Visualize password requirements and their fulfillment

1. Aggregate policies and generate the requirements
2. When user modifies the password, check is each requirement fulfilled
   Update the view accordingly.

Change-Id: I962ed3b81ce844006be1024a493e94ce52a3fdec
Fix: 24900754

src/com/android/settings/password/PasswordRequirementAdapter.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2016 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.password;
+
+import android.support.v7.widget.RecyclerView;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+
+import com.android.settings.R;
+
+import static com.android.settings.password.PasswordRequirementAdapter
+        .PasswordRequirementViewHolder;
+
+/**
+ * Used in {@link com.android.settings.ConfirmLockPassword} to show password requirements.
+ */
+public class PasswordRequirementAdapter extends
+        RecyclerView.Adapter<PasswordRequirementViewHolder> {
+    private String[] mRequirements;
+
+    public PasswordRequirementAdapter() {
+        setHasStableIds(true);
+    }
+
+    @Override
+    public PasswordRequirementViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
+        View v = LayoutInflater.from(parent.getContext())
+                .inflate(R.layout.password_requirement_item, parent, false);
+        return new PasswordRequirementViewHolder(v);
+    }
+
+    @Override
+    public int getItemCount() {
+        return  mRequirements.length;
+    }
+
+    public void setRequirements(String[] requirements) {
+        mRequirements = requirements;
+        notifyDataSetChanged();
+    }
+
+    @Override
+    public long getItemId(int position) {
+        return mRequirements[position].hashCode();
+    }
+
+    @Override
+    public void onBindViewHolder(PasswordRequirementViewHolder holder, int position) {
+        holder.mDescriptionText.setText(mRequirements[position]);
+    }
+
+    public static class PasswordRequirementViewHolder extends RecyclerView.ViewHolder {
+        private TextView mDescriptionText;
+
+        public PasswordRequirementViewHolder(View itemView) {
+            super(itemView);
+            mDescriptionText = (TextView) itemView;
+        }
+    }
+
+}