public void DOCS(View btnDocs)
{
File fileBrochure = new File("android.resource://com.project.datastructure/assets/abc.pdf");
if (!fileBrochure.exists())
{
CopyAssetsbrochure();
}
/** PDF reader code */
File file = new File("android.resource://com.project.datastructure/assets/abc.pdf");
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.fromFile(file),"application/pdf");
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
try
{
getApplicationContext().startActivity(intent);
}
catch (ActivityNotFoundException e)
{
Toast.makeText(Stack_dr.this, "NO Pdf Viewer", Toast.LENGTH_SHORT).show();
}
}
private void CopyAssetsbrochure() {
AssetManager assetManager = getAssets();
String[] files = null;
try
{
files = assetManager.list("");
}
catch (IOException e){}
for(int i=0; i<files.length; i++)
{
String fStr = files[i];
if(fStr.equalsIgnoreCase("abc.pdf"))
{
InputStream in = null;
OutputStream out = null;
try
{
in = assetManager.open(files[i]);
out = new FileOutputStream("/sdcard/" + files[i]);
copyFile(in, out);
in.close();
in = null;
out.flush();
out.close();
out = null;
break;
}
catch(Exception e){}
}
}
}
private void copyFile(InputStream in, OutputStream out) throws IOException
{
byte[] buffer = new byte[1024];
int read;
while((read = in.read(buffer)) != -1){
out.write(buffer, 0, read);
}
}
我正试图从我的应用程序文件夹中存在的资产文件夹中读取pdf文件。当我点击我的DOCS按钮时，一个弹出窗口让我选择一个打开pdf的应用程序，即"abc.pdf"，但在选择一个选项后，我得到一个错误消息"文件路径无效"。我认为他们是一些问题，我在代码中指定的路径。请帮助
试试这个
public class SampleActivity extends Activity
{
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
CopyReadAssets();
}
private void CopyReadAssets()
{
AssetManager assetManager = getAssets();
InputStream in = null;
OutputStream out = null;
File file = new File(getFilesDir(), "abc.pdf");
try
{
in = assetManager.open("abc.pdf");
out = openFileOutput(file.getName(), Context.MODE_WORLD_READABLE);
copyFile(in, out);
in.close();
in = null;
out.flush();
out.close();
out = null;
} catch (Exception e)
{
Log.e("tag", e.getMessage());
}
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(
Uri.parse("file://" + getFilesDir() + "/abc.pdf"),
"application/pdf");
startActivity(intent);
}
private void copyFile(InputStream in, OutputStream out) throws IOException
{
byte[] buffer = new byte[1024];
int read;
while ((read = in.read(buffer)) != -1)
{
out.write(buffer, 0, read);
}
}
}
一定要包括
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
您可以这样做(在API 27上测试并工作)
步骤1在你的应用gradle中添加以下依赖项:
implementation 'com.github.barteksc:android-pdf-viewer:2.8.2'
添加以下XML代码:
<com.github.barteksc.pdfviewer.PDFView
android:id="@+id/pdfv"
android:layout_width="match_parent"
android:layout_height="match_parent">
</com.github.barteksc.pdfviewer.PDFView>
在java文件中添加以下代码:
public class MainActivity extends AppCompatActivity {
PDFView pdfView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
pdfView=findViewById(R.id.pdfv);
pdfView.fromAsset("filename.pdf").load();
}
}
这些更改将在创建activity时加载PDF文件
虽然这个问题已经得到了回答，但我想分享一下我的解决方案，因为我认为它更容易包含。
用法:
new OpenLocalPDF(context, 'nameOfPDFStoredInAssets').execute()
这是OpenLocalPDF类:
public class OpenLocalPDF {
private static String TAG = OpenLocalPDF.class.getSimpleName();
private WeakReference<Context> contextWeakReference;
private String fileName;
public OpenLocalPDF(Context context, String fileName) {
this.contextWeakReference = new WeakReference<>(context);
this.fileName = fileName.endsWith("pdf") ? fileName : fileName + ".pdf";
}
public void execute() {
Context context = contextWeakReference.get();
if (context != null) {
new CopyFileAsyncTask().execute();
}
}
private class CopyFileAsyncTask extends AsyncTask<Void, Void, File> {
final String appDirectoryName = BuildConfig.APPLICATION_ID;
final File fileRoot = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_DOCUMENTS), appDirectoryName);
@Override
protected File doInBackground(Void... params) {
Context context = contextWeakReference.get();
AssetManager assetManager = context.getAssets();
File file = new File(fileRoot, fileName);
InputStream in = null;
OutputStream out = null;
try {
file.mkdirs();
if (file.exists()) {
file.delete();
}
file.createNewFile();
in = assetManager.open(fileName);
Log.d(TAG, "In");
out = new FileOutputStream(file);
Log.d(TAG, "Out");
Log.d(TAG, "Copy file");
copyFile(in, out);
