packages/PrintSpooler/src/com/android/printspooler/ui/PrintPreviewController.java - platform/frameworks/base - Git at Google

 /*
  * 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 com.android.printspooler.ui;

 import android.os.Handler;
 import android.os.Looper;
 import android.os.Message;
 import android.os.ParcelFileDescriptor;
 import android.print.PageRange;
 import android.print.PrintAttributes.MediaSize;
 import android.print.PrintAttributes.Margins;
 import android.print.PrintDocumentInfo;
 import android.support.v7.widget.OrientationHelper;
 import android.support.v7.widget.RecyclerView;
 import android.support.v7.widget.RecyclerView.ViewHolder;
 import android.support.v7.widget.RecyclerView.LayoutManager;
 import android.support.v7.widget.StaggeredGridLayoutManager;
 import android.view.View;
 import com.android.internal.os.SomeArgs;
 import com.android.printspooler.R;
 import com.android.printspooler.model.MutexFileProvider;
 import com.android.printspooler.widget.PrintContentView;
 import com.android.printspooler.widget.EmbeddedContentContainer;
 import com.android.printspooler.widget.PrintOptionsLayout;

 import java.io.File;
 import java.io.FileNotFoundException;
 import java.util.ArrayList;
 import java.util.List;

 class PrintPreviewController implements MutexFileProvider.OnReleaseRequestCallback,
         PageAdapter.PreviewArea, EmbeddedContentContainer.OnSizeChangeListener {

     private final PrintActivity mActivity;

     private final MutexFileProvider mFileProvider;
     private final MyHandler mHandler;

     private final PageAdapter mPageAdapter;
     private final StaggeredGridLayoutManager mLayoutManger;

     private final PrintOptionsLayout mPrintOptionsLayout;
     private final RecyclerView mRecyclerView;
     private final PrintContentView mContentView;
     private final EmbeddedContentContainer mEmbeddedContentContainer;

     private final PreloadController mPreloadController;

     private int mDocumentPageCount;

     public PrintPreviewController(PrintActivity activity, MutexFileProvider fileProvider) {
         mActivity = activity;
         mHandler = new MyHandler(activity.getMainLooper());
         mFileProvider = fileProvider;

         mPrintOptionsLayout = (PrintOptionsLayout) activity.findViewById(R.id.options_container);
         mPageAdapter = new PageAdapter(activity, activity, this);

         final int columnCount = mActivity.getResources().getInteger(
                 R.integer.preview_page_per_row_count);

         mLayoutManger = new StaggeredGridLayoutManager(columnCount, OrientationHelper.VERTICAL);

         mRecyclerView = (RecyclerView) activity.findViewById(R.id.preview_content);
         mRecyclerView.setLayoutManager(mLayoutManger);
         mRecyclerView.setAdapter(mPageAdapter);
         mPreloadController = new PreloadController(mRecyclerView);
         mRecyclerView.setOnScrollListener(mPreloadController);

         mContentView = (PrintContentView) activity.findViewById(R.id.options_content);
         mEmbeddedContentContainer = (EmbeddedContentContainer) activity.findViewById(
                 R.id.embedded_content_container);
         mEmbeddedContentContainer.setOnSizeChangeListener(this);
     }

     @Override
     public void onSizeChanged(int width, int height) {
         mPageAdapter.onPreviewAreaSizeChanged();
     }

     public boolean isOptionsOpened() {
         return mContentView.isOptionsOpened();
     }

     public void closeOptions() {
         mContentView.closeOptions();
     }

     public void setUiShown(boolean shown) {
         if (shown) {
             mRecyclerView.setVisibility(View.VISIBLE);
         } else {
             mRecyclerView.setVisibility(View.GONE);
         }
     }

     public void onOrientationChanged() {
         // Adjust the print option column count.
         final int optionColumnCount = mActivity.getResources().getInteger(
                 R.integer.print_option_column_count);
         mPrintOptionsLayout.setColumnCount(optionColumnCount);
         mPageAdapter.onOrientationChanged();
     }

