25

The following code which consists of downloading a file from a server and save it in the storage works fine when the device has an internal storage.
But when I tried it with a device with no internal storage, only with external storage I get the following exception.

java.io.filenotfoundexception open failed eacces (permission denied)

public void downloadFile(String dlUrl, String dlName) {
    int count;

    HttpURLConnection con = null;
    InputStream is = null;
    FileOutputStream fos = null;

    try {
        URL url = new URL( dlUrl );
        con = (HttpURLConnection) url.openConnection();
        con.setDoInput(true);
        con.connect();

        is = url.openStream();
        String dir = Environment.getExternalStorageDirectory() + Util.DL_DIRECTORY;
        File file = new File( dir );
        if( !file.exists() ){
            file.mkdir();
        }

        Util.LOG_W(TAG, "Downloading: " + dlName + " ...");

        fos = new FileOutputStream(file + "/" +  dlName);
        byte data[] = new byte[1024];

        while( (count = is.read(data)) != -1 ){
            fos.write(data, 0, count);
        }

        Util.LOG_D(TAG, dlName + " Download Complete!");


    } catch (Exception e) {
        Util.LOG_E(TAG, "DOWNLOAD ERROR = " + e.toString() );
        bServiceDownloading = false;
    }
    finally{
        try {
            if( is != null)
                is.close();
            if( fos != null)
                fos.close();
            if( con != null)
                con.disconnect();
        } catch (Exception e) {
            Util.LOG_E(TAG, "CLOSE ERROR = " + e.toString() );
        }
    }
}

And in manifest file I has the following:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

Any suggestions what maybe the cause? By the way Environment.getExternalStorageDirectory() returns /mnt/sdcard/ and file.mkdir() return false.

Lazy Ninja
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11 Answers11

37

This attribute is "false" by default on apps targeting Android 10 or higher.

<application android:requestLegacyExternalStorage="true" ... >
    ...
</application>
Boken
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ankush
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17

This problem seems to be caused by several factors.

Check#1
First add this permission in your manifest file and check if it is working:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<application>
    ...

</application>

  .....

Check#2:

If you are running on an emulator, check the properties to see if it has an SD card.

Check#3:

Disable file transfer from device to computer. If Enabled, the app wont be able to access the SD card.

Check#4:
If still not working, try the following:

 String dir = Environment.getExternalStorageDirectory().getAbsolutePath()

For me the following worked:
The problem is that getExternalStorageDirectory returns /mnt/sdcard whereas I need the actual path of external storage which is /mnt/sdcard-ext and there is no API in android that can get me the absolute path of removable sdcard.
My solution was to hard code the directory as follows:

String dir = "/mnt/sdcard-ext" ;

Since the application is intended to work only on one device, the above did the job.
If you encounter the same problem, use an file explorer application to find out the name of the external directory and hard code it.

Lazy Ninja
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10

Use READ_EXTERNAL_STORAGE permission to read data from the device.

Naresh
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    Thanks for your suggestion but unfortunately it doesnt solve the issue. – Lazy Ninja Jul 09 '13 at 05:42
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    "Any app that declares the WRITE_EXTERNAL_STORAGE permission is implicitly granted this permission." http://developer.android.com/reference/android/Manifest.permission.html#READ_EXTERNAL_STORAGE – Dan Osipov Dec 18 '13 at 19:25
6

Did you try it on emulator? Check the properties if it has an SD card. I had the same problem, and it was because the emulator did not have an SD card. Check if yours has or not.

keybee
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4

I had the same problem, and i solved it by disabling file transfer from device to computer. Because if u enable file transfer, sd card is not accessible to debugging application.

toskebre
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3
try
Environment.getExternalStorageDirectory().getAbsolutePath()

and don't forget to add

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
brzhang
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1

Try using mkdirs instead of mkdir. If you are creating a directory path and parent doesn't exist then you should use mkdirs.

Sagar
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1

I suspect you are running Android 6.0 Marshmallow (API 23) or later. If this is the case, you must implement runtime permissions before you try to read/write external storage. https://developer.android.com/training/permissions/requesting.html

1

i have done very silly mistake. I have already put in AndroidManifest.xml

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

and also add permission in java file,as get permission pragmatically. But there is mistake of Manifest.permission.READ_EXTERNAL_STORAGE. Please use Manifest.permission.WRITE_EXTERNAL_STORAGE.

ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, requestCode);
Sanket Sangani
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  • its integer value.Please refer this link https://stackoverflow.com/questions/44309857/request-code-for-permissions-in-android – Sanket Sangani Nov 29 '19 at 08:44
0

I had the same problem. I used the write and read permission in the manifest correctly , yet it didn't work! The solution was very silly: unplug your phone from the PC before running the application. It seems when your phone is connected as "Mass storage" to the PC, the application cannot access the external storage.

devlin carnate
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Gaby
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0

First in your manifest file declare permissions :

 <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE" />

now in header of application tag of manifest file :

android:requestLegacyExternalStorage="true"

now defines provider for your app in between tag of manifest file. as :

 <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_path" />
    </provider>

now create a folder xml in res folder like this : refer to this picture

now create a xml file provider_path.xml and copy below code in it :

<?xml version="1.0" encoding="utf-8"?>
<path>
<external-path
    name="external_files"
    path="." />

now in your activity :

String filename = null ;
URL url = null;
try {
                        url = new URL("http://websitename.com/sample.pdf");
                        filename = url.getPath();
                        filename = filename.substring(filename.lastIndexOf('/')+1);

                    } catch (MalformedURLException e) {
                        e.printStackTrace();
                    }
  File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS)+"/"+filename);
                    if(file.exists()){
                        Uri uri = FileProvider.getUriForFile(context, "com.example.www"+".provider",file);
                        Intent i = new Intent(Intent.ACTION_VIEW);
                        i.setDataAndType(uri, "application/pdf");
                        i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP|Intent.FLAG_GRANT_READ_URI_PERMISSION);
                        context.startActivity(i);
                    }
                    else {
                        //download file here
                        new AlertDialog.Builder(context)
                                .setTitle("Information")
                                .setMessage("Do you want to download this file ?")
                                .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                                    @Override
                                    public void onClick(DialogInterface dialog, int which) {
                                        dialog.dismiss();
                                    }
                                })
                                .setPositiveButton("Continue", new DialogInterface.OnClickListener() {
                                    @Override
                                    public void onClick(DialogInterface dialog, int which) {
                                        DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url+""));
                                        request.setTitle(filename);
                                        request.setMimeType("application/pdf");
                                        request.allowScanningByMediaScanner();
                                        request.setAllowedOverMetered(true);
                                        request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
                                        request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, filename);
                                        DownloadManager downloadManager = (DownloadManager)context.getSystemService(DOWNLOAD_SERVICE);
                                        downloadManager.enqueue(request);
                                    }
                                }).show();

                    }
MANISH
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