refactor: Use LinearProgressIndicator with delayed show/hide (#525)

Previous code used a normal ProgressBar and a coroutine to delay
hiding/showing the bar for a snappier UI perception.

This is built-in functionality in LinearProgressIndicator, so switch to
that.

While I'm here, implement the "Select list" dialog's layout as a layout
resource.

app/src/main/java/app/pachli/TabPreferenceActivity.kt

@@ -19,13 +19,10 @@ package app.pachli
 
 import android.graphics.Color
 import android.os.Bundle
-import android.view.Gravity
 import android.view.View
 import android.view.ViewGroup
 import android.widget.ArrayAdapter
 import android.widget.FrameLayout
-import android.widget.LinearLayout
-import android.widget.ProgressBar
 import android.widget.TextView
 import androidx.activity.OnBackPressedCallback
 import androidx.appcompat.app.AlertDialog
@@ -42,7 +39,6 @@ import app.pachli.adapter.TabAdapter
 import app.pachli.appstore.EventHub
 import app.pachli.appstore.MainTabsChangedEvent
 import app.pachli.core.activity.BaseActivity
-import app.pachli.core.common.extensions.hide
 import app.pachli.core.common.extensions.show
 import app.pachli.core.common.extensions.viewBinding
 import app.pachli.core.common.extensions.visible
@@ -55,7 +51,7 @@ import app.pachli.core.navigation.ListActivityIntent
 import app.pachli.core.network.model.MastoList
 import app.pachli.core.network.retrofit.MastodonApi
 import app.pachli.databinding.ActivityTabPreferenceBinding
-import app.pachli.util.getDimension
+import app.pachli.databinding.DialogSelectListBinding
 import app.pachli.util.unsafeLazy
 import at.connyduck.sparkbutton.helpers.Utils
 import com.github.michaelbull.result.onFailure
@@ -67,10 +63,7 @@ import com.google.android.material.transition.MaterialContainerTransform
 import dagger.hilt.android.AndroidEntryPoint
 import java.util.regex.Pattern
 import javax.inject.Inject
-import kotlinx.coroutines.CoroutineStart
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.awaitCancellation
-import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
 import timber.log.Timber
 
@@ -296,26 +289,13 @@ class TabPreferenceActivity : BaseActivity(), ItemInteractionListener {
             }
         }
 
-        val statusLayout = LinearLayout(this)
+        val selectListBinding = DialogSelectListBinding.inflate(layoutInflater, null, false)
-        statusLayout.gravity = Gravity.CENTER
-        val progress = ProgressBar(this)
-        val preferredPadding = getDimension(this, androidx.appcompat.R.attr.dialogPreferredPadding)
-        progress.setPadding(preferredPadding, 0, preferredPadding, 0)
-        progress.visible(false)
-
-        val noListsText = TextView(this)
-        noListsText.setPadding(preferredPadding, 0, preferredPadding, 0)
-        noListsText.text = getText(R.string.select_list_empty)
-        noListsText.visible(false)
-
-        statusLayout.addView(progress)
-        statusLayout.addView(noListsText)
 
         val dialog = AlertDialog.Builder(this)
             .setTitle(R.string.select_list_title)
             .setNeutralButton(R.string.select_list_manage, null)
             .setNegativeButton(android.R.string.cancel, null)
-            .setView(statusLayout)
+            .setView(selectListBinding.root)
             .setAdapter(adapter) { _, position ->
                 adapter.getItem(position)?.let { item ->
                     val newTab = TabViewData.from(TabData.UserList(item.id, item.title))
@@ -326,8 +306,7 @@ class TabPreferenceActivity : BaseActivity(), ItemInteractionListener {
                 }
             }.create()
 
-        val showProgressBarJob = getProgressBarJob(progress, 500)
+        selectListBinding.progressBar.show()
-        showProgressBarJob.start()
 
