Improve keying for theme caches, rebase system theme on config change
Themes now use an array of applied styles rather than a String to store
their history. They are keyed based on a hash code computed from the
history of applied styles. The themed drawable cache has been abstracted
out into its own class.
Also updates system context to use DayNight as the default and ensures
that GlobalActions uses the correct context, which exercises the change.
CTS tests have been added in another CL.
Bug: 20421157
Change-Id: I9eb4b7dffd198ad24d02f656eaf0839570b59caa
diff --git a/core/java/android/content/res/DrawableCache.java b/core/java/android/content/res/DrawableCache.java
new file mode 100644
index 0000000..fc70bc60
--- /dev/null
+++ b/core/java/android/content/res/DrawableCache.java
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.content.res;
+
+import android.graphics.drawable.Drawable;
+
+/**
+ * Class which can be used to cache Drawable resources against a theme.
+ */
+class DrawableCache extends ThemedResourceCache<Drawable.ConstantState> {
+ private final Resources mResources;
+
+ /**
+ * Creates a cache for the given Resources instance.
+ *
+ * @param resources the resources to use when creating new instances
+ */
+ public DrawableCache(Resources resources) {
+ mResources = resources;
+ }
+
+ /**
+ * If the resource is cached, creates and returns a new instance of it.
+ *
+ * @param key a key that uniquely identifies the drawable resource
+ * @param theme the theme where the resource will be used
+ * @return a new instance of the resource, or {@code null} if not in
+ * the cache
+ */
+ public Drawable getInstance(long key, Resources.Theme theme) {
+ final Drawable.ConstantState entry = get(key, theme);
+ if (entry != null) {
+ return entry.newDrawable(mResources, theme);
+ }
+
+ return null;
+ }
+
+ @Override
+ public boolean shouldInvalidateEntry(Drawable.ConstantState entry, int configChanges) {
+ return false;
+ }
+}