     public int getFilePageCount() {
         return mPageAdapter.getFilePageCount();
     }

     public PageRange[] getSelectedPages() {
         return mPageAdapter.getSelectedPages();
     }

     public PageRange[] getRequestedPages() {
         return mPageAdapter.getRequestedPages();
     }

     public void onContentUpdated(boolean documentChanged, int documentPageCount,
             PageRange[] writtenPages, PageRange[] selectedPages, MediaSize mediaSize,
             Margins minMargins) {
                 boolean contentChanged = false;

         if (documentChanged) {
             contentChanged = true;
         }

         if (documentPageCount != mDocumentPageCount) {
             mDocumentPageCount = documentPageCount;
             contentChanged = true;
         }

         if (contentChanged) {
             // If not closed, close as we start over.
             if (mPageAdapter.isOpened()) {
                 Message operation = mHandler.obtainMessage(MyHandler.MSG_CLOSE);
                 mHandler.enqueueOperation(operation);
             }
         }

         // The content changed. In this case we have to invalidate
         // all rendered pages and reopen the file...
         if (contentChanged && writtenPages != null) {
             Message operation = mHandler.obtainMessage(MyHandler.MSG_OPEN);
             mHandler.enqueueOperation(operation);
         }

         // Update the attributes before after closed to avoid flicker.
         SomeArgs args = SomeArgs.obtain();
         args.arg1 = writtenPages;
         args.arg2 = selectedPages;
         args.arg3 = mediaSize;
         args.arg4 = minMargins;
         args.argi1 = documentPageCount;

         Message operation = mHandler.obtainMessage(MyHandler.MSG_UPDATE, args);
         mHandler.enqueueOperation(operation);

         // If document changed and has pages we want to start preloading.
         if (contentChanged && writtenPages != null) {
             operation = mHandler.obtainMessage(MyHandler.MSG_START_PRELOAD);
             mHandler.enqueueOperation(operation);
         }
     }

     @Override
     public void onReleaseRequested(final File file) {
         // This is called from the async task's single threaded executor
         // thread, i.e. not on the main thread - so post a message.
         mHandler.post(new Runnable() {
             @Override
             public void run() {
                 // At this point the other end will write to the file, hence
                 // we have to close it and reopen after the write completes.
                 Message operation = mHandler.obtainMessage(MyHandler.MSG_CLOSE);
                 mHandler.enqueueOperation(operation);
             }
         });
     }

     public void destroy() {
         mPageAdapter.destroy();
     }

     @Override
     public int getWidth() {
         return mEmbeddedContentContainer.getWidth();
     }

     @Override
     public int getHeight() {
         return mEmbeddedContentContainer.getHeight();
     }

     @Override
     public void setColumnCount(int columnCount) {
         mLayoutManger.setSpanCount(columnCount);
     }

     @Override
     public void setPadding(int left, int top , int right, int bottom) {
         mRecyclerView.setPadding(left, top, right, bottom);
     }

     private final class MyHandler extends Handler {
         public static final int MSG_OPEN = 1;
         public static final int MSG_CLOSE = 2;
         public static final int MSG_DESTROY = 3;
         public static final int MSG_UPDATE = 4;
         public static final int MSG_START_PRELOAD = 5;

         private boolean mAsyncOperationInProgress;

         private final Runnable mOnAsyncOperationDoneCallback = new Runnable() {
             @Override
             public void run() {
                 mAsyncOperationInProgress = false;
                 handleNextOperation();
             }
         };

         private final List<Message> mPendingOperations = new ArrayList<>();

         public MyHandler(Looper looper) {
             super(looper, null, false);
         }

         public void enqueueOperation(Message message) {
             mPendingOperations.add(message);
             handleNextOperation();
         }

         public void handleNextOperation() {
             while (!mPendingOperations.isEmpty() && !mAsyncOperationInProgress) {
                 Message operation = mPendingOperations.remove(0);
                 handleMessage(operation);
             }
         }

