Share Plugin: improvements for Android 11

* Do not ask for WRITE_EXTERNAL_STORAGE in Android 11+ (writing to "Downloads" is [allowed by default since 11](https://stackoverflow.com/questions/70248631/starting-from-android11-do-i-need-to-comply-to-androids-saf-just-to-even-creat)).
* Do not check for permissions before receiving a file. Try and let it error out, instead of silently doing nothing.
* Fix not offering to open content:// urls (we checked the URLs to be file:// urls to then convert them to content://).
* Better permission explanation text.

res/values/strings.xml

@@ -316,7 +316,7 @@
     <string name="permission_explanation">This plugin needs permissions to work</string>
     <string name="optional_permission_explanation">You need to grant extra permissions to enable all functions</string>
     <string name="plugins_need_optional_permission">Some plugins have features disabled because of lack of permission (tap for more info):</string>
-    <string name="share_optional_permission_explanation">To receive shared files you need to choose a destination directory</string>
+    <string name="share_optional_permission_explanation">To receive files you need to allow storage access</string>
     <string name="telepathy_permission_explanation">To read and write SMS from your desktop you need to give permission to SMS</string>
     <string name="telephony_permission_explanation">To see phone calls on the desktop you need to give permission to phone call logs and phone state</string>
     <string name="telephony_optional_permission_explanation">To see a contact name instead of a phone number you need to give access to the phone\'s contacts</string>

src/org/kde/kdeconnect/Plugins/SharePlugin/ReceiveNotification.java

@@ -132,20 +132,15 @@ class ReceiveNotification {
             }
         }
 
-        if (!"file".equals(destinationUri.getScheme())) {
-            return;
-        }
-
         Intent intent = new Intent(Intent.ACTION_VIEW);
         Intent shareIntent = new Intent(Intent.ACTION_SEND);
         shareIntent.setType(mimeType);
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N && "file".equals(destinationUri.getScheme())) {
             //Nougat and later require "content://" uris instead of "file://" uris
             File file = new File(destinationUri.getPath());
             Uri contentUri = FileProvider.getUriForFile(device.getContext(), "org.kde.kdeconnect_tp.fileprovider", file);
             intent.setDataAndType(contentUri, mimeType);
             intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
-
             shareIntent.putExtra(Intent.EXTRA_STREAM, contentUri);
         } else {
             intent.setDataAndType(destinationUri, mimeType);

src/org/kde/kdeconnect/Plugins/SharePlugin/SharePlugin.java

@@ -13,7 +13,9 @@ import android.content.Context;
 import android.content.Intent;
 import android.graphics.drawable.Drawable;
 import android.net.Uri;
+import android.os.Build;
 import android.os.Bundle;
+import android.os.Environment;
 import android.os.Handler;
 import android.os.Looper;
 import android.util.Log;
@@ -23,6 +25,7 @@ import androidx.annotation.NonNull;
 import androidx.annotation.WorkerThread;
 import androidx.core.content.ContextCompat;
 
+import org.apache.commons.lang3.ArrayUtils;
 import org.apache.commons.lang3.StringUtils;
 import org.kde.kdeconnect.Helpers.FilesHelper;
 import org.kde.kdeconnect.Helpers.IntentHelper;
@@ -127,12 +130,7 @@ public class SharePlugin extends Plugin {
             }
 
             if (np.has("filename")) {
-                if (isPermissionGranted(Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
                 receiveFile(np);
-                } else {
-                    Log.i("SharePlugin", "no Permission for Storage");
-                }
-
             } else if (np.has("text")) {
                 Log.i("SharePlugin", "hasText");
                 receiveText(np);
@@ -289,8 +287,12 @@ public class SharePlugin extends Plugin {
 
     @Override
     public String[] getOptionalPermissions() {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
+            return ArrayUtils.EMPTY_STRING_ARRAY;
+        } else {
             return new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE};
         }
+    }
 
     private class Callback implements BackgroundJob.Callback<Void> {
         @Override