PrintPreviewController.java revision 753c114d84328219a0ccbffdd462a69e04ef8c4f 
1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.printspooler.ui;
18
19import android.os.Handler;
20import android.os.Looper;
21import android.os.Message;
22import android.os.ParcelFileDescriptor;
23import android.print.PageRange;
24import android.print.PrintAttributes.MediaSize;
25import android.print.PrintAttributes.Margins;
26import android.print.PrintDocumentInfo;
27import android.support.v7.widget.OrientationHelper;
28import android.support.v7.widget.RecyclerView;
29import android.support.v7.widget.RecyclerView.ViewHolder;
30import android.support.v7.widget.RecyclerView.LayoutManager;
31import android.support.v7.widget.StaggeredGridLayoutManager;
32import android.view.View;
33import com.android.internal.os.SomeArgs;
34import com.android.printspooler.R;
35import com.android.printspooler.model.MutexFileProvider;
36import com.android.printspooler.widget.PrintContentView;
37import com.android.printspooler.widget.EmbeddedContentContainer;
38import com.android.printspooler.widget.PrintOptionsLayout;
39
40import java.io.File;
41import java.io.FileNotFoundException;
42import java.util.ArrayList;
43import java.util.List;
44
45class PrintPreviewController implements MutexFileProvider.OnReleaseRequestCallback,
46        PageAdapter.PreviewArea, EmbeddedContentContainer.OnSizeChangeListener {
47
48    private final PrintActivity mActivity;
49
50    private final MutexFileProvider mFileProvider;
51    private final MyHandler mHandler;
52
53    private final PageAdapter mPageAdapter;
54    private final StaggeredGridLayoutManager mLayoutManger;
55
56    private final PrintOptionsLayout mPrintOptionsLayout;
57    private final RecyclerView mRecyclerView;
58    private final PrintContentView mContentView;
59    private final EmbeddedContentContainer mEmbeddedContentContainer;
60
61    private final PreloadController mPreloadController;
62
63    private int mDocumentPageCount;
64
65    public PrintPreviewController(PrintActivity activity, MutexFileProvider fileProvider) {
66        mActivity = activity;
67        mHandler = new MyHandler(activity.getMainLooper());
68        mFileProvider = fileProvider;
69
70        mPrintOptionsLayout = (PrintOptionsLayout) activity.findViewById(R.id.options_container);
71        mPageAdapter = new PageAdapter(activity, activity, this);
72
73        final int columnCount = mActivity.getResources().getInteger(
74                R.integer.preview_page_per_row_count);
75
76        mLayoutManger = new StaggeredGridLayoutManager(columnCount, OrientationHelper.VERTICAL);
77
78        mRecyclerView = (RecyclerView) activity.findViewById(R.id.preview_content);
79        mRecyclerView.setLayoutManager(mLayoutManger);
80        mRecyclerView.setAdapter(mPageAdapter);
81        mPreloadController = new PreloadController(mRecyclerView);
82        mRecyclerView.setOnScrollListener(mPreloadController);
83
84        mContentView = (PrintContentView) activity.findViewById(R.id.options_content);
85        mEmbeddedContentContainer = (EmbeddedContentContainer) activity.findViewById(
86                R.id.embedded_content_container);
87        mEmbeddedContentContainer.setOnSizeChangeListener(this);
88    }
89
90    @Override
91    public void onSizeChanged(int width, int height) {
92        mPageAdapter.onPreviewAreaSizeChanged();
93    }
94
95    public boolean isOptionsOpened() {
96        return mContentView.isOptionsOpened();
97    }
98
99    public void closeOptions() {
100        mContentView.closeOptions();
101    }
102
103    public void setUiShown(boolean shown) {
104        if (shown) {
105            mRecyclerView.setVisibility(View.VISIBLE);
106        } else {
107            mRecyclerView.setVisibility(View.GONE);
108        }
109    }
110
111    public void onOrientationChanged() {
112        // Adjust the print option column count.
