Android Studio – PDFRendererBasic – Не удалось заменить sample.pdf?

Каждый раз, когда я редактирую java-код PDFRendererBasicFragment

mFileDescriptor = context.getAssets().openFd("sample.pdf").getParcelFileDescriptor(); 

К другому PDF-файлу, помещенному в папку с ресурсами, приложение аварийно завершает работу.

Отчеты Logcat:

 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.android.pdfrendererbasic/com.example.android.pdfrendererbasic.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'int android.graphics.pdf.PdfRenderer.getPageCount()' on a null object reference 

Почему это происходит? Я даже попробовал переименовать свой PDF в sample.pdf перед его созданием, и он все равно сработает. Все работает отлично с исходным кодом, просто не позволю мне заменить PDF.

Трассировки стека:

 02-11 11:11:50.130 18201-18201/com.example.android.pdfrendererbasic I/art: Not late-enabling -Xcheck:jni (already on) 02-11 11:11:50.130 18201-18201/com.example.android.pdfrendererbasic I/art: Late-enabling JIT 02-11 11:11:50.132 18201-18201/com.example.android.pdfrendererbasic I/art: JIT created with code_cache_capacity=2MB compile_threshold=1000 02-11 11:11:50.201 18201-18201/com.example.android.pdfrendererbasic W/System: ClassLoader referenced unknown path: /data/app/com.example.android.pdfrendererbasic-1/lib/x86 02-11 11:11:50.252 18201-18201/com.example.android.pdfrendererbasic W/System.err: java.io.IOException: cannot create document. Error: 3 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at android.graphics.pdf.PdfRenderer.nativeCreate(Native Method) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at android.graphics.pdf.PdfRenderer.<init>(PdfRenderer.java:153) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at com.example.android.pdfrendererbasic.PdfRendererBasicFragment.openRenderer(PdfRendererBasicFragment.java:141) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at com.example.android.pdfrendererbasic.PdfRendererBasicFragment.onAttach(PdfRendererBasicFragment.java:108) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at android.app.Fragment.onAttach(Fragment.java:1380) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:932) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1148) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at android.app.BackStackRecord.run(BackStackRecord.java:793) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1535) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at android.app.FragmentController.execPendingActions(FragmentController.java:325) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at android.app.Activity.performStart(Activity.java:6252) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2379) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at android.app.ActivityThread.-wrap11(ActivityThread.java) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at android.os.Handler.dispatchMessage(Handler.java:102) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at android.os.Looper.loop(Looper.java:148) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at android.app.ActivityThread.main(ActivityThread.java:5417) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at java.lang.reflect.Method.invoke(Native Method) 02-11 11:11:50.253 18201-18201/com.example.android.pdfrendererbasic W/System.err: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 02-11 11:11:50.254 18201-18201/com.example.android.pdfrendererbasic W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 02-11 11:11:51.082 18201-18201/com.example.android.pdfrendererbasic D/AndroidRuntime: Shutting down VM 02-11 11:11:51.082 18201-18201/com.example.android.pdfrendererbasic E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.android.pdfrendererbasic, PID: 18201 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.android.pdfrendererbasic/com.example.android.pdfrendererbasic.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'int android.graphics.pdf.PdfRenderer.getPageCount()' on a null object reference at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) at android.app.ActivityThread.-wrap11(ActivityThread.java) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:148) at android.app.ActivityThread.main(ActivityThread.java:5417) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int android.graphics.pdf.PdfRenderer.getPageCount()' on a null object reference at com.example.android.pdfrendererbasic.PdfRendererBasicFragment.showPage(PdfRendererBasicFragment.java:163) at com.example.android.pdfrendererbasic.PdfRendererBasicFragment.onViewCreated(PdfRendererBasicFragment.java:101) at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:988) at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1148) at android.app.BackStackRecord.run(BackStackRecord.java:793) at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1535) at android.app.FragmentController.execPendingActions(FragmentController.java:325) at android.app.Activity.performStart(Activity.java:6252) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2379) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) at android.app.ActivityThread.-wrap11(ActivityThread.java) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:148) at android.app.ActivityThread.main(ActivityThread.java:5417) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

