Add theme information for Application, Activity and View descriptors

Summary: This will query for and display all of the associated theme information for each of the descriptors.

Reviewed By: passy

Differential Revision: D19987003

fbshipit-source-id: c9b51311d28712a1af76c45a434bfb25d28d5c54

android/src/main/java/com/facebook/flipper/plugins/inspector/descriptors/ActivityDescriptor.java

@@ -14,6 +14,7 @@ import com.facebook.flipper.core.FlipperObject;
 import com.facebook.flipper.plugins.inspector.Named;
 import com.facebook.flipper.plugins.inspector.NodeDescriptor;
 import com.facebook.flipper.plugins.inspector.Touch;
+import com.facebook.flipper.plugins.inspector.descriptors.utils.ContextDescriptorUtils;
 import com.facebook.flipper.plugins.inspector.descriptors.utils.stethocopies.FragmentActivityAccessor;
 import com.facebook.flipper.plugins.inspector.descriptors.utils.stethocopies.FragmentCompat;
 import com.facebook.flipper.plugins.inspector.descriptors.utils.stethocopies.FragmentManagerAccessor;
@@ -65,7 +66,7 @@ public class ActivityDescriptor extends NodeDescriptor<Activity> {
 
   @Override
   public List<Named<FlipperObject>> getData(Activity node) {
-    return Collections.EMPTY_LIST;
+    return Collections.singletonList(new Named<>("Theme", ContextDescriptorUtils.themeData(node)));
   }
 
   @Override

android/src/main/java/com/facebook/flipper/plugins/inspector/descriptors/ApplicationDescriptor.java

@@ -19,6 +19,7 @@ import com.facebook.flipper.plugins.inspector.ApplicationWrapper;
 import com.facebook.flipper.plugins.inspector.Named;
 import com.facebook.flipper.plugins.inspector.NodeDescriptor;
 import com.facebook.flipper.plugins.inspector.Touch;
+import com.facebook.flipper.plugins.inspector.descriptors.utils.ContextDescriptorUtils;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -204,7 +205,8 @@ public class ApplicationDescriptor extends NodeDescriptor<ApplicationWrapper> {
 
   @Override
   public List<Named<FlipperObject>> getData(ApplicationWrapper node) {
-    return Collections.EMPTY_LIST;
+    return Collections.singletonList(
+        new Named<>("Theme", ContextDescriptorUtils.themeData(node.getApplication())));
   }
 
   @Override

android/src/main/java/com/facebook/flipper/plugins/inspector/descriptors/ViewDescriptor.java

@@ -38,6 +38,7 @@ import com.facebook.flipper.plugins.inspector.Touch;
 import com.facebook.flipper.plugins.inspector.descriptors.utils.AccessibilityEvaluationUtil;
 import com.facebook.flipper.plugins.inspector.descriptors.utils.AccessibilityRoleUtil;
 import com.facebook.flipper.plugins.inspector.descriptors.utils.AccessibilityUtil;
+import com.facebook.flipper.plugins.inspector.descriptors.utils.ContextDescriptorUtils;
 import com.facebook.flipper.plugins.inspector.descriptors.utils.EnumMapping;
 import com.facebook.flipper.plugins.inspector.descriptors.utils.stethocopies.ResourcesUtil;
 import java.lang.reflect.Field;
@@ -190,7 +191,9 @@ public class ViewDescriptor extends NodeDescriptor<View> {
       viewProps.put("foreground", fromDrawable(node.getForeground()));
     }
 
-    return Arrays.asList(new Named<>("View", viewProps.build()));
+    return Arrays.asList(
+        new Named<>("View", viewProps.build()),
+        new Named<>("Theme", ContextDescriptorUtils.themeData(node.getContext())));
   }
 
   @Override

android/src/main/java/com/facebook/flipper/plugins/inspector/descriptors/utils/ContextDescriptorUtils.java

