car/core/src/main/java/androidx/car/widget/CompoundButtonListItem.java - platform/frameworks/support - Git at Google

 /*
  * 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 androidx.car.widget;

 import static java.lang.annotation.RetentionPolicy.SOURCE;

 import android.content.Context;
 import android.content.res.Resources;
 import android.graphics.drawable.Drawable;
 import android.text.TextUtils;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewGroup.MarginLayoutParams;
 import android.widget.CompoundButton;
 import android.widget.ImageView;
 import android.widget.TextView;

 import androidx.annotation.CallSuper;
 import androidx.annotation.DimenRes;
 import androidx.annotation.Dimension;
 import androidx.annotation.DrawableRes;
 import androidx.annotation.IntDef;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.car.R;
 import androidx.car.widget.ListItemAdapter.ListItemType;
 import androidx.constraintlayout.widget.ConstraintLayout;
 import androidx.constraintlayout.widget.Guideline;

 import java.lang.annotation.Retention;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.function.Function;

 /**
  * Class to build a list item with {@link CompoundButton}.
  *
  * <p>A compound button list item is visually composed of 5 parts.
  * <ul>
  * <li>optional {@code Primary Action Icon}.
  * <li>optional {@code Title}.
  * <li>optional {@code Body}.
  * <li>optional {@code Divider}.
  * <li>A {@link CompoundButton}.
  * </ul>
  *
  * @param <VH> ViewHolder that extends {@link CompoundButtonListItem.ViewHolder}.
  */
 public abstract class CompoundButtonListItem<VH extends CompoundButtonListItem.ViewHolder> extends
         ListItem<VH> {

     @Retention(SOURCE)
     @IntDef({
             PRIMARY_ACTION_ICON_SIZE_SMALL, PRIMARY_ACTION_ICON_SIZE_MEDIUM,
             PRIMARY_ACTION_ICON_SIZE_LARGE})
     private @interface PrimaryActionIconSize {
     }

     /**
      * Small sized icon is the mostly commonly used size. It's the same as supplemental action icon.
      */
     public static final int PRIMARY_ACTION_ICON_SIZE_SMALL = 0;
     /**
      * Medium sized icon is slightly bigger than {@code SMALL} ones. It is intended for profile
      * pictures (avatar), in which case caller is responsible for passing in a circular image.
      */
     public static final int PRIMARY_ACTION_ICON_SIZE_MEDIUM = 1;
     /**
      * Large sized icon is as tall as a list item with only {@code title} text. It is intended for
      * album art.
      */
     public static final int PRIMARY_ACTION_ICON_SIZE_LARGE = 2;

     @Retention(SOURCE)
     @IntDef({
             PRIMARY_ACTION_TYPE_NO_ICON, PRIMARY_ACTION_TYPE_EMPTY_ICON,
             PRIMARY_ACTION_TYPE_ICON})
     private @interface PrimaryActionType {
     }

     private static final int PRIMARY_ACTION_TYPE_NO_ICON = 0;
     private static final int PRIMARY_ACTION_TYPE_EMPTY_ICON = 1;
     private static final int PRIMARY_ACTION_TYPE_ICON = 2;

     private final Context mContext;
     private boolean mIsEnabled = true;
     private boolean mIsClickable;

     private final List<ViewBinder<ViewHolder>> mBinders = new ArrayList<>();

     @PrimaryActionType
     private int mPrimaryActionType = PRIMARY_ACTION_TYPE_NO_ICON;
     private Drawable mPrimaryActionIconDrawable;
     @PrimaryActionIconSize
     private int mPrimaryActionIconSize = PRIMARY_ACTION_ICON_SIZE_SMALL;

     private CharSequence mTitle;
     private CharSequence mBody;

     @Dimension
     private final int mSupplementalGuidelineBegin;

     private boolean mIsChecked;
     /**
      * {@code true} if the checked state of the item has changed programmatically and
      * {@link #mOnCheckedChangeListener} needs to be notified.
      */
     private boolean mShouldNotifyChecked;
     private boolean mShowCompoundButtonDivider;
     private CompoundButton.OnCheckedChangeListener mOnCheckedChangeListener;

     /**
      * Creates a {@link CompoundButtonListItem} that will be used to display a list item with a
      * {@link CompoundButton}.
      *
      * @param context The context to be used by this {@link CompoundButtonListItem}.
      */
     public CompoundButtonListItem(@NonNull Context context) {
         mContext = context;
         Resources res = mContext.getResources();
         mSupplementalGuidelineBegin = res.getDimensionPixelSize(
                 R.dimen.car_list_item_supplemental_guideline_top);
         markDirty();
     }

     /**
      * Classes that extend {@link CompoundButtonListItem} should register its view type in
      * {@link ListItemAdapter#registerListItemViewType(int, int, Function)}.
      *
      * @return Type of this {@link CompoundButtonListItem}.
      */
     @ListItemType
     @Override
     public abstract int getViewType();

     /**
      * Calculates the layout params for views in {@link ViewHolder}.
      */
     @Override
     @CallSuper
     protected void resolveDirtyState() {
         mBinders.clear();

         // Create binders that adjust layout params of each view.
         setPrimaryAction();
         setText();
         setCompoundButton();
         setItemClickable();
     }

     /**
      * Hides all views in {@link ViewHolder} then applies ViewBinders to adjust view layout params.
      */
     @Override
     @SuppressWarnings("unchecked")
     public void onBind(@NonNull VH viewHolder) {
         hideSubViews(viewHolder);
         for (ViewBinder binder : mBinders) {
             binder.bind(viewHolder);
         }

         for (View v : viewHolder.getWidgetViews()) {
             v.setEnabled(mIsEnabled);
         }
         // SwitchListItem supports clicking on the item so we also update the entire itemView.
         viewHolder.itemView.setEnabled(mIsEnabled);
     }

