fix NPE in MediaUtils.getMediaSize

app/src/main/java/com/keylesspalace/tusky/ComposeActivity.java

@@ -1355,11 +1355,11 @@ public final class ComposeActivity extends BaseActivity
 
 
     private void pickMedia(Uri uri, long mediaSize) {
-        ContentResolver contentResolver = getContentResolver();
         if (mediaSize == MediaUtils.MEDIA_SIZE_UNKNOWN) {
             displayTransientError(R.string.error_media_upload_opening);
             return;
         }
+        ContentResolver contentResolver = getContentResolver();
         String mimeType = contentResolver.getType(uri);
         if (mimeType != null) {
             String topLevelType = mimeType.substring(0, mimeType.indexOf('/'));

app/src/main/java/com/keylesspalace/tusky/util/MediaUtils.java

@@ -24,6 +24,7 @@ import android.media.MediaMetadataRetriever;
 import android.media.ThumbnailUtils;
 import android.net.Uri;
 import android.provider.OpenableColumns;
+import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.annotation.Px;
 
@@ -66,7 +67,8 @@ public class MediaUtils {
      *
      * @return the size of the media or {@link MediaUtils#MEDIA_SIZE_UNKNOWN}
      */
-    public static long getMediaSize(ContentResolver contentResolver, Uri uri) {
+    public static long getMediaSize(@NonNull ContentResolver contentResolver, @Nullable Uri uri) {
+        if(uri == null) return MEDIA_SIZE_UNKNOWN;
         long mediaSize;
         Cursor cursor = contentResolver.query(uri, null, null, null, null);
         if (cursor != null) {