src/com/android/car/media/widgets/AppBarView.java - platform/packages/apps/Car/Media - Git at Google

 package com.android.car.media.widgets;

 import android.annotation.Nullable;
 import android.content.Context;
 import android.content.res.TypedArray;
 import android.graphics.Bitmap;
 import android.graphics.drawable.Drawable;
 import android.transition.Fade;
 import android.transition.Transition;
 import android.transition.TransitionManager;
 import android.util.AttributeSet;
 import android.util.Log;
 import android.util.TypedValue;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.ImageView;
 import android.widget.LinearLayout;
 import android.widget.RelativeLayout;
 import android.widget.TextView;

 import com.android.car.media.R;
 import com.android.car.media.common.MediaItemMetadata;

 import com.google.android.material.tabs.TabLayout;

 import java.util.List;
 import java.util.Objects;

 /**
  * Media template application bar. A detailed explanation of all possible states of this
  * application bar can be seen at {@link AppBarView.State}.
  */
 public class AppBarView extends RelativeLayout {
     private static final String TAG = "AppBarView";
     /** Default number of tabs to show on this app bar */
     private static int DEFAULT_MAX_TABS = 4;

     private LinearLayout mTabsContainer;
     private ImageView mAppIcon;
     private ImageView mAppSwitchIcon;
     private ImageView mNavIcon;
     private ViewGroup mNavIconContainer;
     private TextView mTitle;
     private ViewGroup mAppSwitchContainer;
     private Context mContext;
     private int mMaxTabs;
     private Drawable mArrowDropDown;
     private Drawable mArrowDropUp;
     private Drawable mArrowBack;
     private Drawable mCollapse;
     private State mState = State.BROWSING;
     private AppBarListener mListener;
     private int mFadeDuration;
     private float mSelectedTabAlpha;
     private float mUnselectedTabAlpha;
     private MediaItemMetadata mSelectedItem;
     private String mMediaAppTitle;
     private Drawable mDefaultIcon;
     private boolean mContentForwardEnabled;

     /**
      * Application bar listener
      */
     public interface AppBarListener {
         /**
          * Invoked when the user selects an item from the tabs
          */
         void onTabSelected(MediaItemMetadata item);

         /**
          * Invoked when the user clicks on the back button
          */
         void onBack();

         /**
          * Invoked when the user clicks on the collapse button
          */
         void onCollapse();

         /**
          * Invoked when the user clicks on the app selection switch
          */
         void onAppSelection();
     }

     /**
      * Possible states of this application bar
      */
     public enum State {
         /**
          * Normal application state. If we are able to obtain media items from the media
          * source application, we display them as tabs. Otherwise we show the application name.
          */
         BROWSING,
         /**
          * Indicates that the user has navigated into an element. In this case we show
          * the name of the element and we disable the back button.
          */
         STACKED,
         /**
          * Indicates that we have expanded a view that can be collapsed. We show the
          * title of the application and a collapse icon
          */
         PLAYING,
         /**
          * Used to indicate that the user is inside the app selector. In this case we disable
          * navigation, we show the title of the application and we show the app switch icon
          * point up
          */
         APP_SELECTION
     }

     public AppBarView(Context context) {
         this(context, null);
     }

     public AppBarView(Context context, AttributeSet attrs) {
         this(context, attrs, 0);
     }

     public AppBarView(Context context, AttributeSet attrs, int defStyleAttr) {
         this(context, attrs, defStyleAttr, 0);
     }

     public AppBarView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
         super(context, attrs, defStyleAttr, defStyleRes);
         init(context, attrs, defStyleAttr, defStyleRes);
     }

     private void init(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
         TypedArray ta = context.obtainStyledAttributes(
                 attrs, R.styleable.AppBarView, defStyleAttr, defStyleRes);
         mMaxTabs = ta.getInteger(R.styleable.AppBarView_max_tabs, DEFAULT_MAX_TABS);
         ta.recycle();