PDFRendererBasicFragment.java:

 /* * 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.example.android.pdfrendererbasic; import android.app.Activity; import android.app.Fragment; import android.content.Context; import android.graphics.Bitmap; import android.graphics.pdf.PdfRenderer; import android.os.Bundle; import android.os.ParcelFileDescriptor; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.Button; import android.widget.ImageView; import android.widget.Toast; import java.io.IOException; /** * This fragment has a big {@ImageView} that shows PDF pages, and 2 {@link android.widget.Button}s to move between * pages. We use a {@link android.graphics.pdf.PdfRenderer} to render PDF pages as {@link android.graphics.Bitmap}s. */ public class PdfRendererBasicFragment extends Fragment implements View.OnClickListener { /** * Key string for saving the state of current page index. */ private static final String STATE_CURRENT_PAGE_INDEX = "current_page_index"; /** * File descriptor of the PDF. */ private ParcelFileDescriptor mFileDescriptor; /** * {@link android.graphics.pdf.PdfRenderer} to render the PDF. */ private PdfRenderer mPdfRenderer; /** * Page that is currently shown on the screen. */ private PdfRenderer.Page mCurrentPage; /** * {@link android.widget.ImageView} that shows a PDF page as a {@link android.graphics.Bitmap} */ private ImageView mImageView; /** * {@link android.widget.Button} to move to the previous page. */ private Button mButtonPrevious; /** * {@link android.widget.Button} to move to the next page. */ private Button mButtonNext; public PdfRendererBasicFragment() { } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { return inflater.inflate(R.layout.fragment_pdf_renderer_basic, container, false); } @Override public void onViewCreated(View view, Bundle savedInstanceState) { super.onViewCreated(view, savedInstanceState); // Retain view references. mImageView = (ImageView) view.findViewById(R.id.image); mButtonPrevious = (Button) view.findViewById(R.id.previous); mButtonNext = (Button) view.findViewById(R.id.next); // Bind events. mButtonPrevious.setOnClickListener(this); mButtonNext.setOnClickListener(this); // Show the first page by default. int index = 0; // If there is a savedInstanceState (screen orientations, etc.), we restore the page index. if (null != savedInstanceState) { index = savedInstanceState.getInt(STATE_CURRENT_PAGE_INDEX, 0); } showPage(index); } @Override public void onAttach(Activity activity) { super.onAttach(activity); try { openRenderer(activity); } catch (IOException e) { e.printStackTrace(); Toast.makeText(activity, "Error! " + e.getMessage(), Toast.LENGTH_SHORT).show(); activity.finish(); } } @Override public void onDetach() { try { closeRenderer(); } catch (IOException e) { e.printStackTrace(); } super.onDetach(); } @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); if (null != mCurrentPage) { outState.putInt(STATE_CURRENT_PAGE_INDEX, mCurrentPage.getIndex()); } } /** * Sets up a {@link android.graphics.pdf.PdfRenderer} and related resources. */ private void openRenderer(Context context) throws IOException { // In this sample, we read a PDF from the assets directory. mFileDescriptor = context.getAssets().openFd("sample.pdf").getParcelFileDescriptor(); // This is the PdfRenderer we use to render the PDF. mPdfRenderer = new PdfRenderer(mFileDescriptor); } /** * Closes the {@link android.graphics.pdf.PdfRenderer} and related resources. * * @throws java.io.IOException When the PDF file cannot be closed. */ private void closeRenderer() throws IOException { if (null != mCurrentPage) { mCurrentPage.close(); } mPdfRenderer.close(); mFileDescriptor.close(); } /** * Shows the specified page of PDF to the screen. * * @param index The page index. */ private void showPage(int index) { if (mPdfRenderer.getPageCount() <= index) { return; } // Make sure to close the current page before opening another one. if (null != mCurrentPage) { mCurrentPage.close(); } // Use `openPage` to open a specific page in PDF. mCurrentPage = mPdfRenderer.openPage(index); // Important: the destination bitmap must be ARGB (not RGB). Bitmap bitmap = Bitmap.createBitmap(mCurrentPage.getWidth(), mCurrentPage.getHeight(), Bitmap.Config.ARGB_8888); // Here, we render the page onto the Bitmap. // To render a portion of the page, use the second and third parameter. Pass nulls to get // the default result. // Pass either RENDER_MODE_FOR_DISPLAY or RENDER_MODE_FOR_PRINT for the last parameter. mCurrentPage.render(bitmap, null, null, PdfRenderer.Page.RENDER_MODE_FOR_DISPLAY); // We are ready to show the Bitmap to user. mImageView.setImageBitmap(bitmap); updateUi(); } /** * Updates the state of 2 control buttons in response to the current page index. */ private void updateUi() { int index = mCurrentPage.getIndex(); int pageCount = mPdfRenderer.getPageCount(); mButtonPrevious.setEnabled(0 != index); mButtonNext.setEnabled(index + 1 < pageCount); getActivity().setTitle(getString(R.string.app_name_with_index, index + 1, pageCount)); } /** * Gets the number of pages in the PDF. This method is marked as public for testing. * * @return The number of pages. */ public int getPageCount() { return mPdfRenderer.getPageCount(); } @Override public void onClick(View view) { switch (view.getId()) { case R.id.previous: { // Move to the previous page showPage(mCurrentPage.getIndex() - 1); break; } case R.id.next: { // Move to the next page showPage(mCurrentPage.getIndex() + 1); break; } } } } 

