PrintPreviewController.java revision 6f249835a4ff9e7e7e3ca0190b7ecf72e689656d 
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.GridLayoutManager;
28import android.support.v7.widget.OrientationHelper;
29import android.support.v7.widget.RecyclerView;
30import android.support.v7.widget.RecyclerView.ViewHolder;
31import android.support.v7.widget.RecyclerView.LayoutManager;
32import android.support.v7.widget.StaggeredGridLayoutManager;
33import android.view.View;
34import com.android.internal.os.SomeArgs;
35import com.android.printspooler.R;
36import com.android.printspooler.model.MutexFileProvider;
37import com.android.printspooler.widget.PrintContentView;
38import com.android.printspooler.widget.EmbeddedContentContainer;
39import com.android.printspooler.widget.PrintOptionsLayout;
40
41import java.io.File;
42import java.io.FileNotFoundException;
43import java.util.ArrayList;
44import java.util.List;
45
46class PrintPreviewController implements MutexFileProvider.OnReleaseRequestCallback,
47        PageAdapter.PreviewArea, EmbeddedContentContainer.OnSizeChangeListener {
48
49    private final PrintActivity mActivity;
50
51    private final MutexFileProvider mFileProvider;
52    private final MyHandler mHandler;
53
54    private final PageAdapter mPageAdapter;
55    private final GridLayoutManager mLayoutManger;
56
57    private final PrintOptionsLayout mPrintOptionsLayout;
58    private final RecyclerView mRecyclerView;
59    private final PrintContentView mContentView;
60    private final EmbeddedContentContainer mEmbeddedContentContainer;
61
62    private final PreloadController mPreloadController;
63
64    private int mDocumentPageCount;
65
66    public PrintPreviewController(PrintActivity activity, MutexFileProvider fileProvider) {
67        mActivity = activity;
68        mHandler = new MyHandler(activity.getMainLooper());
69        mFileProvider = fileProvider;
70
71        mPrintOptionsLayout = (PrintOptionsLayout) activity.findViewById(R.id.options_container);
72        mPageAdapter = new PageAdapter(activity, activity, this);
73
74        final int columnCount = mActivity.getResources().getInteger(
75                R.integer.preview_page_per_row_count);
76
77        mLayoutManger = new GridLayoutManager(mActivity, columnCount);
78
79        mRecyclerView = (RecyclerView) activity.findViewById(R.id.preview_content);
80        mRecyclerView.setLayoutManager(mLayoutManger);
81        mRecyclerView.setAdapter(mPageAdapter);
82        mPreloadController = new PreloadController(mRecyclerView);
83        mRecyclerView.setOnScrollListener(mPreloadController);
84
85        mContentView = (PrintContentView) activity.findViewById(R.id.options_content);
86        mEmbeddedContentContainer = (EmbeddedContentContainer) activity.findViewById(
87                R.id.embedded_content_container);
88        mEmbeddedContentContainer.setOnSizeChangeListener(this);
89    }
90
91    @Override
92    public void onSizeChanged(int width, int height) {
93        mPageAdapter.onPreviewAreaSizeChanged();
94    }
95
96    public boolean isOptionsOpened() {
97        return mContentView.isOptionsOpened();
98    }
99
100    public void closeOptions() {
101        mContentView.closeOptions();
102    }
103
104    public void setUiShown(boolean shown) {
105        if (shown) {
106            mRecyclerView.setVisibility(View.VISIBLE);
107        } else {
108            mRecyclerView.setVisibility(View.GONE);
109        }
110    }
111
112    public void onOrientationChanged() {
113        // Adjust the print option column count.
114        final int optionColumnCount = mActivity.getResources().getInteger(
115                R.integer.print_option_column_count);
116        mPrintOptionsLayout.setColumnCount(optionColumnCount);
117        mPageAdapter.onOrientationChanged();
118    }
119
120    public int getFilePageCount() {
121        return mPageAdapter.getFilePageCount();
122    }
123
124    public PageRange[] getSelectedPages() {
125        return mPageAdapter.getSelectedPages();
126    }
127
128    public PageRange[] getRequestedPages() {
129        return mPageAdapter.getRequestedPages();
130    }
131
132    public void onContentUpdated(boolean documentChanged, int documentPageCount,
133            PageRange[] writtenPages, PageRange[] selectedPages, MediaSize mediaSize,
134            Margins minMargins) {
135                boolean contentChanged = false;
136
137        if (documentChanged) {
138            contentChanged = true;
139        }
140
141        if (documentPageCount != mDocumentPageCount) {
142            mDocumentPageCount = documentPageCount;
143            contentChanged = true;
144        }
145
146        if (contentChanged) {
147            // If not closed, close as we start over.
