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android URLからPDFをダウンロードし、PDFリーダーで開きます

URLからPDFをダウンロードし、SDに保存し、Adobe PDFリーダーまたはPDFを開くことができる他のアプリで開くためのアプリを作成しようとしています。

今まで、「Sdカードに正常にダウンロードして保存しました」（ただし、pdfリーダーでPDFを開こうとすると、リーダーがクラッシュし、予期しないエラーが発生すると言うたびに）、たとえば、 http：// maven.Apache.org/maven-1.x/maven.pdf

これが私のダウンローダーのコードです：

//........code set ui stuff
//........code set ui stuff
     new DownloadFile().execute(fileUrl, fileName); 


private class DownloadFile extends AsyncTask<String, Void, Void>{

        @Override
        protected Void doInBackground(String... strings) {
            String fileUrl = strings[0];   // -> http://maven.Apache.org/maven-1.x/maven.pdf
            String fileName = strings[1];  // -> maven.pdf
            String extStorageDirectory = Environment.getExternalStorageDirectory().toString();
            File folder = new File(extStorageDirectory, "testthreepdf");
            folder.mkdir();

            File pdfFile = new File(folder, fileName);

            try{
                pdfFile.createNewFile();
            }catch (IOException e){
                e.printStackTrace();
            }
            FileDownloader.downloadFile(fileUrl, pdfFile);
            return null;
        }
    }



public class FileDownloader {
    private static final int  MEGABYTE = 1024 * 1024;

    public static void downloadFile(String fileUrl, File directory){
        try {

            URL url = new URL(fileUrl);
            HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();
            urlConnection.setRequestMethod("GET");
            urlConnection.setDoOutput(true);
            urlConnection.connect();

            InputStream inputStream = urlConnection.getInputStream();
            FileOutputStream fileOutputStream = new FileOutputStream(directory);
            int totalSize = urlConnection.getContentLength();

            byte[] buffer = new byte[MEGABYTE];
            int bufferLength = 0;
            while((bufferLength = inputStream.read(buffer))>0 ){
                fileOutputStream.write(buffer, 0, bufferLength);
            }
            fileOutputStream.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

デバッグモードでは、アプリがダウンロードしたのを見て、このpdfを/storage/sdcard/testpdf/maven.pdfに保存できますが、ダウンロード中にファイルが何らかの形で破損している可能性があるため、正しく開きません...

他のリーダーアプリで開くためのコードは次のとおりです。

File pdfFile = new File(Environment.getExternalStorageDirectory() + "/testthreepdf/" + fileName);  // -> filename = maven.pdf
                    Uri path = Uri.fromFile(pdfFile);
                    Intent pdfIntent = new Intent(Intent.ACTION_VIEW);
                    pdfIntent.setDataAndType(path, "application/pdf");
                    pdfIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

                    try{
                        startActivity(pdfIntent);
                    }catch(ActivityNotFoundException e){
                        Toast.makeText(documentActivity, "No Application available to view PDF", Toast.LENGTH_SHORT).show();
                    }
androidpdfdownloadhttpurlconnectionfileinputstream
33
sefirosu

こんにちは、問題はFileDownloaderクラスにあります

 urlConnection.setRequestMethod("GET");
    urlConnection.setDoOutput(true);

上記の2行を削除する必要があり、すべて正常に機能します。期待どおりに機能する場合は、質問に回答済みのマークを付けてください。

同じ問題の最新のソリューションが更新されました Android PDF Write/Read using Android 9（API level 28）

作業コードをスクリーンショットに添付します。

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MainActivity.Java

package com.example.downloadread;

import Java.io.File;
import Java.io.IOException;

import Android.app.Activity;
import Android.content.ActivityNotFoundException;
import Android.content.Intent;
import Android.net.Uri;
import Android.os.AsyncTask;
import Android.os.Bundle;
import Android.os.Environment;
import Android.view.Menu;
import Android.view.View;
import Android.widget.Toast;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    public void download(View v)
    {
        new DownloadFile().execute("http://maven.Apache.org/maven-1.x/maven.pdf", "maven.pdf"); 
    }

    public void view(View v)
    {
        File pdfFile = new File(Environment.getExternalStorageDirectory() + "/testthreepdf/" + "maven.pdf");  // -> filename = maven.pdf
        Uri path = Uri.fromFile(pdfFile);
        Intent pdfIntent = new Intent(Intent.ACTION_VIEW);
        pdfIntent.setDataAndType(path, "application/pdf");
        pdfIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

        try{
            startActivity(pdfIntent);
        }catch(ActivityNotFoundException e){
            Toast.makeText(MainActivity.this, "No Application available to view PDF", Toast.LENGTH_SHORT).show();
        }
    }

    private class DownloadFile extends AsyncTask<String, Void, Void>{

        @Override
        protected Void doInBackground(String... strings) {
            String fileUrl = strings[0];   // -> http://maven.Apache.org/maven-1.x/maven.pdf
            String fileName = strings[1];  // -> maven.pdf
            String extStorageDirectory = Environment.getExternalStorageDirectory().toString();
            File folder = new File(extStorageDirectory, "testthreepdf");
            folder.mkdir();

