material-components_material-components-android/lib/java/com/google/android/material/picker/MaterialCalendar.java

/*
 * Copyright 2019 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.google.android.material.picker;

import com.google.android.material.R;

import android.os.Build.VERSION;
import android.os.Build.VERSION_CODES;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.RestrictTo;
import androidx.annotation.RestrictTo.Scope;
import androidx.fragment.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.GridView;
import java.util.Calendar;

/**
 * Fragment for a days of week {@link Calendar} represented as a header row of days labels and
 * {@link GridView} of days backed by {@link MonthInYearAdapter}.
 *
 * @hide
 */
@RestrictTo(Scope.LIBRARY_GROUP)
public abstract class MaterialCalendar<S> extends Fragment {

  private MonthInYear monthInYear;
  private MonthInYearAdapter monthInYearAdapter;

  @Override
  public void onCreate(@Nullable Bundle bundle) {
    super.onCreate(bundle);
    Calendar calendar = Calendar.getInstance();
    monthInYear = MonthInYear.create(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH));
    monthInYearAdapter = new MonthInYearAdapter(getContext(), monthInYear);
  }

  @Nullable
  @Override
  public View onCreateView(
      @NonNull LayoutInflater layoutInflater,
      @Nullable ViewGroup viewGroup,
      @Nullable Bundle bundle) {
    final View root = layoutInflater.inflate(R.layout.mtrl_calendar, viewGroup, false);
    GridView daysHeader = root.findViewById(R.id.calendar_days_header);
    GridView daysGrid = root.findViewById(R.id.calendar_grid);

    daysHeader.setAdapter(new DaysHeaderAdapter());
    daysHeader.setNumColumns(monthInYear.daysInWeek);
    daysGrid.setAdapter(monthInYearAdapter);
    daysGrid.setNumColumns(monthInYear.daysInWeek);
    daysGrid.setOnItemClickListener(
        new OnItemClickListener() {

          @Override
          public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            getOnItemClickListener().onItemClick(parent, view, position, id);
            drawSelection(parent);
            // Allows users of MaterialCalendar to set an OnClickListener
            if (VERSION.SDK_INT >= VERSION_CODES.JELLY_BEAN) {
              root.callOnClick();
            } else {
              root.performClick();
            }
          }
        });
    return root;
  }

  protected final MonthInYearAdapter getMonthInYearAdapter() {
    return monthInYearAdapter;
  }

  @Nullable
  protected abstract S getSelection();

  protected abstract void drawSelection(AdapterView<?> parent);

  protected abstract OnItemClickListener getOnItemClickListener();
}