请下列文件/方法添加到您的项目
- PdfDownloader.java
- PDFDownloaderAsyncTask.java
然后使用以下方法handleViewPdf查看PDF：
private void handleViewPdf() {
File folder = getAppDirectory(context);
String fileName = "test.pdf";// getPdfFileName(pdfUrl);
File pdfFile = new File(folder, fileName);
if (pdfFile.exists() && pdfFile.length() > 0) {
openPDFFile (context, Uri.fromFile(pdfFile));
}
else {
if (pdfFile.length() == 0) {
pdfFile.delete();
}
try {
pdfFile.createNewFile();
}
catch (IOException e) {
e.printStackTrace();
}
ArrayList<String> fileNameAndURL = new ArrayList<>();
fileNameAndURL.add (pdfFile.toString());
fileNameAndURL.add (pdfUrl);
fileNameAndURL.add (fileName);
if (pdfDownloaderAsyncTask == null) {
pdfDownloaderAsyncTask = new PDFDownloaderAsyncTask (context, pdfFile);
}
if (hasInternetConnection (context)) {
if (!pdfDownloaderAsyncTask.isDownloadingPdf()) {
pdfDownloaderAsyncTask = new PDFDownloaderAsyncTask (context, pdfFile);
pdfDownloaderAsyncTask.execute (fileNameAndURL);
}
}
else {
//show error
}
}
}
PDFDownloaderAsyncTask.java
import java.io.File;
import java.util.ArrayList;
import android.content.Context;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Handler;
import android.text.TextUtils;
import android.widget.Toast;
public class PDFDownloaderAsyncTask extends AsyncTask<ArrayList<String>, Void, String> {
private boolean isDownloadingPdf = false;
private File file;
private Context context;
public PDFDownloaderAsyncTask (Context context, File file) {
this.file = file;
this.context = context;
this.isDownloadingPdf = false;
}
public boolean isDownloadingPdf() {
return this.isDownloadingPdf;
}
@Override
protected void onPreExecute() {
super.onPreExecute();
//show loader etc
}
@Override
protected String doInBackground (ArrayList<String>... params) {
isDownloadingPdf = true;
File file = new File (params[0].get (0));
String fileStatus = PdfDownloader.downloadFile (params[0].get (1), file);
return fileStatus;
}
@Override
protected void onPostExecute (String result) {
super.onPostExecute (result);
Loader.hideLoader();
if (!TextUtils.isEmpty (result) && result.equalsIgnoreCase (context.getString (R.string.txt_success))) {
showPdf();
}
else {
isDownloadingPdf = false;
Toast.makeText (context, context.getString (R.string.error_could_not_download_pdf), Toast.LENGTH_LONG).show();
file.delete();
}
}
@Override
protected void onCancelled() {
isDownloadingPdf = false;
super.onCancelled();
//Loader.hideLoader();
}
@Override
protected void onCancelled (String s) {
isDownloadingPdf = false;
super.onCancelled (s);
//Loader.hideLoader();
}
private void showPdf() {
new Handler().postDelayed (new Runnable() {
@Override
public void run() {
isDownloadingPdf = false;
openPDFFile (context, Uri.fromFile (file));
}
}, 1000);
}
}
PdfDownloader.java
package com.pdf;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
public class PdfDownloader {
private static final int MEGABYTE = 1024 * 1024;
public static String downloadFile (String fileUrl, File directory) {
String downloadStatus;
try {
URL url = new URL (fileUrl);
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.connect();
InputStream inputStream = urlConnection.getInputStream();
FileOutputStream fileOutputStream = new FileOutputStream (directory);
int totalSize = urlConnection.getContentLength();
Log.d ("PDF", "Total size: " + totalSize);
byte[] buffer = new byte[MEGABYTE];
int bufferLength = 0;
while ((bufferLength = inputStream.read (buffer)) > 0) {
fileOutputStream.write (buffer, 0, bufferLength);
}
downloadStatus = "success";
fileOutputStream.close();
}
catch (FileNotFoundException e) {
downloadStatus = "FileNotFoundException";
e.printStackTrace();
}
catch (MalformedURLException e) {
downloadStatus = "MalformedURLException";
e.printStackTrace();
}
catch (IOException e) {
downloadStatus = "IOException";
e.printStackTrace();
}
Log.d ("PDF", "Download Status: " + downloadStatus);
return downloadStatus;
}
public static void openPDFFile (Context context, Uri path) {
Intent intent = new Intent (Intent.ACTION_VIEW);
intent.setDataAndType (path, "application/pdf");
intent.setFlags (Intent.FLAG_ACTIVITY_CLEAR_TOP);
try {
context.startActivity (intent);
}
catch (ActivityNotFoundException e) {
Toast.makeText (context, context.getString (R.string.txt_no_pdf_available), Toast.LENGTH_SHORT).show();
}
Loader.hideLoader();
}
public static File getAppDirectory (Context context) {
String extStorageDirectory = Environment.getExternalStorageDirectory().toString();
File folder = new File (extStorageDirectory, context.getString (R.string.app_folder_name).trim());
if (!folder.exists()) {
boolean success = folder.mkdirs();
Log.d ("Directory", "mkdirs():" + success);
}
return folder;
}
}
当你说“它给出的错误，该文件无法打开”，你能有更多的具体说明吗？你在一些日志中看到这个吗？请准确显示您所看到的内容。 –