     @Override
     public void setEnabled(boolean isEnabled) {
         mIsEnabled = isEnabled;
     }

     /**
      * Sets whether a click anywhere on the list toggles the state of compound button. The
      * default state of {@code false} requires an explicit click on the compound button to toggle
      * its state.
      *
      * @param isClickable {@code true} for a click anywhere on the list to toggle the state of
      *                    the compound button.
      * @deprecated Use {@link #setEntireItemClickable(boolean)} instead.
      */
     @Deprecated
     public void setClickable(boolean isClickable) {
         mIsClickable = isClickable;
         markDirty();
     }

     /**
      * Sets whether a click anywhere on the list toggles the state of compound button. The
      * default state of {@code false} requires an explicit click on the compound button to toggle
      * its state.
      *
      * @param isClickable {@code true} for a click anywhere on the list to toggle the state of
      *                    the compound button.
      */
     public void setEntireItemClickable(boolean isClickable) {
         mIsClickable = isClickable;
         markDirty();
     }

     /**
      * Sets {@code Primary Action} to be represented by an icon.
      *
      * @param drawable the {@link Drawable} to set.
      * @param size     small/medium/large. Available as {@link #PRIMARY_ACTION_ICON_SIZE_SMALL},
      *                 {@link #PRIMARY_ACTION_ICON_SIZE_MEDIUM},
      *                 {@link #PRIMARY_ACTION_ICON_SIZE_LARGE}.
      */
     public void setPrimaryActionIcon(@NonNull Drawable drawable, @PrimaryActionIconSize int size) {
         mPrimaryActionType = PRIMARY_ACTION_TYPE_ICON;
         mPrimaryActionIconDrawable = drawable;
         mPrimaryActionIconSize = size;
         markDirty();
     }

     /**
      * Sets {@code Primary Action} to be represented by an icon.
      *
      * @param iconResId the resource identifier of the drawable.
      * @param size      small/medium/large. Available as {@link #PRIMARY_ACTION_ICON_SIZE_SMALL},
      *                  {@link #PRIMARY_ACTION_ICON_SIZE_MEDIUM},
      *                  {@link #PRIMARY_ACTION_ICON_SIZE_LARGE}.
      */
     public void setPrimaryActionIcon(@DrawableRes int iconResId, @PrimaryActionIconSize int size) {
         setPrimaryActionIcon(mContext.getDrawable(iconResId), size);
     }

     /**
      * Sets {@code Primary Action} to be empty icon.
      *
      * <p>{@code Text} would have a start margin as if {@code Primary Action} were set to primary
      * icon.
      */
     public void setPrimaryActionEmptyIcon() {
         mPrimaryActionType = PRIMARY_ACTION_TYPE_EMPTY_ICON;
         markDirty();
     }

     /**
      * Sets {@code Primary Action} to have no icon. Text would align to the start of item.
      */
     public void setPrimaryActionNoIcon() {
         mPrimaryActionType = PRIMARY_ACTION_TYPE_NO_ICON;
         markDirty();
     }

     /**
      * Sets the title of item.
      *
      * <p>{@code Title} text is limited to one line, and ellipses at the end.
      *
      * @param title text to display as title.
      */
     public void setTitle(@Nullable CharSequence title) {
         mTitle = title;
         markDirty();
     }

     /**
      * Sets the body text of item.
      *
      * <p>Text beyond length required by regulation will be truncated.
      *
      * @param body text to be displayed.
      */
     public void setBody(@Nullable CharSequence body) {
         mBody = body;
         markDirty();
     }

     /**
      * Sets the state of {@link CompoundButton}.
      *
      * @param isChecked sets the "checked/unchecked, namely on/off" state of compound button.
      */
     public void setChecked(boolean isChecked) {
         if (mIsChecked == isChecked) {
             return;
         }
         mIsChecked = isChecked;
         mShouldNotifyChecked = true;
         markDirty();
     }

     /**
      * Registers a callback to be invoked when the checked state of compound button changes.
      *
      * @param listener callback to be invoked when the checked state shown in the UI changes.
      */
     public void setOnCheckedChangeListener(
             @Nullable CompoundButton.OnCheckedChangeListener listener) {
         mOnCheckedChangeListener = listener;
         // This method invalidates previous listener. Reset so that we *only*
         // notify when the checked state changes and not on the initial bind.
         mShouldNotifyChecked = false;
         markDirty();
     }

     /**
      * Sets whether to display a vertical bar between compound button and text.
      */
     public void setShowCompoundButtonDivider(boolean showCompoundButtonDivider) {
         mShowCompoundButtonDivider = showCompoundButtonDivider;
         markDirty();
     }

     private void hideSubViews(ViewHolder vh) {
         for (View v : vh.getWidgetViews()) {
             v.setVisibility(View.GONE);
         }
     }

     private void setPrimaryAction() {
         setPrimaryIconContent();
         setPrimaryIconLayout();
     }

     private void setText() {
         setTextContent();
         setTextVerticalMargin();
         setTextStartMargin();
         setTextEndMargin();
     }

     private void setPrimaryIconContent() {
         switch (mPrimaryActionType) {
             case PRIMARY_ACTION_TYPE_ICON:
                 mBinders.add(vh -> {
                     vh.getPrimaryIcon().setVisibility(View.VISIBLE);
                     vh.getPrimaryIcon().setImageDrawable(mPrimaryActionIconDrawable);
                 });
                 break;
             case PRIMARY_ACTION_TYPE_EMPTY_ICON:
                 // Do nothing.
                 break;
             case PRIMARY_ACTION_TYPE_NO_ICON:
                 mBinders.add(vh -> {
                     vh.getPrimaryIcon().setVisibility(View.GONE);
                 });
                 break;
             default:
                 throw new IllegalStateException("Unknown primary action type.");
         }
     }