         @Override
         public void handleMessage(Message message) {
             switch (message.what) {
                 case MSG_OPEN: {
                     try {
                         File file = mFileProvider.acquireFile(PrintPreviewController.this);
                         ParcelFileDescriptor pfd = ParcelFileDescriptor.open(file,
                                 ParcelFileDescriptor.MODE_READ_ONLY);

                         mAsyncOperationInProgress = true;
                         mPageAdapter.open(pfd, new Runnable() {
                             @Override
                             public void run() {
                                 if (mDocumentPageCount == PrintDocumentInfo.PAGE_COUNT_UNKNOWN) {
                                     mDocumentPageCount = mPageAdapter.getFilePageCount();
                                     mActivity.updateOptionsUi();
                                 }
                                 mOnAsyncOperationDoneCallback.run();
                             }
                         });
                     } catch (FileNotFoundException fnfe) {
                         /* ignore - file guaranteed to be there */
                     }
                 } break;

                 case MSG_CLOSE: {
                     mAsyncOperationInProgress = true;
                     mPageAdapter.close(new Runnable() {
                         @Override
                         public void run() {
                             mFileProvider.releaseFile();
                             mOnAsyncOperationDoneCallback.run();
                         }
                     });
                 } break;

                 case MSG_DESTROY: {
                     mPageAdapter.destroy();
                     handleNextOperation();
                 } break;

                 case MSG_UPDATE: {
                     SomeArgs args = (SomeArgs) message.obj;
                     PageRange[] writtenPages = (PageRange[]) args.arg1;
                     PageRange[] selectedPages = (PageRange[]) args.arg2;
                     MediaSize mediaSize = (MediaSize) args.arg3;
                     Margins margins = (Margins) args.arg4;
                     final int pageCount = args.argi1;
                     args.recycle();

                     mPageAdapter.update(writtenPages, selectedPages, pageCount,
                             mediaSize, margins);

                 } break;

                 case MSG_START_PRELOAD: {
                     mPreloadController.startPreloadContent();
                 } break;
             }
         }
     }

     private final class PreloadController extends RecyclerView.OnScrollListener {
         private final RecyclerView mRecyclerView;

         private int mOldScrollState;

         public PreloadController(RecyclerView recyclerView) {
             mRecyclerView = recyclerView;
             mOldScrollState = mRecyclerView.getScrollState();
         }

         @Override
         public void onScrollStateChanged(RecyclerView recyclerView, int state) {
             switch (mOldScrollState) {
                 case RecyclerView.SCROLL_STATE_SETTLING: {
                     if (state == RecyclerView.SCROLL_STATE_IDLE
                             || state == RecyclerView.SCROLL_STATE_DRAGGING){
                         startPreloadContent();
                     }
                 } break;

                 case RecyclerView.SCROLL_STATE_IDLE:
                 case RecyclerView.SCROLL_STATE_DRAGGING: {
                     if (state == RecyclerView.SCROLL_STATE_SETTLING) {
                         stopPreloadContent();
                     }
                 } break;
             }
             mOldScrollState = state;
         }

         public void startPreloadContent() {
             PageAdapter pageAdapter = (PageAdapter) mRecyclerView.getAdapter();

             if (pageAdapter.isOpened()) {
                 PageRange shownPages = computeShownPages();
                 if (shownPages != null) {
                     pageAdapter.startPreloadContent(shownPages);
                 }
             }
         }

         public void stopPreloadContent() {
             PageAdapter pageAdapter = (PageAdapter) mRecyclerView.getAdapter();

             if (pageAdapter.isOpened()) {
                 pageAdapter.stopPreloadContent();
             }
         }

         private PageRange computeShownPages() {
             final int childCount = mRecyclerView.getChildCount();
             if (childCount > 0) {
                 LayoutManager layoutManager = mRecyclerView.getLayoutManager();

                 View firstChild = layoutManager.getChildAt(0);
                 ViewHolder firstHolder = mRecyclerView.getChildViewHolder(firstChild);