Log.d(TAG, "Close");
in.close();
out.flush();
out.close();
return file;
} catch (Exception e)
{
Log.e(TAG, e.getMessage());
}
return null;
}
private void copyFile(InputStream in, OutputStream out) throws IOException
{
byte[] buffer = new byte[1024];
int read;
while ((read = in.read(buffer)) != -1)
{
out.write(buffer, 0, read);
}
}
@Override
protected void onPostExecute(File file) {
super.onPostExecute(file);
Context context = contextWeakReference.get();
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(
Uri.fromFile(file),
"application/pdf");
context.startActivity(intent);
}
}
}
在Manifest.xml中添加此权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
就像sunsil一样，但在外部目录的情况下。
import android.app.Activity;
import android.content.Intent;
import android.content.res.AssetManager;
import android.net.Uri;
import android.os.Environment;
import android.os.Bundle;
import android.util.Log;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
copyReadAssets();
}
private void copyReadAssets()
{
AssetManager assetManager = getAssets();
InputStream in = null;
OutputStream out = null;
String strDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS)+ File.separator + "Pdfs";
File fileDir = new File(strDir);
fileDir.mkdirs(); // crear la ruta si no existe
File file = new File(fileDir, "example2.pdf");
try
{
in = assetManager.open("example.pdf"); //leer el archivo de assets
out = new BufferedOutputStream(new FileOutputStream(file)); //crear el archivo
copyFile(in, out);
in.close();
in = null;
out.flush();
out.close();
out = null;
} catch (Exception e)
{
Log.e("tag", e.getMessage());
}
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.parse("file://" + Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS) + File.separator + "Pdfs" + "/example2.pdf"), "application/pdf");
startActivity(intent);
}
private void copyFile(InputStream in, OutputStream out) throws IOException
{
byte[] buffer = new byte[1024];
int read;
while ((read = in.read(buffer)) != -1)
{
out.write(buffer, 0, read);
}
}
}
更改部分代码，如:
out = new BufferedOutputStream(new FileOutputStream(file));
前面的例子适用于pdf文件，如果没有example .txt
FileOutputStream fos = new FileOutputStream(file);
这对我很有用。
步骤1:在MainActivity.java
public class SampleActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//call this method by passing file name in params.
readFromAssets("User guide.pdf");
}
public static void readFromAssets(String fileName) {
AssetManager assetManager = getAssets();
InputStream in = null;
OutputStream out = null;
File file = new File(mContext.getFilesDir(), fileName);
try {
in = assetManager.open(fileName);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
out = mContext.openFileOutput(file.getName(), Context.MODE_PRIVATE);
} else {
out = mContext.openFileOutput(file.getName(), Context.MODE_WORLD_READABLE);
}
copyFile(in, out);
in.close();
in = null;
out.flush();
out.close();
out = null;
} catch (Exception e) {
Log.e("tag", e.getMessage());
}
Uri pdfFileURI;
Intent intent = new Intent(Intent.ACTION_VIEW);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
pdfFileURI = FileProvider.getUriForFile(mContext,
BuildConfig.APPLICATION_ID + ".provider", file);
intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
} else {
pdfFileURI = Uri.parse("file://" + mContext.getFilesDir() + "/" + fileName);
}
intent.setDataAndType(pdfFileURI, "application/pdf");
mContext.startActivity(intent);
}
private static void copyFile(InputStream in, OutputStream out) throws IOException {
byte[] buffer = new byte[1024];
int read;
while ((read = in.read(buffer)) != -1) {
out.write(buffer, 0, read);
}
}
}
步骤2:在res->xml->provider_paths.xml中创建provider_paths.xml。看到
<?xml version="1.0" encoding="utf-8"?>
<paths>
<external-path
name="external"
path="." />
<root-path
name="root"
path="." />
</paths>
步骤3:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<application
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppThemeMaterial">
<!-- INSIDE APPLICATION TAG -->
<provider
android:name="androidx.core.content.FileProvider"
android:authorities="${applicationId}.provider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/provider_paths"/>
</provider>
</application>
当我试图通过意图从资产文件夹打开文件(在我的情况下是PDF)时，没有答案为我开箱即用。所以这里是我的解决方案，结合了两个精彩的答案，我相信它会帮助别人。必须为api>= 24.
