src/com/android/documentsui/HorizontalBreadcrumb.java - platform/packages/apps/DocumentsUI - Git at Google

 /*
  * 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.documentsui;

 import android.content.Context;
 import android.support.v7.widget.LinearLayoutManager;
 import android.support.v7.widget.RecyclerView;
 import android.util.AttributeSet;
 import android.view.GestureDetector;
 import android.view.KeyEvent;
 import android.view.LayoutInflater;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.ImageView;

 import com.android.documentsui.NavigationViewManager.Breadcrumb;
 import com.android.documentsui.NavigationViewManager.Environment;
 import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.base.RootInfo;
 import com.android.documentsui.dirlist.AccessibilityEventRouter;

 import java.util.function.Consumer;
 import java.util.function.IntConsumer;

 /**
  * Horizontal implementation of breadcrumb used for tablet / desktop device layouts
  */
 public final class HorizontalBreadcrumb extends RecyclerView
         implements Breadcrumb, ItemDragListener.DragHost {

     private static final int USER_NO_SCROLL_OFFSET_THRESHOLD = 5;

     private LinearLayoutManager mLayoutManager;
     private BreadcrumbAdapter mAdapter;
     private IntConsumer mClickListener;

     public HorizontalBreadcrumb(Context context, AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
     }

     public HorizontalBreadcrumb(Context context, AttributeSet attrs) {
         super(context, attrs);
     }

     public HorizontalBreadcrumb(Context context) {
         super(context);
     }

     @Override
     public void setup(Environment env,
             com.android.documentsui.base.State state,
             IntConsumer listener) {

         mClickListener = listener;
         mLayoutManager = new LinearLayoutManager(
                 getContext(), LinearLayoutManager.HORIZONTAL, false);
         mAdapter = new BreadcrumbAdapter(
                 state, env, new ItemDragListener<>(this), this::onKey);
         // Since we are using GestureDetector to detect click events, a11y services don't know which views
         // are clickable because we aren't using View.OnClickListener. Thus, we need to use a custom
         // accessibility delegate to route click events correctly. See AccessibilityClickEventRouter
         // for more details on how we are routing these a11y events.
         setAccessibilityDelegateCompat(
                 new AccessibilityEventRouter(this,
                         (View child) -> onAccessibilityClick(child)));

         setLayoutManager(mLayoutManager);
         addOnItemTouchListener(new ClickListener(getContext(), this::onSingleTapUp));
     }

     @Override
     public void show(boolean visibility) {
         if (visibility) {
             setVisibility(VISIBLE);
             boolean shouldScroll = !hasUserDefineScrollOffset();
             if (getAdapter() == null) {
                 setAdapter(mAdapter);
             } else {
                 int currentItemCount = mAdapter.getItemCount();
                 int lastItemCount = mAdapter.getLastItemSize();
                 if (currentItemCount > lastItemCount) {
                     mAdapter.notifyItemRangeInserted(lastItemCount,
                             currentItemCount - lastItemCount);
                     mAdapter.notifyItemChanged(lastItemCount - 1);
                 } else if (currentItemCount < lastItemCount) {
                     mAdapter.notifyItemRangeRemoved(currentItemCount,
                             lastItemCount - currentItemCount);
                     mAdapter.notifyItemChanged(currentItemCount - 1);
                 }
             }
             if (shouldScroll) {
                 mLayoutManager.scrollToPosition(mAdapter.getItemCount() - 1);
             }
         } else {
             setVisibility(GONE);
             setAdapter(null);
         }
         mAdapter.updateLastItemSize();
     }

     private boolean hasUserDefineScrollOffset() {
         final int maxOffset = computeHorizontalScrollRange() - computeHorizontalScrollExtent();
         return (maxOffset - computeHorizontalScrollOffset() > USER_NO_SCROLL_OFFSET_THRESHOLD);
     }

     private boolean onAccessibilityClick(View child) {
         int pos = getChildAdapterPosition(child);
         if (pos != getAdapter().getItemCount() - 1) {
             mClickListener.accept(pos);
             return true;
         }
         return false;
     }

     private boolean onKey(View v, int keyCode, KeyEvent event) {
         switch (keyCode) {
             case KeyEvent.KEYCODE_ENTER:
                 return onAccessibilityClick(v);
             default:
                 return false;
         }
     }

     @Override
     public void postUpdate() {
     }

     @Override
     public void runOnUiThread(Runnable runnable) {
         post(runnable);
     }