                 View lastChild = layoutManager.getChildAt(layoutManager.getChildCount() - 1);
                 ViewHolder lastHolder = mRecyclerView.getChildViewHolder(lastChild);

                 return new PageRange(firstHolder.getPosition(), lastHolder.getPosition());
             }
             return null;
         }
     }
 }
	/*
	* 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 com.android.printspooler.ui;

	import android.os.Handler;
	import android.os.Looper;
	import android.os.Message;
	import android.os.ParcelFileDescriptor;
	import android.print.PageRange;
	import android.print.PrintAttributes.MediaSize;
	import android.print.PrintAttributes.Margins;
	import android.print.PrintDocumentInfo;
	import android.support.v7.widget.OrientationHelper;
	import android.support.v7.widget.RecyclerView;
	import android.support.v7.widget.RecyclerView.ViewHolder;
	import android.support.v7.widget.RecyclerView.LayoutManager;
	import android.support.v7.widget.StaggeredGridLayoutManager;
	import android.view.View;
	import com.android.internal.os.SomeArgs;
	import com.android.printspooler.R;
	import com.android.printspooler.model.MutexFileProvider;
	import com.android.printspooler.widget.PrintContentView;
	import com.android.printspooler.widget.EmbeddedContentContainer;
	import com.android.printspooler.widget.PrintOptionsLayout;

	import java.io.File;
	import java.io.FileNotFoundException;
	import java.util.ArrayList;
	import java.util.List;

	class PrintPreviewController implements MutexFileProvider.OnReleaseRequestCallback,
	PageAdapter.PreviewArea, EmbeddedContentContainer.OnSizeChangeListener {

	private final PrintActivity mActivity;

	private final MutexFileProvider mFileProvider;
	private final MyHandler mHandler;

	private final PageAdapter mPageAdapter;
	private final StaggeredGridLayoutManager mLayoutManger;

	private final PrintOptionsLayout mPrintOptionsLayout;
	private final RecyclerView mRecyclerView;
	private final PrintContentView mContentView;
	private final EmbeddedContentContainer mEmbeddedContentContainer;

	private final PreloadController mPreloadController;

	private int mDocumentPageCount;

	public PrintPreviewController(PrintActivity activity, MutexFileProvider fileProvider) {
	mActivity = activity;
	mHandler = new MyHandler(activity.getMainLooper());
	mFileProvider = fileProvider;

	mPrintOptionsLayout = (PrintOptionsLayout) activity.findViewById(R.id.options_container);
	mPageAdapter = new PageAdapter(activity, activity, this);

	final int columnCount = mActivity.getResources().getInteger(
	R.integer.preview_page_per_row_count);

	mLayoutManger = new StaggeredGridLayoutManager(columnCount, OrientationHelper.VERTICAL);

	mRecyclerView = (RecyclerView) activity.findViewById(R.id.preview_content);
	mRecyclerView.setLayoutManager(mLayoutManger);
	mRecyclerView.setAdapter(mPageAdapter);
	mPreloadController = new PreloadController(mRecyclerView);
	mRecyclerView.setOnScrollListener(mPreloadController);

	mContentView = (PrintContentView) activity.findViewById(R.id.options_content);
	mEmbeddedContentContainer = (EmbeddedContentContainer) activity.findViewById(
	R.id.embedded_content_container);
	mEmbeddedContentContainer.setOnSizeChangeListener(this);
	}

	@Override
	public void onSizeChanged(int width, int height) {
	mPageAdapter.onPreviewAreaSizeChanged();
	}

	public boolean isOptionsOpened() {
	return mContentView.isOptionsOpened();
	}

	public void closeOptions() {
	mContentView.closeOptions();
	}

	public void setUiShown(boolean shown) {
	if (shown) {
	mRecyclerView.setVisibility(View.VISIBLE);
	} else {
	mRecyclerView.setVisibility(View.GONE);
	}
	}

	public void onOrientationChanged() {
	// Adjust the print option column count.
	final int optionColumnCount = mActivity.getResources().getInteger(
	R.integer.print_option_column_count);
	mPrintOptionsLayout.setColumnCount(optionColumnCount);
	mPageAdapter.onOrientationChanged();
	}

