[Android] Implement StateListDrawableBuilder

This CL adds StateListDrawableBuilder, a helper class that simplifies
StateListDrawable and AnimatedListDrawable creation.

Bug: 814728
Change-Id: If2f07e1dab0cd7f5a6d46c81e37f4153b6259caa
Reviewed-on: https://chromium-review.googlesource.com/1101325
Commit-Queue: Boris Sazonov <bsazonov@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568374}

ui/android/BUILD.gn

@@ -228,6 +228,7 @@ android_library("ui_full_java") {
     "java/src/org/chromium/ui/display/DisplayUtil.java",
     "java/src/org/chromium/ui/display/PhysicalDisplayAndroid.java",
     "java/src/org/chromium/ui/display/VirtualDisplayAndroid.java",
+    "java/src/org/chromium/ui/drawable/StateListDrawableBuilder.java",
     "java/src/org/chromium/ui/events/devices/InputDeviceObserver.java",
     "java/src/org/chromium/ui/gfx/BitmapHelper.java",
     "java/src/org/chromium/ui/gfx/ViewConfigurationHelper.java",
@@ -295,7 +296,11 @@ junit_binary("ui_junit_tests") {
   java_files = [
     "junit/src/org/chromium/ui/base/ClipboardTest.java",
     "junit/src/org/chromium/ui/base/SelectFileDialogTest.java",
+    "junit/src/org/chromium/ui/drawable/StateListDrawableBuilderTest.java",
     "junit/src/org/chromium/ui/text/SpanApplierTest.java",
+    "junit/src/org/chromium/ui/shadows/ShadowAppCompatResources.java",
+    "junit/src/org/chromium/ui/shadows/ShadowAppCompatResourcesTest.java",
+    "junit/src/org/chromium/ui/shadows/ShadowAnimatedStateListDrawable.java",
     "junit/src/org/chromium/ui/widget/AnchoredPopupWindowTest.java",
   ]
   deps = [