         // Set the "Manage lists" button listener after creating the dialog. This ensures
         // that clicking the button does not dismiss the dialog, so when the user returns
@@ -338,21 +317,23 @@ class TabPreferenceActivity : BaseActivity(), ItemInteractionListener {
                 startActivity(ListActivityIntent(applicationContext))
             }
         }
+
         dialog.show()
 
         lifecycleScope.launch {
             listsRepository.lists.collect { result ->
                 result.onSuccess { lists ->
                     if (lists is Lists.Loaded) {
-                        showProgressBarJob.cancel()
+                        selectListBinding.progressBar.hide()
                         adapter.clear()
                         adapter.addAll(lists.lists.sortedWith(compareByListTitle))
-                        if (lists.lists.isEmpty()) noListsText.show()
+                        if (lists.lists.isEmpty()) selectListBinding.noLists.show()
                     }
                 }
 
                 result.onFailure {
-                    dialog.hide()
+                    selectListBinding.progressBar.hide()
+                    dialog.dismiss()
                     Snackbar.make(binding.root, R.string.error_list_load, Snackbar.LENGTH_LONG).show()
                     Timber.w(it.throwable, "failed to load lists")
                 }
@@ -360,18 +341,6 @@ class TabPreferenceActivity : BaseActivity(), ItemInteractionListener {
         }
     }
 
-    private fun getProgressBarJob(progressView: View, delayMs: Long) = this.lifecycleScope.launch(
-        start = CoroutineStart.LAZY,
-    ) {
-        try {
-            delay(delayMs)
-            progressView.show()
-            awaitCancellation()
-        } finally {
-            progressView.hide()
-        }
-    }
-
     private fun validateHashtag(input: CharSequence?): Boolean {
         val trimmedInput = input?.trim() ?: ""
         return trimmedInput.isNotEmpty() && hashtagRegex.matcher(trimmedInput).matches()

app/src/main/java/app/pachli/components/viewthread/ViewThreadFragment.kt

@@ -23,7 +23,6 @@ import android.view.MenuInflater
 import android.view.MenuItem
 import android.view.View
 import android.view.ViewGroup
-import androidx.annotation.CheckResult
 import androidx.core.view.MenuProvider
 import androidx.fragment.app.commit
 import androidx.fragment.app.viewModels
@@ -53,9 +52,6 @@ import com.google.android.material.color.MaterialColors
 import com.google.android.material.divider.MaterialDividerItemDecoration
 import com.google.android.material.snackbar.Snackbar
 import dagger.hilt.android.AndroidEntryPoint
-import kotlinx.coroutines.CoroutineStart
-import kotlinx.coroutines.awaitCancellation
-import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
 import timber.log.Timber
 
@@ -130,9 +126,6 @@ class ViewThreadFragment :
 
         (binding.recyclerView.itemAnimator as SimpleItemAnimator).supportsChangeAnimations = false
 
-        var initialProgressBar = getProgressBarJob(binding.initialProgressBar, 500)
-        var threadProgressBar = getProgressBarJob(binding.threadProgressBar, 500)
-
         viewLifecycleOwner.lifecycleScope.launch {
             viewModel.uiState.collect { uiState ->
                 when (uiState) {
@@ -142,8 +135,7 @@ class ViewThreadFragment :
                         binding.recyclerView.hide()
                         binding.statusView.hide()
 
-                        initialProgressBar = getProgressBarJob(binding.initialProgressBar, 500)
+                        binding.initialProgressBar.show()
-                        initialProgressBar.start()
                     }
                     is ThreadUiState.LoadingThread -> {
                         if (uiState.statusViewDatum == null) {
@@ -152,9 +144,8 @@ class ViewThreadFragment :
                             return@collect
                         }
 
-                        initialProgressBar.cancel()
+                        binding.initialProgressBar.hide()
-                        threadProgressBar = getProgressBarJob(binding.threadProgressBar, 500)
+                        binding.threadProgressBar.show()
-                        threadProgressBar.start()
 
                         if (viewModel.isInitialLoad) {
                             adapter.submitList(listOf(uiState.statusViewDatum))
@@ -170,8 +161,8 @@ class ViewThreadFragment :
                     }
                     is ThreadUiState.Error -> {
                         Timber.w(uiState.throwable, "failed to load status")
-                        initialProgressBar.cancel()
+                        binding.initialProgressBar.hide()
-                        threadProgressBar.cancel()
+                        binding.threadProgressBar.hide()
 