Уменьшить версию градиента с 2.2.0 до 2.1.2, и авария исчезнет.

В build.gradle (Project) заменить

 classpath 'com.android.tools.build:gradle:2.2.0' 

с

 classpath 'com.android.tools.build:gradle:2.1.2' 

О той же проблеме, о которой вы говорили, сообщается и описывается здесь . Проблема заключается в том, что Android Studio создает окончательный файл apk. Хотя решение для ручной переупакивания файла apk предоставляется в данной ссылке, это не очень практично. Ошибка, похоже, не имеет другого простого решения.

РЕДАКТИРОВАТЬ

Вот решение из предоставленной ссылки. Однако в упомянутой проблеме упоминается несколько другое сообщение об ошибке, поэтому это может не сработать.

  1. Запустить Android Studio
  2. Нажмите «Импортировать образец кода Android».
  3. Выберите Графика> Pdf Renderer Basic
  4. Нажмите "Далее
  5. Нажмите «Готово».
  6. Нажмите «Выполнить»> «Запустить» приложение «

Запуск приложения неявно создает файл Application / build / output / apk / Application-debug.apk.

6.a: Проверка работоспособности: убедитесь, что записи META-INF находятся в конце файла:

 $ unzip -lv Application/build/outputs/apk/Application-debug.apk ... 1569 Defl:N 702 55% 12-16-14 17:35 c7cb7a03 META-INF/MANIFEST.MF 1598 Defl:N 724 55% 12-16-14 17:35 034c0dfc META-INF/CERT.SF 776 Defl:N 605 22% 12-16-14 17:35 2be8b27c META-INF/CERT.RSA -------- ------- --- ------- 1565085 849785 46% 21 files 
  1. Повторно подпишите пакет вручную с помощью jarsigner. Цель этого – обеспечить, чтобы записи META-INF находились в начале .apk:

    $ Yes android | Keytool -genkey -v -keystore demo.keystore -alias demo -keyalg RSA -keysize 2048 -validity 10000 -dname "CN = Mark Smith" $ cp Application / build / output / apk / Application-debug.apk A.apk $ zip -d A.apk META-INF / MANIFEST.MF $ zip -d A.apk META-INF / CERT.SF $ zip -d A.apk META-INF / CERT.RSA $ jarsigner -keystore demo.keystore -storepass android \ -keypass android -digestalg SHA1 -sigalg md5withRSA \ -signedjar A-unaligned.apk A.apk \ demo $ zipalign 4 A-unaligned.apk A-aligned.apk

  2. Установите повторно подписанный пакет:

    $ Adb uninstall com.example.android.pdfrendererbasic $ adb install A-aligned.apk

  3. Запустите новый пакет:

    $ Adb shell am start com.example.android.pdfrendererbasic / .MainActivity

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