我正在尝试使用代码从dropbox下载PDF文件，并在点击项目后下载SD卡中的所有文件后，PDF book应该加载到PDF查看器系统应用程序中。 但实际上通过使用此代码，所有PDF文件都在下载，但是当加载PDF应用程序时，它会显示错误“文档无法打开”，并且不会查看PDF书籍。任何人都可以帮我解决这个问题 提前感谢你 而且我不善于用有效的方式发帖提问，所以我真的很抱歉。
{
MainActivity
package com.example.mahvishponum.pdfviewer;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.Uri;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.Toast;
import java.io.File;
import java.util.ArrayList;
public class MainActivity extends Activity implements AsyncResponse {
ProgressDialog mProgressDialog;
ListView list;
int counter = 0;
ArrayList<DataModel> _data = new ArrayList<>();
String[] web = {
"A Textbook of Paediatric Orthopaedics" +
"By Nigel S. Broughton",
"Basic Pediatric Protocols 2013" +
"By Ministry of Health Kenya",
"Basic Pediatric Protocols 2016" +
"By Ministry of Health Kenya",
"Current Diagnosis & Treatment" +
"PEDIATRICS 19th Edition" +
"By McGrawHill LANGE",
"Hospital Care For Children" +
"Pocket Book 2013 Edition" +
"By WHO",
"Textbook of Pediatrics" +
"20th Edition" +
"By Nelson",
"The Care and Feeding of Children" +
"By L. Emmett Holt. M. D.",
"Updates on the Management of Severe Acute Malnutrition in Infants
and Children" +
"Guidelines by WHO"
};
String[] titles = {
"helptextbookpedortho.pdf",
"BasicPaediatricProcotolsNovember2013.pdf",
"basicpaediatricprotocols2016.pdf",
"currentdiagnosisandtreatmentpediatrics.pdf",
"HospitalCareForChildrenPocketBooks.pdf",
"NelsonTextbookofPediatrics.pdf",
"TheCareAndFeedingOfChildren.pdf"
};
String[] urls = {
"https://www.dropbox.com/s/ruds35lyz672jjk/helptextbookpedortho.pdf?dl=1",
"https://www.dropbox.com/s/n2snurxnvijbqya/BasicPaediatricProcotolsNovember2013.pdf?dl=1",
"https://www.dropbox.com/s/a1tyrfqd5jhdu7k/basicpaediatricprotocols2016.pdf?dl=1",
"https://www.dropbox.com/s/hgs7pp97ut3mti3/currentdiagnosisandtreatmentpediatrics.pdf?dl=1",
"https://www.dropbox.com/s/gvz2805gj39hbc4/HospitalCareForChildrenPocketBooks.pdf?dl=1",
"https://www.dropbox.com/s/avlj81qctl83otk/NelsonTextbookofPediatrics.pdf?dl=1",
"https://www.dropbox.com/s/j0e5p9hx6jwf2kg/TheCareAndFeedingOfChildren.pdf?dl=1",
"https://www.dropbox.com/s/xtfurbb0umbns03/WHOMalnutritionGuidelines.pdf?dl=1"
};
Integer[] imageId = {
R.drawable.book,
R.drawable.book,
R.drawable.book,
R.drawable.book,
R.drawable.book,
R.drawable.book,
R.drawable.book,
R.drawable.book
};
void filSdCard() {
mProgressDialog = new ProgressDialog(MainActivity.this);
mProgressDialog.setIndeterminate(true);
mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
mProgressDialog.setCancelable(true);
if (counter < urls.length) {
final Downloader downloadTask = new Downloader(MainActivity.this, mProgressDialog, titles[counter], urls[counter],counter);
downloadTask.delegate = MainActivity.this;
downloadTask.execute();
mProgressDialog.setOnCancelListener(new DialogInterface.OnCancelListener() {
@Override
public void onCancel(DialogInterface dialog) {
downloadTask.cancel(true);
}
});
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.pdfviewer);
CustomList adapter = new
CustomList(MainActivity.this, web, imageId);
list = (ListView) findViewById(R.id.listvid);
list.setAdapter(adapter);
list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
//give the title according to the title of your disease. every file
should have different title.
if (ifFileExists(titles[position])) {
String filePath = Environment.getExternalStorageDirectory() + "/Pediatric/" + "helptextbookpedortho.pdf";
Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(filePath));
intent.setDataAndType(Uri.parse(filePath), "application/pdf");
startActivity(intent);
} else {
//constructor contains url as well as title with which the file will be saved. make sure you give the same title here and above.
