diff --git a/core/java/android/view/inputmethod/InputMethodManager.java b/core/java/android/view/inputmethod/InputMethodManager.java
index 0d21673..5f8b13b 100644
--- a/core/java/android/view/inputmethod/InputMethodManager.java
+++ b/core/java/android/view/inputmethod/InputMethodManager.java
@@ -611,7 +611,8 @@
         @Override
         public void startInputAsyncOnWindowFocusGain(View focusedView,
                 @SoftInputModeFlags int softInputMode, int windowFlags, boolean forceNewFocus) {
-            final int startInputFlags = getStartInputFlags(focusedView, 0);
+            int startInputFlags = getStartInputFlags(focusedView, 0);
+            startInputFlags |= StartInputFlags.WINDOW_GAINED_FOCUS;
 
             final ImeFocusController controller = getFocusController();
             if (controller == null) {
diff --git a/core/java/com/android/internal/inputmethod/InputMethodDebug.java b/core/java/com/android/internal/inputmethod/InputMethodDebug.java
index 37f6823..3bcba75 100644
--- a/core/java/com/android/internal/inputmethod/InputMethodDebug.java
+++ b/core/java/com/android/internal/inputmethod/InputMethodDebug.java
@@ -224,6 +224,8 @@
                 return "HIDE_DOCKED_STACK_ATTACHED";
             case SoftInputShowHideReason.HIDE_RECENTS_ANIMATION:
                 return "HIDE_RECENTS_ANIMATION";
+            case SoftInputShowHideReason.HIDE_SAME_WINDOW_FOCUSED_WITHOUT_EDITOR:
+                return "HIDE_SAME_WINDOW_FOCUSED_WITHOUT_EDITOR";
             default:
                 return "Unknown=" + reason;
         }
diff --git a/core/java/com/android/internal/inputmethod/SoftInputShowHideReason.java b/core/java/com/android/internal/inputmethod/SoftInputShowHideReason.java
index 4b968b4..f46626b 100644
--- a/core/java/com/android/internal/inputmethod/SoftInputShowHideReason.java
+++ b/core/java/com/android/internal/inputmethod/SoftInputShowHideReason.java
@@ -47,7 +47,8 @@
         SoftInputShowHideReason.HIDE_POWER_BUTTON_GO_HOME,
         SoftInputShowHideReason.HIDE_DOCKED_STACK_ATTACHED,
         SoftInputShowHideReason.HIDE_RECENTS_ANIMATION,
-        SoftInputShowHideReason.HIDE_BUBBLES})
+        SoftInputShowHideReason.HIDE_BUBBLES,
+        SoftInputShowHideReason.HIDE_SAME_WINDOW_FOCUSED_WITHOUT_EDITOR})
 public @interface SoftInputShowHideReason {
     /** Show soft input by {@link android.view.inputmethod.InputMethodManager#showSoftInput}. */
     int SHOW_SOFT_INPUT = 0;
@@ -147,4 +148,17 @@
      * switching, or collapsing Bubbles.
      */
     int HIDE_BUBBLES = 19;
+
+    /**
+     * Hide soft input when focusing the same window (e.g. screen turned-off and turn-on) which no
+     * valid focused editor.
+     *
+     * Note: From Android R, the window focus change callback is processed by InputDispatcher,
+     * some focus behavior changes (e.g. There are an activity with a dialog window, after
+     * screen turned-off and turned-on, before Android R the window focus sequence would be
+     * the activity first and then the dialog focused, however, in R the focus sequence would be
+     * only the dialog focused as it's the latest window with input focus) makes we need to hide
+     * soft-input when the same window focused again to align with the same behavior prior to R.
+     */
+    int HIDE_SAME_WINDOW_FOCUSED_WITHOUT_EDITOR = 20;
 }
diff --git a/core/java/com/android/internal/inputmethod/StartInputFlags.java b/core/java/com/android/internal/inputmethod/StartInputFlags.java
index 5a8d2c2..ac83987 100644
--- a/core/java/com/android/internal/inputmethod/StartInputFlags.java
+++ b/core/java/com/android/internal/inputmethod/StartInputFlags.java
@@ -47,4 +47,10 @@
      * documented hence we probably need to revisit this though.
      */
     int INITIAL_CONNECTION = 4;
+
+    /**
+     * The start input happens when the window gained focus to call
+     * {@code android.view.inputmethod.InputMethodManager#startInputAsyncOnWindowFocusGain}.
+     */
+    int WINDOW_GAINED_FOCUS = 8;
 }
diff --git a/services/core/java/com/android/server/inputmethod/InputMethodManagerService.java b/services/core/java/com/android/server/inputmethod/InputMethodManagerService.java
index 7cce78b..bcfbcd1 100644
--- a/services/core/java/com/android/server/inputmethod/InputMethodManagerService.java
+++ b/services/core/java/com/android/server/inputmethod/InputMethodManagerService.java
@@ -3275,6 +3275,9 @@
 