148            if (mPageAdapter.isOpened()) {
149                Message operation = mHandler.obtainMessage(MyHandler.MSG_CLOSE);
150                mHandler.enqueueOperation(operation);
151            }
152        }
153
154        // The content changed. In this case we have to invalidate
155        // all rendered pages and reopen the file...
156        if (contentChanged && writtenPages != null) {
157            Message operation = mHandler.obtainMessage(MyHandler.MSG_OPEN);
158            mHandler.enqueueOperation(operation);
159        }
160
161        // Update the attributes before after closed to avoid flicker.
162        SomeArgs args = SomeArgs.obtain();
163        args.arg1 = writtenPages;
164        args.arg2 = selectedPages;
165        args.arg3 = mediaSize;
166        args.arg4 = minMargins;
167        args.argi1 = documentPageCount;
168
169        Message operation = mHandler.obtainMessage(MyHandler.MSG_UPDATE, args);
170        mHandler.enqueueOperation(operation);
171
172        // If document changed and has pages we want to start preloading.
173        if (contentChanged && writtenPages != null) {
174            operation = mHandler.obtainMessage(MyHandler.MSG_START_PRELOAD);
175            mHandler.enqueueOperation(operation);
176        }
177    }
178
179    @Override
180    public void onReleaseRequested(final File file) {
181        // This is called from the async task's single threaded executor
182        // thread, i.e. not on the main thread - so post a message.
183        mHandler.post(new Runnable() {
184            @Override
185            public void run() {
186                // At this point the other end will write to the file, hence
187                // we have to close it and reopen after the write completes.
188                Message operation = mHandler.obtainMessage(MyHandler.MSG_CLOSE);
189                mHandler.enqueueOperation(operation);
190            }
191        });
192    }
193
194    public void destroy() {
195        if (mPageAdapter.isOpened()) {
196            mPageAdapter.close(null);
197        }
198        mPageAdapter.destroy();
199    }
200
201    @Override
202    public int getWidth() {
203        return mEmbeddedContentContainer.getWidth();
204    }
205
206    @Override
207    public int getHeight() {
208        return mEmbeddedContentContainer.getHeight();
209    }
210
211    @Override
212    public void setColumnCount(int columnCount) {
213        mLayoutManger.setSpanCount(columnCount);
214    }
215
216    @Override
217    public void setPadding(int left, int top , int right, int bottom) {
218        mRecyclerView.setPadding(left, top, right, bottom);
219    }
220
221    private final class MyHandler extends Handler {
222        public static final int MSG_OPEN = 1;
223        public static final int MSG_CLOSE = 2;
224        public static final int MSG_DESTROY = 3;
225        public static final int MSG_UPDATE = 4;
226        public static final int MSG_START_PRELOAD = 5;
227
228        private boolean mAsyncOperationInProgress;
229
230        private final Runnable mOnAsyncOperationDoneCallback = new Runnable() {
231            @Override
232            public void run() {
233                mAsyncOperationInProgress = false;
234                handleNextOperation();
235            }
236        };
237
238        private final List<Message> mPendingOperations = new ArrayList<>();
239
240        public MyHandler(Looper looper) {
241            super(looper, null, false);
242        }
243
244        public void enqueueOperation(Message message) {
245            mPendingOperations.add(message);
246            handleNextOperation();
247        }
248
249        public void handleNextOperation() {
250            while (!mPendingOperations.isEmpty() && !mAsyncOperationInProgress) {
251                Message operation = mPendingOperations.remove(0);
252                handleMessage(operation);
253            }
254        }
255
256        @Override
257        public void handleMessage(Message message) {
258            switch (message.what) {
259                case MSG_OPEN: {
260                    try {
261                        File file = mFileProvider.acquireFile(PrintPreviewController.this);
262                        ParcelFileDescriptor pfd = ParcelFileDescriptor.open(file,
263                                ParcelFileDescriptor.MODE_READ_ONLY);
264
265                        mAsyncOperationInProgress = true;
266                        mPageAdapter.open(pfd, new Runnable() {
267                            @Override
268                            public void run() {
269                                if (mDocumentPageCount == PrintDocumentInfo.PAGE_COUNT_UNKNOWN) {