//Also look at the url im using. you can see these files on your dropbox and see we have a different url. upload file to dropbox and make it public to get url, then compare it with any
//of these urls, you will know what to replace.
filSdCard();
}
}
});
}
boolean ifFileExists(String title) {
String root = Environment.getExternalStorageDirectory().toString();
File myDir = new File(root + "/Pediatric");
myDir.mkdirs();
File file = new File(myDir, title);
if (file.exists()) {
return true;
} else
return false;
}
@Override
public void processFinish(String output) {
if (output.equals("Success")) {
if (counter < urls.length) {
counter = counter + 1;
filSdCard();
}
} else {
if(mProgressDialog.isShowing())
mProgressDialog.dismiss();
Toast.makeText(getApplicationContext(), "Some error occured!", Toast.LENGTH_LONG).show();
}
}
private class DataModel {
String Title = "";
String Url = "";
public String getTitle() {
return Title;
}
public void setTitle(String title) {
Title = title;
}
public String getUrl() {
return Url;
}
public void setUrl(String url) {
Url = url;
}
}
}
}
Downloader.java
package com.example.mahvishponum.pdfviewer;
import android.app.ProgressDialog;
import android.content.Context;
import android.os.AsyncTask;
import android.os.Environment;
import android.os.PowerManager;
import android.widget.Toast;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
/**
* Created by Mahvish on 6/6/2017.
*/
public class Downloader extends AsyncTask<String, Integer, String> {
ProgressDialog mProgressDialog;
private Context context;
String title="";
public AsyncResponse delegate = null;
int counter=0;
private PowerManager.WakeLock mWakeLock;
String urlString ="";
public Downloader(Context context, ProgressDialog mProgressDialog, String
title, String urlString, int counter) {
this.context = context;
this.mProgressDialog = mProgressDialog;
this.title = title;
this.urlString = urlString;
this.counter = counter;
}
@Override
protected String doInBackground(String... sUrl) {
InputStream input = null;
OutputStream output = null;
HttpURLConnection connection = null;
try {
URL url = new URL(urlString);
connection = (HttpURLConnection) url.openConnection();
connection.connect();
// expect HTTP 200 OK, so we don't mistakenly save error report
// instead of the file
if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) {
return "Server returned HTTP " + connection.getResponseCode()
+ " " + connection.getResponseMessage();
}
// this will be useful to display download percentage
// might be -1: server did not report the length
int fileLength = connection.getContentLength();
// download the file
input = connection.getInputStream();
String root = Environment.getExternalStorageDirectory().toString();
File myDir = new File(root + "/Pediatric");
myDir.mkdirs();
File file = new File(myDir, title);
output = new FileOutputStream(file);
byte data[] = new byte[4096];
long total = 0;
int count;
while ((count = input.read(data)) != -1) {
// allow canceling with back button
if (isCancelled()) {
input.close();
return null;
}
total += count;
// publishing the progress....
