forked from android/compose-samples
-
Notifications
You must be signed in to change notification settings - Fork 0
/
HomeViewModel.kt
110 lines (96 loc) · 3.73 KB
/
HomeViewModel.kt
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
/*
* Copyright 2020 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.jetcaster.ui.home
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import com.example.jetcaster.Graph
import com.example.jetcaster.data.PodcastStore
import com.example.jetcaster.data.PodcastWithExtraInfo
import com.example.jetcaster.data.PodcastsRepository
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow
import kotlinx.coroutines.flow.catch
import kotlinx.coroutines.flow.collect
import kotlinx.coroutines.flow.combine
import kotlinx.coroutines.launch
class HomeViewModel(
private val podcastsRepository: PodcastsRepository = Graph.podcastRepository,
private val podcastStore: PodcastStore = Graph.podcastStore
) : ViewModel() {
// Holds our currently selected home category
private val selectedCategory = MutableStateFlow(HomeCategory.Discover)
// Holds the currently available home categories
private val categories = MutableStateFlow(HomeCategory.values().asList())
// Holds our view state which the UI collects via [state]
private val _state = MutableStateFlow(HomeViewState())
private val refreshing = MutableStateFlow(false)
val state: StateFlow<HomeViewState>
get() = _state
init {
viewModelScope.launch {
// Combines the latest value from each of the flows, allowing us to generate a
// view state instance which only contains the latest values.
combine(
categories,
selectedCategory,
podcastStore.followedPodcastsSortedByLastEpisode(limit = 20),
refreshing
) { categories, selectedCategory, podcasts, refreshing ->
HomeViewState(
homeCategories = categories,
selectedHomeCategory = selectedCategory,
featuredPodcasts = podcasts,
refreshing = refreshing,
errorMessage = null /* TODO */
)
}.catch { throwable ->
// TODO: emit a UI error here. For now we'll just rethrow
throw throwable
}.collect {
_state.value = it
}
}
refresh(force = false)
}
private fun refresh(force: Boolean) {
viewModelScope.launch {
runCatching {
refreshing.value = true
podcastsRepository.updatePodcasts(force)
}
// TODO: look at result of runCatching and show any errors
refreshing.value = false
}
}
fun onHomeCategorySelected(category: HomeCategory) {
selectedCategory.value = category
}
fun onPodcastUnfollowed(podcastUri: String) {
viewModelScope.launch {
podcastStore.unfollowPodcast(podcastUri)
}
}
}
enum class HomeCategory {
Library, Discover
}
data class HomeViewState(
val featuredPodcasts: List<PodcastWithExtraInfo> = emptyList(),
val refreshing: Boolean = false,
val selectedHomeCategory: HomeCategory = HomeCategory.Discover,
val homeCategories: List<HomeCategory> = emptyList(),
val errorMessage: String? = null
)