[@capacitor/share] Android: sharing several images with text to WhatsApp only sends the text (intent type forced to */*) #2605

Bug Report

Plugin(s)

@capacitor/share 8.0.2

Capacitor Version

Latest Dependencies:
  @capacitor/cli: 8.5.2
  @capacitor/core: 8.5.2
  @capacitor/android: 8.5.2
  @capacitor/ios: 8.5.2
Installed Dependencies:
  @capacitor/ios: not installed
  @capacitor/cli: 8.5.2
  @capacitor/core: 8.5.2
  @capacitor/android: 8.5.2

Platform(s)

Android

Current Behavior

Sharing several image files together with a text to WhatsApp only delivers the text: WhatsApp drops all the images. Sharing a single image with the same text works.

In SharePlugin.shareFiles, the intent type is forced to */* as soon as more than one file is shared, even when every file has a known MIME type:

String type = getMimeType(file);
if (type == null || filesList.size() > 1) {
    type = "*/*";
}
intent.setType(type);

With three JPEG files, the ACTION_SEND_MULTIPLE intent is sent as */*, and WhatsApp treats it as a text-only share.

We confirmed it on a physical Android phone. Our logs showed the three files written to the cache and passed to Share.share, the plugin resolving with activityType: com.whatsapp, and still only the text reaching the conversation.

Expected Behavior

The intent should carry the common MIME type of the shared files, as Chrome's Web Share does: image/jpeg when all files are JPEG, image/* when they are mixed image types, and */* only when the types differ or are unknown. WhatsApp then receives all the images with the text.

Code Reproduction

import { Directory, Filesystem } from '@capacitor/filesystem'
import { Share } from '@capacitor/share'

// three small JPEGs written to the cache
const uris = []
for (const name of ['a.jpg', 'b.jpg', 'c.jpg']) {
  const { uri } = await Filesystem.writeFile({ path: `share/${name}`, data: JPEG_BASE64, directory: Directory.Cache, recursive: true })
  uris.push(uri)
}
await Share.share({ text: 'Three photos', files: uris })
// choose WhatsApp → only "Three photos" is sent
// with files: [uris[0]] → the photo and the text are sent

Other Technical Details

The following change fixes it for us. We apply it with patch-package, and three images plus the text now reach WhatsApp:

-                    String type = getMimeType(file);
-                    if (type == null || filesList.size() > 1) {
-                        type = "*/*";
-                    }
-                    intent.setType(type);
+                    String type = getMimeType(file);
+                    if (type == null) {
+                        sharedType = "*/*";
+                    } else if (sharedType == null) {
+                        sharedType = type;
+                    } else if (!sharedType.equals(type)) {
+                        boolean bothImages = sharedType.startsWith("image/") && type.startsWith("image/");
+                        sharedType = bothImages ? "image/*" : "*/*";
+                    }
+                    intent.setType(sharedType);

(sharedType is a String declared as null before the loop.)

We also set a ClipData covering every URI for ACTION_SEND_MULTIPLE, since the plugin currently only does it for a single file. That was not enough on its own: the MIME type was the deciding factor.

if (fileUris.size() > 1) {
    ClipData clipData = ClipData.newRawUri("", fileUris.get(0));
    for (int i = 1; i < fileUris.size(); i++) {
        clipData.addItem(new ClipData.Item(fileUris.get(i)));
    }
    intent.setClipData(clipData);
    intent.putParcelableArrayListExtra(Intent.EXTRA_STREAM, fileUris);
}

Related: #2474 (unknown extensions also fall back to */*, which WhatsApp likewise discards).