PreferenceControllers are the way of the future.

Migrates Notification settings (app level, group level, and channel
level) into PreferenceControllers (and most importantly:
PreferenceControllerTest)

Note: this removes the 'Advanced' preference group, but does
not yet use the standard system 'Advanced' grouping as it does
not currently support our use case (where we don't know how many
fields to show outside of 'Advanced' until onResume() and also
where we need fields to show below the 'Advanced' group).

Test: make RunSettingsRoboTests
Change-Id: Iddd1b4771922db322e5f73562e9d63ed077c5396

src/com/android/settings/notification/BlockPreferenceController.java

@@ -0,0 +1,113 @@
+/*
+ * 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.notification;
+
+import static android.app.NotificationChannel.DEFAULT_CHANNEL_ID;
+import static android.app.NotificationManager.IMPORTANCE_DEFAULT;
+import static android.app.NotificationManager.IMPORTANCE_NONE;
+import static android.app.NotificationManager.IMPORTANCE_UNSPECIFIED;
+
+import android.app.NotificationManager;
+import android.content.Context;
+import android.support.v7.preference.Preference;
+import android.widget.Switch;
+
+import com.android.settings.R;
+import com.android.settings.applications.LayoutPreference;
+import com.android.settings.core.PreferenceControllerMixin;
+import com.android.settings.widget.SwitchBar;
+
+public class BlockPreferenceController extends NotificationPreferenceController
+        implements PreferenceControllerMixin, SwitchBar.OnSwitchChangeListener {
+
+    private static final String KEY_BLOCK = "block";
+    private NotificationSettingsBase.ImportanceListener mImportanceListener;
+
+    public BlockPreferenceController(Context context,
+            NotificationSettingsBase.ImportanceListener importanceListener,
+            NotificationBackend backend) {
+        super(context, backend);
+        mImportanceListener = importanceListener;
+    }
+
+    @Override
+    public String getPreferenceKey() {
+        return KEY_BLOCK;
+    }
+
+    @Override
+    public boolean isAvailable() {
+        if (mAppRow == null) {
+            return false;
+        }
+        if (mChannel != null) {
+            return isChannelBlockable();
+        } else if (mChannelGroup != null && mChannelGroup.getGroup() != null) {
+            return isChannelGroupBlockable();
+        } else {
+            return !mAppRow.systemApp || (mAppRow.systemApp && mAppRow.banned);
+        }
+    }
+
+    public void updateState(Preference preference) {
+        LayoutPreference pref = (LayoutPreference) preference;
+        SwitchBar bar = pref.findViewById(R.id.switch_bar);
+        if (bar != null) {
+            bar.show();
+            try {
+                bar.addOnSwitchChangeListener(this);
+            } catch (IllegalStateException e) {
+                // an exception is thrown if you try to add the listener twice
+            }
+            bar.setDisabledByAdmin(mAdmin);
+
+            if (mChannel != null) {
+                bar.setChecked(!mAppRow.banned
+                        && mChannel.getImportance() != NotificationManager.IMPORTANCE_NONE);
+            } else if (mChannelGroup != null && mChannelGroup.getGroup() != null) {
+                bar.setChecked(!mAppRow.banned && !mChannelGroup.isBlocked());
+            } else {
+                bar.setChecked(!mAppRow.banned);
+            }
+        }
+    }
+
+    @Override
+    public void onSwitchChanged(Switch switchView, boolean isChecked) {
+        boolean blocked = !isChecked;
+        if (mChannel != null) {
+            final int originalImportance = mChannel.getImportance();
+            // setting the initial state of the switch in updateState() triggers this callback.
+            // It's always safe to override the importance if it's meant to be blocked or if
+            // it was blocked and we are unblocking it.
+            if (blocked || originalImportance == IMPORTANCE_NONE) {
+                final int importance = blocked ? IMPORTANCE_NONE
+                        : DEFAULT_CHANNEL_ID.equals(mChannel.getId())
+                                ? IMPORTANCE_UNSPECIFIED : IMPORTANCE_DEFAULT;
+                mChannel.setImportance(importance);
+                saveChannel();
+            }
+        } else if (mChannelGroup != null && mChannelGroup.getGroup() != null) {
+            mChannelGroup.setBlocked(blocked);
+            mBackend.updateChannelGroup(mAppRow.pkg, mAppRow.uid, mChannelGroup.getGroup());
+        } else if (mAppRow != null) {
+            mAppRow.banned = blocked;
+            mBackend.setNotificationsEnabledForPackage(mAppRow.pkg, mAppRow.uid, !blocked);
+        }
+        mImportanceListener.onImportanceChanged();
+    }
+}