270                                    mDocumentPageCount = mPageAdapter.getFilePageCount();
271                                    mActivity.updateOptionsUi();
272                                }
273                                mOnAsyncOperationDoneCallback.run();
274                            }
275                        });
276                    } catch (FileNotFoundException fnfe) {
277                        /* ignore - file guaranteed to be there */
278                    }
279                } break;
280
281                case MSG_CLOSE: {
282                    mAsyncOperationInProgress = true;
283                    mPageAdapter.close(new Runnable() {
284                        @Override
285                        public void run() {
286                            mFileProvider.releaseFile();
287                            mOnAsyncOperationDoneCallback.run();
288                        }
289                    });
290                } break;
291
292                case MSG_DESTROY: {
293                    mPageAdapter.destroy();
294                    handleNextOperation();
295                } break;
296
297                case MSG_UPDATE: {
298                    SomeArgs args = (SomeArgs) message.obj;
299                    PageRange[] writtenPages = (PageRange[]) args.arg1;
300                    PageRange[] selectedPages = (PageRange[]) args.arg2;
301                    MediaSize mediaSize = (MediaSize) args.arg3;
302                    Margins margins = (Margins) args.arg4;
303                    final int pageCount = args.argi1;
304                    args.recycle();
305
306                    mPageAdapter.update(writtenPages, selectedPages, pageCount,
307                            mediaSize, margins);
308
309                } break;
310
311                case MSG_START_PRELOAD: {
312                    mPreloadController.startPreloadContent();
313                } break;
314            }
315        }
316    }
317
318    private final class PreloadController extends RecyclerView.OnScrollListener {
319        private final RecyclerView mRecyclerView;
320
321        private int mOldScrollState;
322
323        public PreloadController(RecyclerView recyclerView) {
324            mRecyclerView = recyclerView;
325            mOldScrollState = mRecyclerView.getScrollState();
326        }
327
328        @Override
329        public void onScrollStateChanged(RecyclerView recyclerView, int state) {
330            switch (mOldScrollState) {
331                case RecyclerView.SCROLL_STATE_SETTLING: {
332                    if (state == RecyclerView.SCROLL_STATE_IDLE
333                            || state == RecyclerView.SCROLL_STATE_DRAGGING){
334                        startPreloadContent();
335                    }
336                } break;
337
338                case RecyclerView.SCROLL_STATE_IDLE:
339                case RecyclerView.SCROLL_STATE_DRAGGING: {
340                    if (state == RecyclerView.SCROLL_STATE_SETTLING) {
341                        stopPreloadContent();
342                    }
343                } break;
344            }
345            mOldScrollState = state;
346        }
347
348        public void startPreloadContent() {
349            PageAdapter pageAdapter = (PageAdapter) mRecyclerView.getAdapter();
350
351            if (pageAdapter.isOpened()) {
352                PageRange shownPages = computeShownPages();
353                if (shownPages != null) {
354                    pageAdapter.startPreloadContent(shownPages);
355                }
356            }
357        }
358
359        public void stopPreloadContent() {
360            PageAdapter pageAdapter = (PageAdapter) mRecyclerView.getAdapter();
361
362            if (pageAdapter.isOpened()) {
363                pageAdapter.stopPreloadContent();
364            }
365        }
366
367        private PageRange computeShownPages() {
368            final int childCount = mRecyclerView.getChildCount();
369            if (childCount > 0) {
370                LayoutManager layoutManager = mRecyclerView.getLayoutManager();
371
372                View firstChild = layoutManager.getChildAt(0);
373                ViewHolder firstHolder = mRecyclerView.getChildViewHolder(firstChild);
374
375                View lastChild = layoutManager.getChildAt(layoutManager.getChildCount() - 1);
376                ViewHolder lastHolder = mRecyclerView.getChildViewHolder(lastChild);
377
378                return new PageRange(firstHolder.getPosition(), lastHolder.getPosition());
379            }
380            return null;
381        }
382    }
383}
384