113        final int optionColumnCount = mActivity.getResources().getInteger(
114                R.integer.print_option_column_count);
115        mPrintOptionsLayout.setColumnCount(optionColumnCount);
116        mPageAdapter.onOrientationChanged();
117    }
118
119    public int getFilePageCount() {
120        return mPageAdapter.getFilePageCount();
121    }
122
123    public PageRange[] getSelectedPages() {
124        return mPageAdapter.getSelectedPages();
125    }
126
127    public PageRange[] getRequestedPages() {
128        return mPageAdapter.getRequestedPages();
129    }
130
131    public void onContentUpdated(boolean documentChanged, int documentPageCount,
132            PageRange[] writtenPages, PageRange[] selectedPages, MediaSize mediaSize,
133            Margins minMargins) {
134                boolean contentChanged = false;
135
136        if (documentChanged) {
137            contentChanged = true;
138        }
139
140        if (documentPageCount != mDocumentPageCount) {
141            mDocumentPageCount = documentPageCount;
142            contentChanged = true;
143        }
144
145        if (contentChanged) {
146            // If not closed, close as we start over.
147            if (mPageAdapter.isOpened()) {
148                Message operation = mHandler.obtainMessage(MyHandler.MSG_CLOSE);
149                mHandler.enqueueOperation(operation);
150            }
151        }
152
153        // The content changed. In this case we have to invalidate
154        // all rendered pages and reopen the file...
155        if (contentChanged && writtenPages != null) {
156            Message operation = mHandler.obtainMessage(MyHandler.MSG_OPEN);
157            mHandler.enqueueOperation(operation);
158        }
159
160        // Update the attributes before after closed to avoid flicker.
161        SomeArgs args = SomeArgs.obtain();
162        args.arg1 = writtenPages;
163        args.arg2 = selectedPages;
164        args.arg3 = mediaSize;
165        args.arg4 = minMargins;
166        args.argi1 = documentPageCount;
167
168        Message operation = mHandler.obtainMessage(MyHandler.MSG_UPDATE, args);
169        mHandler.enqueueOperation(operation);
170
171        // If document changed and has pages we want to start preloading.
172        if (contentChanged && writtenPages != null) {
173            operation = mHandler.obtainMessage(MyHandler.MSG_START_PRELOAD);
174            mHandler.enqueueOperation(operation);
175        }
176    }
177
178    @Override
179    public void onReleaseRequested(final File file) {
180        // This is called from the async task's single threaded executor
181        // thread, i.e. not on the main thread - so post a message.
182        mHandler.post(new Runnable() {
183            @Override
184            public void run() {
185                // At this point the other end will write to the file, hence
186                // we have to close it and reopen after the write completes.
187                Message operation = mHandler.obtainMessage(MyHandler.MSG_CLOSE);
188                mHandler.enqueueOperation(operation);
189            }
190        });
191    }
192
193    public void destroy() {
194        mPageAdapter.destroy();
195    }
196
197    @Override
198    public int getWidth() {
199        return mEmbeddedContentContainer.getWidth();
200    }
201
202    @Override
203    public int getHeight() {
204        return mEmbeddedContentContainer.getHeight();
205    }
206
207    @Override
208    public void setColumnCount(int columnCount) {
209        mLayoutManger.setSpanCount(columnCount);
210    }
211
212    @Override
213    public void setPadding(int left, int top , int right, int bottom) {
214        mRecyclerView.setPadding(left, top, right, bottom);
215    }
216
217    private final class MyHandler extends Handler {
218        public static final int MSG_OPEN = 1;
219        public static final int MSG_CLOSE = 2;
220        public static final int MSG_DESTROY = 3;
221        public static final int MSG_UPDATE = 4;
222        public static final int MSG_START_PRELOAD = 5;
223
224        private boolean mAsyncOperationInProgress;
225
226        private final Runnable mOnAsyncOperationDoneCallback = new Runnable() {
227            @Override
228            public void run() {
229                mAsyncOperationInProgress = false;
230                handleNextOperation();
231            }
232        };
233
234        private final List<Message> mPendingOperations = new ArrayList<>();
235
236        public MyHandler(Looper looper) {
237            super(looper, null, false);
238        }
239
240        public void enqueueOperation(Message message) {
241            mPendingOperations.add(message);
242            handleNextOperation();
243        }
244
245        public void handleNextOperation() {
246            while (!mPendingOperations.isEmpty() && !mAsyncOperationInProgress) {
247                Message operation = mPendingOperations.remove(0);
248                handleMessage(operation);
249            }
250        }
251
252        @Override
253        public void handleMessage(Message message) {
254            switch (message.what) {
255                case MSG_OPEN: {