     /**
      * Returns whether the compound button will be placed at the end of the list item layout. This
      * value is used to determine start margins for the {@code Title} and {@code Body}.
      *
      * @return Whether compound button is placed at the end of the list item layout.
      */
     public abstract boolean isCompoundButtonPositionEnd();

     /**
      * Sets the size, start margin, and vertical position of primary icon.
      *
      * <p>Large icon will have no start margin, and always align center vertically.
      *
      * <p>Small/medium icon will have start margin, and uses a top margin such that it is "pinned"
      * at the same position in list item regardless of item height.
      */
     private void setPrimaryIconLayout() {
         if (mPrimaryActionType == PRIMARY_ACTION_TYPE_EMPTY_ICON
                 || mPrimaryActionType == PRIMARY_ACTION_TYPE_NO_ICON) {
             return;
         }

         // Size of icon.
         @DimenRes int sizeResId;
         switch (mPrimaryActionIconSize) {
             case PRIMARY_ACTION_ICON_SIZE_SMALL:
                 sizeResId = R.dimen.car_primary_icon_size;
                 break;
             case PRIMARY_ACTION_ICON_SIZE_MEDIUM:
                 sizeResId = R.dimen.car_avatar_icon_size;
                 break;
             case PRIMARY_ACTION_ICON_SIZE_LARGE:
                 sizeResId = R.dimen.car_single_line_list_item_height;
                 break;
             default:
                 throw new IllegalStateException("Unknown primary action icon size.");
         }

         int iconSize = mContext.getResources().getDimensionPixelSize(sizeResId);

         // Start margin of icon.
         int startMargin;
         switch (mPrimaryActionIconSize) {
             case PRIMARY_ACTION_ICON_SIZE_SMALL:
             case PRIMARY_ACTION_ICON_SIZE_MEDIUM:
                 startMargin = mContext.getResources().getDimensionPixelSize(R.dimen.car_keyline_1);
                 break;
             case PRIMARY_ACTION_ICON_SIZE_LARGE:
                 startMargin = 0;
                 break;
             default:
                 throw new IllegalStateException("Unknown primary action icon size.");
         }

         mBinders.add(vh -> {
             ConstraintLayout.LayoutParams layoutParams =
                     (ConstraintLayout.LayoutParams) vh.getPrimaryIcon().getLayoutParams();
             layoutParams.height = layoutParams.width = iconSize;
             layoutParams.setMarginStart(startMargin);

             if (mPrimaryActionIconSize == PRIMARY_ACTION_ICON_SIZE_LARGE) {
                 // A large icon is always vertically centered.
                 layoutParams.verticalBias = 0.5f;
                 layoutParams.topMargin = 0;
             } else {
                 // Align the icon to the top of the parent. This allows the topMargin to shift it
                 // down relative to the top.
                 layoutParams.verticalBias = 0f;

                 // For all other icon sizes, the icon should be centered within the height of
                 // car_double_line_list_item_height. Note: the actual height of the item can be
                 // larger than this.
                 int itemHeight = mContext.getResources().getDimensionPixelSize(
                         R.dimen.car_double_line_list_item_height);
                 layoutParams.topMargin = (itemHeight - iconSize) / 2;
             }

             vh.getPrimaryIcon().requestLayout();
         });
     }

     private void setTextContent() {
         boolean hasTitle = !TextUtils.isEmpty(mTitle);
         boolean hasBody = !TextUtils.isEmpty(mBody);

         if (!hasTitle && !hasBody) {
             return;
         }

         mBinders.add(vh -> {
             if (hasTitle) {
                 vh.getTitle().setVisibility(View.VISIBLE);
                 vh.getTitle().setText(mTitle);
             }

             if (hasBody) {
                 vh.getBody().setVisibility(View.VISIBLE);
                 vh.getBody().setText(mBody);
             }

             if (hasTitle && !hasBody) {
                 // If only title, then center the supplemental actions.
                 vh.getSupplementalGuideline().setGuidelineBegin(
                         ConstraintLayout.LayoutParams.UNSET);
                 vh.getSupplementalGuideline().setGuidelinePercent(0.5f);
             } else {
                 // Otherwise, position it a fixed distance from the top.
                 vh.getSupplementalGuideline().setGuidelinePercent(
                         ConstraintLayout.LayoutParams.UNSET);
                 vh.getSupplementalGuideline().setGuidelineBegin(
                         mSupplementalGuidelineBegin);
             }
         });
     }

     /**
      * Sets start margin of text view depending on icon type.
      */
     private void setTextStartMargin() {
         @DimenRes int startMarginResId;
         if (!isCompoundButtonPositionEnd()) {
             startMarginResId = R.dimen.car_keyline_3;
         } else {
             switch (mPrimaryActionType) {
                 case PRIMARY_ACTION_TYPE_NO_ICON:
                     startMarginResId = R.dimen.car_keyline_1;
                     break;
                 case PRIMARY_ACTION_TYPE_EMPTY_ICON:
                     startMarginResId = R.dimen.car_keyline_3;
                     break;
                 case PRIMARY_ACTION_TYPE_ICON:
                     startMarginResId = mPrimaryActionIconSize == PRIMARY_ACTION_ICON_SIZE_LARGE
                             ? R.dimen.car_keyline_4
                             : R.dimen.car_keyline_3;  // Small and medium sized icon.
                     break;
                 default:
                     throw new IllegalStateException("Unknown primary action type.");
             }
         }

         int startMargin = mContext.getResources().getDimensionPixelSize(startMarginResId);
         mBinders.add(vh -> {
             MarginLayoutParams titleLayoutParams =
                     (MarginLayoutParams) vh.getTitle().getLayoutParams();
             titleLayoutParams.setMarginStart(startMargin);
             vh.getTitle().requestLayout();

