Fix accessibility button footer preference did not announced correct by TalkBack

Root Cause: Description would be altered after displayPreference(), but getSummary() would be called after it.

Solution: Update title before displayPreference(), then it could be set correctly.

Fix: 192738520
Test: atest AccessibilityButtonFooterPreferenceControllerTest
Change-Id: I068994fca8202b166fedf43f9d9657b0c1a64c4e

src/com/android/settings/accessibility/AccessibilityButtonFooterPreferenceController.java

@@ -18,6 +18,8 @@ package com.android.settings.accessibility;
 
 import android.content.Context;
 
+import androidx.preference.PreferenceScreen;
+
 import com.android.settings.R;
 
 /**
@@ -36,9 +38,16 @@ public class AccessibilityButtonFooterPreferenceController extends
     }
 
     @Override
-    public CharSequence getSummary() {
-        return AccessibilityUtil.isGestureNavigateEnabled(mContext)
-                ? mContext.getString(R.string.accessibility_button_gesture_description)
-                : mContext.getString(R.string.accessibility_button_description);
+    public void displayPreference(PreferenceScreen screen) {
+        // Need to update footerPreference's data before super.displayPreference(), then it will use
+        // data to update related property of footerPreference.
+        if (AccessibilityUtil.isGestureNavigateEnabled(mContext)) {
+            final AccessibilityFooterPreference footerPreference =
+                    screen.findPreference(getPreferenceKey());
+            footerPreference.setTitle(
+                    mContext.getString(R.string.accessibility_button_gesture_description));
+        }
+
+        super.displayPreference(screen);
     }
 }