	public int getFilePageCount() {
	return mPageAdapter.getFilePageCount();
	}

	public PageRange[] getSelectedPages() {
	return mPageAdapter.getSelectedPages();
	}

	public PageRange[] getRequestedPages() {
	return mPageAdapter.getRequestedPages();
	}

	public void onContentUpdated(boolean documentChanged, int documentPageCount,
	PageRange[] writtenPages, PageRange[] selectedPages, MediaSize mediaSize,
	Margins minMargins) {
	boolean contentChanged = false;

	if (documentChanged) {
	contentChanged = true;
	}

	if (documentPageCount != mDocumentPageCount) {
	mDocumentPageCount = documentPageCount;
	contentChanged = true;
	}

	if (contentChanged) {
	// If not closed, close as we start over.
	if (mPageAdapter.isOpened()) {
	Message operation = mHandler.obtainMessage(MyHandler.MSG_CLOSE);
	mHandler.enqueueOperation(operation);
	}
	}

	// The content changed. In this case we have to invalidate
	// all rendered pages and reopen the file...
	if (contentChanged && writtenPages != null) {
	Message operation = mHandler.obtainMessage(MyHandler.MSG_OPEN);
	mHandler.enqueueOperation(operation);
	}

	// Update the attributes before after closed to avoid flicker.
	SomeArgs args = SomeArgs.obtain();
	args.arg1 = writtenPages;
	args.arg2 = selectedPages;
	args.arg3 = mediaSize;
	args.arg4 = minMargins;
	args.argi1 = documentPageCount;

	Message operation = mHandler.obtainMessage(MyHandler.MSG_UPDATE, args);
	mHandler.enqueueOperation(operation);

	// If document changed and has pages we want to start preloading.
	if (contentChanged && writtenPages != null) {
	operation = mHandler.obtainMessage(MyHandler.MSG_START_PRELOAD);
	mHandler.enqueueOperation(operation);
	}
	}

	@Override
	public void onReleaseRequested(final File file) {
	// This is called from the async task's single threaded executor
	// thread, i.e. not on the main thread - so post a message.
	mHandler.post(new Runnable() {
	@Override
	public void run() {
	// At this point the other end will write to the file, hence
	// we have to close it and reopen after the write completes.
	Message operation = mHandler.obtainMessage(MyHandler.MSG_CLOSE);
	mHandler.enqueueOperation(operation);
	}
	});
	}

	public void destroy() {
	mPageAdapter.destroy();
	}

	@Override
	public int getWidth() {
	return mEmbeddedContentContainer.getWidth();
	}

	@Override
	public int getHeight() {
	return mEmbeddedContentContainer.getHeight();
	}

	@Override
	public void setColumnCount(int columnCount) {
	mLayoutManger.setSpanCount(columnCount);
	}

	@Override
	public void setPadding(int left, int top , int right, int bottom) {
	mRecyclerView.setPadding(left, top, right, bottom);
	}

	private final class MyHandler extends Handler {
	public static final int MSG_OPEN = 1;
	public static final int MSG_CLOSE = 2;
	public static final int MSG_DESTROY = 3;
	public static final int MSG_UPDATE = 4;
	public static final int MSG_START_PRELOAD = 5;

	private boolean mAsyncOperationInProgress;

	private final Runnable mOnAsyncOperationDoneCallback = new Runnable() {
	@Override
	public void run() {
	mAsyncOperationInProgress = false;
	handleNextOperation();
	}
	};

	private final List<Message> mPendingOperations = new ArrayList<>();

	public MyHandler(Looper looper) {
	super(looper, null, false);
	}

	public void enqueueOperation(Message message) {
	mPendingOperations.add(message);
	handleNextOperation();
	}

	public void handleNextOperation() {
	while (!mPendingOperations.isEmpty() && !mAsyncOperationInProgress) {
	Message operation = mPendingOperations.remove(0);
	handleMessage(operation);
	}
	}

