Base implementation of WFC disclaimer UI

Test: manual - Check that no error occurred when changing the wifi
calling settings to turn on.
Test: auto - Passed WifiCallingSettingsForSubTest,
WifiCallingDisclaimerFragmentTest and DisclaimerItemListAdapterTest.
Bug: 67872298

Change-Id: I789f530d3e16baa6e56feaa4269f6696976f747e

src/com/android/settings/wifi/calling/WifiCallingDisclaimerFragment.java

@@ -0,0 +1,148 @@
+/*
+ * Copyright (C) 2018 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.wifi.calling;
+
+import android.app.Activity;
+import android.os.Bundle;
+import android.telephony.SubscriptionManager;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Button;
+
+import androidx.recyclerview.widget.DividerItemDecoration;
+import androidx.recyclerview.widget.LinearLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
+import androidx.recyclerview.widget.RecyclerView.OnScrollListener;
+
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.internal.logging.nano.MetricsProto.MetricsEvent;
+import com.android.settings.R;
+import com.android.settings.core.InstrumentedFragment;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Fragment for displaying disclaimers for WFC.
+ */
+public class WifiCallingDisclaimerFragment extends InstrumentedFragment
+        implements View.OnClickListener {
+    private static final String TAG = "WifiCallingDisclaimerFragment";
+
+    private static final String STATE_IS_SCROLL_TO_BOTTOM = "state_is_scroll_to_bottom";
+
+    private List<DisclaimerItem> mDisclaimerItemList = new ArrayList<DisclaimerItem>();
+    private Button mAgreeButton;
+    private Button mDisagreeButton;
+    private boolean mScrollToBottom;
+
+    @Override
+    public int getMetricsCategory() {
+        return MetricsEvent.WIFI_CALLING;
+    }
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        final Bundle args = getArguments();
+        final int subId = (args != null) ? args.getInt(WifiCallingSettingsForSub.EXTRA_SUB_ID)
+                : SubscriptionManager.DEFAULT_SUBSCRIPTION_ID;
+
+        mDisclaimerItemList = DisclaimerItemFactory.create(getActivity(), subId);
+        if (mDisclaimerItemList.isEmpty()) {
+            finish(Activity.RESULT_OK);
+            return;
+        }
+
+        if (savedInstanceState != null) {
+            mScrollToBottom = savedInstanceState.getBoolean(
+                    STATE_IS_SCROLL_TO_BOTTOM, mScrollToBottom);
+        }
+    }
+
+    @Override
+    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+            Bundle savedInstanceState) {
+
+        final View view = inflater.inflate(R.layout.wfc_disclaimer_fragment, container, false);
+
+        mAgreeButton = view.findViewById(R.id.agree_button);
+        mAgreeButton.setOnClickListener(this);
+        mDisagreeButton = view.findViewById(R.id.disagree_button);
+        mDisagreeButton.setOnClickListener(this);
+
+        final RecyclerView recyclerView = (RecyclerView) view.findViewById(
+                R.id.disclaimer_item_list);
+        recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
+        recyclerView.setAdapter(new DisclaimerItemListAdapter(mDisclaimerItemList));
+
+        RecyclerView.ItemDecoration itemDecoration =
+                new DividerItemDecoration(getActivity(), DividerItemDecoration.VERTICAL);
+        recyclerView.addItemDecoration(itemDecoration);
+
+        recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
+            @Override
+            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
+                super.onScrolled(recyclerView, dx, dy);
+                if (!recyclerView.canScrollVertically(1 /* scrolling down */)) {
+                    mScrollToBottom = true;
+                    updateButtonState();
+                    recyclerView.removeOnScrollListener(this);
+                }
+            }
+        });
+
+        return view;
+    }
+
+    @Override
+    public void onResume() {
+        super.onResume();
+        updateButtonState();
+    }
+
+    @Override
+    public void onSaveInstanceState(Bundle outState) {
+        super.onSaveInstanceState(outState);
+        outState.putBoolean(STATE_IS_SCROLL_TO_BOTTOM, mScrollToBottom);
+    }
+
+    private void updateButtonState() {
+        mAgreeButton.setEnabled(mScrollToBottom);
+    }
+
+    @Override
+    public void onClick(View v) {
+        if (v == mAgreeButton) {
+            for (DisclaimerItem item : mDisclaimerItemList) {
+                item.onAgreed();
+            }
+            finish(Activity.RESULT_OK);
+        } else if (v == mDisagreeButton) {
+            finish(Activity.RESULT_CANCELED);
+        }
+    }
+
+    @VisibleForTesting
+    void finish(int result) {
+        Activity activity = getActivity();
+        activity.setResult(result, null);
+        activity.finish();
+    }
+}