256                    try {
257                        File file = mFileProvider.acquireFile(PrintPreviewController.this);
258                        ParcelFileDescriptor pfd = ParcelFileDescriptor.open(file,
259                                ParcelFileDescriptor.MODE_READ_ONLY);
260
261                        mAsyncOperationInProgress = true;
262                        mPageAdapter.open(pfd, new Runnable() {
263                            @Override
264                            public void run() {
265                                if (mDocumentPageCount == PrintDocumentInfo.PAGE_COUNT_UNKNOWN) {
266                                    mDocumentPageCount = mPageAdapter.getFilePageCount();
267                                    mActivity.updateOptionsUi();
268                                }
269                                mOnAsyncOperationDoneCallback.run();
270                            }
271                        });
272                    } catch (FileNotFoundException fnfe) {
273                        /* ignore - file guaranteed to be there */
274                    }
275                } break;
276
277                case MSG_CLOSE: {
278                    mAsyncOperationInProgress = true;
279                    mPageAdapter.close(new Runnable() {
280                        @Override
281                        public void run() {
282                            mFileProvider.releaseFile();
283                            mOnAsyncOperationDoneCallback.run();
284                        }
285                    });
286                } break;
287
288                case MSG_DESTROY: {
289                    mPageAdapter.destroy();
290                    handleNextOperation();
291                } break;
292
293                case MSG_UPDATE: {
294                    SomeArgs args = (SomeArgs) message.obj;
295                    PageRange[] writtenPages = (PageRange[]) args.arg1;
296                    PageRange[] selectedPages = (PageRange[]) args.arg2;
297                    MediaSize mediaSize = (MediaSize) args.arg3;
298                    Margins margins = (Margins) args.arg4;
299                    final int pageCount = args.argi1;
300                    args.recycle();
301
302                    mPageAdapter.update(writtenPages, selectedPages, pageCount,
303                            mediaSize, margins);
304
305                } break;
306
307                case MSG_START_PRELOAD: {
308                    mPreloadController.startPreloadContent();
309                } break;
310            }
311        }
312    }
313
314    private final class PreloadController extends RecyclerView.OnScrollListener {
315        private final RecyclerView mRecyclerView;
316
317        private int mOldScrollState;
318
319        public PreloadController(RecyclerView recyclerView) {
320            mRecyclerView = recyclerView;
321            mOldScrollState = mRecyclerView.getScrollState();
322        }
323
324        @Override
325        public void onScrollStateChanged(RecyclerView recyclerView, int state) {
326            switch (mOldScrollState) {
327                case RecyclerView.SCROLL_STATE_SETTLING: {
328                    if (state == RecyclerView.SCROLL_STATE_IDLE
329                            || state == RecyclerView.SCROLL_STATE_DRAGGING){
330                        startPreloadContent();
331                    }
332                } break;
333
334                case RecyclerView.SCROLL_STATE_IDLE:
335                case RecyclerView.SCROLL_STATE_DRAGGING: {
336                    if (state == RecyclerView.SCROLL_STATE_SETTLING) {
337                        stopPreloadContent();
338                    }
339                } break;
340            }
341            mOldScrollState = state;
342        }
343
344        public void startPreloadContent() {
345            PageAdapter pageAdapter = (PageAdapter) mRecyclerView.getAdapter();
346
347            if (pageAdapter.isOpened()) {
348                PageRange shownPages = computeShownPages();
349                if (shownPages != null) {
350                    pageAdapter.startPreloadContent(shownPages);
351                }
352            }
353        }
354
355        public void stopPreloadContent() {
356            PageAdapter pageAdapter = (PageAdapter) mRecyclerView.getAdapter();
357
358            if (pageAdapter.isOpened()) {
359                pageAdapter.stopPreloadContent();
360            }
361        }
362
363        private PageRange computeShownPages() {
364            final int childCount = mRecyclerView.getChildCount();
365            if (childCount > 0) {
366                LayoutManager layoutManager = mRecyclerView.getLayoutManager();
367
368                View firstChild = layoutManager.getChildAt(0);
369                ViewHolder firstHolder = mRecyclerView.getChildViewHolder(firstChild);
370
371                View lastChild = layoutManager.getChildAt(layoutManager.getChildCount() - 1);
372                ViewHolder lastHolder = mRecyclerView.getChildViewHolder(lastChild);
373
374                return new PageRange(firstHolder.getPosition(), lastHolder.getPosition());
375            }
376            return null;
377        }
378    }
379}
380