             MarginLayoutParams bodyLayoutParams =
                     (MarginLayoutParams) vh.getBody().getLayoutParams();
             bodyLayoutParams.setMarginStart(startMargin);
             vh.getBody().requestLayout();
         });
     }

     private void setTextEndMargin() {
         int endMargin = mContext.getResources().getDimensionPixelSize(R.dimen.car_padding_4);

         mBinders.add(vh -> {
             MarginLayoutParams titleLayoutParams =
                     (MarginLayoutParams) vh.getTitle().getLayoutParams();
             titleLayoutParams.setMarginEnd(endMargin);

             MarginLayoutParams bodyLayoutParams =
                     (MarginLayoutParams) vh.getBody().getLayoutParams();
             bodyLayoutParams.setMarginEnd(endMargin);
         });
     }

     /**
      * Sets top/bottom margins of {@code Title} and {@code Body}.
      */
     private void setTextVerticalMargin() {
         // Set all relevant fields in layout params to avoid carried over params when the item
         // gets bound to a recycled view holder.
         if (!TextUtils.isEmpty(mTitle) && TextUtils.isEmpty(mBody)) {
             // Title only - view is aligned center vertically by itself.
             mBinders.add(vh -> {
                 MarginLayoutParams layoutParams =
                         (MarginLayoutParams) vh.getTitle().getLayoutParams();
                 layoutParams.topMargin = 0;
                 vh.getTitle().requestLayout();
             });
         } else if (TextUtils.isEmpty(mTitle) && !TextUtils.isEmpty(mBody)) {
             mBinders.add(vh -> {
                 // Body uses top and bottom margin.
                 int margin = mContext.getResources().getDimensionPixelSize(
                         R.dimen.car_padding_3);
                 MarginLayoutParams layoutParams =
                         (MarginLayoutParams) vh.getBody().getLayoutParams();
                 layoutParams.topMargin = margin;
                 layoutParams.bottomMargin = margin;
                 vh.getBody().requestLayout();
             });
         } else {
             mBinders.add(vh -> {
                 Resources resources = mContext.getResources();
                 int padding2 = resources.getDimensionPixelSize(R.dimen.car_padding_2);

                 // Title has a top margin
                 MarginLayoutParams titleLayoutParams =
                         (MarginLayoutParams) vh.getTitle().getLayoutParams();
                 titleLayoutParams.topMargin = padding2;
                 vh.getTitle().requestLayout();

                 // Body is below title with no margin and has bottom margin.
                 MarginLayoutParams bodyLayoutParams =
                         (MarginLayoutParams) vh.getBody().getLayoutParams();
                 bodyLayoutParams.topMargin = 0;
                 bodyLayoutParams.bottomMargin = padding2;
                 vh.getBody().requestLayout();
             });
         }
     }

     /**
      * Sets up view(s) for supplemental action.
      */
     private void setCompoundButton() {
         mBinders.add(vh -> {
             vh.getCompoundButton().setVisibility(View.VISIBLE);
             vh.getCompoundButton().setOnCheckedChangeListener(null);
             vh.getCompoundButton().setChecked(mIsChecked);
             vh.getCompoundButton().setOnCheckedChangeListener((buttonView, isChecked) -> {
                 if (mOnCheckedChangeListener != null) {
                     // The checked state changed via user interaction with the compound button.
                     mOnCheckedChangeListener.onCheckedChanged(buttonView, isChecked);
                 }
                 mIsChecked = isChecked;
             });
             if (mShouldNotifyChecked && mOnCheckedChangeListener != null) {
                 // The checked state was changed programmatically.
                 mOnCheckedChangeListener.onCheckedChanged(vh.getCompoundButton(),
                         mIsChecked);
                 mShouldNotifyChecked = false;
             }

             if (mShowCompoundButtonDivider) {
                 vh.getCompoundButtonDivider().setVisibility(View.VISIBLE);
             }
         });
     }

     private void setItemClickable() {
         mBinders.add(vh -> {
             // If applicable (namely item is clickable), clicking item always toggles the
             // compound button.
             vh.itemView.setOnClickListener(v -> vh.getCompoundButton().toggle());
             vh.itemView.setClickable(mIsClickable);
         });
     }

     /**
      * Holds views of CompoundButtonListItem.
      */
     public abstract static class ViewHolder extends ListItem.ViewHolder {

         /**
          * Creates a {@link ViewHolder} for a {@link CompoundButtonListItem}.
          *
          * @param itemView The view to be used to display a {@link CompoundButtonListItem}.
          */
         public ViewHolder(@NonNull View itemView) {
             super(itemView);
         }

         /**
          * Returns the primary icon view within this view holder's view.
          *
          * @return Icon view within this view holder's view.
          */
         @NonNull
         public abstract ImageView getPrimaryIcon();

         /**
          * Returns the title view within this view holder's view.
          *
          * @return Title view within this view holder's view.
          */
         @NonNull
         public abstract TextView getTitle();

         /**
          * Returns the body view within this view holder's view.
          *
          * @return Body view within this view holder's view.
          */
         @NonNull
         public abstract TextView getBody();

         /**
          * Returns the compound button divider view within this view holder's view.
          *
          * @return Compound button divider view within this view holder's view.
          */
         @NonNull
         public abstract View getCompoundButtonDivider();

         /**
          * Returns the compound button within this view holder's view.
          *
          * @return Compound button within this view holder's view.
          */
         @NonNull
         public abstract CompoundButton getCompoundButton();

         @NonNull
         abstract Guideline getSupplementalGuideline();

         @NonNull
         abstract ViewGroup getContainerLayout();

