`showEmptyState()` -> EmptyStateUiHelper

As part of ongoing work to pull low-level empty state responsibilities
out of the pager adapter, this CL generally replicates the change
prototyped in ag/24516421/5..7, in smaller incremental steps to "show
the work." As originally described in that CL:

  "... moves most of the low-level logic of `showEmptyState()` into
the UI helper. (...) also has the UI helper take responsibility for
setting the visibility of the main "list view" in sync (opposite of)
the empty state visibility."

As presented in this CL, the "incremental steps" per-snapshot are:

 1. Extract most of the implementation directly to the new method at
    `EmptyStateUiHelper.showEmptyState()`. The general functionality
    is covered by existing integration tests (e.g., commenting-out the
    new method body causes `UnbundledChooserActivityWorkProfileTest`
    to fail). New `EmptyStateUiHelper` unit tests cover finer points
    of the empty-state "button" conditions, and I've added a TODO
    comment at one place legacy behavior seemingly may not align with
    the original developer intent.

 2. Also make the UI helper responsible for propagating empty-state
    visibility changes back to the main list view (hiding the main
    list when we show an empty state, and restoring it when the empty
    state is hidden).

 3. Look up all the sub-views during `EmptyStateUiHelper` construction
    so we don't have to keep repeating their View IDs throughout.

 4. Tighten visibility on `EmptyStateUiHelper.resetViewVisibilities()`
    now that it's a private `showEmptyState()` implementation detail
    (updated to package-protected/visible-for-testing). Also move the
    method to the end of the class (after all the public methods).

Bug: 302311217
Test: IntentResolverUnitTests
Change-Id: Iac0cf3d62e2c3bf22afa6a2796ae4e731b706c02

1 files changed, 85 insertions, 3 deletions

diff --git a/java/tests/src/com/android/intentresolver/v2/emptystate/EmptyStateUiHelperTest.kt b/java/tests/src/com/android/intentresolver/v2/emptystate/EmptyStateUiHelperTest.kt
index 27ed7e38..696dd1fd 100644
--- a/java/tests/src/com/android/intentresolver/v2/emptystate/EmptyStateUiHelperTest.kt
+++ b/java/tests/src/com/android/intentresolver/v2/emptystate/EmptyStateUiHelperTest.kt
@@ -20,12 +20,18 @@ import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import android.widget.FrameLayout
+import android.widget.TextView
 import androidx.test.platform.app.InstrumentationRegistry
+import com.android.intentresolver.any
+import com.android.intentresolver.emptystate.EmptyState
+import com.android.intentresolver.mock
 import com.google.common.truth.Truth.assertThat
 import java.util.Optional
 import java.util.function.Supplier
 import org.junit.Before
 import org.junit.Test
+import org.mockito.Mockito.never
+import org.mockito.Mockito.verify
 
 class EmptyStateUiHelperTest {
     private val context = InstrumentationRegistry.getInstrumentation().getContext()
@@ -37,8 +43,9 @@ class EmptyStateUiHelperTest {
         }
 
     lateinit var rootContainer: ViewGroup
-    lateinit var emptyStateTitleView: View
-    lateinit var emptyStateSubtitleView: View
+    lateinit var mainListView: View // Visible when no empty state is showing.
+    lateinit var emptyStateTitleView: TextView
+    lateinit var emptyStateSubtitleView: TextView
     lateinit var emptyStateButtonView: View
     lateinit var emptyStateProgressView: View
     lateinit var emptyStateDefaultTextView: View
@@ -55,6 +62,7 @@ class EmptyStateUiHelperTest {
                 rootContainer,
                 true
             )
+        mainListView = rootContainer.requireViewById(com.android.internal.R.id.resolver_list)
         emptyStateRootView =
             rootContainer.requireViewById(com.android.internal.R.id.resolver_empty_state)
         emptyStateTitleView =
@@ -68,7 +76,12 @@ class EmptyStateUiHelperTest {
         emptyStateDefaultTextView = rootContainer.requireViewById(com.android.internal.R.id.empty)
         emptyStateContainerView =
             rootContainer.requireViewById(com.android.internal.R.id.resolver_empty_state_container)
-        emptyStateUiHelper = EmptyStateUiHelper(rootContainer, containerPaddingSupplier)
+        emptyStateUiHelper =
+            EmptyStateUiHelper(
+                rootContainer,
+                com.android.internal.R.id.resolver_list,
+                containerPaddingSupplier
+            )
     }
 
