Merge #60

60: Make saving a swipe action r=msfjarvis a=msfjarvis

~~This isn't ready yet, because when done we want to make this use just `Modifier.swipeable` and not actually dismiss the view.~~ Good to go now 


Co-authored-by: Harsh Shandilya <me@msfjarvis.dev>

app/build.gradle

@@ -53,6 +53,7 @@ tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).configureEach {
       "-Xskip-prerelease-check",
       "-Xopt-in=kotlin.RequiresOptIn",
       "-Xopt-in=kotlinx.coroutines.ExperimentalCoroutinesApi",
+      "-Xopt-in=androidx.compose.material.ExperimentalMaterialApi",
     ]
   }
 }

app/src/main/java/dev/msfjarvis/lobsters/ui/posts/EmptyList.kt

@@ -8,11 +8,11 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.unit.dp
 import dev.msfjarvis.lobsters.R
 import dev.msfjarvis.lobsters.util.IconResource
-import dev.msfjarvis.lobsters.ui.theme.savedTitleColor
 
 @Composable
 fun EmptyList(saved: Boolean) {
@@ -24,7 +24,7 @@ fun EmptyList(saved: Boolean) {
     if (saved) {
       IconResource(
         R.drawable.ic_favorite_border_24px,
-        tint = savedTitleColor,
+        tint = Color(0xFFD97373),
         modifier = Modifier.padding(16.dp)
       )
       Text(stringResource(R.string.no_saved_posts))

app/src/main/java/dev/msfjarvis/lobsters/ui/posts/LobstersItem.kt

@@ -6,18 +6,23 @@ import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.offsetPx
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.layout.wrapContentHeight
 import androidx.compose.foundation.lazy.LazyColumnFor
 import androidx.compose.foundation.lazy.LazyItemScope
 import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.FractionalThreshold
+import androidx.compose.material.rememberSwipeableState
+import androidx.compose.material.swipeable
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.gesture.scrollorientationlocking.Orientation
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.platform.ConfigurationAmbient
+import androidx.compose.ui.platform.DensityAmbient
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 import androidx.ui.tooling.preview.Preview
@@ -27,9 +32,13 @@ import dev.msfjarvis.lobsters.injection.ApiModule
 import dev.msfjarvis.lobsters.model.LobstersPost
 import dev.msfjarvis.lobsters.model.Submitter
 import dev.msfjarvis.lobsters.ui.theme.LobstersTheme
-import dev.msfjarvis.lobsters.ui.theme.savedTitleColor
 import dev.msfjarvis.lobsters.ui.theme.titleColor
 
+private enum class SwipeState {
+  NotSwiped,
+  FullySwiped,
+}
+
 @Composable
 fun LazyItemScope.LobstersItem(
   post: LobstersPost,
@@ -38,20 +47,29 @@ fun LazyItemScope.LobstersItem(
   commentOpenAction: (LobstersPost) -> Unit,
   saveAction: (LobstersPost) -> Unit,
 ) {
-  val liked = remember { mutableStateOf(false) }
+  val width = with(DensityAmbient.current) {
-  val titleColor = if (post.isLiked || liked.value) savedTitleColor else titleColor
+    ConfigurationAmbient.current.screenWidthDp.toDp().toPx()
+  }
+  val swipeableState = rememberSwipeableState(SwipeState.NotSwiped)
+  val anchors = mapOf(0f to SwipeState.NotSwiped, width to SwipeState.FullySwiped)
+  if (swipeableState.offset.value >= (width / 2)) {
+    saveAction.invoke(post)
+    swipeableState.animateTo(SwipeState.NotSwiped)
+  }
 
   Column(
     modifier = modifier
       .fillParentMaxWidth()
+      .swipeable(
+        state = swipeableState,
+        anchors = anchors,
+        thresholds = { _, _ -> FractionalThreshold(0.5f) },
+        orientation = Orientation.Horizontal
+      )
+      .offsetPx(swipeableState.offset)
       .clickable(
         onClick = { linkOpenAction.invoke(post) },
         onLongClick = { commentOpenAction.invoke(post) },
-        onDoubleClick = {
-          post.isLiked = true
-          liked.value = true
-          saveAction.invoke(post)
-        },
       ),
   ) {
     Text(
@@ -128,7 +146,8 @@ fun PreviewLobstersItem() {
         post = item,
         linkOpenAction = {},
         commentOpenAction = {},
-        saveAction = {})
+        saveAction = {},
+      )
     }
   }
 }

app/src/main/java/dev/msfjarvis/lobsters/ui/theme/Theme.kt

@@ -6,7 +6,6 @@ import androidx.compose.runtime.Composable
 import androidx.compose.ui.graphics.Color
 
 val titleColor = Color(0xFF7395D9)
-val savedTitleColor = Color(0xFFD97373)
 
 val darkColors = darkColors(
   primary = Color.White,

app/src/main/java/dev/msfjarvis/lobsters/ui/viewmodel/LobstersViewModel.kt

@@ -54,15 +54,9 @@ class LobstersViewModel @ViewModelInject constructor(
     getMorePostsInternal(false)
   }
 
-  fun refreshPosts() {
-    apiPage = 1
-    getMorePostsInternal(true)
-  }
-
   private fun getMorePostsInternal(firstLoad: Boolean) {
     viewModelScope.launch(coroutineExceptionHandler) {
       val newPosts = lobstersApi.getHottestPosts(apiPage)
-        .transformLikedFlag()
         .toList()
       if (firstLoad) {
         _posts.value = newPosts
@@ -79,7 +73,6 @@ class LobstersViewModel @ViewModelInject constructor(
     viewModelScope.launch {
       savedPostsDao.insertPosts(post)
       getSavedPosts()
-      _posts.value = _posts.value.transformLikedFlag().toList()
     }
   }
 
@@ -87,11 +80,6 @@ class LobstersViewModel @ViewModelInject constructor(
     viewModelScope.launch {
       savedPostsDao.deletePostById(post.shortId)
       getSavedPosts()
-      _posts.value = _posts.value.transformLikedFlag().toList()
     }
   }
-
-  private suspend fun List<LobstersPost>.transformLikedFlag() = map {
-    it.apply { isLiked = savedPostsDao.isLiked(shortId) }
-  }
 }

model/src/main/java/dev/msfjarvis/lobsters/model/LobstersPost.kt

@@ -23,5 +23,6 @@ class LobstersPost(
   @Json(name = "submitter_user")
   val submitterUser: Submitter,
   val tags: List<String>,
-  var isLiked: Boolean = false,
+  @Deprecated("Retained for database compatibility as I am too lazy to write migrations")
+  val isLiked: Boolean = false,
 )