         /**
          * Returns the container layout of this view holder.
          *
          * @return Container layout of this view holder.
          */
         @NonNull
         abstract View[] getWidgetViews();
     }
 }
	/*
	* 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 androidx.car.widget;

	import static java.lang.annotation.RetentionPolicy.SOURCE;

	import android.content.Context;
	import android.content.res.Resources;
	import android.graphics.drawable.Drawable;
	import android.text.TextUtils;
	import android.view.View;
	import android.view.ViewGroup;
	import android.view.ViewGroup.MarginLayoutParams;
	import android.widget.CompoundButton;
	import android.widget.ImageView;
	import android.widget.TextView;

	import androidx.annotation.CallSuper;
	import androidx.annotation.DimenRes;
	import androidx.annotation.Dimension;
	import androidx.annotation.DrawableRes;
	import androidx.annotation.IntDef;
	import androidx.annotation.NonNull;
	import androidx.annotation.Nullable;
	import androidx.car.R;
	import androidx.car.widget.ListItemAdapter.ListItemType;
	import androidx.constraintlayout.widget.ConstraintLayout;
	import androidx.constraintlayout.widget.Guideline;

	import java.lang.annotation.Retention;
	import java.util.ArrayList;
	import java.util.List;
	import java.util.function.Function;

	/**
	* Class to build a list item with {@link CompoundButton}.
	*
	* <p>A compound button list item is visually composed of 5 parts.
	* <ul>
	* <li>optional {@code Primary Action Icon}.
	* <li>optional {@code Title}.
	* <li>optional {@code Body}.
	* <li>optional {@code Divider}.
	* <li>A {@link CompoundButton}.
	* </ul>
	*
	* @param <VH> ViewHolder that extends {@link CompoundButtonListItem.ViewHolder}.
	*/
	public abstract class CompoundButtonListItem<VH extends CompoundButtonListItem.ViewHolder> extends
	ListItem<VH> {

	@Retention(SOURCE)
	@IntDef({
	PRIMARY_ACTION_ICON_SIZE_SMALL, PRIMARY_ACTION_ICON_SIZE_MEDIUM,
	PRIMARY_ACTION_ICON_SIZE_LARGE})
	private @interface PrimaryActionIconSize {
	}

	/**
	* Small sized icon is the mostly commonly used size. It's the same as supplemental action icon.
	*/
	public static final int PRIMARY_ACTION_ICON_SIZE_SMALL = 0;
	/**
	* Medium sized icon is slightly bigger than {@code SMALL} ones. It is intended for profile
	* pictures (avatar), in which case caller is responsible for passing in a circular image.
	*/
	public static final int PRIMARY_ACTION_ICON_SIZE_MEDIUM = 1;
	/**
	* Large sized icon is as tall as a list item with only {@code title} text. It is intended for
	* album art.
	*/
	public static final int PRIMARY_ACTION_ICON_SIZE_LARGE = 2;

	@Retention(SOURCE)
	@IntDef({
	PRIMARY_ACTION_TYPE_NO_ICON, PRIMARY_ACTION_TYPE_EMPTY_ICON,
	PRIMARY_ACTION_TYPE_ICON})
	private @interface PrimaryActionType {
	}

	private static final int PRIMARY_ACTION_TYPE_NO_ICON = 0;
	private static final int PRIMARY_ACTION_TYPE_EMPTY_ICON = 1;
	private static final int PRIMARY_ACTION_TYPE_ICON = 2;

	private final Context mContext;
	private boolean mIsEnabled = true;
	private boolean mIsClickable;

	private final List<ViewBinder<ViewHolder>> mBinders = new ArrayList<>();

	@PrimaryActionType
	private int mPrimaryActionType = PRIMARY_ACTION_TYPE_NO_ICON;
	private Drawable mPrimaryActionIconDrawable;
	@PrimaryActionIconSize
	private int mPrimaryActionIconSize = PRIMARY_ACTION_ICON_SIZE_SMALL;

	private CharSequence mTitle;
	private CharSequence mBody;

	@Dimension
	private final int mSupplementalGuidelineBegin;

	private boolean mIsChecked;
	/**
	* {@code true} if the checked state of the item has changed programmatically and
	* {@link #mOnCheckedChangeListener} needs to be notified.
	*/
	private boolean mShouldNotifyChecked;
	private boolean mShowCompoundButtonDivider;
	private CompoundButton.OnCheckedChangeListener mOnCheckedChangeListener;

	/**
	* Creates a {@link CompoundButtonListItem} that will be used to display a list item with a
	* {@link CompoundButton}.
	*
	* @param context The context to be used by this {@link CompoundButtonListItem}.
	*/
	public CompoundButtonListItem(@NonNull Context context) {
	mContext = context;
	Resources res = mContext.getResources();
	mSupplementalGuidelineBegin = res.getDimensionPixelSize(
	R.dimen.car_list_item_supplemental_guideline_top);
	markDirty();
	}

	/**
	* Classes that extend {@link CompoundButtonListItem} should register its view type in
	* {@link ListItemAdapter#registerListItemViewType(int, int, Function)}.
	*
	* @return Type of this {@link CompoundButtonListItem}.
	*/
	@ListItemType
	@Override
	public abstract int getViewType();

	/**
	* Calculates the layout params for views in {@link ViewHolder}.
	*/
	@Override
	@CallSuper
	protected void resolveDirtyState() {
	mBinders.clear();

	// Create binders that adjust layout params of each view.
	setPrimaryAction();
	setText();
	setCompoundButton();
	setItemClickable();
	}

	/**
	* Hides all views in {@link ViewHolder} then applies ViewBinders to adjust view layout params.
	*/
	@Override
	@SuppressWarnings("unchecked")
	public void onBind(@NonNull VH viewHolder) {
	hideSubViews(viewHolder);
	for (ViewBinder binder : mBinders) {
	binder.bind(viewHolder);
	}

	for (View v : viewHolder.getWidgetViews()) {
	v.setEnabled(mIsEnabled);
	}
	// SwitchListItem supports clicking on the item so we also update the entire itemView.
	viewHolder.itemView.setEnabled(mIsEnabled);
	}

