From 6a847bba04e417b41645f2d85c0fd13fdae9bbde Mon Sep 17 00:00:00 2001
From: Peter Liang <peterliang@google.com>
Date: Wed, 21 Sep 2022 20:45:19 +0800
Subject: [PATCH] Fix that display size and text preview is going blank while
 scrolling the page in landscape view.

Problem:
It seems that the inconsistent index would cause the view stub couldn't be inflated successfully.

Solution:
Adjust it to the same index.

Fix: 244336110
Test: manual test
Change-Id: I2688e6feb61ac64f989e5f8e4910e6eeca3a97bf
---
 .../TextReadingPreviewController.java         | 31 ++++++++++---------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/src/com/android/settings/accessibility/TextReadingPreviewController.java b/src/com/android/settings/accessibility/TextReadingPreviewController.java
index 98767d9d0ca..dab57babaed 100644
--- a/src/com/android/settings/accessibility/TextReadingPreviewController.java
+++ b/src/com/android/settings/accessibility/TextReadingPreviewController.java
@@ -42,6 +42,8 @@ import java.util.Objects;
 class TextReadingPreviewController extends BasePreferenceController implements
         PreviewSizeSeekBarController.ProgressInteractionListener {
     private static final String TAG = "TextReadingPreviewCtrl";
+    private static final int LAYER_INITIAL_INDEX = 0;
+    private static final int FRAME_INITIAL_INDEX = 0;
     static final int[] PREVIEW_SAMPLE_RES_IDS = new int[]{
             R.layout.accessibility_text_reading_preview_app_grid,
             R.layout.screen_zoom_preview_1,
@@ -108,25 +110,15 @@ class TextReadingPreviewController extends BasePreferenceController implements
         final PreviewPagerAdapter pagerAdapter = new PreviewPagerAdapter(mContext, isLayoutRtl,
                 PREVIEW_SAMPLE_RES_IDS, createConfig(origConfig));
         mPreviewPreference.setPreviewAdapter(pagerAdapter);
-        mPreviewPreference.setCurrentItem(isLayoutRtl ? PREVIEW_SAMPLE_RES_IDS.length - 1 : 0);
-        pagerAdapter.setPreviewLayer(/* newLayerIndex= */ 0,
-                /* currentLayerIndex= */ 0,
-                /* currentFrameIndex= */ 0, /* animate= */ false);
+        mPreviewPreference.setCurrentItem(
+                isLayoutRtl ? PREVIEW_SAMPLE_RES_IDS.length - 1 : FRAME_INITIAL_INDEX);
+        pagerAdapter.setPreviewLayer(getPagerIndex(), LAYER_INITIAL_INDEX,
+                FRAME_INITIAL_INDEX, /* animate= */ false);
     }
 
     @Override
     public void notifyPreferenceChanged() {
-        final int displayDataSize = mDisplaySizeData.getValues().size();
-        final int fontSizeProgress = mFontSizePreference.getProgress();
-        final int displaySizeProgress = mDisplaySizePreference.getProgress();
-
-        // To be consistent with the
-        // {@link PreviewPagerAdapter#setPreviewLayer(int, int, int, boolean)} behavior,
-        // here also needs the same design. In addition, please also refer to
-        // the {@link #createConfig(Configuration)}.
-        final int pagerIndex = fontSizeProgress * displayDataSize + displaySizeProgress;
-
-        mPreviewPreference.notifyPreviewPagerChanged(pagerIndex);
+        mPreviewPreference.notifyPreviewPagerChanged(getPagerIndex());
     }
 
     @Override
@@ -174,6 +166,15 @@ class TextReadingPreviewController extends BasePreferenceController implements
         choreographer.postFrameCallbackDelayed(mCommit, commitDelayMs);
     }
 
+    private int getPagerIndex() {
+        final int displayDataSize = mDisplaySizeData.getValues().size();
+
+        // To be consistent with the {@link PreviewPagerAdapter#setPreviewLayer(int, int, int,
+        // boolean)} behavior, here also needs the same design. In addition, please also refer to
+        // the {@link #createConfig(Configuration)}.
+        return mLastFontProgress * displayDataSize + mLastDisplayProgress;
+    }
+
     private void tryCommitFontSizeConfig() {
         final int fontProgress = mFontSizePreference.getProgress();
         if (fontProgress != mLastFontProgress) {