从外部存储打开图像

Question

I've been trying for several hours to open an image from Android's external storage with Intent.ACTION_VIEW . And as you might have figured out already, I'm still not able to do that.

I've searched all over Google and I've tried a lot of ways to make this work, however none of them did. All what I could find are questions that are up to 1 year old. I tried using FileProvider and here's what I ended up with:

File imagePath = new File(Environment.getExternalStorageDirectory(), "LyceeLamartine/cache");
File newFile = new File(imagePath, "calendrier.png");
Uri contentUri = FileProvider.getUriForFile(MainActivity.this, "ml.toufic.lyceelamartine.fileprovider", newFile);

Intent intent = new Intent();
intent.setAction(Intent.ACTION_VIEW);
intent.setDataAndType(contentUri, "image/*");
startActivity(intent);

The code above opens Google Photos successfully but it shows a black screen and the path seems to be: content://ml.toufic.lyceelamartine.fileprovider/name/calendrier.png and this seems like an internal storage path.

The image I want to access is stored at: "/storage/emulated/0/LyceeLamartine/cache/calendrier.png" and I'm using a phone with Android O (8.0).

I'm still a beginner in Java and any help would be greatly appreciated!

Answer 1

the path seems to be: content://ml.toufic.lyceelamartine.fileprovider/name/calendrier.png and this seems like an internal storage path.

That is not a path. That is a Uri . It has a scheme ( content ). It points to your FileProvider ( ml.toufic.lyceelamartine.fileprovider ). It seems fine — if there were a problem with the Uri , FileProvider would have thrown an exception when you tried to create it.

The code above opens Google Photos successfully but it shows a black screen

There are two problems with your Intent .

First, do not use a wildcard MIME type. It is your file. You know what the MIME type is. Use the actual MIME type (in this case, image/png ).

Second, call addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION) on the Intent as part of setting it up, before calling startActivity() . Right now, no app has rights to use your content.