	@Override
	public void setEnabled(boolean isEnabled) {
	mIsEnabled = isEnabled;
	}

	/**
	* Sets whether a click anywhere on the list toggles the state of compound button. The
	* default state of {@code false} requires an explicit click on the compound button to toggle
	* its state.
	*
	* @param isClickable {@code true} for a click anywhere on the list to toggle the state of
	* the compound button.
	* @deprecated Use {@link #setEntireItemClickable(boolean)} instead.
	*/
	@Deprecated
	public void setClickable(boolean isClickable) {
	mIsClickable = isClickable;
	markDirty();
	}

	/**
	* Sets whether a click anywhere on the list toggles the state of compound button. The
	* default state of {@code false} requires an explicit click on the compound button to toggle
	* its state.
	*
	* @param isClickable {@code true} for a click anywhere on the list to toggle the state of
	* the compound button.
	*/
	public void setEntireItemClickable(boolean isClickable) {
	mIsClickable = isClickable;
	markDirty();
	}

	/**
	* Sets {@code Primary Action} to be represented by an icon.
	*
	* @param drawable the {@link Drawable} to set.
	* @param size small/medium/large. Available as {@link #PRIMARY_ACTION_ICON_SIZE_SMALL},
	* {@link #PRIMARY_ACTION_ICON_SIZE_MEDIUM},
	* {@link #PRIMARY_ACTION_ICON_SIZE_LARGE}.
	*/
	public void setPrimaryActionIcon(@NonNull Drawable drawable, @PrimaryActionIconSize int size) {
	mPrimaryActionType = PRIMARY_ACTION_TYPE_ICON;
	mPrimaryActionIconDrawable = drawable;
	mPrimaryActionIconSize = size;
	markDirty();
	}

	/**
	* Sets {@code Primary Action} to be represented by an icon.
	*
	* @param iconResId the resource identifier of the drawable.
	* @param size small/medium/large. Available as {@link #PRIMARY_ACTION_ICON_SIZE_SMALL},
	* {@link #PRIMARY_ACTION_ICON_SIZE_MEDIUM},
	* {@link #PRIMARY_ACTION_ICON_SIZE_LARGE}.
	*/
	public void setPrimaryActionIcon(@DrawableRes int iconResId, @PrimaryActionIconSize int size) {
	setPrimaryActionIcon(mContext.getDrawable(iconResId), size);
	}

	/**
	* Sets {@code Primary Action} to be empty icon.
	*
	* <p>{@code Text} would have a start margin as if {@code Primary Action} were set to primary
	* icon.
	*/
	public void setPrimaryActionEmptyIcon() {
	mPrimaryActionType = PRIMARY_ACTION_TYPE_EMPTY_ICON;
	markDirty();
	}

	/**
	* Sets {@code Primary Action} to have no icon. Text would align to the start of item.
	*/
	public void setPrimaryActionNoIcon() {
	mPrimaryActionType = PRIMARY_ACTION_TYPE_NO_ICON;
	markDirty();
	}

	/**
	* Sets the title of item.
	*
	* <p>{@code Title} text is limited to one line, and ellipses at the end.
	*
	* @param title text to display as title.
	*/
	public void setTitle(@Nullable CharSequence title) {
	mTitle = title;
	markDirty();
	}

	/**
	* Sets the body text of item.
	*
	* <p>Text beyond length required by regulation will be truncated.
	*
	* @param body text to be displayed.
	*/
	public void setBody(@Nullable CharSequence body) {
	mBody = body;
	markDirty();
	}

	/**
	* Sets the state of {@link CompoundButton}.
	*
	* @param isChecked sets the "checked/unchecked, namely on/off" state of compound button.
	*/
	public void setChecked(boolean isChecked) {
	if (mIsChecked == isChecked) {
	return;
	}
	mIsChecked = isChecked;
	mShouldNotifyChecked = true;
	markDirty();
	}

	/**
	* Registers a callback to be invoked when the checked state of compound button changes.
	*
	* @param listener callback to be invoked when the checked state shown in the UI changes.
	*/
	public void setOnCheckedChangeListener(
	@Nullable CompoundButton.OnCheckedChangeListener listener) {
	mOnCheckedChangeListener = listener;
	// This method invalidates previous listener. Reset so that we only
	// notify when the checked state changes and not on the initial bind.
	mShouldNotifyChecked = false;
	markDirty();
	}

	/**
	* Sets whether to display a vertical bar between compound button and text.
	*/
	public void setShowCompoundButtonDivider(boolean showCompoundButtonDivider) {
	mShowCompoundButtonDivider = showCompoundButtonDivider;
	markDirty();
	}

	private void hideSubViews(ViewHolder vh) {
	for (View v : vh.getWidgetViews()) {
	v.setVisibility(View.GONE);
	}
	}

	private void setPrimaryAction() {
	setPrimaryIconContent();
	setPrimaryIconLayout();
	}

	private void setText() {
	setTextContent();
	setTextVerticalMargin();
	setTextStartMargin();
	setTextEndMargin();
	}

	private void setPrimaryIconContent() {
	switch (mPrimaryActionType) {
	case PRIMARY_ACTION_TYPE_ICON:
	mBinders.add(vh -> {
	vh.getPrimaryIcon().setVisibility(View.VISIBLE);
	vh.getPrimaryIcon().setImageDrawable(mPrimaryActionIconDrawable);
	});
	break;
	case PRIMARY_ACTION_TYPE_EMPTY_ICON:
	// Do nothing.
	break;
	case PRIMARY_ACTION_TYPE_NO_ICON:
	mBinders.add(vh -> {
	vh.getPrimaryIcon().setVisibility(View.GONE);
	});
	break;
	default:
	throw new IllegalStateException("Unknown primary action type.");
	}
	}