            File pdfFile = new File(folder, fileName);

            try{
                pdfFile.createNewFile();
            }catch (IOException e){
                e.printStackTrace();
            }
            FileDownloader.downloadFile(fileUrl, pdfFile);
            return null;
        }
    }


}

FileDownloader.Java

package com.example.downloadread;

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 FileDownloader {
    private static final int  MEGABYTE = 1024 * 1024;

    public static void downloadFile(String fileUrl, File directory){
        try {

            URL url = new URL(fileUrl);
            HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();
            //urlConnection.setRequestMethod("GET");
            //urlConnection.setDoOutput(true);
            urlConnection.connect();

            InputStream inputStream = urlConnection.getInputStream();
            FileOutputStream fileOutputStream = new FileOutputStream(directory);
            int totalSize = urlConnection.getContentLength();

            byte[] buffer = new byte[MEGABYTE];
            int bufferLength = 0;
            while((bufferLength = inputStream.read(buffer))>0 ){
                fileOutputStream.write(buffer, 0, bufferLength);
            }
            fileOutputStream.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:Android="http://schemas.Android.com/apk/res/Android"
    package="com.example.downloadread"
    Android:versionCode="1"
    Android:versionName="1.0" >

    <uses-sdk
        Android:minSdkVersion="14"
        Android:targetSdkVersion="18" />
    <uses-permission Android:name="Android.permission.INTERNET"></uses-permission>
    <uses-permission Android:name="Android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>
    <uses-permission Android:name="Android.permission.ACCESS_NETWORK_STATE"></uses-permission>
    <uses-permission Android:name="Android.permission.READ_PHONE_STATE"></uses-permission>
    <application
        Android:allowBackup="true"
        Android:icon="@drawable/ic_launcher"
        Android:label="@string/app_name"
        Android:theme="@style/AppTheme" >
        <activity
            Android:name="com.example.downloadread.MainActivity"
            Android:label="@string/app_name" >
            <intent-filter>
                <action Android:name="Android.intent.action.MAIN" />

                <category Android:name="Android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

activity_main.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" >

    <Button
        Android:id="@+id/button1"
        Android:layout_width="match_parent"
        Android:layout_height="wrap_content"
        Android:layout_alignParentLeft="true"
        Android:layout_alignParentTop="true"
        Android:layout_marginTop="15dp"
        Android:text="download"
        Android:onClick="download" />

    <Button
        Android:id="@+id/button2"
        Android:layout_width="match_parent"
        Android:layout_height="wrap_content"
        Android:layout_alignParentLeft="true"
        Android:layout_alignParentRight="true"
        Android:layout_below="@+id/button1"
        Android:layout_marginTop="38dp"
        Android:text="view"
        Android:onClick="view" />

</RelativeLayout>
71
Zack Dawood

これはPDFファイルをダウンロードして表示するための最良の方法です。

PDFTools.showPDFUrl(context, url);

以下にコードを配置します。それはうまくいきます

public class PDFTools {
private static final String TAG = "PDFTools";
private static final String GOOGLE_DRIVE_PDF_READER_PREFIX = "http://drive.google.com/viewer?url=";
private static final String PDF_MIME_TYPE = "application/pdf";
private static final String HTML_MIME_TYPE = "text/html";


public static void showPDFUrl(final Context context, final String pdfUrl ) {
    if ( isPDFSupported( context ) ) {
        downloadAndOpenPDF(context, pdfUrl);
    } else {
        askToOpenPDFThroughGoogleDrive( context, pdfUrl );
    }
}


@TargetApi(Build.VERSION_CODES.Gingerbread)
public static void downloadAndOpenPDF(final Context context, final String pdfUrl) {
    // Get filename
    //final String filename = pdfUrl.substring( pdfUrl.lastIndexOf( "/" ) + 1 );
    String filename = "";
    try {
        filename = new GetFileInfo().execute(pdfUrl).get();
    } catch (InterruptedException e) {
        e.printStackTrace();
    } catch (ExecutionException e) {
        e.printStackTrace();
    }
    // The place where the downloaded PDF file will be put
    final File tempFile = new File( context.getExternalFilesDir( Environment.DIRECTORY_DOWNLOADS ), filename );
    Log.e(TAG,"File Path:"+tempFile);
    if ( tempFile.exists() ) {
        // If we have downloaded the file before, just go ahead and show it.
        openPDF( context, Uri.fromFile( tempFile ) );
        return;
    }

    // Show progress dialog while downloading
    final ProgressDialog progress = ProgressDialog.show( context, context.getString( R.string.pdf_show_local_progress_title ), context.getString( R.string.pdf_show_local_progress_content ), true );

