Pass mime type so that SAF treats file extension correctly

app/src/main/java/org/schabi/newpipe/download/DownloadDialog.java

@@ -717,7 +717,7 @@ public class DownloadDialog extends DialogFragment
             }
 
             startActivityForResult(StoredFileHelper.getNewPicker(context, startPath,
-                    filenameTmp), REQUEST_DOWNLOAD_SAVE_AS);
+                    filenameTmp, mimeTmp), REQUEST_DOWNLOAD_SAVE_AS);
 
             return;
         }

app/src/main/java/org/schabi/newpipe/local/subscription/SubscriptionFragment.kt

@@ -191,7 +191,7 @@ class SubscriptionFragment : BaseStateFragment<SubscriptionState>() {
         val date = SimpleDateFormat("yyyyMMddHHmm", Locale.ENGLISH).format(Date())
         val exportName = "newpipe_subscriptions_$date.json"
 
-        startActivityForResult(StoredFileHelper.getNewPicker(activity, null, exportName), REQUEST_EXPORT_CODE)
+        startActivityForResult(StoredFileHelper.getNewPicker(activity, null, exportName, "application/json"), REQUEST_EXPORT_CODE)
     }
 
     private fun openReorderDialog() {

app/src/main/java/org/schabi/newpipe/settings/ContentSettingsFragment.java

@@ -66,7 +66,8 @@ public class ContentSettingsFragment extends BasePreferenceFragment {
         exportDataPreference.setOnPreferenceClickListener((final Preference p) -> {
             final SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.US);
             startActivityForResult(StoredFileHelper.getNewPicker(getContext(), null,
-                    "NewPipeData-" + sdf.format(new Date()) + ".zip"), REQUEST_EXPORT_PATH);
+                    "NewPipeData-" + sdf.format(new Date()) + ".zip", "application/zip"),
+                    REQUEST_EXPORT_PATH);
             return true;
         });
 

app/src/main/java/org/schabi/newpipe/streams/io/StoredFileHelper.java

@@ -467,13 +467,15 @@ public class StoredFileHelper implements Serializable {
         }
     }
 
-    public static Intent getNewPicker(@NonNull final Context ctx, @Nullable final String startPath,
+    public static Intent getNewPicker(@NonNull final Context ctx,
-                                      @Nullable final String filename) {
+                                      @Nullable final String startPath,
+                                      @Nullable final String filename,
+                                      @NonNull final String mimeType) {
         final Intent i;
         if (NewPipeSettings.useStorageAccessFramework(ctx)) {
             i = new Intent(Intent.ACTION_CREATE_DOCUMENT)
                     .putExtra("android.content.extra.SHOW_ADVANCED", true)
-                    .setType("*/*")
+                    .setType(mimeType)
                     .addCategory(Intent.CATEGORY_OPENABLE)
                     .addFlags(Intent.FLAG_GRANT_PERSISTABLE_URI_PERMISSION
                             | StoredDirectoryHelper.PERMISSION_FLAGS);

app/src/main/java/us/shandian/giga/ui/fragment/MissionsFragment.java

@@ -256,7 +256,7 @@ public class MissionsFragment extends Fragment {
         }
 
         startActivityForResult(StoredFileHelper.getNewPicker(mContext, startPath,
-                mission.storage.getName()), REQUEST_DOWNLOAD_SAVE_AS);
+                mission.storage.getName(), mission.storage.getType()), REQUEST_DOWNLOAD_SAVE_AS);
     }
 
     @Override