content: /*
   * Copyright (C) 2014 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 android.widget;
  
  import android.content.Context;
  import android.content.res.Resources;
  import android.icu.util.Calendar;
  import android.util.AttributeSet;
  import android.view.LayoutInflater;
  import android.view.View;
  import android.view.ViewGroup;
  import android.view.accessibility.AccessibilityEvent;
  
  import com.android.internal.R;
  
  /**
   * Displays a selectable list of years.
   */
  class YearPickerView extends ListView {
      private final YearAdapter mAdapter;
      private final int mViewSize;
      private final int mChildSize;
  
      private OnYearSelectedListener mOnYearSelectedListener;
  
      public YearPickerView(Context context, AttributeSet attrs) {
          this(context, attrs, R.attr.listViewStyle);
      }
  
      public YearPickerView(Context context, AttributeSet attrs, int defStyleAttr) {
          this(context, attrs, defStyleAttr, 0);
      }
  
      public YearPickerView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
          super(context, attrs, defStyleAttr, defStyleRes);
  
          final LayoutParams frame = new LayoutParams(
                  LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
          setLayoutParams(frame);
  
          final Resources res = context.getResources();
          mViewSize = res.getDimensionPixelOffset(R.dimen.datepicker_view_animator_height);
          mChildSize = res.getDimensionPixelOffset(R.dimen.datepicker_year_label_height);
  
          setOnItemClickListener(new OnItemClickListener() {
              @Override
              public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                  final int year = mAdapter.getYearForPosition(position);
                  mAdapter.setSelection(year);
  
                  if (mOnYearSelectedListener != null) {
                      mOnYearSelectedListener.onYearChanged(YearPickerView.this, year);
                  }
              }
          });
  
          mAdapter = new YearAdapter(getContext());
          setAdapter(mAdapter);
      }
  
      public void setOnYearSelectedListener(OnYearSelectedListener listener) {
          mOnYearSelectedListener = listener;
      }
  
      /**
       * Sets the currently selected year. Jumps immediately to the new year.
       *
       * @param year the target year
       */
      public void setYear(final int year) {
          mAdapter.setSelection(year);
  
          post(new Runnable() {
              @Override
              public void run() {
                  final int position = mAdapter.getPositionForYear(year);
                  if (position >= 0 && position < getCount()) {
                      setSelectionCentered(position);
                  }
              }
          });
      }
  
      public void setSelectionCentered(int position) {
          final int offset = mViewSize / 2 - mChildSize / 2;
          setSelectionFromTop(position, offset);
      }
  
      public void setRange(Calendar min, Calendar max) {
          mAdapter.setRange(min, max);
      }
  
      private static class YearAdapter extends BaseAdapter {
          private static final int ITEM_LAYOUT = R.layout.year_label_text_view;
          private static final int ITEM_TEXT_APPEARANCE =
                  R.style.TextAppearance_Material_DatePicker_List_YearLabel;
          private static final int ITEM_TEXT_ACTIVATED_APPEARANCE =
                  R.style.TextAppearance_Material_DatePicker_List_YearLabel_Activated;
  
          private final LayoutInflater mInflater;
  
          private int mActivatedYear;
          private int mMinYear;
          private int mCount;
  
          public YearAdapter(Context context) {
              mInflater = LayoutInflater.from(context);
          }
  
          public void setRange(Calendar minDate, Calendar maxDate) {
              final int minYear = minDate.get(Calendar.YEAR);
              final int count = maxDate.get(Calendar.YEAR) - minYear + 1;
  
              if (mMinYear != minYear || mCount != count) {
                  mMinYear = minYear;
                  mCount = count;
                  notifyDataSetInvalidated();
              }
          }
  
          public boolean setSelection(int year) {
              if (mActivatedYear != year) {
                  mActivatedYear = year;
                  notifyDataSetChanged();
                  return true;
              }
              return false;
          }
  
          @Override
          public int getCount() {
              return mCount;
          }
  
          @Override
          public Integer getItem(int position) {
              return getYearForPosition(position);
          }
  
          @Override
          public long getItemId(int position) {
              return getYearForPosition(position);
          }
  
          public int getPositionForYear(int year) {
              return year - mMinYear;
          }
  
          public int getYearForPosition(int position) {
              return mMinYear + position;
          }
  
          @Override
          public boolean hasStableIds() {
              return true;
          }
  
          @Override
          public View getView(int position, View convertView, ViewGroup parent) {
              final TextView v;
              final boolean hasNewView = convertView == null;
              if (hasNewView) {
                  v = (TextView) mInflater.inflate(ITEM_LAYOUT, parent, false);
              } else {
                  v = (TextView) convertView;
              }
  
              final int year = getYearForPosition(position);
              final boolean activated = mActivatedYear == year;
  
              if (hasNewView || v.isActivated() != activated) {
                  final int textAppearanceResId;
                  if (activated && ITEM_TEXT_ACTIVATED_APPEARANCE != 0) {
                      textAppearanceResId = ITEM_TEXT_ACTIVATED_APPEARANCE;
                  } else {
                      textAppearanceResId = ITEM_TEXT_APPEARANCE;
                  }
                  v.setTextAppearance(textAppearanceResId);
                  v.setActivated(activated);
              }
  
              v.setText(Integer.toString(year));
              return v;
          }
  
          @Override
          public int getItemViewType(int position) {
              return 0;
          }
  
          @Override
          public int getViewTypeCount() {
              return 1;
          }
  
          @Override
          public boolean isEmpty() {
              return false;
          }
  
          @Override
          public boolean areAllItemsEnabled() {
              return true;
          }
  
          @Override
          public boolean isEnabled(int position) {
              return true;
          }
      }
  
      public int getFirstPositionOffset() {
          final View firstChild = getChildAt(0);
          if (firstChild == null) {
              return 0;
          }
          return firstChild.getTop();
      }
  
      /** @hide */
      @Override
      public void onInitializeAccessibilityEventInternal(AccessibilityEvent event) {
          super.onInitializeAccessibilityEventInternal(event);
  
          // There are a bunch of years, so don't bother.
          if (event.getEventType() == AccessibilityEvent.TYPE_VIEW_SCROLLED) {
              event.setFromIndex(0);
              event.setToIndex(0);
          }
      }
  
      /**
       * The callback used to indicate the user changed the year.
       */
      public interface OnYearSelectedListener {
          /**
           * Called upon a year change.
           *
           * @param view The view associated with this listener.
           * @param year The year that was set.
           */
          void onYearChanged(YearPickerView view, int year);
      }
  }