ui/android/java/src/org/chromium/ui/drawable/StateListDrawableBuilder.java

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.ui.drawable;
+
+import android.annotation.TargetApi;
+import android.content.Context;
+import android.graphics.drawable.Animatable;
+import android.graphics.drawable.AnimatedStateListDrawable;
+import android.graphics.drawable.Drawable;
+import android.graphics.drawable.StateListDrawable;
+import android.os.Build;
+import android.support.annotation.DrawableRes;
+import android.support.v7.content.res.AppCompatResources;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Helper that simplifies StateListDrawable and AnimatedStateListDrawable creation. Stateful
+ * drawables have to be created in Java for now, as drawables specified in XML can't reference
+ * vector drawables on platform versions where VectorDrawableCompat is used (API level 23 and
+ * below).
+ *
+ * {@link #build()} will instantiate AnimatedStateListDrawable on platforms where it is supported
+ * (API level 21+). On older APIs, transition animations will be ignored and StateListDrawable will
+ * be instantiated instead.
+ *
+ * Usage:
+ * StateListDrawableBuilder builder = new StateListDrawableBuilder(context);
+ * StateListDrawableBuilder.State checked =
+ *         builder.addState(R.drawable.checked, android.R.attr.state_checked);
+ * StateListDrawableBuilder.State unchecked = builder.addState(R.drawable.unchecked);
+ * builder.addTransition(checked, unchecked, R.drawable.transition_checked_unchecked);
+ * builder.addTransition(unchecked, checked, R.drawable.transition_unchecked_checked);
+ * StateListDrawable drawable = builder.build();
+ */
+public class StateListDrawableBuilder {
+    /** Identifies single state of the drawable. Used by {@link #addTransition}. */
+    public static class State {
+        private final @DrawableRes int mDrawable;
+        private final int[] mStateSet;
+        private final int mStateId;
+
+        private State(@DrawableRes int drawable, int[] stateSet, int stateId) {
+            mDrawable = drawable;
+            mStateSet = stateSet;
+            mStateId = stateId;
+        }
+
+        private @DrawableRes int getDrawable() {
+            return mDrawable;
+        }
+
+        private int[] getStateSet() {
+            return mStateSet;
+        }
+
+        private int getStateId() {
+            return mStateId;
+        }
+    }
+
+    private static class Transition {
+        private final @DrawableRes int mDrawable;
+        private final int mFromStateId;
+        private final int mToStateId;
+
+        private Transition(@DrawableRes int drawable, int fromStateId, int toStateId) {
+            mDrawable = drawable;
+            mFromStateId = fromStateId;
+            mToStateId = toStateId;
+        }
+
+        private @DrawableRes int getDrawable() {
+            return mDrawable;
+        }
+
+        private int getFromId() {
+            return mFromStateId;
+        }
+
+        private int getToId() {
+            return mToStateId;
+        }
+    }
+
+    private final Context mContext;
+    private final List<State> mStates = new ArrayList<>();
+    private final List<Transition> mTransitions = new ArrayList<>();
+
+    public StateListDrawableBuilder(Context context) {
+        mContext = context;
+    }
+
+    /**
+     * Add state to the drawable. Please note that order of calls to this method is important, as
+     * StateListDrawable will pick the first state which stateSet matches View state.
+     * @param drawable Id of the drawable for the added state. May refer to a vector drawable.
+     * @param stateSet Array of state ids that specify the state. See {@link android.R.attr}
+     *         for the list of state ids provided by the platform.
+     */
+    public State addState(@DrawableRes int drawable, int... stateSet) {
+        int nextStateId = mStates.size() + 1; // State ids should be greater than 1.
+        State state = new State(drawable, stateSet, nextStateId);
+        mStates.add(state);
+        return state;
+    }
+
+    /**
+     * Add transition animation to the stateful drawable.
+     * @param from The state of the stateful drawable before the transition.
+     * @param to The state of the stateful drawable after the transition.
+     * @param drawable Id of the animated drawable for the transition. Must refer to animated vector
+     *         drawable.
+     */
+    public void addTransition(State from, State to, @DrawableRes int drawable) {
+        assert mStates.contains(from) && mStates.contains(to) : "State from a different builder!";
+        Transition transition = new Transition(drawable, from.getStateId(), to.getStateId());
+        mTransitions.add(transition);
+    }
+
+    /**
+     * Build drawable from added states and transitions.
+     * @return AnimatedStateListDrawable if platform supports it, StateListDrawable otherwise.
+     */
+    public StateListDrawable build() {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
+            return buildPostL();
+        } else {
+            return buildPreL();
+        }
+    }
+
+    private StateListDrawable buildPreL() {
+        // Create StateListDrawable on API levels where AnimatedStateListDrawable is not available.
+        StateListDrawable result = new StateListDrawable();
+        int size = mStates.size();
+        for (int i = 0; i < size; ++i) {
+            State state = mStates.get(i);
+            Drawable drawable = AppCompatResources.getDrawable(mContext, state.getDrawable());
+            assert drawable != null;
+            result.addState(state.getStateSet(), drawable);
+        }
+        return result;
+    }
+
+    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
+    private StateListDrawable buildPostL() {
+        AnimatedStateListDrawable result = new AnimatedStateListDrawable();
+        int statesSize = mStates.size();
+        for (int i = 0; i < statesSize; ++i) {
+            State state = mStates.get(i);
+            Drawable drawable = AppCompatResources.getDrawable(mContext, state.getDrawable());
+            assert drawable != null;
+            result.addState(state.getStateSet(), drawable, state.getStateId());
+        }
+        int transitionsSize = mTransitions.size();
+        for (int i = 0; i < transitionsSize; ++i) {
+            Transition transition = mTransitions.get(i);
+            Drawable drawable = AppCompatResources.getDrawable(mContext, transition.getDrawable());
+            result.addTransition(transition.getFromId(), transition.getToId(),
+                    castToAnimatableDrawable(drawable), false);
+        }
+        return result;
+    }
+
+    @SuppressWarnings("unchecked") // Need Java 8 to cast to intersection types
+    private static <T> T castToAnimatableDrawable(Drawable drawable) {
+        if (!(drawable instanceof Animatable)) throw new IllegalArgumentException("drawable");
+        return (T) drawable;
+    }
+}