     @Override
     public void setDropTargetHighlight(View v, boolean highlight) {
         RecyclerView.ViewHolder vh = getChildViewHolder(v);
         if (vh instanceof BreadcrumbHolder) {
             ((BreadcrumbHolder) vh).setHighlighted(highlight);
         }
     }

     @Override
     public void onDragEntered(View v) {
         // do nothing
     }

     @Override
     public void onDragExited(View v) {
         // do nothing
     }

     @Override
     public void onViewHovered(View v) {
         int pos = getChildAdapterPosition(v);
         if (pos != mAdapter.getItemCount() - 1) {
             mClickListener.accept(pos);
         }
     }

     @Override
     public void onDragEnded() {
         // do nothing
     }

     private void onSingleTapUp(MotionEvent e) {
         View itemView = findChildViewUnder(e.getX(), e.getY());
         int pos = getChildAdapterPosition(itemView);
         if (pos != mAdapter.getItemCount() - 1) {
             mClickListener.accept(pos);
         }
     }

     private static final class BreadcrumbAdapter
             extends RecyclerView.Adapter<BreadcrumbHolder> {

         private final Environment mEnv;
         private final com.android.documentsui.base.State mState;
         private final OnDragListener mDragListener;
         private final View.OnKeyListener mClickListener;
         // We keep the old item size so the breadcrumb will only re-render views that are necessary
         private int mLastItemSize;

         public BreadcrumbAdapter(com.android.documentsui.base.State state,
                 Environment env,
                 OnDragListener dragListener,
                 View.OnKeyListener clickListener) {
             mState = state;
             mEnv = env;
             mDragListener = dragListener;
             mClickListener = clickListener;
             mLastItemSize = mState.stack.size();
         }

         @Override
         public BreadcrumbHolder onCreateViewHolder(ViewGroup parent, int viewType) {
             View v = LayoutInflater.from(parent.getContext())
                     .inflate(R.layout.navigation_breadcrumb_item, null);
             return new BreadcrumbHolder(v);
         }

         @Override
         public void onBindViewHolder(BreadcrumbHolder holder, int position) {
             final DocumentInfo doc = getItem(position);
             final int horizontalPadding = (int) holder.itemView.getResources()
                     .getDimension(R.dimen.breadcrumb_item_padding);

             if (position == 0) {
                 final RootInfo root = mEnv.getCurrentRoot();
                 holder.title.setText(root.title);
                 holder.title.setPadding(0, 0, horizontalPadding, 0);
             } else {
                 holder.title.setText(doc.displayName);
                 holder.title.setPadding(horizontalPadding, 0, horizontalPadding, 0);
             }

             if (position == getItemCount() - 1) {
                 holder.arrow.setVisibility(View.GONE);
             } else {
                 holder.arrow.setVisibility(View.VISIBLE);
             }
             holder.itemView.setOnDragListener(mDragListener);
             holder.itemView.setOnKeyListener(mClickListener);
         }

         private DocumentInfo getItem(int position) {
             return mState.stack.get(position);
         }

         @Override
         public int getItemCount() {
             return mState.stack.size();
         }

         public int getLastItemSize() {
             return mLastItemSize;
         }

         public void updateLastItemSize() {
             mLastItemSize = mState.stack.size();
         }
     }

     private static class BreadcrumbHolder extends RecyclerView.ViewHolder {

         protected DragOverTextView title;
         protected ImageView arrow;

         public BreadcrumbHolder(View itemView) {
             super(itemView);
             title = (DragOverTextView) itemView.findViewById(R.id.breadcrumb_text);
             arrow = (ImageView) itemView.findViewById(R.id.breadcrumb_arrow);
         }

         /**
          * Highlights the associated item view.
          * @param highlighted
          */
         public void setHighlighted(boolean highlighted) {
             title.setHighlight(highlighted);
         }
     }

     private static final class ClickListener extends GestureDetector
             implements OnItemTouchListener {

         public ClickListener(Context context, Consumer<MotionEvent> listener) {
             super(context, new SimpleOnGestureListener() {
                 @Override
                 public boolean onSingleTapUp(MotionEvent e) {
                     listener.accept(e);
                     return true;
                 }
             });
         }

         @Override
         public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
             onTouchEvent(e);
             return false;
         }

         @Override
         public void onTouchEvent(RecyclerView rv, MotionEvent e) {
             onTouchEvent(e);
         }