	/**
	* Returns whether the compound button will be placed at the end of the list item layout. This
	* value is used to determine start margins for the {@code Title} and {@code Body}.
	*
	* @return Whether compound button is placed at the end of the list item layout.
	*/
	public abstract boolean isCompoundButtonPositionEnd();

	/**
	* Sets the size, start margin, and vertical position of primary icon.
	*
	* <p>Large icon will have no start margin, and always align center vertically.
	*
	* <p>Small/medium icon will have start margin, and uses a top margin such that it is "pinned"
	* at the same position in list item regardless of item height.
	*/
	private void setPrimaryIconLayout() {
	if (mPrimaryActionType == PRIMARY_ACTION_TYPE_EMPTY_ICON
	\|\| mPrimaryActionType == PRIMARY_ACTION_TYPE_NO_ICON) {
	return;
	}

	// Size of icon.
	@DimenRes int sizeResId;
	switch (mPrimaryActionIconSize) {
	case PRIMARY_ACTION_ICON_SIZE_SMALL:
	sizeResId = R.dimen.car_primary_icon_size;
	break;
	case PRIMARY_ACTION_ICON_SIZE_MEDIUM:
	sizeResId = R.dimen.car_avatar_icon_size;
	break;
	case PRIMARY_ACTION_ICON_SIZE_LARGE:
	sizeResId = R.dimen.car_single_line_list_item_height;
	break;
	default:
	throw new IllegalStateException("Unknown primary action icon size.");
	}

	int iconSize = mContext.getResources().getDimensionPixelSize(sizeResId);

	// Start margin of icon.
	int startMargin;
	switch (mPrimaryActionIconSize) {
	case PRIMARY_ACTION_ICON_SIZE_SMALL:
	case PRIMARY_ACTION_ICON_SIZE_MEDIUM:
	startMargin = mContext.getResources().getDimensionPixelSize(R.dimen.car_keyline_1);
	break;
	case PRIMARY_ACTION_ICON_SIZE_LARGE:
	startMargin = 0;
	break;
	default:
	throw new IllegalStateException("Unknown primary action icon size.");
	}

	mBinders.add(vh -> {
	ConstraintLayout.LayoutParams layoutParams =
	(ConstraintLayout.LayoutParams) vh.getPrimaryIcon().getLayoutParams();
	layoutParams.height = layoutParams.width = iconSize;
	layoutParams.setMarginStart(startMargin);

	if (mPrimaryActionIconSize == PRIMARY_ACTION_ICON_SIZE_LARGE) {
	// A large icon is always vertically centered.
	layoutParams.verticalBias = 0.5f;
	layoutParams.topMargin = 0;
	} else {
	// Align the icon to the top of the parent. This allows the topMargin to shift it
	// down relative to the top.
	layoutParams.verticalBias = 0f;

	// For all other icon sizes, the icon should be centered within the height of
	// car_double_line_list_item_height. Note: the actual height of the item can be
	// larger than this.
	int itemHeight = mContext.getResources().getDimensionPixelSize(
	R.dimen.car_double_line_list_item_height);
	layoutParams.topMargin = (itemHeight - iconSize) / 2;
	}

	vh.getPrimaryIcon().requestLayout();
	});
	}

	private void setTextContent() {
	boolean hasTitle = !TextUtils.isEmpty(mTitle);
	boolean hasBody = !TextUtils.isEmpty(mBody);

	if (!hasTitle && !hasBody) {
	return;
	}

	mBinders.add(vh -> {
	if (hasTitle) {
	vh.getTitle().setVisibility(View.VISIBLE);
	vh.getTitle().setText(mTitle);
	}

	if (hasBody) {
	vh.getBody().setVisibility(View.VISIBLE);
	vh.getBody().setText(mBody);
	}

	if (hasTitle && !hasBody) {
	// If only title, then center the supplemental actions.
	vh.getSupplementalGuideline().setGuidelineBegin(
	ConstraintLayout.LayoutParams.UNSET);
	vh.getSupplementalGuideline().setGuidelinePercent(0.5f);
	} else {
	// Otherwise, position it a fixed distance from the top.
	vh.getSupplementalGuideline().setGuidelinePercent(
	ConstraintLayout.LayoutParams.UNSET);
	vh.getSupplementalGuideline().setGuidelineBegin(
	mSupplementalGuidelineBegin);
	}
	});
	}

	/**
	* Sets start margin of text view depending on icon type.
	*/
	private void setTextStartMargin() {
	@DimenRes int startMarginResId;
	if (!isCompoundButtonPositionEnd()) {
	startMarginResId = R.dimen.car_keyline_3;
	} else {
	switch (mPrimaryActionType) {
	case PRIMARY_ACTION_TYPE_NO_ICON:
	startMarginResId = R.dimen.car_keyline_1;
	break;
	case PRIMARY_ACTION_TYPE_EMPTY_ICON:
	startMarginResId = R.dimen.car_keyline_3;
	break;
	case PRIMARY_ACTION_TYPE_ICON:
	startMarginResId = mPrimaryActionIconSize == PRIMARY_ACTION_ICON_SIZE_LARGE
	? R.dimen.car_keyline_4
	: R.dimen.car_keyline_3; // Small and medium sized icon.
	break;
	default:
	throw new IllegalStateException("Unknown primary action type.");
	}
	}

	int startMargin = mContext.getResources().getDimensionPixelSize(startMarginResId);
	mBinders.add(vh -> {
	MarginLayoutParams titleLayoutParams =
	(MarginLayoutParams) vh.getTitle().getLayoutParams();
	titleLayoutParams.setMarginStart(startMargin);
	vh.getTitle().requestLayout();