     boolean hideCurrentInputLocked(IBinder windowToken, int flags, ResultReceiver resultReceiver,
             @SoftInputShowHideReason int reason) {
+        if (mCurClient == null || mCurClient.curSession == null) {
+            return false;
+        }
         if ((flags&InputMethodManager.HIDE_IMPLICIT_ONLY) != 0
                 && (mShowExplicitlyRequested || mShowForced)) {
             if (DEBUG) Slog.v(TAG, "Not hiding: explicit show not cancelled by non-explicit hide");
@@ -3459,7 +3462,12 @@
         // pre-rendering not supported on low-ram devices.
         cs.shouldPreRenderIme = DebugFlags.FLAG_PRE_RENDER_IME_VIEWS.value() && !mIsLowRam;
 
-        if (mCurFocusedWindow == windowToken) {
+        final boolean sameWindowFocused = mCurFocusedWindow == windowToken;
+        final boolean isTextEditor = (startInputFlags & StartInputFlags.IS_TEXT_EDITOR) != 0;
+        final boolean startInputByWinGainedFocus =
+                (startInputFlags & StartInputFlags.WINDOW_GAINED_FOCUS) != 0;
+
+        if (sameWindowFocused && isTextEditor) {
             if (DEBUG) {
                 Slog.w(TAG, "Window already focused, ignoring focus gain of: " + client
                         + " attribute=" + attribute + ", token = " + windowToken
@@ -3474,6 +3482,7 @@
                     InputBindResult.ResultCode.SUCCESS_REPORT_WINDOW_FOCUS_ONLY,
                     null, null, null, -1, null);
         }
+
         mCurFocusedWindow = windowToken;
         mCurFocusedWindowSoftInputMode = softInputMode;
         mCurFocusedWindowClient = cs;
@@ -3491,7 +3500,6 @@
                         == LayoutParams.SOFT_INPUT_ADJUST_RESIZE
                 || mRes.getConfiguration().isLayoutSizeAtLeast(
                         Configuration.SCREENLAYOUT_SIZE_LARGE);
-        final boolean isTextEditor = (startInputFlags & StartInputFlags.IS_TEXT_EDITOR) != 0;
 