         @Override
         public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
         }
     }
 }
	/*
	* 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.documentsui;

	import android.content.Context;
	import android.support.v7.widget.LinearLayoutManager;
	import android.support.v7.widget.RecyclerView;
	import android.util.AttributeSet;
	import android.view.GestureDetector;
	import android.view.KeyEvent;
	import android.view.LayoutInflater;
	import android.view.MotionEvent;
	import android.view.View;
	import android.view.ViewGroup;
	import android.widget.ImageView;

	import com.android.documentsui.NavigationViewManager.Breadcrumb;
	import com.android.documentsui.NavigationViewManager.Environment;
	import com.android.documentsui.base.DocumentInfo;
	import com.android.documentsui.base.RootInfo;
	import com.android.documentsui.dirlist.AccessibilityEventRouter;

	import java.util.function.Consumer;
	import java.util.function.IntConsumer;

	/**
	* Horizontal implementation of breadcrumb used for tablet / desktop device layouts
	*/
	public final class HorizontalBreadcrumb extends RecyclerView
	implements Breadcrumb, ItemDragListener.DragHost {

	private static final int USER_NO_SCROLL_OFFSET_THRESHOLD = 5;

	private LinearLayoutManager mLayoutManager;
	private BreadcrumbAdapter mAdapter;
	private IntConsumer mClickListener;

	public HorizontalBreadcrumb(Context context, AttributeSet attrs, int defStyleAttr) {
	super(context, attrs, defStyleAttr);
	}

	public HorizontalBreadcrumb(Context context, AttributeSet attrs) {
	super(context, attrs);
	}

	public HorizontalBreadcrumb(Context context) {
	super(context);
	}

	@Override
	public void setup(Environment env,
	com.android.documentsui.base.State state,
	IntConsumer listener) {

	mClickListener = listener;
	mLayoutManager = new LinearLayoutManager(
	getContext(), LinearLayoutManager.HORIZONTAL, false);
	mAdapter = new BreadcrumbAdapter(
	state, env, new ItemDragListener<>(this), this::onKey);
	// Since we are using GestureDetector to detect click events, a11y services don't know which views
	// are clickable because we aren't using View.OnClickListener. Thus, we need to use a custom
	// accessibility delegate to route click events correctly. See AccessibilityClickEventRouter
	// for more details on how we are routing these a11y events.
	setAccessibilityDelegateCompat(
	new AccessibilityEventRouter(this,
	(View child) -> onAccessibilityClick(child)));

	setLayoutManager(mLayoutManager);
	addOnItemTouchListener(new ClickListener(getContext(), this::onSingleTapUp));
	}

	@Override
	public void show(boolean visibility) {
	if (visibility) {
	setVisibility(VISIBLE);
	boolean shouldScroll = !hasUserDefineScrollOffset();
	if (getAdapter() == null) {
	setAdapter(mAdapter);
	} else {
	int currentItemCount = mAdapter.getItemCount();
	int lastItemCount = mAdapter.getLastItemSize();
	if (currentItemCount > lastItemCount) {
	mAdapter.notifyItemRangeInserted(lastItemCount,
	currentItemCount - lastItemCount);
	mAdapter.notifyItemChanged(lastItemCount - 1);
	} else if (currentItemCount < lastItemCount) {
	mAdapter.notifyItemRangeRemoved(currentItemCount,
	lastItemCount - currentItemCount);
	mAdapter.notifyItemChanged(currentItemCount - 1);
	}
	}
	if (shouldScroll) {
	mLayoutManager.scrollToPosition(mAdapter.getItemCount() - 1);
	}
	} else {
	setVisibility(GONE);
	setAdapter(null);
	}
	mAdapter.updateLastItemSize();
	}

	private boolean hasUserDefineScrollOffset() {
	final int maxOffset = computeHorizontalScrollRange() - computeHorizontalScrollExtent();
	return (maxOffset - computeHorizontalScrollOffset() > USER_NO_SCROLL_OFFSET_THRESHOLD);
	}

	private boolean onAccessibilityClick(View child) {
	int pos = getChildAdapterPosition(child);
	if (pos != getAdapter().getItemCount() - 1) {
	mClickListener.accept(pos);
	return true;
	}
	return false;
	}

	private boolean onKey(View v, int keyCode, KeyEvent event) {
	switch (keyCode) {
	case KeyEvent.KEYCODE_ENTER:
	return onAccessibilityClick(v);
	default:
	return false;
	}
	}

