Move `setupProfileTabs()` to the pager adapter

This splits out aspects of the "setup" behavior that are generic to
the pager adapter (building the tabs, setting up the event handlers)
from "application-specific" parameterizations (like providing the
strings for the tab labels, or implementing the event handlers in a
way that integrates with other UI elements in our app).

These changes are as prototyped in ag/25335069 and described in
go/chooser-ntab-refactoring, in particular replicating the changes of
"snapshot 31" and "snapshot 32." See below for a "by-snapshot"
breakdown of the incremental changes composed in this CL.

Snapshot 1: separate the `setupProfileTabs()` design within
`ResolverActivity` so it's easier to see the diffs before moving to
the pager adapter. A newly-introduced static method (of the same name)
takes over most of the implementation, while parameterizing the
details we'll consider "application-specific." Notably, this splits
up two existing "callback" designs that had both "generic" and
"application-specific" responsibilities -- our `OnTabChangedListener`
and `MultiProfilePagerAdapter.OnProfileSelectedListener` (which,
TODO: might be consolidated to a single design in the future?).
The "generic" aspects of these listeners move to the newly-extracted
static method, but the listeners also compose-in application-specific
behavior that's provided in the parameterization.

Snapshot 2: move the parameterized method into the pager-adapter
(replace "static" and use the pager-adapter "implicit this" instead
of taking it as the explicit first parameter).

Snapshot 3: integrate ChooserActivity with the "parameterized method"
that was extracted to the pager adapter. This wasn't part of the
original prototype but is needed now that ChooserActivity no longer
inherits a shared implementation from ResolverActivity. Equivalence
is clear from side-by-side reading of the pager-adapter implementation
and the (before-change) ChooserActivity implementation.

Snapshot 4: move `updateActiveTabStyle()` from a caller "parameter"
of `setupProfileTabs()` to an internal implementation detail in the
pager-adapter, and generalize the behavior to support any number of
tabs. (This was "snapshot 32" in the original prototype.)

Bug: 310211468
Test: `IntentResolver-tests-actvity`, `ResolverActivityTest`
Change-Id: Ifc3a0d81d148241966041f7efd74774f22a933d7

3 files changed, 119 insertions, 113 deletions

diff --git a/java/src/com/android/intentresolver/v2/ChooserActivity.java b/java/src/com/android/intentresolver/v2/ChooserActivity.java
index aa2b792a..2e020743 100644
--- a/java/src/com/android/intentresolver/v2/ChooserActivity.java
+++ b/java/src/com/android/intentresolver/v2/ChooserActivity.java
@@ -88,11 +88,9 @@ import android.view.ViewTreeObserver;
 import android.view.Window;
 import android.view.WindowInsets;
 import android.view.WindowManager;
-import android.widget.Button;
 import android.widget.FrameLayout;
 import android.widget.ImageView;
 import android.widget.TabHost;
-import android.widget.TabWidget;
 import android.widget.TextView;
 import android.widget.Toast;
 
@@ -1158,63 +1156,24 @@ public class ChooserActivity extends Hilt_ChooserActivity implements
 
     private void setupProfileTabs() {
         TabHost tabHost = findViewById(com.android.internal.R.id.profile_tabhost);
-        tabHost.setup();
         ViewPager viewPager = findViewById(com.android.internal.R.id.profile_pager);
-        viewPager.setSaveEnabled(false);
-
-        Button personalButton = (Button) getLayoutInflater().inflate(
-                R.layout.resolver_profile_tab_button, tabHost.getTabWidget(), false);
-        personalButton.setText(mDevicePolicyResources.getPersonalTabLabel());
-        personalButton.setContentDescription(
-                mDevicePolicyResources.getPersonalTabAccessibilityLabel());
-
-        TabHost.TabSpec tabSpec = tabHost.newTabSpec(TAB_TAG_PERSONAL)
-                .setContent(com.android.internal.R.id.profile_pager)
-                .setIndicator(personalButton);
-        tabHost.addTab(tabSpec);
-
-        Button workButton = (Button) getLayoutInflater().inflate(
-                R.layout.resolver_profile_tab_button, tabHost.getTabWidget(), false);
-        workButton.setText(mDevicePolicyResources.getWorkTabLabel());
-        workButton.setContentDescription(mDevicePolicyResources.getWorkTabAccessibilityLabel());
-
-        tabSpec = tabHost.newTabSpec(TAB_TAG_WORK)
-                .setContent(com.android.internal.R.id.profile_pager)
-                .setIndicator(workButton);
-        tabHost.addTab(tabSpec);
-
-        TabWidget tabWidget = tabHost.getTabWidget();
-        tabWidget.setVisibility(View.VISIBLE);
-
-        Runnable updateActiveTabStyle = () -> {
-            int currentTab = tabHost.getCurrentTab();
-            TextView selected = (TextView) tabHost.getTabWidget().getChildAt(currentTab);
-            TextView unselected = (TextView) tabHost.getTabWidget().getChildAt(1 - currentTab);
-            selected.setSelected(true);
-            unselected.setSelected(false);
-        };
-
-        updateActiveTabStyle.run();
-
-        tabHost.setOnTabChangedListener(tabId -> {
-            updateActiveTabStyle.run();
-            if (TAB_TAG_PERSONAL.equals(tabId)) {
-                viewPager.setCurrentItem(0);
-            } else {
-                viewPager.setCurrentItem(1);
-            }
-            onProfileTabSelected(viewPager.getCurrentItem());
-        });
 
