Focus content or button on AlertController

Requests focus for the content view, or if the content does not accept
focus, a button on an alert dialog if not in touch mode.

Before, the ScrollView containing the buttons received focus, and the
user had to navigate to a button before being able to click it.

Tries to focus the first available button in the order of positive
button, negative button, neutral button.

Test: Manual test on Android TV:
       - Suspend YouTube package using `adb shell pm suspend com.google.android.youtube.tv`
       - Try starting the YouTube app, observe focus on alert dialog
       - Also tested with AlertDialogs with custom views, list view
Bug: 129467676
Change-Id: I69f39d0ade5a8b275f865ef1a76984407413c282

core/java/com/android/internal/app/AlertController.java

@@ -559,6 +559,13 @@ public class AlertController {
         final boolean hasButtonPanel = buttonPanel != null
                 && buttonPanel.getVisibility() != View.GONE;
 
+        if (!parentPanel.isInTouchMode()) {
+            final View content = hasCustomPanel ? customPanel : contentPanel;
+            if (!requestFocusForContent(content)) {
+                requestFocusForDefaultButton();
+            }
+        }
+
         // Only display the text spacer if we don't have buttons.
         if (!hasButtonPanel) {
             if (contentPanel != null) {
@@ -624,6 +631,29 @@ public class AlertController {
         a.recycle();
     }
 
+    private boolean requestFocusForContent(View content) {
+        if (content != null && content.requestFocus()) {
+            return true;
+        }
+
+        if (mListView != null) {
+            mListView.setSelection(0);
+            return true;
+        }
+
+        return false;
+    }
+
+    private void requestFocusForDefaultButton() {
+        if (mButtonPositive.getVisibility() == View.VISIBLE) {
+            mButtonPositive.requestFocus();
+        } else if (mButtonNegative.getVisibility() == View.VISIBLE) {
+            mButtonNegative.requestFocus();
+        } else if (mButtonNeutral.getVisibility() == View.VISIBLE) {
+            mButtonNeutral.requestFocus();
+        }
+    }
+
     private void setupCustomContent(ViewGroup customPanel) {
         final View customView;
         if (mView != null) {