                         revealButtonState = RevealButtonState.NO_BUTTON
                         binding.swipeRefreshLayout.isRefreshing = false
@@ -188,7 +179,7 @@ class ViewThreadFragment :
                             return@collect
                         }
 
-                        threadProgressBar.cancel()
+                        binding.threadProgressBar.hide()
 
                         adapter.submitList(uiState.statusViewData) {
                             if (lifecycle.currentState.isAtLeast(Lifecycle.State.STARTED) && viewModel.isInitialLoad) {
@@ -209,7 +200,7 @@ class ViewThreadFragment :
                         binding.statusView.hide()
                     }
                     is ThreadUiState.Refreshing -> {
-                        threadProgressBar.cancel()
+                        binding.threadProgressBar.hide()
                     }
                 }
             }
@@ -275,28 +266,6 @@ class ViewThreadFragment :
         requireActivity().title = getString(R.string.title_view_thread)
     }
 
-    /**
-     * Create a job to implement a delayed-visible progress bar.
-     *
-     * Delaying the visibility of the progress bar can improve user perception of UI speed because
-     * fewer UI elements are appearing and disappearing.
-     *
-     * When started the job will wait `delayMs` then show `view`. If the job is cancelled at
-     * any time `view` is hidden.
-     */
-    @CheckResult
-    private fun getProgressBarJob(view: View, delayMs: Long) = viewLifecycleOwner.lifecycleScope.launch(
-        start = CoroutineStart.LAZY,
-    ) {
-        try {
-            delay(delayMs)
-            view.show()
-            awaitCancellation()
-        } finally {
-            view.hide()
-        }
-    }
-
     override fun onRefresh() {
         viewModel.refresh(thisThreadsStatusId)
     }

app/src/main/res/layout/dialog_select_list.xml

@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="utf-8"?><!--
+  ~ Copyright 2024 Pachli Association
+  ~
+  ~ This file is a part of Pachli.
+  ~
+  ~ This program 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 of the
+  ~ License, or (at your option) any later version.
+  ~
+  ~ Pachli 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 Pachli; if not,
+  ~ see <http://www.gnu.org/licenses>.
+  -->
+
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    android:layout_gravity="top">
+
+    <com.google.android.material.progressindicator.LinearProgressIndicator
+        android:id="@+id/progressBar"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:paddingStart="?dialogPreferredPadding"
+        android:paddingEnd="?dialogPreferredPadding"
+        android:layout_gravity="top"
+        android:indeterminate="true"
+        android:visibility="gone" />
+
+    <TextView
+        android:id="@+id/noLists"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:paddingStart="?dialogPreferredPadding"
+        android:paddingEnd="?dialogPreferredPadding"
+        android:text="@string/select_list_empty"
+        android:visibility="gone" />
+</LinearLayout>

app/src/main/res/layout/fragment_view_thread.xml

@@ -45,7 +45,7 @@
         </androidx.swiperefreshlayout.widget.SwipeRefreshLayout>
     </LinearLayout>
 
-    <ProgressBar
+    <com.google.android.material.progressindicator.LinearProgressIndicator
         android:id="@+id/initialProgressBar"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"

core/designsystem/src/main/res/values/styles.xml

@@ -84,6 +84,8 @@
         <item name="graphViewStyle">@style/Pachli.Widget.GraphView</item>
 
         <item name="snackbarTextViewStyle">@style/snackbar_text</item>
+
+        <item name="linearProgressIndicatorStyle">@style/Pachli.Widget.Material3.LinearProgressIndicator</item>
     </style>
 
     <style name="AppTheme" parent="Theme.Pachli" />
@@ -169,6 +171,11 @@
         <item name="lineWidth">2sp</item>
     </style>
 
+    <style name="Pachli.Widget.Material3.LinearProgressIndicator" parent="Widget.Material3.LinearProgressIndicator">
+        <item name="minHideDelay">500</item>
+        <item name="showDelay">500</item>
+    </style>
+
     <style name="Theme.Pachli.Black" parent="Base.Theme.Black" />
 
     <!-- customize the shape of the avatars in account selection list -->