一旦您遵循此链接并添加了自己的GenericFileProvider并在Application标签内的清单中声明它并创建了provider_paths.xml，只需使用下面的类并将其称为:
OpenLocalPDF(this, "YOUR_PDF_NAME_IN_ASSETS_FOLDER.pdf").execute()
OpenLocalPdf。kt: (OP也很好https://stackoverflow.com/a/41212708/1133011)
import android.content.Context
import android.content.Intent
import android.content.res.AssetManager
import android.os.AsyncTask
import android.util.Log
import androidx.core.content.FileProvider
import java.io.File
import java.io.FileOutputStream
import java.io.InputStream
import java.io.OutputStream
import java.lang.ref.WeakReference
class OpenLocalPDF(context: Context?, fileName: String?) {
private val contextWeakReference: WeakReference<Context?>?
private val fileName: String?
fun execute() {
val context: Context = contextWeakReference!!.get()!!
if (context != null) {
CopyFileAsyncTask().execute()
}
}
private inner class CopyFileAsyncTask :
AsyncTask<Void?, Void?, File?>() {
val appDirectoryName: String? = co.za.umbiflow.BuildConfig.APPLICATION_ID
val fileRoot: File? = File(
android.os.Environment.getExternalStoragePublicDirectory(
android.os.Environment.DIRECTORY_DOCUMENTS
), appDirectoryName
)
override fun doInBackground(vararg params: Void?): File? {
val context: Context = contextWeakReference!!.get()!!
val assetManager: AssetManager = context.getAssets()
val file = File(fileRoot, fileName)
var `in`: InputStream? = null
var out: OutputStream? = null
try {
file.mkdirs()
if (file.exists()) {
file.delete()
}
file.createNewFile()
`in` = assetManager.open(fileName)
out = FileOutputStream(file)
copyFile(`in`, out)
`in`.close()
out.flush()
out.close()
return file
} catch (e: Exception) {
Log.e(TAG, e.message)
}
return null
}
private fun copyFile(`in`: InputStream, out: OutputStream) {
val buffer = ByteArray(1024)
var read: Int
while (`in`.read(buffer).also { read = it } != -1) {
out.write(buffer, 0, read)
}
}
override fun onPostExecute(file: File?) {
super.onPostExecute(file)
val context: Context = contextWeakReference!!.get()!!
var pdfUri =
FileProvider.getUriForFile(
context,
context.packageName + ".provider",
file!!
