Sharing images from internal storage using FileProvider

问题

I have some files stored in my application's internal storage that I would like to open in an external application (sending an image to the Gallery for viewing, for example.) I've set up a FileProvider to do so.

From AndroidManifest.xml:

<application>
  ...
    <provider
        android:name="android.support.v4.content.FileProvider"
        android:authorities="${packageName}"
        android:exported="false"
        android:grantUriPermissions="true">

        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/files"/>

    </provider>
</application>

From res/xml/files.xml:

<paths>
    <files-path name="internal_logs" path="logs/"/>
    <files-path name="shared_files" path="shared/"/>
</paths>

From the Fragment where I attempt to open the file:

File sharedFolderPath = new File(getActivity().getFilesDir(), "shared");
File toOpen = new File(sharedFolderPath.getAbsolutePath(), sharedFile.getFileName());

if (toOpen.exists()) {
    Log.w("File exists: " + toOpen.getAbsolutePath());

    Uri fileUri = FileProvider.getUriForFile(getActivity(), BuildConfig.PACKAGE_NAME, toOpen);

    Log.w("Attempting to attach file " + fileUri.getEncodedPath() + " with mime type: " + URLConnection.guessContentTypeFromName(fileUri.toString()));

    Intent viewFile = new Intent(Intent.ACTION_VIEW);

    viewFile.setData(fileUri);
    viewFile.setType(URLConnection.guessContentTypeFromName(fileUri.toString()));
    viewFile.putExtra(Intent.EXTRA_STREAM, fileUri);
    viewFile.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    viewFile.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);

    try {
        startActivity(viewFile);
    } catch (android.content.ActivityNotFoundException ex) {
        Toast.makeText(getActivity(), "Please install an appropriate application to open this file.", Toast.LENGTH_SHORT).show();
    }
} else {
    log.w("File does not exist: " + toOpen.getAbsolutePath());
    Toast.makeText(getActivity(), "file not found.", Toast.LENGTH_SHORT).show();
}

From the logcat output (sharing to the Gallery app):

PACKAGE_NAME W/TAG: File exists: /data/data/PACKAGE_NAME/files/shared/IMG_20140506_141221.jpg
PACKAGE_NAME W/TAG: Attempting to attach file /shared_files/IMG_20140506_141221.jpg with mime type: image/jpeg
778-791/? I/PackageManager﹕ Action: "android.intent.action.VIEW"
778-791/? I/PackageManager﹕ Category: "android.intent.category.DEFAULT"
778-791/? I/PackageManager﹕ Type: "image/jpeg"
778-791/? I/PackageManager﹕ Adding preferred activity ComponentInfo{com.google.android.gallery3d/com.android.gallery3d.app.GalleryActivity} for user 0 :
778-788/? I/ActivityManager﹕ START u0 {act=android.intent.action.VIEW typ=image/jpeg flg=0x3000001 cmp=com.google.android.gallery3d/com.android.gallery3d.app.GalleryActivity (has extras)} from pid 6209
778-1872/? I/ActivityManager﹕ Start proc com.google.android.gallery3d for activity com.google.android.gallery3d/com.android.gallery3d.app.GalleryActivity: pid=10602 uid=10039 gids={50039, 3003, 1028, 1015}
10602-10602/? V/StateManager﹕ startState class com.android.gallery3d.app.AlbumSetPage

What's happening is that the file is found, a URI is generated, and the mimetype is detected correctly; I get an accurate list of handlers from Android, and when I choose "Gallery", the Gallery activity is launched, but it goes straight to the device's own gallery - no error message, but also no open image. This behavior seems consistent with other image viewers - G+ Photos for example.

The really strange thing is if I execute the same code with the Intent ACTION_SEND declared, the file correctly attaches to an email in Gmail. (In fact, this is what I do with my app's internal logging.) So it seems really unlikely that I'm formatting the content URI incorrectly. My best guess is that I'm using the wrong Intent action? But I have no idea what would be better than ACTION_VIEW.

Any ideas?

回答1:

Change setType() to setDataAndType(), and get rid of EXTRA_STREAM. EXTRA_STREAM is used for ACTION_SEND, not ACTION_VIEW, and so the Gallery has no idea what it is that you are asking it to view.

回答2:

There is a good example here: https://developer.android.com/reference/android/support/v4/content/FileProvider.html

来源：https://stackoverflow.com/questions/24496847/sharing-images-from-internal-storage-using-fileprovider