DecorView#mNavigationGuard is gone

With this CL, DecorView#mNavigationGuard that handles navigation bar
only for IME windows [1] is finally gone and replaced with the
standard mechanism to handle navigation bar layout padding /
background color.

This CL addresses multiple anomalies regarding how the following APIs
work for IME windows.

 * Window#setNavigationBarColor()
   * Previous behavior:
    - Only works for Color#TRANSPARENT [2].
    - Ignores FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS.
   * New behavior:
    - Works as documented.
    - Requires FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS to work.

 * SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION flag
   * Previous behavior:
    - The system automatically sets
      SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION to the IME windows [3].
    - Does not work as documented. Content area is not extended to the
      navigation bar area.
    - Manually unsetting SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION can cause
      unexpected layout, because the system expects that this flag is
      always set to the IME window.
    - Had a special logic for FLAG_LAYOUT_IN_OVERSCAN [4].
   * New behavior:
    - Works as documented.
    - Can set/unset as necessary.

From the viewpoint of IME developers, this CL enables IME windows to
 * correctly extend the input view to the navigation bar region by
   using SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION as documented, instead of
   relying on a special hack with FLAG_LAYOUT_IN_OVERSCAN hack.
 * use Window#setNavigationBarColor() to easily change the navigation
   bar background color, like other non-floating windows.

Note that SYSTEM_UI_FLAG_LIGHT_NAVIGATION_BAR is not yet supported for
IME windows, which will be implemented in a subsequent CL.

 [1]: I6a93f30aec83f1cecfb854073046cbc87ab4aa66
      ae3349e1c34f7aceddc526cd11d9ac44951e97b6
 [2]: Iea77915ecc55eedaf19899e72c44f704ba9d852c
      0a9d1ea015af24056018ec02f6d9afd2f62243ba
 [3]: I460912ee7c117480c57b947ed31eca330819f32c
      c68d577f29604d205573ee4253704c5b2c5e4f81
 [4]: Ic38f204a892bf34e8dae65990d5aa8c95af555d8
      9b32a35aa7d47d39da919e777e2fe271cc83fa1c
 [5]: I4b10a19641bd3ce6c43e7629404b6f202d4186e8

Fix: 25706186
Bug: 69002467
Test: ThemedNavBarKeyboard sample [5] works for the following cases
      * Extended Dark Navigation Bar
      * Separate Dark Navigation Bar
      * Floating Mode (if the target app uses dark navigation bar)
Change-Id: I664630099b6eb3fe31675444ba94944cb0eb98b0

1 files changed, 6 insertions, 2 deletions

diff --git a/core/java/android/inputmethodservice/InputMethodService.java b/core/java/android/inputmethodservice/InputMethodService.java
index 02b1c658b2ec..8937490091d0 100644
--- a/core/java/android/inputmethodservice/InputMethodService.java
+++ b/core/java/android/inputmethodservice/InputMethodService.java
@@ -18,6 +18,7 @@ package android.inputmethodservice;
 
 import static android.view.ViewGroup.LayoutParams.MATCH_PARENT;
 import static android.view.ViewGroup.LayoutParams.WRAP_CONTENT;
+import static android.view.WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS;
 
 import android.annotation.CallSuper;
 import android.annotation.DrawableRes;
@@ -852,6 +853,11 @@ public class InputMethodService extends AbstractInputMethodService {
                 Context.LAYOUT_INFLATER_SERVICE);
         mWindow = new SoftInputWindow(this, "InputMethod", mTheme, null, null, mDispatcherState,
                 WindowManager.LayoutParams.TYPE_INPUT_METHOD, Gravity.BOTTOM, false);
+        // For ColorView in DecorView to work, FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS needs to be set
+        // by default (but IME developers can opt this out later if they want a new behavior).
+        mWindow.getWindow().setFlags(
+                FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS, FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
+
         initViews();
         mWindow.getWindow().setLayout(MATCH_PARENT, WRAP_CONTENT);
     }
@@ -882,8 +888,6 @@ public class InputMethodService extends AbstractInputMethodService {
         mThemeAttrs = obtainStyledAttributes(android.R.styleable.InputMethodService);
         mRootView = mInflater.inflate(
                 com.android.internal.R.layout.input_method, null);
-        mRootView.setSystemUiVisibility(
-                View.SYSTEM_UI_FLAG_LAYOUT_STABLE | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION);
         mWindow.setContentView(mRootView);
         mRootView.getViewTreeObserver().removeOnComputeInternalInsetsListener(mInsetsComputer);
         mRootView.getViewTreeObserver().addOnComputeInternalInsetsListener(mInsetsComputer);