	@Override
	public void postUpdate() {
	}

	@Override
	public void runOnUiThread(Runnable runnable) {
	post(runnable);
	}

	@Override
	public void setDropTargetHighlight(View v, boolean highlight) {
	RecyclerView.ViewHolder vh = getChildViewHolder(v);
	if (vh instanceof BreadcrumbHolder) {
	((BreadcrumbHolder) vh).setHighlighted(highlight);
	}
	}

	@Override
	public void onDragEntered(View v) {
	// do nothing
	}

	@Override
	public void onDragExited(View v) {
	// do nothing
	}

	@Override
	public void onViewHovered(View v) {
	int pos = getChildAdapterPosition(v);
	if (pos != mAdapter.getItemCount() - 1) {
	mClickListener.accept(pos);
	}
	}

	@Override
	public void onDragEnded() {
	// do nothing
	}

	private void onSingleTapUp(MotionEvent e) {
	View itemView = findChildViewUnder(e.getX(), e.getY());
	int pos = getChildAdapterPosition(itemView);
	if (pos != mAdapter.getItemCount() - 1) {
	mClickListener.accept(pos);
	}
	}

	private static final class BreadcrumbAdapter
	extends RecyclerView.Adapter<BreadcrumbHolder> {

	private final Environment mEnv;
	private final com.android.documentsui.base.State mState;
	private final OnDragListener mDragListener;
	private final View.OnKeyListener mClickListener;
	// We keep the old item size so the breadcrumb will only re-render views that are necessary
	private int mLastItemSize;

	public BreadcrumbAdapter(com.android.documentsui.base.State state,
	Environment env,
	OnDragListener dragListener,
	View.OnKeyListener clickListener) {
	mState = state;
	mEnv = env;
	mDragListener = dragListener;
	mClickListener = clickListener;
	mLastItemSize = mState.stack.size();
	}

	@Override
	public BreadcrumbHolder onCreateViewHolder(ViewGroup parent, int viewType) {
	View v = LayoutInflater.from(parent.getContext())
	.inflate(R.layout.navigation_breadcrumb_item, null);
	return new BreadcrumbHolder(v);
	}

	@Override
	public void onBindViewHolder(BreadcrumbHolder holder, int position) {
	final DocumentInfo doc = getItem(position);
	final int horizontalPadding = (int) holder.itemView.getResources()
	.getDimension(R.dimen.breadcrumb_item_padding);

	if (position == 0) {
	final RootInfo root = mEnv.getCurrentRoot();
	holder.title.setText(root.title);
	holder.title.setPadding(0, 0, horizontalPadding, 0);
	} else {
	holder.title.setText(doc.displayName);
	holder.title.setPadding(horizontalPadding, 0, horizontalPadding, 0);
	}

	if (position == getItemCount() - 1) {
	holder.arrow.setVisibility(View.GONE);
	} else {
	holder.arrow.setVisibility(View.VISIBLE);
	}
	holder.itemView.setOnDragListener(mDragListener);
	holder.itemView.setOnKeyListener(mClickListener);
	}

	private DocumentInfo getItem(int position) {
	return mState.stack.get(position);
	}

	@Override
	public int getItemCount() {
	return mState.stack.size();
	}

	public int getLastItemSize() {
	return mLastItemSize;
	}

	public void updateLastItemSize() {
	mLastItemSize = mState.stack.size();
	}
	}

	private static class BreadcrumbHolder extends RecyclerView.ViewHolder {

	protected DragOverTextView title;
	protected ImageView arrow;

	public BreadcrumbHolder(View itemView) {
	super(itemView);
	title = (DragOverTextView) itemView.findViewById(R.id.breadcrumb_text);
	arrow = (ImageView) itemView.findViewById(R.id.breadcrumb_arrow);
	}

	/**
	* Highlights the associated item view.
	* @param highlighted
	*/
	public void setHighlighted(boolean highlighted) {
	title.setHighlight(highlighted);
	}
	}

	private static final class ClickListener extends GestureDetector
	implements OnItemTouchListener {

	public ClickListener(Context context, Consumer<MotionEvent> listener) {
	super(context, new SimpleOnGestureListener() {
	@Override
	public boolean onSingleTapUp(MotionEvent e) {
	listener.accept(e);
	return true;
	}
	});
	}

	@Override
	public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
	onTouchEvent(e);
	return false;
	}

	@Override
	public void onTouchEvent(RecyclerView rv, MotionEvent e) {
	onTouchEvent(e);
	}

	@Override
	public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
	}
	}
	}