-        viewPager.setVisibility(View.VISIBLE);
-        tabHost.setCurrentTab(mChooserMultiProfilePagerAdapter.getCurrentPage());
-        mChooserMultiProfilePagerAdapter.setOnProfileSelectedListener(
+        mChooserMultiProfilePagerAdapter.setupProfileTabs(
+                getLayoutInflater(),
+                tabHost,
+                viewPager,
+                R.layout.resolver_profile_tab_button,
+                com.android.internal.R.id.profile_pager,
+                mDevicePolicyResources.getPersonalTabLabel(),
+                mDevicePolicyResources.getPersonalTabAccessibilityLabel(),
+                TAB_TAG_PERSONAL,
+                mDevicePolicyResources.getWorkTabLabel(),
+                mDevicePolicyResources.getWorkTabAccessibilityLabel(),
+                TAB_TAG_WORK,
+                () -> onProfileTabSelected(viewPager.getCurrentItem()),
                 new MultiProfilePagerAdapter.OnProfileSelectedListener() {
                     @Override
-                    public void onProfilePageSelected(@Profile int profileId, int pageNumber) {
-                        tabHost.setCurrentTab(pageNumber);
-
-                    }
+                    public void onProfilePageSelected(@Profile int profileId, int pageNumber) {}
 
                     @Override
                     public void onProfilePageStateChanged(int state) {
@@ -1222,7 +1181,9 @@ public class ChooserActivity extends Hilt_ChooserActivity implements
                     }
                 });
         mOnSwitchOnWorkSelectedListener = () -> {
-            final View workTab = tabHost.getTabWidget().getChildAt(1);
+            final View workTab =
+                    tabHost.getTabWidget().getChildAt(
+                            mChooserMultiProfilePagerAdapter.getPageNumberForProfile(PROFILE_WORK));
             workTab.setFocusable(true);
             workTab.setFocusableInTouchMode(true);
             workTab.requestFocus();
diff --git a/java/src/com/android/intentresolver/v2/MultiProfilePagerAdapter.java b/java/src/com/android/intentresolver/v2/MultiProfilePagerAdapter.java
index dc821e88..3387a73f 100644
--- a/java/src/com/android/intentresolver/v2/MultiProfilePagerAdapter.java
+++ b/java/src/com/android/intentresolver/v2/MultiProfilePagerAdapter.java
@@ -19,8 +19,12 @@ import android.annotation.IntDef;
 import android.annotation.Nullable;
 import android.os.Trace;
 import android.os.UserHandle;
+import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
+import android.widget.Button;
+import android.widget.TabHost;
+import android.widget.TextView;
 
 import androidx.viewpager.widget.PagerAdapter;
 import androidx.viewpager.widget.ViewPager;
@@ -170,7 +174,7 @@ class MultiProfilePagerAdapter<
         return -1;
     }
 
-    private int getPageNumberForProfile(@Profile int profile) {
+    public int getPageNumberForProfile(@Profile int profile) {
         for (int i = 0; i < mItems.size(); ++i) {
             if (profile == mItems.get(i).mProfile) {
                 return i;
@@ -179,8 +183,85 @@ class MultiProfilePagerAdapter<
         return -1;
     }
 