    // Create the download request
    DownloadManager.Request r = new DownloadManager.Request( Uri.parse( pdfUrl ) );
    r.setDestinationInExternalFilesDir( context, Environment.DIRECTORY_DOWNLOADS, filename );
    final DownloadManager dm = (DownloadManager) context.getSystemService( Context.DOWNLOAD_SERVICE );
    BroadcastReceiver onComplete = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            if ( !progress.isShowing() ) {
                return;
            }
            context.unregisterReceiver( this );

            progress.dismiss();
            long downloadId = intent.getLongExtra( DownloadManager.EXTRA_DOWNLOAD_ID, -1 );
            Cursor c = dm.query( new DownloadManager.Query().setFilterById( downloadId ) );

            if ( c.moveToFirst() ) {
                int status = c.getInt( c.getColumnIndex( DownloadManager.COLUMN_STATUS ) );
                if ( status == DownloadManager.STATUS_SUCCESSFUL ) {
                    openPDF( context, Uri.fromFile( tempFile ) );
                }
            }
            c.close();
        }
    };
    context.registerReceiver( onComplete, new IntentFilter( DownloadManager.ACTION_DOWNLOAD_COMPLETE ) );

    // Enqueue the request
    dm.enqueue( r );
}


public static void askToOpenPDFThroughGoogleDrive( final Context context, final String pdfUrl ) {
    new AlertDialog.Builder( context )
            .setTitle( R.string.pdf_show_online_dialog_title )
            .setMessage( R.string.pdf_show_online_dialog_question )
            .setNegativeButton( R.string.pdf_show_online_dialog_button_no, null )
            .setPositiveButton( R.string.pdf_show_online_dialog_button_yes, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    openPDFThroughGoogleDrive(context, pdfUrl);
                }
            })
            .show();
}

public static void openPDFThroughGoogleDrive(final Context context, final String pdfUrl) {
    Intent i = new Intent( Intent.ACTION_VIEW );
    i.setDataAndType(Uri.parse(GOOGLE_DRIVE_PDF_READER_PREFIX + pdfUrl ), HTML_MIME_TYPE );
    context.startActivity( i );
}

public static final void openPDF(Context context, Uri localUri ) {
    Intent i = new Intent( Intent.ACTION_VIEW );
    i.setDataAndType( localUri, PDF_MIME_TYPE );
    context.startActivity( i );
}

public static boolean isPDFSupported( Context context ) {
    Intent i = new Intent( Intent.ACTION_VIEW );
    final File tempFile = new File( context.getExternalFilesDir( Environment.DIRECTORY_DOWNLOADS ), "test.pdf" );
    i.setDataAndType( Uri.fromFile( tempFile ), PDF_MIME_TYPE );
    return context.getPackageManager().queryIntentActivities( i, PackageManager.MATCH_DEFAULT_ONLY ).size() > 0;
}

// get File name from url
static class GetFileInfo extends AsyncTask<String, Integer, String>
{
    protected String doInBackground(String... urls)
    {
        URL url;
        String filename = null;
        try {
            url = new URL(urls[0]);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.connect();
            conn.setInstanceFollowRedirects(false);
            if(conn.getHeaderField("Content-Disposition")!=null){
                String depo = conn.getHeaderField("Content-Disposition");

                String depoSplit[] = depo.split("filename=");
                filename = depoSplit[1].replace("filename=", "").replace("\"", "").trim();
            }else{
                filename = "download.pdf";
            }
        } catch (MalformedURLException e1) {
            e1.printStackTrace();
        } catch (IOException e) {
        }
        return filename;
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
    }
    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);
        // use result as file name
    }
}

}

それを試してみてください。それは動作します、お楽しみください

9
Jijo

ここからソースコードをダウンロードします（ RLからPDFを開くAndroidプログラムで ）

MainActivity.Java

package com.deepshikha.openpdf;

import Android.support.v7.app.AppCompatActivity;
import Android.os.Bundle;
import Android.view.View;
import Android.webkit.WebView;
import Android.webkit.WebViewClient;
import Android.widget.ProgressBar;

public class MainActivity extends AppCompatActivity {
    WebView webview;
    ProgressBar progressbar;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        webview = (WebView)findViewById(R.id.webview);
        progressbar = (ProgressBar) findViewById(R.id.progressbar);
        webview.getSettings().setJavaScriptEnabled(true);
        String filename ="http://www3.nd.edu/~cpoellab/teaching/cse40816/Android_tutorial.pdf";
        webview.loadUrl("http://docs.google.com/gview?embedded=true&url=" + filename);

        webview.setWebViewClient(new WebViewClient() {

            public void onPageFinished(WebView view, String url) {
                // do your stuff here
                progressbar.setVisibility(View.GONE);
            }
        });

    }
}

ありがとう！

3
Deepshikha Puri