         LayoutInflater inflater = (LayoutInflater) context
                 .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
         inflater.inflate(R.layout.appbar_view, this, true);

         mContext = context;
         mTabsContainer = findViewById(R.id.tabs);
         mNavIcon = findViewById(R.id.nav_icon);
         mNavIconContainer = findViewById(R.id.nav_icon_container);
         mNavIconContainer.setOnClickListener(view -> onNavIconClicked());
         mAppIcon = findViewById(R.id.app_icon);
         mAppSwitchIcon = findViewById(R.id.app_switch_icon);
         mAppSwitchContainer = findViewById(R.id.app_switch_container);
         mAppSwitchContainer.setOnClickListener(view -> onAppSwitchClicked());
         mTitle = findViewById(R.id.title);
         mArrowDropDown = getResources().getDrawable(R.drawable.ic_arrow_drop_down, null);
         mArrowDropUp = getResources().getDrawable(R.drawable.ic_arrow_drop_up, null);
         mArrowBack = getResources().getDrawable(R.drawable.ic_arrow_back, null);
         mCollapse = getResources().getDrawable(R.drawable.ic_expand_more, null);
         mFadeDuration = getResources().getInteger(R.integer.app_selector_fade_duration);
         TypedValue outValue = new TypedValue();
         getResources().getValue(R.dimen.browse_tab_alpha_selected, outValue, true);
         mSelectedTabAlpha = outValue.getFloat();
         getResources().getValue(R.dimen.browse_tab_alpha_unselected, outValue, true);
         mUnselectedTabAlpha = outValue.getFloat();
         mMediaAppTitle = getResources().getString(R.string.media_app_title);
         mDefaultIcon = getResources().getDrawable(R.drawable.ic_music);

         setState(State.BROWSING);
     }

     private void onNavIconClicked() {
         if (mListener == null) {
             return;
         }
         switch (mState) {
             case STACKED:
                 mListener.onBack();
                 break;
             case PLAYING:
                 mListener.onCollapse();
                 break;
         }
     }

     private void onAppSwitchClicked() {
         if (mListener == null) {
             return;
         }
         mListener.onAppSelection();
     }

     /**
      * Sets a listener of this application bar events. In order to avoid memory leaks, consumers
      * must reset this reference by setting the listener to null.
      */
     public void setListener(AppBarListener listener) {
         mListener = listener;
     }

     /**
      * Updates the list of items to show in the application bar tabs.
      *
      * @param items list of tabs to show, or null if no tabs should be shown.
      */
     public void setItems(@Nullable List<MediaItemMetadata> items) {
         mTabsContainer.removeAllViews();

         if (items != null) {
             int count = 0;
             int padding = mContext.getResources().getDimensionPixelSize(R.dimen.car_padding_4);
             int tabWidth = mContext.getResources().getDimensionPixelSize(R.dimen.browse_tab_width) +
                     2 * padding;
             LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
                     tabWidth, ViewGroup.LayoutParams.MATCH_PARENT);
             for (MediaItemMetadata item : items) {
                 MediaItemTabView tab = new MediaItemTabView(mContext, item);
                 mTabsContainer.addView(tab);
                 tab.setLayoutParams(layoutParams);
                 tab.setOnClickListener(view -> {
                     if (mListener != null) {
                         mListener.onTabSelected(item);
                     }
                 });
                 tab.setPadding(padding, 0, padding, 0);
                 tab.requestLayout();
                 tab.setTag(item);

                 count++;
                 if (count >= mMaxTabs) {
                     break;
                 }
             }
         }

         // Refresh the views visibility
         setState(mState);
     }

     /**
      * Updates the title to display when the bar is not showing tabs.
      */
     public void setTitle(CharSequence title) {
         mTitle.setText(title != null ? title : mMediaAppTitle);
     }

     /**
      * Whether content forward browsing is enabled or not
      */
     public void setContentForwardEnabled(boolean enabled) {
         mContentForwardEnabled = enabled;
     }

     /**
      * Updates the application icon to show next to the application switcher.
      */
     public void setAppIcon(Bitmap icon) {
         if (icon != null) {
             mAppIcon.setImageBitmap(icon);
         } else {
             mAppIcon.setImageDrawable(mDefaultIcon);
         }
     }

     /**
      * Indicates whether or not the application switcher should be enabled.
      */
     public void setAppSelection(boolean enabled) {
         mAppSwitchIcon.setVisibility(enabled ? View.VISIBLE : View.GONE);
     }

     /**
      * Updates the currently active item
      */
     public void setActiveItem(MediaItemMetadata item) {
         mSelectedItem = item;
         // TODO(b/79264184): Updating tabs alpha is causing them to disappear randomly. We are
         // de-activating this feature for not.
         // updateTabs();
     }

     private void updateTabs() {
         for (int i = 0; i < mTabsContainer.getChildCount(); i++) {
             View child = mTabsContainer.getChildAt(i);
             if (child instanceof MediaItemTabView) {
                 MediaItemTabView tabView = (MediaItemTabView) child;
                 boolean match = mSelectedItem != null && Objects.equals(
                         mSelectedItem.getId(),
                         ((MediaItemMetadata) tabView.getTag()).getId());
                 tabView.setAlpha(match ? mSelectedTabAlpha : mUnselectedTabAlpha);
             }
         }
     }

