Display a list of feature flags

Bug: 36222960
Test: robotests
Change-Id: I31fbe7f4d42e72846aa4f025ebcf8ea8a1b6d2fd

src/com/android/settings/development/featureflags/FeatureFlagsPreferenceController.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2017 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 com.android.settings.development.featureflags;
+
+import android.content.Context;
+import android.support.v7.preference.Preference;
+import android.support.v7.preference.PreferenceScreen;
+import android.util.FeatureFlagUtils;
+
+import com.android.settings.core.PreferenceControllerMixin;
+import com.android.settingslib.core.AbstractPreferenceController;
+import com.android.settingslib.core.lifecycle.Lifecycle;
+import com.android.settingslib.core.lifecycle.LifecycleObserver;
+import com.android.settingslib.core.lifecycle.events.OnStart;
+
+import java.util.Map;
+
+public class FeatureFlagsPreferenceController extends AbstractPreferenceController
+        implements PreferenceControllerMixin, LifecycleObserver, OnStart {
+
+    private PreferenceScreen mScreen;
+
+    public FeatureFlagsPreferenceController(Context context, Lifecycle lifecycle) {
+        super(context);
+        if (lifecycle != null) {
+            lifecycle.addObserver(this);
+        }
+    }
+
+    @Override
+    public boolean isAvailable() {
+        return true;
+    }
+
+    @Override
+    public String getPreferenceKey() {
+        return null;
+    }
+
+    @Override
+    public void displayPreference(PreferenceScreen screen) {
+        super.displayPreference(screen);
+        mScreen = screen;
+    }
+
+    @Override
+    public void onStart() {
+        if (mScreen == null) {
+            return;
+        }
+        final Map<String, String> featureMap = FeatureFlagUtils.getAllFeatureFlags();
+        if (featureMap == null) {
+            return;
+        }
+        mScreen.removeAll();
+        final Context prefContext = mScreen.getContext();
+        for (String prefixedFeature : featureMap.keySet()) {
+            if (prefixedFeature.startsWith(FeatureFlagUtils.FFLAG_PREFIX)
+                    && !prefixedFeature.startsWith(FeatureFlagUtils.FFLAG_OVERRIDE_PREFIX)) {
+                final String feature = prefixedFeature.substring(
+                        FeatureFlagUtils.FFLAG_PREFIX.length());
+                final Preference pref = new FeatureFlagPreference(prefContext, feature);
+                mScreen.addPreference(pref);
+            }
+        }
+    }
+}