Merge "Fix a flicker problem on top app bar" into sc-dev am: e7b17ece47

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Settings/+/15067023

Change-Id: I28cd085bdee109258f09cb0caf7f43a0d7d6fd2b

src/com/android/settings/core/SettingsBaseActivity.java

@@ -48,7 +48,8 @@ import com.google.android.setupcompat.util.WizardManagerHelper;
 import com.google.android.setupdesign.util.ThemeHelper;
 
 /** Base activity for Settings pages */
-public class SettingsBaseActivity extends FragmentActivity implements CategoryHandler {
+public class SettingsBaseActivity extends FragmentActivity implements CategoryHandler,
+        AppBarLayout.OnOffsetChangedListener {
 
     /**
      * What type of page transition should be apply.
@@ -58,11 +59,15 @@ public class SettingsBaseActivity extends FragmentActivity implements CategoryHa
     protected static final boolean DEBUG_TIMING = false;
     private static final String TAG = "SettingsBaseActivity";
     private static final int DEFAULT_REQUEST = -1;
+    private static final int FULLY_EXPANDED_OFFSET = 0;
+    private static final int TOOLBAR_MAX_LINE_NUMBER = 2;
+    private static final String KEY_IS_TOOLBAR_COLLAPSED = "is_toolbar_collapsed";
 
     protected CategoryMixin mCategoryMixin;
     protected CollapsingToolbarLayout mCollapsingToolbarLayout;
     protected AppBarLayout mAppBarLayout;
     private Toolbar mToolbar;
+    private boolean mIsToolbarCollapsed;
 
     @Override
     public CategoryMixin getCategoryMixin() {
@@ -100,6 +105,11 @@ public class SettingsBaseActivity extends FragmentActivity implements CategoryHa
             super.setContentView(R.layout.collapsing_toolbar_base_layout);
             mCollapsingToolbarLayout = findViewById(R.id.collapsing_toolbar);
             mAppBarLayout = findViewById(R.id.app_bar);
+            mAppBarLayout.addOnOffsetChangedListener(this);
+            if (savedInstanceState != null) {
+                mIsToolbarCollapsed = savedInstanceState.getBoolean(KEY_IS_TOOLBAR_COLLAPSED);
+            }
+            initCollapsingToolbar();
             disableCollapsingToolbarLayoutScrollingBehavior();
         } else {
             super.setContentView(R.layout.settings_base_layout);
@@ -191,6 +201,23 @@ public class SettingsBaseActivity extends FragmentActivity implements CategoryHa
         }
     }
 
+    @Override
+    public void onOffsetChanged(AppBarLayout appBarLayout, int offset) {
+        if (offset == FULLY_EXPANDED_OFFSET) {
+            mIsToolbarCollapsed = false;
+        } else {
+            mIsToolbarCollapsed = true;
+        }
+    }
+
+    @Override
+    protected void onSaveInstanceState(@NonNull Bundle outState) {
+        super.onSaveInstanceState(outState);
+        if (isChangingConfigurations()) {
+            outState.putBoolean(KEY_IS_TOOLBAR_COLLAPSED, mIsToolbarCollapsed);
+        }
+    }
+
     /**
      * SubSetting page should show a toolbar by default. If the page wouldn't show a toolbar,
      * override this method and return false value.
@@ -238,6 +265,9 @@ public class SettingsBaseActivity extends FragmentActivity implements CategoryHa
     }
 
     private void disableCollapsingToolbarLayoutScrollingBehavior() {
+        if (mAppBarLayout == null) {
+            return;
+        }
         final CoordinatorLayout.LayoutParams params =
                 (CoordinatorLayout.LayoutParams) mAppBarLayout.getLayoutParams();
         final AppBarLayout.Behavior behavior = new AppBarLayout.Behavior();
@@ -254,4 +284,39 @@ public class SettingsBaseActivity extends FragmentActivity implements CategoryHa
     private int getTransitionType(Intent intent) {
         return intent.getIntExtra(EXTRA_PAGE_TRANSITION_TYPE, TransitionType.TRANSITION_NONE);
     }
+
+    @SuppressWarnings("RestrictTo")
+    private void initCollapsingToolbar() {
+        if (mCollapsingToolbarLayout == null || mAppBarLayout == null) {
+            return;
+        }
+        mCollapsingToolbarLayout.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
+            @Override
+            public void onLayoutChange(View v, int left, int top, int right, int bottom,
+                    int oldLeft, int oldTop, int oldRight, int oldBottom) {
+                v.removeOnLayoutChangeListener(this);
+                if (mIsToolbarCollapsed) {
+                    return;
+                }
+                final int count = mCollapsingToolbarLayout.getLineCount();
+                if (count > TOOLBAR_MAX_LINE_NUMBER) {
+                    final ViewGroup.LayoutParams lp = mCollapsingToolbarLayout.getLayoutParams();
+                    lp.height = getResources()
+                            .getDimensionPixelSize(R.dimen.toolbar_three_lines_height);
+                    mCollapsingToolbarLayout.setScrimVisibleHeightTrigger(
+                            getResources().getDimensionPixelSize(
+                                    R.dimen.scrim_visible_height_trigger_three_lines));
+                    mCollapsingToolbarLayout.setLayoutParams(lp);
+                } else if (count == TOOLBAR_MAX_LINE_NUMBER) {
+                    final ViewGroup.LayoutParams lp = mCollapsingToolbarLayout.getLayoutParams();
+                    lp.height = getResources()
+                            .getDimensionPixelSize(R.dimen.toolbar_two_lines_height);
+                    mCollapsingToolbarLayout.setScrimVisibleHeightTrigger(
+                            getResources().getDimensionPixelSize(
+                                    R.dimen.scrim_visible_height_trigger_two_lines));
+                    mCollapsingToolbarLayout.setLayoutParams(lp);
+                }
+            }
+        });
+    }
 }