-    public void setOnProfileSelectedListener(OnProfileSelectedListener listener) {
-        mOnProfileSelectedListener = listener;
+    private void updateActiveTabStyle(TabHost tabHost) {
+        int currentTab = tabHost.getCurrentTab();
+
+        for (int pageNumber = 0; pageNumber < getItemCount(); ++pageNumber) {
+            // TODO: can we avoid this downcast by pushing our knowledge of the intended view type
+            // somewhere else?
+            TextView tabText = (TextView) tabHost.getTabWidget().getChildAt(pageNumber);
+            tabText.setSelected(currentTab == pageNumber);
+        }
+    }
+
+    public void setupProfileTabs(
+            LayoutInflater layoutInflater,
+            TabHost tabHost,
+            ViewPager viewPager,
+            int tabButtonLayoutResId,
+            int tabPageContentViewId,
+            String personalTabLabel,
+            String personalTabAccessibilityLabel,
+            String personalTabTag,
+            String workTabLabel,
+            String workTabAccessibilityLabel,
+            String workTabTag,
+            Runnable onTabChangeListener,
+            MultiProfilePagerAdapter.OnProfileSelectedListener clientOnProfileSelectedListener) {
+        tabHost.setup();
+        viewPager.setSaveEnabled(false);
+
+        Button personalButton = (Button) layoutInflater.inflate(
+                tabButtonLayoutResId, tabHost.getTabWidget(), false);
+        personalButton.setText(personalTabLabel);
+        personalButton.setContentDescription(personalTabAccessibilityLabel);
+
+        TabHost.TabSpec personalTabSpec = tabHost.newTabSpec(personalTabTag)
+                .setContent(tabPageContentViewId)
+                .setIndicator(personalButton);
+        tabHost.addTab(personalTabSpec);
+
+        Button workButton = (Button) layoutInflater.inflate(
+                tabButtonLayoutResId, tabHost.getTabWidget(), false);
+        workButton.setText(workTabLabel);
+        workButton.setContentDescription(workTabAccessibilityLabel);
+
+        TabHost.TabSpec workTabSpec = tabHost.newTabSpec(workTabTag)
+                .setContent(tabPageContentViewId)
+                .setIndicator(workButton);
+        tabHost.addTab(workTabSpec);
+
+        tabHost.getTabWidget().setVisibility(View.VISIBLE);
+
+        updateActiveTabStyle(tabHost);
+
+        tabHost.setOnTabChangedListener(tabId -> {
+            updateActiveTabStyle(tabHost);
+            // TODO: update for 3+ tabs.
+            if (personalTabTag.equals(tabId)) {
+                viewPager.setCurrentItem(0);
+            } else {
+                viewPager.setCurrentItem(1);
+            }
+            onTabChangeListener.run();
+        });
+
+        viewPager.setVisibility(View.VISIBLE);
+        tabHost.setCurrentTab(getCurrentPage());
+        mOnProfileSelectedListener =
+                new MultiProfilePagerAdapter.OnProfileSelectedListener() {
+                    @Override
+                    public void onProfilePageSelected(@Profile int profileId, int pageNumber) {
+                        tabHost.setCurrentTab(pageNumber);
+                        clientOnProfileSelectedListener.onProfilePageSelected(
+                                profileId, pageNumber);
+                    }
+
+                    @Override
+                    public void onProfilePageStateChanged(int state) {
+                        clientOnProfileSelectedListener.onProfilePageStateChanged(state);
+                    }
+                };
     }
 
     /**
diff --git a/java/src/com/android/intentresolver/v2/ResolverActivity.java b/java/src/com/android/intentresolver/v2/ResolverActivity.java
index bc3fb16b..2a6ed9d5 100644
--- a/java/src/com/android/intentresolver/v2/ResolverActivity.java
+++ b/java/src/com/android/intentresolver/v2/ResolverActivity.java
@@ -81,7 +81,6 @@ import android.widget.ImageView;
 import android.widget.ListView;
 import android.widget.Space;
 import android.widget.TabHost;
-import android.widget.TabWidget;
 import android.widget.TextView;
 import android.widget.Toast;
 