     /**
      * Updates the state of the bar.
      */
     public void setState(State state) {
         boolean hasItems = mTabsContainer.getChildCount() > 0;
         mState = state;

         Transition transition = new Fade().setDuration(mFadeDuration);
         TransitionManager.beginDelayedTransition(this, transition);
         Log.d(TAG, "Updating state: " + state + " (has items: " + hasItems + ")");
         switch (state) {
             case BROWSING:
                 mNavIconContainer.setVisibility(View.GONE);
                 mTabsContainer.setVisibility(hasItems ? View.VISIBLE : View.GONE);
                 mTitle.setVisibility(hasItems ? View.GONE : View.VISIBLE);
                 mAppSwitchIcon.setImageDrawable(mArrowDropDown);
                 break;
             case STACKED:
                 mNavIcon.setImageDrawable(mArrowBack);
                 mNavIconContainer.setVisibility(View.VISIBLE);
                 mTabsContainer.setVisibility(View.GONE);
                 mTitle.setVisibility(View.VISIBLE);
                 mAppSwitchIcon.setImageDrawable(mArrowDropDown);
                 break;
             case PLAYING:
                 mNavIcon.setImageDrawable(mCollapse);
                 mNavIconContainer.setVisibility(hasItems || !mContentForwardEnabled ? View.GONE
                         : View.VISIBLE);
                 mTabsContainer.setVisibility(hasItems && mContentForwardEnabled ? View.VISIBLE
                         : View.GONE);
                 mTitle.setVisibility(hasItems || !mContentForwardEnabled ? View.GONE
                         : View.VISIBLE);
                 mAppSwitchIcon.setImageDrawable(mArrowDropDown);
                 break;
             case APP_SELECTION:
                 mNavIconContainer.setVisibility(View.GONE);
                 mTabsContainer.setVisibility(View.GONE);
                 mTitle.setVisibility(mContentForwardEnabled ? View.VISIBLE : View.GONE);
                 mAppSwitchIcon.setImageDrawable(mArrowDropUp);
                 break;
         }
     }
 }
	package com.android.car.media.widgets;

	import android.annotation.Nullable;
	import android.content.Context;
	import android.content.res.TypedArray;
	import android.graphics.Bitmap;
	import android.graphics.drawable.Drawable;
	import android.transition.Fade;
	import android.transition.Transition;
	import android.transition.TransitionManager;
	import android.util.AttributeSet;
	import android.util.Log;
	import android.util.TypedValue;
	import android.view.LayoutInflater;
	import android.view.View;
	import android.view.ViewGroup;
	import android.widget.ImageView;
	import android.widget.LinearLayout;
	import android.widget.RelativeLayout;
	import android.widget.TextView;

	import com.android.car.media.R;
	import com.android.car.media.common.MediaItemMetadata;

	import com.google.android.material.tabs.TabLayout;

	import java.util.List;
	import java.util.Objects;

	/**
	* Media template application bar. A detailed explanation of all possible states of this
	* application bar can be seen at {@link AppBarView.State}.
	*/
	public class AppBarView extends RelativeLayout {
	private static final String TAG = "AppBarView";
	/** Default number of tabs to show on this app bar */
	private static int DEFAULT_MAX_TABS = 4;

	private LinearLayout mTabsContainer;
	private ImageView mAppIcon;
	private ImageView mAppSwitchIcon;
	private ImageView mNavIcon;
	private ViewGroup mNavIconContainer;
	private TextView mTitle;
	private ViewGroup mAppSwitchContainer;
	private Context mContext;
	private int mMaxTabs;
	private Drawable mArrowDropDown;
	private Drawable mArrowDropUp;
	private Drawable mArrowBack;
	private Drawable mCollapse;
	private State mState = State.BROWSING;
	private AppBarListener mListener;
	private int mFadeDuration;
	private float mSelectedTabAlpha;
	private float mUnselectedTabAlpha;
	private MediaItemMetadata mSelectedItem;
	private String mMediaAppTitle;
	private Drawable mDefaultIcon;
	private boolean mContentForwardEnabled;

	/**
	* Application bar listener
	*/
	public interface AppBarListener {
	/**
	* Invoked when the user selects an item from the tabs
	*/
	void onTabSelected(MediaItemMetadata item);