)
val intent = Intent()
intent.action = Intent.ACTION_VIEW
intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
intent.setDataAndType(
pdfUri,
"application/pdf"
)
context.startActivity(intent)
}
}
companion object {
private val TAG = OpenLocalPDF::class.java.simpleName
}
init {
contextWeakReference = WeakReference(context)
this.fileName = if (fileName!!.endsWith("pdf")) fileName else "$fileName.pdf"
}
}
这是一种使用zip文件从资源中打开多个PDF文件的方法。
步骤1:复制一个zip文件(
pdf.zip)到包含pdf列表的assets文件夹
步骤2:在Utils类中写入PDF文件到应用程序内部的外部缓存
public static void writePDFs(Context context) {
try {
InputStream inputStream = context.getApplicationContext().getAssets().open("pdf.zip");
ZipInputStream zipInputStream = new ZipInputStream(inputStream);
ZipEntry zipEntry;
File file = new File(context.getExternalCacheDir().getAbsolutePath(), "PDFs");
if (!file.getAbsoluteFile().exists()) {
if (file.mkdir()) {
BufferedOutputStream outputStream;
byte[] buffer = new byte[1024];
int count;
while ((zipEntry = zipInputStream.getNextEntry()) != null) {
String s1 = file + "/" + zipEntry.getName();
File file1 = new File(s1);
if (!file1.exists()) {
file1.createNewFile();
}
outputStream = new BufferedOutputStream(new FileOutputStream(file1));
while ((count = zipInputStream.read(buffer)) != -1) {
outputStream.write(buffer, 0, count);
}
outputStream.flush();
outputStream.close();
zipInputStream.closeEntry();
}
}
zipInputStream.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
步骤3:在Activities onCreate
中调用上述函数
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
FileUtils.writePDFs(this);
}
步骤4:在Utils类中创建一个公共函数来打开PDF
public static void openPDF(Activity activity, String fileName) {
if (activity == null) return;
File file = new File(activity.getExternalCacheDir().getAbsolutePath() + "/PDFs" + "/" + fileName);
Uri docUri = GenericFileProvider.getUriForFile(activity, activity.getApplicationContext().getPackageName(), file);
try {
Intent intent = new Intent();
intent.setAction(Intent.ACTION_VIEW);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
intent.setDataAndType(docUri, "application/pdf");
} else {
intent.setDataAndType(Uri.fromFile(file), "application/pdf");
}
activity.startActivityForResult(intent, ACTIVITY_VIEW_ATTACHMENT);
} catch (ActivityNotFoundException e) {
e.printStackTrace();
}
}
Step5:调用
中的视图openPDF函数点击活动
myView.setOnClickListener(v -> ApplicationUtils.openPDF(this, "MyPdfFile.pdf"));
我成功了，使用cYrixmorten的答案，使用OpenLocalPDF类。
,但环境。Android 18不支持DIRECTORY_DOCUMENTS。为了支持Android 18 - 28，我必须做以下更改:
在"CopyFileAsyncTask"中，更改fileRoot声明:
final File fileRoot = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_DOCUMENTS), appDirectoryName);
:
final File fileRoot = new File(Environment.getExternalStorageDirectory() + "/YourAppName");
在"onPostExecute"中，修改如下:
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(
Uri.fromFile(file),
"application/pdf");
context.startActivity(intent);
:
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(FileProvider.getUriForFile(context, "com.example.yourappname.provider", file), "application/pdf");
intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
context.startActivity(intent);
最后，设置你的manifest以支持本文中描述的FileProvider
try this:
public String getAssetsPdfPath(Context context) {
String filePath = context.getFilesDir() + File.separator + "myFile.pdf";
File destinationFile = new File(filePath);
try {
FileOutputStream outputStream = new FileOutputStream(destinationFile);
InputStream inputStream = context.getAssets().open("myFile.pdf");
byte[] buffer = new byte[1024];
int length = 0;
while ((length = inputStream.read(buffer)) != -1) {
outputStream.write(buffer, 0, length);
}
outputStream.close();
inputStream.close();
} catch (IOException e) {
Log.e(context.getClass().getSimpleName(), "Error.");
}
return destinationFile.getPath();
}
如果你想打开存储在本地资产文件夹中的.pdf文件而不使用Intent来启动外部应用程序，我建议使用Android类PdfRenderer。
这对我来说是一个很好的例子。
但是，当我下载它时，这个例子不会运行。我不得不稍微改变一下，使用copyReadAssets()函数，就像这里的其他答案中提到的那样，然后引用文件(在它被复制之后)，我使用:
File file = new File("/data/data/" + getContext().getPackageName() + "/files/mypdf.pdf");
我也最终修改了onAttach()，因为它使用了onAttach()和closeRenderer()的过时形式，因为它在关闭null对象时抛出错误。
完整的pdfrendererbasicfragment。java文件如下所示:
package com.example.android.pdfrendererbasic;