@@ -1895,72 +1894,37 @@ public class ResolverActivity extends Hilt_ResolverActivity implements
 
     private void setupProfileTabs() {
         maybeHideDivider();
+
         TabHost tabHost = findViewById(com.android.internal.R.id.profile_tabhost);
-        tabHost.setup();
         ViewPager viewPager = findViewById(com.android.internal.R.id.profile_pager);
-        viewPager.setSaveEnabled(false);
-
-        Button personalButton = (Button) getLayoutInflater().inflate(
-                R.layout.resolver_profile_tab_button, tabHost.getTabWidget(), false);
-        personalButton.setText(mDevicePolicyResources.getPersonalTabLabel());
-        personalButton.setContentDescription(
-                mDevicePolicyResources.getPersonalTabAccessibilityLabel());
-
-        TabHost.TabSpec tabSpec = tabHost.newTabSpec(TAB_TAG_PERSONAL)
-                .setContent(com.android.internal.R.id.profile_pager)
-                .setIndicator(personalButton);
-        tabHost.addTab(tabSpec);
-
-        Button workButton = (Button) getLayoutInflater().inflate(
-                R.layout.resolver_profile_tab_button, tabHost.getTabWidget(), false);
-        workButton.setText(mDevicePolicyResources.getWorkTabLabel());
-        workButton.setContentDescription(mDevicePolicyResources.getWorkTabAccessibilityLabel());
-
-        tabSpec = tabHost.newTabSpec(TAB_TAG_WORK)
-                .setContent(com.android.internal.R.id.profile_pager)
-                .setIndicator(workButton);
-        tabHost.addTab(tabSpec);
-
-        TabWidget tabWidget = tabHost.getTabWidget();
-        tabWidget.setVisibility(View.VISIBLE);
-
-        Runnable updateActiveTabStyle = () -> {
-            int currentTab = tabHost.getCurrentTab();
-            TextView selected = (TextView) tabHost.getTabWidget().getChildAt(currentTab);
-            TextView unselected = (TextView) tabHost.getTabWidget().getChildAt(1 - currentTab);
-            selected.setSelected(true);
-            unselected.setSelected(false);
-        };
-
-        updateActiveTabStyle.run();
-
-        tabHost.setOnTabChangedListener(tabId -> {
-            updateActiveTabStyle.run();
-            if (TAB_TAG_PERSONAL.equals(tabId)) {
-                viewPager.setCurrentItem(0);
-            } else {
-                viewPager.setCurrentItem(1);
-            }
-            onProfileTabSelected(viewPager.getCurrentItem());
-        });
 
-        viewPager.setVisibility(View.VISIBLE);
-        tabHost.setCurrentTab(mMultiProfilePagerAdapter.getCurrentPage());
-        mMultiProfilePagerAdapter.setOnProfileSelectedListener(
+        mMultiProfilePagerAdapter.setupProfileTabs(
+                getLayoutInflater(),
+                tabHost,
+                viewPager,
+                R.layout.resolver_profile_tab_button,
+                com.android.internal.R.id.profile_pager,
+                mDevicePolicyResources.getPersonalTabLabel(),
+                mDevicePolicyResources.getPersonalTabAccessibilityLabel(),
+                TAB_TAG_PERSONAL,
+                mDevicePolicyResources.getWorkTabLabel(),
+                mDevicePolicyResources.getWorkTabAccessibilityLabel(),
+                TAB_TAG_WORK,
+                () -> onProfileTabSelected(viewPager.getCurrentItem()),
                 new MultiProfilePagerAdapter.OnProfileSelectedListener() {
                     @Override
                     public void onProfilePageSelected(@Profile int profileId, int pageNumber) {
-                        tabHost.setCurrentTab(pageNumber);
                         resetButtonBar();
                         resetCheckedItem();
                     }
 
                     @Override
-                    public void onProfilePageStateChanged(int state) {
-                    }
+                    public void onProfilePageStateChanged(int state) {}
                 });
         mOnSwitchOnWorkSelectedListener = () -> {
-            final View workTab = tabHost.getTabWidget().getChildAt(1);
+            final View workTab =
+                    tabHost.getTabWidget().getChildAt(
+                            mMultiProfilePagerAdapter.getPageNumberForProfile(PROFILE_WORK));
             workTab.setFocusable(true);
             workTab.setFocusableInTouchMode(true);
             workTab.requestFocus();