if (fileLength > 0) // only if total length is known
publishProgress((int) (total * 100 / fileLength));
output.write(data, 0, count);
}
} catch (Exception e) {
return e.toString();
} finally {
try {
if (output != null)
output.close();
if (input != null)
input.close();
} catch (IOException ignored) {
}
if (connection != null)
connection.disconnect();
}
return null;
}
@Override
protected void onPreExecute() {
super.onPreExecute();
// take CPU lock to prevent CPU from going off if the user
// presses the power button during download
PowerManager pm = (PowerManager)
context.getSystemService(Context.POWER_SERVICE);
mWakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
getClass().getName());
mWakeLock.acquire();
mProgressDialog.setMessage("Downloading "+(counter+1)+"/"+8 );
mProgressDialog.show();
}
@Override
protected void onProgressUpdate(Integer... progress) {
super.onProgressUpdate(progress);
// if we get here, length is known, now set indeterminate to false
mProgressDialog.setIndeterminate(false);
mProgressDialog.setMax(100);
mProgressDialog.setSecondaryProgress(30);
mProgressDialog.setProgress(progress[0]);
}
@Override
protected void onPostExecute(String result) {
mWakeLock.release();
mProgressDialog.dismiss();
if (result != null) {
Toast.makeText(context, "Download error: " + result,
Toast.LENGTH_LONG).show();
delegate.processFinish("Error");
} else {
delegate.processFinish("Success");
/* String mediaPath = Environment.getExternalStorageDirectory() +
"/Pediatric/" + title;
Intent intent = new Intent(Intent.ACTION_VIEW,
Uri.parse(mediaPath));
intent.setDataAndType(Uri.parse(mediaPath), "video/mp4");
context. startActivity(intent);*/
}
}
}
AsyncResponse Inteerface
package com.example.mahvishponum.pdfviewer;
/**
* Created by Mahvish on 12/22/2016.
*/
public interface AsyncResponse {
void processFinish(String output);
}
pdfviewer.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<ListView
android:id="@+id/listvid"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
</ListView>
</RelativeLayout>
Menifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.mahvishponum.pdfviewer">
<uses-permission android:name="android.permission.WAKE_LOCK"/>
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
CustomList.java
package com.example.mahvishponum.pdfviewer;
import android.app.Activity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;
public class CustomList extends ArrayAdapter<String>{
private final Activity context;
private final String[] web;
private final Integer[] imageId;
public CustomList(Activity context,
String[] web, Integer[] imageId) {
super(context, R.layout.list_single, web);
this.context = context;
this.web = web;
this.imageId = imageId;
}
@Override
public View getView(int position, View view, ViewGroup parent) {
LayoutInflater inflater = context.getLayoutInflater();
View rowView= inflater.inflate(R.layout.list_single, null, true);
TextView txtTitle = (TextView) rowView.findViewById(R.id.txt);
ImageView imageView = (ImageView) rowView.findViewById(R.id.img);
txtTitle.setText(web[position]);
imageView.setImageResource(imageId[position]);
return rowView;
}
}
list_single.xml
<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TableRow>
<ImageView
android:id="@+id/img"
android:layout_width="50dp"
android:layout_height="50dp"/>
<TextView
android:id="@+id/txt"
android:layout_width="wrap_content"
android:layout_height="50dp" />
</TableRow>
</TableLayout>
答案 0 :(得分：0)
您可以从普通数据文件管理器/自己的文件中打开它吗？如果这不起作用，则下载出错
此处将代码更改为MainActivity中的代码：
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
CustomList adapter = new CustomList(MainActivity.this, web, imageId);
list = (ListView) findViewById(R.id.listvid);
list.setAdapter(adapter);
list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
//give the title according to the title of your disease. every file
//should have different title.
if (ifFileExists(titles[position])) {
String filePath = Environment.getExternalStorageDirectory() + "/Pediatric/" + "helptextbookpedortho.pdf";
File f = new File(filePath);
Log.d("Main","file exits " + f.exists());
Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(filePath));
intent.setDataAndType(Uri.fromFile(f), "application/pdf");
//intent.setDataAndType(Uri.parse(filePath), "application/pdf");
startActivity(intent);
} else {
//constructor contains url as well as title with which the file will be saved. make sure you give the same title here and above.
//Also look at the url im using. you can see these files on your dropbox and see we have a different url. upload file to dropbox and make it public to get url, then compare it with any
//of these urls, you will know what to replace.
filSdCard();
}
}
});
}
我改变了这句话：
File f = new File(filePath);
intent.setDataAndType(Uri.fromFile(f), "application/pdf");