<in S>) { + throw UnsupportedOperationException() + } + + override fun <T : Any?> removeSource(toRemote: LiveData<T>) { + throw UnsupportedOperationException() + } + +} |