@@ -0,0 +1,121 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.flipper.plugins.inspector.descriptors.utils;
+
+import android.content.Context;
+import android.content.res.AssetManager;
+import android.content.res.Resources;
+import android.util.Log;
+import android.util.TypedValue;
+import com.facebook.flipper.core.FlipperObject;
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.util.HashMap;
+import java.util.Map;
+
+public final class ContextDescriptorUtils {
+  private static String TAG = "ContextDescriptor";
+
+  private static Field sThemeImplField;
+  private static Field sThemeImplThemeKeyField;
+  private static Field sThemeImplAssetManagerField;
+  private static Field sThemeKeyResIdField;
+  private static Method sAssetManagerGetStyleAttributesMethod;
+
+  private ContextDescriptorUtils() {}
+
+  public static FlipperObject themeData(Context context) {
+    FlipperObject.Builder themeData = new FlipperObject.Builder();
+    Map<String, FlipperObject.Builder> builders = collectThemeValues(context);
+    for (Map.Entry<String, FlipperObject.Builder> entry : builders.entrySet()) {
+      themeData.put(entry.getKey(), entry.getValue().build());
+    }
+    return themeData.build();
+  }
+
+  private static Map<String, FlipperObject.Builder> collectThemeValues(Context context) {
+    Map<String, FlipperObject.Builder> builderMap = new HashMap<>(3);
+    try {
+      Resources.Theme theme = context.getTheme();
+      AssetManager assetManager = context.getAssets();
+      final Object themeImpl;
+      final Object themeKey;
+
+      // Nasty reflection to get a list of theme attributes that apply to this context.
+      if (sThemeImplField == null
+          || sThemeImplThemeKeyField == null
+          || sThemeKeyResIdField == null
+          || sThemeImplAssetManagerField == null) {
+        sThemeImplField = theme.getClass().getDeclaredField("mThemeImpl");
+        sThemeImplField.setAccessible(true);
+
+        themeImpl = sThemeImplField.get(theme);
+        sThemeImplThemeKeyField = themeImpl.getClass().getDeclaredField("mKey");
+        sThemeImplThemeKeyField.setAccessible(true);
+
+        sThemeImplAssetManagerField = themeImpl.getClass().getDeclaredField("mAssets");
+        sThemeImplAssetManagerField.setAccessible(true);
+
+        sAssetManagerGetStyleAttributesMethod =
+            assetManager.getClass().getDeclaredMethod("getStyleAttributes", int.class);
+        sAssetManagerGetStyleAttributesMethod.setAccessible(true);
+
+        themeKey = sThemeImplThemeKeyField.get(themeImpl);
+        sThemeKeyResIdField = themeKey.getClass().getDeclaredField("mResId");
+        sThemeKeyResIdField.setAccessible(true);
+      } else {
+        themeImpl = sThemeImplField.get(theme);
+        themeKey = sThemeImplThemeKeyField.get(themeImpl);
+      }
+
+      int[] appliedThemeResIds = (int[]) sThemeKeyResIdField.get(themeKey);
+      TypedValue typedValue = new TypedValue();
+      Resources resources = context.getResources();
+      for (int themeId : appliedThemeResIds) {
+        String name = resources.getResourceName(themeId);
+        // The res id array can have duplicates
+        if (builderMap.containsKey(name)) {
+          continue;
+        }
+
+        FlipperObject.Builder builder = new FlipperObject.Builder();
+        builderMap.put(name, builder);
+
+        int[] attributes =
+            (int[]) sAssetManagerGetStyleAttributesMethod.invoke(assetManager, themeId);
+        for (int attribute : attributes) {
+          if (!theme.resolveAttribute(attribute, typedValue, true)) {
+            continue;
+          }
+          String attributeName = context.getResources().getResourceName(attribute);
+          String[] nameParts = attributeName.split(":");
+          if (nameParts.length < 2) {
+            Log.d(TAG, "Unknown attribute name format " + attributeName);
+          } else {
+            attributeName = nameParts[1].split("/")[1];
+          }
+          String strValue = TypedValue.coerceToString(typedValue.type, typedValue.data);
+          if (strValue == null) {
+            strValue = "null";
+          } else if (strValue.startsWith("@")) {
+            int resId = Integer.parseInt(strValue.substring(1));
+            if (resId == 0) {
+              strValue = "null";
+            } else {
+              strValue = context.getResources().getResourceName(resId);
+            }
+          }
+          builder.put(attributeName, strValue);
+        }
+      }
+    } catch (Throwable ignored) {
+      Log.d(TAG, "Failed to generate theme attribute data!", ignored);
+    }
+    return builderMap;
+  }
+}