三星s8和s9中的Android外部写入权限问题

Question

I have a downloader class in my app that handles downloading new apk from the server into user android devices, to update the app. the whole module works great and grants read-write permission and download and installs the apk with no issue. The only problem is with Galaxy s9 and Galaxy s8 with version 8.0.0, I'm experiencing permission denied exception for external storage. I have tested it with multiple device and SDKs , nexus, nexus 5x, zte, sony Xperia. But It looks like only effects Galaxy S8 and S9.

Error

No permission to write to /storage/emulated/0/Download/app-release.apk: Neither user 10390 nor current process has android.permission.WRITE_EXTERNAL_STORAGE.

Update activity code

    void downloadOrCancel() {

        if (downloader != null && downloader.isDownloading()) {
             cancel();
         } else {
            download();
         }
        //  updateUi();
    }

    private void cancel() {
        if(downloader != null)
                  downloader.cancel();
    }

    private void download() {
        //   Uri uri = Uri.parse(url);
        downloader = Downloader.newInstance(this);
        downloader.download(URL_APK);
    }


    private void checkPErmissions(){
        if (ContextCompat.checkSelfPermission(this,
                Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED
                && ContextCompat.checkSelfPermission(this,
                Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {

            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
                    12);
            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},
                    13);

        } else {
            downloadOrCancel();
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode) {
            case 12:
            case 13: {
                // If request is cancelled, the result arrays are empty.
                if (grantResults.length > 0
                        && grantResults[0] ==
                        PackageManager.PERMISSION_GRANTED) {
                    // get locations
                    checkPErmissions();
                } else {
                    //Close it
                    finish();
                }
            }
            break;
        }
    }

Manifest permissions

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.READ_CONTACTS" />
<uses-permission android:name="android.permission.READ_PROFILE" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.CALL_PHONE" />
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.MANAGE_ACCOUNTS" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.VIBRATE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permissionandroid:name="android.permission.REQUEST_INSTALL_PACKAGES"/>
<uses-permission android:name="android.permission.ACCESS_ALL_DOWNLOADS" />

Answer 1

I looked up some stuff on your code, but everything seems fine to me. I post this as an answer because it's too long for a comment.

The last thing I can suggest is because it happens only on Samsung S8 and S9, maybe it has something to do with the permission to install/download files from unknown sources. In your Samsung go to:

Settings --> Locked Screen and Security --> Install unknown apps

And try to turn it on for your application.