	@Override
	public void handleMessage(Message message) {
	switch (message.what) {
	case MSG_OPEN: {
	try {
	File file = mFileProvider.acquireFile(PrintPreviewController.this);
	ParcelFileDescriptor pfd = ParcelFileDescriptor.open(file,
	ParcelFileDescriptor.MODE_READ_ONLY);

	mAsyncOperationInProgress = true;
	mPageAdapter.open(pfd, new Runnable() {
	@Override
	public void run() {
	if (mDocumentPageCount == PrintDocumentInfo.PAGE_COUNT_UNKNOWN) {
	mDocumentPageCount = mPageAdapter.getFilePageCount();
	mActivity.updateOptionsUi();
	}
	mOnAsyncOperationDoneCallback.run();
	}
	});
	} catch (FileNotFoundException fnfe) {
	/* ignore - file guaranteed to be there */
	}
	} break;

	case MSG_CLOSE: {
	mAsyncOperationInProgress = true;
	mPageAdapter.close(new Runnable() {
	@Override
	public void run() {
	mFileProvider.releaseFile();
	mOnAsyncOperationDoneCallback.run();
	}
	});
	} break;

	case MSG_DESTROY: {
	mPageAdapter.destroy();
	handleNextOperation();
	} break;

	case MSG_UPDATE: {
	SomeArgs args = (SomeArgs) message.obj;
	PageRange[] writtenPages = (PageRange[]) args.arg1;
	PageRange[] selectedPages = (PageRange[]) args.arg2;
	MediaSize mediaSize = (MediaSize) args.arg3;
	Margins margins = (Margins) args.arg4;
	final int pageCount = args.argi1;
	args.recycle();

	mPageAdapter.update(writtenPages, selectedPages, pageCount,
	mediaSize, margins);

	} break;

	case MSG_START_PRELOAD: {
	mPreloadController.startPreloadContent();
	} break;
	}
	}
	}

	private final class PreloadController extends RecyclerView.OnScrollListener {
	private final RecyclerView mRecyclerView;

	private int mOldScrollState;

	public PreloadController(RecyclerView recyclerView) {
	mRecyclerView = recyclerView;
	mOldScrollState = mRecyclerView.getScrollState();
	}

	@Override
	public void onScrollStateChanged(RecyclerView recyclerView, int state) {
	switch (mOldScrollState) {
	case RecyclerView.SCROLL_STATE_SETTLING: {
	if (state == RecyclerView.SCROLL_STATE_IDLE
	\|\| state == RecyclerView.SCROLL_STATE_DRAGGING){
	startPreloadContent();
	}
	} break;

	case RecyclerView.SCROLL_STATE_IDLE:
	case RecyclerView.SCROLL_STATE_DRAGGING: {
	if (state == RecyclerView.SCROLL_STATE_SETTLING) {
	stopPreloadContent();
	}
	} break;
	}
	mOldScrollState = state;
	}

	public void startPreloadContent() {
	PageAdapter pageAdapter = (PageAdapter) mRecyclerView.getAdapter();

	if (pageAdapter.isOpened()) {
	PageRange shownPages = computeShownPages();
	if (shownPages != null) {
	pageAdapter.startPreloadContent(shownPages);
	}
	}
	}

	public void stopPreloadContent() {
	PageAdapter pageAdapter = (PageAdapter) mRecyclerView.getAdapter();

	if (pageAdapter.isOpened()) {
	pageAdapter.stopPreloadContent();
	}
	}

	private PageRange computeShownPages() {
	final int childCount = mRecyclerView.getChildCount();
	if (childCount > 0) {
	LayoutManager layoutManager = mRecyclerView.getLayoutManager();

	View firstChild = layoutManager.getChildAt(0);
	ViewHolder firstHolder = mRecyclerView.getChildViewHolder(firstChild);

	View lastChild = layoutManager.getChildAt(layoutManager.getChildCount() - 1);
	ViewHolder lastHolder = mRecyclerView.getChildViewHolder(lastChild);

	return new PageRange(firstHolder.getPosition(), lastHolder.getPosition());
	}
	return null;
	}
	}
	}