	/**
	* Invoked when the user clicks on the back button
	*/
	void onBack();

	/**
	* Invoked when the user clicks on the collapse button
	*/
	void onCollapse();

	/**
	* Invoked when the user clicks on the app selection switch
	*/
	void onAppSelection();
	}

	/**
	* Possible states of this application bar
	*/
	public enum State {
	/**
	* Normal application state. If we are able to obtain media items from the media
	* source application, we display them as tabs. Otherwise we show the application name.
	*/
	BROWSING,
	/**
	* Indicates that the user has navigated into an element. In this case we show
	* the name of the element and we disable the back button.
	*/
	STACKED,
	/**
	* Indicates that we have expanded a view that can be collapsed. We show the
	* title of the application and a collapse icon
	*/
	PLAYING,
	/**
	* Used to indicate that the user is inside the app selector. In this case we disable
	* navigation, we show the title of the application and we show the app switch icon
	* point up
	*/
	APP_SELECTION
	}

	public AppBarView(Context context) {
	this(context, null);
	}

	public AppBarView(Context context, AttributeSet attrs) {
	this(context, attrs, 0);
	}

	public AppBarView(Context context, AttributeSet attrs, int defStyleAttr) {
	this(context, attrs, defStyleAttr, 0);
	}

	public AppBarView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
	super(context, attrs, defStyleAttr, defStyleRes);
	init(context, attrs, defStyleAttr, defStyleRes);
	}

	private void init(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
	TypedArray ta = context.obtainStyledAttributes(
	attrs, R.styleable.AppBarView, defStyleAttr, defStyleRes);
	mMaxTabs = ta.getInteger(R.styleable.AppBarView_max_tabs, DEFAULT_MAX_TABS);
	ta.recycle();

	LayoutInflater inflater = (LayoutInflater) context
	.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
	inflater.inflate(R.layout.appbar_view, this, true);

	mContext = context;
	mTabsContainer = findViewById(R.id.tabs);
	mNavIcon = findViewById(R.id.nav_icon);
	mNavIconContainer = findViewById(R.id.nav_icon_container);
	mNavIconContainer.setOnClickListener(view -> onNavIconClicked());
	mAppIcon = findViewById(R.id.app_icon);
	mAppSwitchIcon = findViewById(R.id.app_switch_icon);
	mAppSwitchContainer = findViewById(R.id.app_switch_container);
	mAppSwitchContainer.setOnClickListener(view -> onAppSwitchClicked());
	mTitle = findViewById(R.id.title);
	mArrowDropDown = getResources().getDrawable(R.drawable.ic_arrow_drop_down, null);
	mArrowDropUp = getResources().getDrawable(R.drawable.ic_arrow_drop_up, null);
	mArrowBack = getResources().getDrawable(R.drawable.ic_arrow_back, null);
	mCollapse = getResources().getDrawable(R.drawable.ic_expand_more, null);
	mFadeDuration = getResources().getInteger(R.integer.app_selector_fade_duration);
	TypedValue outValue = new TypedValue();
	getResources().getValue(R.dimen.browse_tab_alpha_selected, outValue, true);
	mSelectedTabAlpha = outValue.getFloat();
	getResources().getValue(R.dimen.browse_tab_alpha_unselected, outValue, true);
	mUnselectedTabAlpha = outValue.getFloat();
	mMediaAppTitle = getResources().getString(R.string.media_app_title);
	mDefaultIcon = getResources().getDrawable(R.drawable.ic_music);

	setState(State.BROWSING);
	}

	private void onNavIconClicked() {
	if (mListener == null) {
	return;
	}
	switch (mState) {
	case STACKED:
	mListener.onBack();
	break;
	case PLAYING:
	mListener.onCollapse();
	break;
	}
	}

	private void onAppSwitchClicked() {
	if (mListener == null) {
	return;
	}
	mListener.onAppSelection();
	}

	/**
	* Sets a listener of this application bar events. In order to avoid memory leaks, consumers
	* must reset this reference by setting the listener to null.
	*/
	public void setListener(AppBarListener listener) {
	mListener = listener;
	}