	MarginLayoutParams bodyLayoutParams =
	(MarginLayoutParams) vh.getBody().getLayoutParams();
	bodyLayoutParams.setMarginStart(startMargin);
	vh.getBody().requestLayout();
	});
	}

	private void setTextEndMargin() {
	int endMargin = mContext.getResources().getDimensionPixelSize(R.dimen.car_padding_4);

	mBinders.add(vh -> {
	MarginLayoutParams titleLayoutParams =
	(MarginLayoutParams) vh.getTitle().getLayoutParams();
	titleLayoutParams.setMarginEnd(endMargin);

	MarginLayoutParams bodyLayoutParams =
	(MarginLayoutParams) vh.getBody().getLayoutParams();
	bodyLayoutParams.setMarginEnd(endMargin);
	});
	}

	/**
	* Sets top/bottom margins of {@code Title} and {@code Body}.
	*/
	private void setTextVerticalMargin() {
	// Set all relevant fields in layout params to avoid carried over params when the item
	// gets bound to a recycled view holder.
	if (!TextUtils.isEmpty(mTitle) && TextUtils.isEmpty(mBody)) {
	// Title only - view is aligned center vertically by itself.
	mBinders.add(vh -> {
	MarginLayoutParams layoutParams =
	(MarginLayoutParams) vh.getTitle().getLayoutParams();
	layoutParams.topMargin = 0;
	vh.getTitle().requestLayout();
	});
	} else if (TextUtils.isEmpty(mTitle) && !TextUtils.isEmpty(mBody)) {
	mBinders.add(vh -> {
	// Body uses top and bottom margin.
	int margin = mContext.getResources().getDimensionPixelSize(
	R.dimen.car_padding_3);
	MarginLayoutParams layoutParams =
	(MarginLayoutParams) vh.getBody().getLayoutParams();
	layoutParams.topMargin = margin;
	layoutParams.bottomMargin = margin;
	vh.getBody().requestLayout();
	});
	} else {
	mBinders.add(vh -> {
	Resources resources = mContext.getResources();
	int padding2 = resources.getDimensionPixelSize(R.dimen.car_padding_2);

	// Title has a top margin
	MarginLayoutParams titleLayoutParams =
	(MarginLayoutParams) vh.getTitle().getLayoutParams();
	titleLayoutParams.topMargin = padding2;
	vh.getTitle().requestLayout();

	// Body is below title with no margin and has bottom margin.
	MarginLayoutParams bodyLayoutParams =
	(MarginLayoutParams) vh.getBody().getLayoutParams();
	bodyLayoutParams.topMargin = 0;
	bodyLayoutParams.bottomMargin = padding2;
	vh.getBody().requestLayout();
	});
	}
	}

	/**
	* Sets up view(s) for supplemental action.
	*/
	private void setCompoundButton() {
	mBinders.add(vh -> {
	vh.getCompoundButton().setVisibility(View.VISIBLE);
	vh.getCompoundButton().setOnCheckedChangeListener(null);
	vh.getCompoundButton().setChecked(mIsChecked);
	vh.getCompoundButton().setOnCheckedChangeListener((buttonView, isChecked) -> {
	if (mOnCheckedChangeListener != null) {
	// The checked state changed via user interaction with the compound button.
	mOnCheckedChangeListener.onCheckedChanged(buttonView, isChecked);
	}
	mIsChecked = isChecked;
	});
	if (mShouldNotifyChecked && mOnCheckedChangeListener != null) {
	// The checked state was changed programmatically.
	mOnCheckedChangeListener.onCheckedChanged(vh.getCompoundButton(),
	mIsChecked);
	mShouldNotifyChecked = false;
	}

	if (mShowCompoundButtonDivider) {
	vh.getCompoundButtonDivider().setVisibility(View.VISIBLE);
	}
	});
	}

	private void setItemClickable() {
	mBinders.add(vh -> {
	// If applicable (namely item is clickable), clicking item always toggles the
	// compound button.
	vh.itemView.setOnClickListener(v -> vh.getCompoundButton().toggle());
	vh.itemView.setClickable(mIsClickable);
	});
	}

	/**
	* Holds views of CompoundButtonListItem.
	*/
	public abstract static class ViewHolder extends ListItem.ViewHolder {

	/**
	* Creates a {@link ViewHolder} for a {@link CompoundButtonListItem}.
	*
	* @param itemView The view to be used to display a {@link CompoundButtonListItem}.
	*/
	public ViewHolder(@NonNull View itemView) {
	super(itemView);
	}

	/**
	* Returns the primary icon view within this view holder's view.
	*
	* @return Icon view within this view holder's view.
	*/
	@NonNull
	public abstract ImageView getPrimaryIcon();

	/**
	* Returns the title view within this view holder's view.
	*
	* @return Title view within this view holder's view.
	*/
	@NonNull
	public abstract TextView getTitle();

	/**
	* Returns the body view within this view holder's view.
	*
	* @return Body view within this view holder's view.
	*/
	@NonNull
	public abstract TextView getBody();

	/**
	* Returns the compound button divider view within this view holder's view.
	*
	* @return Compound button divider view within this view holder's view.
	*/
	@NonNull
	public abstract View getCompoundButtonDivider();

	/**
	* Returns the compound button within this view holder's view.
	*
	* @return Compound button within this view holder's view.
	*/
	@NonNull
	public abstract CompoundButton getCompoundButton();

	@NonNull
	abstract Guideline getSupplementalGuideline();

	@NonNull
	abstract ViewGroup getContainerLayout();

	/**
	* Returns the container layout of this view holder.
	*
	* @return Container layout of this view holder.
	*/
	@NonNull
	abstract View[] getWidgetViews();
	}
	}