import android.app.Activity;
import android.app.Fragment;
import android.content.Context;
import android.content.res.AssetManager;
import android.graphics.Bitmap;
import android.graphics.pdf.PdfRenderer;
import android.os.Bundle;
import android.os.ParcelFileDescriptor;
import android.util.Log;
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.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
* 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(Context context) {
super.onAttach(context);
try {
openRenderer(context);
} catch (IOException e) {
e.printStackTrace();
Toast.makeText(context, "Error! " + e.getMessage(), Toast.LENGTH_SHORT).show();
getActivity().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 {
// Copy the pdf to a usable location
CopyReadAssets();
File file = new File("/data/data/" + context.getPackageName() + "/files/sample.pdf");
mPdfRenderer = new PdfRenderer(ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_ONLY));
}
/**
* 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 (mCurrentPage != null) {
mCurrentPage.close();
}
if (mPdfRenderer != null) {
mPdfRenderer.close();
}
if (mFileDescriptor != null) {
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;
}
}
}
private void CopyReadAssets()
{
AssetManager assetManager = getActivity().getAssets();
InputStream in = null;
OutputStream out = null;
File file = new File(getActivity().getFilesDir(), "sample.pdf");
if(!file.exists()) {
try {
in = assetManager.open("sample.pdf");
out = getActivity().openFileOutput(file.getName(), Context.MODE_WORLD_READABLE);
copyFile(in, out);
in.close();
in = null;
out.flush();
out.close();
out = null;
} catch (Exception e) {
Log.e("tag", e.getMessage());
}
}
else {
Log.d("test", "file already exists");
}
}
private void copyFile(InputStream in, OutputStream out) throws IOException
{
byte[] buffer = new byte[1024];
int read;
while ((read = in.read(buffer)) != -1)
{
out.write(buffer, 0, read);
}
}
}
此代码适用于所有android版本:
活动:import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.res.AssetManager;
import android.net.Uri;
import android.os.Environment;
import android.os.Bundle;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v4.content.FileProvider;
import android.util.Log;
import android.widget.Toast;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import unimedbh.UnimedBH.R;
public class MainActivity extends Activity {
private static final int MY_PERMISSION_REQUEST_STORAGE = 1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (ContextCompat.checkSelfPermission(MainActivity.this, android.Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(MainActivity.this, new String[]{android.Manifest.permission.WRITE_EXTERNAL_STORAGE}, MY_PERMISSION_REQUEST_STORAGE);
} else {
copyReadAssets("YOUR_PDF_NAME.pdf");
}
}
private void copyReadAssets(String fileName) {
String dirPath = Environment.getExternalStorageDirectory().getAbsolutePath() + "/MyFiles";
File dir = new File(dirPath);
if (!dir.exists()) {
dir.mkdirs();
}
AssetManager assetManager = getAssets();
InputStream in = null;
OutputStream out = null;
try {
in = assetManager.open(fileName);
File outFile = new File(dirPath, fileName);
out = new FileOutputStream(outFile);
copyFile(in, out);
Intent intent = new Intent(Intent.ACTION_VIEW, FileProvider.getUriForFile(this, "com.package.name.fileprovider", outFile));
intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_ACTIVITY_NO_HISTORY);
startActivity(intent);
} catch (IOException e) {
e.printStackTrace();
Toast.makeText(this, "Error!", Toast.LENGTH_SHORT).show();
} finally {
if (in != null) {
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (out != null) {
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
private void copyFile(InputStream in, OutputStream out) throws IOException {
byte[] buffer = new byte[1024];
int read;
while ((read = in.read(buffer)) != -1) {
out.write(buffer, 0, read);
}
}
}
Manifest.xml:
<provider
android:name="android.support.v4.content.FileProvider"
android:authorities="com.package.name.fileprovider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/file_paths" />
</provider>
file_paths.xml:
<paths>
<files-path name="app_directory" path="directory/"/>
</paths>
在API 16-28中测试，可在所有API上工作!