         // We want to start input before showing the IME, but after closing
         // it.  We want to do this after closing it to help the IME disappear
@@ -3502,7 +3510,7 @@
         InputBindResult res = null;
         switch (softInputMode & LayoutParams.SOFT_INPUT_MASK_STATE) {
             case LayoutParams.SOFT_INPUT_STATE_UNSPECIFIED:
-                if (!isTextEditor || !doAutoShow) {
+                if (!sameWindowFocused && (!isTextEditor || !doAutoShow)) {
                     if (LayoutParams.mayUseInputMethod(windowFlags)) {
                         // There is no focus view, and this window will
                         // be behind any soft input window, so hide the
@@ -3551,9 +3559,11 @@
                 }
                 break;
             case LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN:
-                if (DEBUG) Slog.v(TAG, "Window asks to hide input");
-                hideCurrentInputLocked(mCurFocusedWindow, 0, null,
-                        SoftInputShowHideReason.HIDE_ALWAYS_HIDDEN_STATE);
+                if (!sameWindowFocused) {
+                    if (DEBUG) Slog.v(TAG, "Window asks to hide input");
+                    hideCurrentInputLocked(mCurFocusedWindow, 0, null,
+                            SoftInputShowHideReason.HIDE_ALWAYS_HIDDEN_STATE);
+                }
                 break;
             case LayoutParams.SOFT_INPUT_STATE_VISIBLE:
                 if ((softInputMode & LayoutParams.SOFT_INPUT_IS_FORWARD_NAVIGATION) != 0) {
@@ -3578,13 +3588,15 @@
                 if (DEBUG) Slog.v(TAG, "Window asks to always show input");
                 if (InputMethodUtils.isSoftInputModeStateVisibleAllowed(
                         unverifiedTargetSdkVersion, startInputFlags)) {
-                    if (attribute != null) {
-                        res = startInputUncheckedLocked(cs, inputContext, missingMethods,
-                                attribute, startInputFlags, startInputReason);
-                        didStart = true;
+                    if (!sameWindowFocused) {
+                        if (attribute != null) {
+                            res = startInputUncheckedLocked(cs, inputContext, missingMethods,
+                                    attribute, startInputFlags, startInputReason);
+                            didStart = true;
+                        }
+                        showCurrentInputLocked(windowToken, InputMethodManager.SHOW_IMPLICIT, null,
+                                SoftInputShowHideReason.SHOW_STATE_ALWAYS_VISIBLE);
                     }
-                    showCurrentInputLocked(windowToken, InputMethodManager.SHOW_IMPLICIT, null,
-                            SoftInputShowHideReason.SHOW_STATE_ALWAYS_VISIBLE);
                 } else {
                     Slog.e(TAG, "SOFT_INPUT_STATE_ALWAYS_VISIBLE is ignored because"
                             + " there is no focused view that also returns true from"
@@ -3595,7 +3607,20 @@
 
         if (!didStart) {
             if (attribute != null) {
-                if (!DebugFlags.FLAG_OPTIMIZE_START_INPUT.value()
+                if (sameWindowFocused) {
+                    // On previous platforms, when Dialogs re-gained focus, the Activity behind
+                    // would briefly gain focus first, and dismiss the IME.
+                    // On R that behavior has been fixed, but unfortunately apps have come
+                    // to rely on this behavior to hide the IME when the editor no longer has focus
+                    // To maintain compatibility, we are now hiding the IME when we don't have
+                    // an editor upon refocusing a window.
+                    if (startInputByWinGainedFocus) {
+                        hideCurrentInputLocked(mCurFocusedWindow, 0, null,
+                                SoftInputShowHideReason.HIDE_SAME_WINDOW_FOCUSED_WITHOUT_EDITOR);
+                    }
+                    res = startInputUncheckedLocked(cs, inputContext, missingMethods, attribute,
+                            startInputFlags, startInputReason);
+                } else if (!DebugFlags.FLAG_OPTIMIZE_START_INPUT.value()
                         || (startInputFlags & StartInputFlags.IS_TEXT_EDITOR) != 0) {
                     res = startInputUncheckedLocked(cs, inputContext, missingMethods, attribute,
                             startInputFlags, startInputReason);
@@ -3609,6 +3634,10 @@
         return res;
     }
 
+    private boolean isImeVisible() {
+        return (mImeWindowVis & InputMethodService.IME_VISIBLE) != 0;
+    }
+
     private boolean canShowInputMethodPickerLocked(IInputMethodClient client) {
         // TODO(yukawa): multi-display support.
         final int uid = Binder.getCallingUid();