ui/android/junit/src/org/chromium/ui/drawable/StateListDrawableBuilderTest.java

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.ui.drawable;
+
+import static org.junit.Assert.assertEquals;
+import static org.robolectric.Shadows.shadowOf;
+
+import android.graphics.drawable.AnimatedStateListDrawable;
+import android.graphics.drawable.StateListDrawable;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RuntimeEnvironment;
+import org.robolectric.annotation.Config;
+import org.robolectric.shadow.api.Shadow;
+import org.robolectric.shadows.ShadowStateListDrawable;
+
+import org.chromium.base.test.BaseRobolectricTestRunner;
+import org.chromium.ui.shadows.ShadowAnimatedStateListDrawable;
+import org.chromium.ui.shadows.ShadowAppCompatResources;
+
+@RunWith(BaseRobolectricTestRunner.class)
+@Config(manifest = Config.NONE,
+        shadows = {ShadowAppCompatResources.class, ShadowAnimatedStateListDrawable.class})
+public class StateListDrawableBuilderTest {
+    private static final int[] CHECKED_STATE = new int[] {android.R.attr.state_checked};
+    private static final int[] WILDCARD_STATE = new int[0];
+    private static final int CHECKED_DRAWABLE = 34567;
+    private static final int DEFAULT_DRAWABLE = 45678;
+
+    @Test
+    @Config(sdk = 18)
+    public void testPreL() {
+        StateListDrawableBuilder b = new StateListDrawableBuilder(RuntimeEnvironment.application);
+        b.addState(CHECKED_DRAWABLE, android.R.attr.state_checked);
+        b.addState(DEFAULT_DRAWABLE, WILDCARD_STATE);
+        StateListDrawable result = b.build();
+        assertEquals(result.getClass(), StateListDrawable.class);
+        ShadowStateListDrawable drawable = shadowOf(result);
+        assertEquals(CHECKED_DRAWABLE,
+                shadowOf(drawable.getDrawableForState(CHECKED_STATE)).getCreatedFromResId());
+        assertEquals(DEFAULT_DRAWABLE,
+                shadowOf(drawable.getDrawableForState(WILDCARD_STATE)).getCreatedFromResId());
+    }
+
+    @Test
+    @Config(sdk = 21)
+    public void testPostL() {
+        StateListDrawableBuilder b = new StateListDrawableBuilder(RuntimeEnvironment.application);
+        b.addState(CHECKED_DRAWABLE, android.R.attr.state_checked);
+        b.addState(DEFAULT_DRAWABLE, WILDCARD_STATE);
+        StateListDrawable result = b.build();
+        assertEquals(result.getClass(), AnimatedStateListDrawable.class);
+        ShadowAnimatedStateListDrawable drawable = Shadow.extract(result);
+        assertEquals(CHECKED_DRAWABLE,
+                shadowOf(drawable.getDrawableForState(CHECKED_STATE)).getCreatedFromResId());
+        assertEquals(DEFAULT_DRAWABLE,
+                shadowOf(drawable.getDrawableForState(WILDCARD_STATE)).getCreatedFromResId());
+    }
+}

ui/android/junit/src/org/chromium/ui/shadows/ShadowAnimatedStateListDrawable.java

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.ui.shadows;
+
+import android.graphics.drawable.AnimatedStateListDrawable;
+import android.graphics.drawable.Drawable;
+
+import org.robolectric.annotation.Implements;
+import org.robolectric.shadows.ShadowStateListDrawable;
+
+@Implements(AnimatedStateListDrawable.class)
+public class ShadowAnimatedStateListDrawable extends ShadowStateListDrawable {
+    public void addState(int[] stateSet, Drawable drawable, int stateId) {
+        addState(stateSet, drawable);
+    }
+}

ui/android/junit/src/org/chromium/ui/shadows/ShadowAppCompatResources.java

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.ui.shadows;
+
+import android.content.Context;
+import android.graphics.drawable.Drawable;
+import android.support.annotation.DrawableRes;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.support.v7.content.res.AppCompatResources;
+
+import org.robolectric.annotation.Implementation;
+import org.robolectric.annotation.Implements;
+import org.robolectric.shadows.ShadowDrawable;
+
+@Implements(AppCompatResources.class)
+public class ShadowAppCompatResources {
+    @Implementation
+    @Nullable
+    public static Drawable getDrawable(@NonNull Context context, @DrawableRes int resId) {
+        return ShadowDrawable.createFromResourceId(resId);
+    }
+}

ui/android/junit/src/org/chromium/ui/shadows/ShadowAppCompatResourcesTest.java

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.ui.shadows;
+
+import static org.junit.Assert.assertEquals;
+import static org.robolectric.Shadows.shadowOf;
+
+import android.graphics.drawable.Drawable;
+import android.support.v7.content.res.AppCompatResources;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RuntimeEnvironment;
+import org.robolectric.annotation.Config;
+
+import org.chromium.base.test.BaseRobolectricTestRunner;
+
+/** Tests logic in the ShadowAppCompatResources class. */
+@RunWith(BaseRobolectricTestRunner.class)
+@Config(manifest = Config.NONE, shadows = {ShadowAppCompatResources.class})
+public class ShadowAppCompatResourcesTest {
+    private static final int DRAWABLE_RES_ID = 34567;
+
+    @Test
+    public void testShadowAppCompatResources() {
+        Drawable drawable =
+                AppCompatResources.getDrawable(RuntimeEnvironment.application, DRAWABLE_RES_ID);
+        assertEquals(DRAWABLE_RES_ID, shadowOf(drawable).getCreatedFromResId());
+    }
+}