Problems displaying pdf files on pdf apps using Android 10

Question

I have been trying to display a pdf file choosing some pdf app installed on my Android 10 mobile phone. This is the code I'm using:

Activity

        File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS) + "/sample.pdf");

                    if(file.exists()) {

                        Uri path = FileProvider.getUriForFile(this, this.getApplicationContext().getPackageName() + ".provider", file);

                        this.grantUriPermission(this.getPackageName(), path, Intent.FLAG_GRANT_READ_URI_PERMISSION);
                        Intent pdfOpenintent = new Intent(Intent.ACTION_VIEW);
                        pdfOpenintent.setFlags(Intent.FLAG_ACTIVITY_NO_HISTORY);
                        pdfOpenintent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION | Intent.FLAG_GRANT_READ_URI_PERMISSION);
                        pdfOpenintent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);


                        pdfOpenintent.setDataAndType(path, "application/pdf");


                        try {
                           // ((Activity) ctx).startActivityForResult(pdfOpenintent, 6);
                           this.startActivity(pdfOpenintent);
                        } catch (ActivityNotFoundException e) {

                        }
                    }  else
                        Toast.makeText(this, "No file found" , Toast.LENGTH_LONG).show();

AndroidManifest

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.VIBRATE" />

........


        <provider
            android:name="android.support.v4.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>

provider_paths

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <external-path name="external_files" path="."/>
</paths>

When I choose one of the pdf apps some of them crashes and If I choose Drive pdf Viewer it shows me the name of the file but the screen gets black, so I presume that I'm not opening in the correct way the pdf apps.

As you can see on the Activity I placed several flags, because it seems that new android versions need some kind of permissions to access internal storage.

Answer 1

setFlags() wipes out any previous flags that you have set on the Intent . So, you have three setFlags() calls, and only the last one matters.

Either:

• Have one setFlags() call, or
• Use addFlags() instead of setFlags() , at least for the second and subsequent calls

Answer 2

Problem solved. This code should be placed on Manifest according to this link :

<!-- This attribute is "false" by default on apps targeting
     Android 10 or higher. -->
  <application android:requestLegacyExternalStorage="true" ... >
    ...
  </application>