     @Test
@@ -112,10 +125,12 @@ class EmptyStateUiHelperTest {
     @Test
     fun testHide() {
         emptyStateRootView.visibility = View.VISIBLE
+        mainListView.visibility = View.GONE
 
         emptyStateUiHelper.hide()
 
         assertThat(emptyStateRootView.visibility).isEqualTo(View.GONE)
+        assertThat(mainListView.visibility).isEqualTo(View.VISIBLE)
     }
 
     @Test
@@ -143,4 +158,71 @@ class EmptyStateUiHelperTest {
         assertThat(emptyStateContainerView.paddingRight).isEqualTo(3)
         assertThat(emptyStateContainerView.paddingBottom).isEqualTo(42)
     }
+
+    @Test
+    fun testShowEmptyState_noOnClickHandler() {
+        mainListView.visibility = View.VISIBLE
+
+        // Note: an `EmptyState.ClickListener` isn't invoked directly by the UI helper; it has to be
+        // built into the "on-click handler" that's injected to implement the button-press. We won't
+        // display the button without a click "handler," even if it *does* have a `ClickListener`.
+        val clickListener = mock<EmptyState.ClickListener>()
+
+        val emptyState =
+            object : EmptyState {
+                override fun getTitle() = "Test title"
+                override fun getSubtitle() = "Test subtitle"
+
+                override fun getButtonClickListener() = clickListener
+            }
+        emptyStateUiHelper.showEmptyState(emptyState, null)
+
+        assertThat(mainListView.visibility).isEqualTo(View.GONE)
+        assertThat(emptyStateRootView.visibility).isEqualTo(View.VISIBLE)
+        assertThat(emptyStateTitleView.visibility).isEqualTo(View.VISIBLE)
+        assertThat(emptyStateSubtitleView.visibility).isEqualTo(View.VISIBLE)
+        assertThat(emptyStateButtonView.visibility).isEqualTo(View.GONE)
+        assertThat(emptyStateProgressView.visibility).isEqualTo(View.GONE)
+        assertThat(emptyStateDefaultTextView.visibility).isEqualTo(View.GONE)
+
+        assertThat(emptyStateTitleView.text).isEqualTo("Test title")
+        assertThat(emptyStateSubtitleView.text).isEqualTo("Test subtitle")
+
+        verify(clickListener, never()).onClick(any())
+    }
+
+    @Test
+    fun testShowEmptyState_withOnClickHandlerAndClickListener() {
+        mainListView.visibility = View.VISIBLE
+
+        val clickListener = mock<EmptyState.ClickListener>()
+        val onClickHandler = mock<View.OnClickListener>()
+
+        val emptyState =
+            object : EmptyState {
+                override fun getTitle() = "Test title"
+                override fun getSubtitle() = "Test subtitle"
+
+                override fun getButtonClickListener() = clickListener
+            }
+        emptyStateUiHelper.showEmptyState(emptyState, onClickHandler)
+
+        assertThat(mainListView.visibility).isEqualTo(View.GONE)
+        assertThat(emptyStateRootView.visibility).isEqualTo(View.VISIBLE)
+        assertThat(emptyStateTitleView.visibility).isEqualTo(View.VISIBLE)
+        assertThat(emptyStateSubtitleView.visibility).isEqualTo(View.VISIBLE)
+        assertThat(emptyStateButtonView.visibility).isEqualTo(View.VISIBLE) // Now shown.
+        assertThat(emptyStateProgressView.visibility).isEqualTo(View.GONE)
+        assertThat(emptyStateDefaultTextView.visibility).isEqualTo(View.GONE)
+
+        assertThat(emptyStateTitleView.text).isEqualTo("Test title")
+        assertThat(emptyStateSubtitleView.text).isEqualTo("Test subtitle")
+
+        emptyStateButtonView.performClick()
+
+        verify(onClickHandler).onClick(emptyStateButtonView)
+        // The test didn't explicitly configure its `OnClickListener` to relay the click event on
+        // to the `EmptyState.ClickListener`, so it still won't have fired here.
+        verify(clickListener, never()).onClick(any())
+    }
 }