	/**
	* Updates the list of items to show in the application bar tabs.
	*
	* @param items list of tabs to show, or null if no tabs should be shown.
	*/
	public void setItems(@Nullable List<MediaItemMetadata> items) {
	mTabsContainer.removeAllViews();

	if (items != null) {
	int count = 0;
	int padding = mContext.getResources().getDimensionPixelSize(R.dimen.car_padding_4);
	int tabWidth = mContext.getResources().getDimensionPixelSize(R.dimen.browse_tab_width) +
	2 * padding;
	LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
	tabWidth, ViewGroup.LayoutParams.MATCH_PARENT);
	for (MediaItemMetadata item : items) {
	MediaItemTabView tab = new MediaItemTabView(mContext, item);
	mTabsContainer.addView(tab);
	tab.setLayoutParams(layoutParams);
	tab.setOnClickListener(view -> {
	if (mListener != null) {
	mListener.onTabSelected(item);
	}
	});
	tab.setPadding(padding, 0, padding, 0);
	tab.requestLayout();
	tab.setTag(item);

	count++;
	if (count >= mMaxTabs) {
	break;
	}
	}
	}

	// Refresh the views visibility
	setState(mState);
	}

	/**
	* Updates the title to display when the bar is not showing tabs.
	*/
	public void setTitle(CharSequence title) {
	mTitle.setText(title != null ? title : mMediaAppTitle);
	}

	/**
	* Whether content forward browsing is enabled or not
	*/
	public void setContentForwardEnabled(boolean enabled) {
	mContentForwardEnabled = enabled;
	}

	/**
	* Updates the application icon to show next to the application switcher.
	*/
	public void setAppIcon(Bitmap icon) {
	if (icon != null) {
	mAppIcon.setImageBitmap(icon);
	} else {
	mAppIcon.setImageDrawable(mDefaultIcon);
	}
	}

	/**
	* Indicates whether or not the application switcher should be enabled.
	*/
	public void setAppSelection(boolean enabled) {
	mAppSwitchIcon.setVisibility(enabled ? View.VISIBLE : View.GONE);
	}

	/**
	* Updates the currently active item
	*/
	public void setActiveItem(MediaItemMetadata item) {
	mSelectedItem = item;
	// TODO(b/79264184): Updating tabs alpha is causing them to disappear randomly. We are
	// de-activating this feature for not.
	// updateTabs();
	}

	private void updateTabs() {
	for (int i = 0; i < mTabsContainer.getChildCount(); i++) {
	View child = mTabsContainer.getChildAt(i);
	if (child instanceof MediaItemTabView) {
	MediaItemTabView tabView = (MediaItemTabView) child;
	boolean match = mSelectedItem != null && Objects.equals(
	mSelectedItem.getId(),
	((MediaItemMetadata) tabView.getTag()).getId());
	tabView.setAlpha(match ? mSelectedTabAlpha : mUnselectedTabAlpha);
	}
	}
	}

	/**
	* Updates the state of the bar.
	*/
	public void setState(State state) {
	boolean hasItems = mTabsContainer.getChildCount() > 0;
	mState = state;

	Transition transition = new Fade().setDuration(mFadeDuration);
	TransitionManager.beginDelayedTransition(this, transition);
	Log.d(TAG, "Updating state: " + state + " (has items: " + hasItems + ")");
	switch (state) {
	case BROWSING:
	mNavIconContainer.setVisibility(View.GONE);
	mTabsContainer.setVisibility(hasItems ? View.VISIBLE : View.GONE);
	mTitle.setVisibility(hasItems ? View.GONE : View.VISIBLE);
	mAppSwitchIcon.setImageDrawable(mArrowDropDown);
	break;
	case STACKED:
	mNavIcon.setImageDrawable(mArrowBack);
	mNavIconContainer.setVisibility(View.VISIBLE);
	mTabsContainer.setVisibility(View.GONE);
	mTitle.setVisibility(View.VISIBLE);
	mAppSwitchIcon.setImageDrawable(mArrowDropDown);
	break;
	case PLAYING:
	mNavIcon.setImageDrawable(mCollapse);
	mNavIconContainer.setVisibility(hasItems \|\| !mContentForwardEnabled ? View.GONE
	: View.VISIBLE);
	mTabsContainer.setVisibility(hasItems && mContentForwardEnabled ? View.VISIBLE
	: View.GONE);
	mTitle.setVisibility(hasItems \|\| !mContentForwardEnabled ? View.GONE
	: View.VISIBLE);
	mAppSwitchIcon.setImageDrawable(mArrowDropDown);
	break;
	case APP_SELECTION:
	mNavIconContainer.setVisibility(View.GONE);
	mTabsContainer.setVisibility(View.GONE);
	mTitle.setVisibility(mContentForwardEnabled ? View.VISIBLE : View.GONE);
	mAppSwitchIcon.setImageDrawable(mArrowDropUp);
	break;
	}
	}
	}