问题
I have between one and three photos I'd like my app to display. I won't know until runtime exactly how many photos are downloaded from the Internet.
I can't figure out how to create an Intent to display the photos. Right now I'm caching them on the sdcard under a folder I create by doing something like (sans error checking):
final File externalDirectory = Environment.getExternalStorageDirectory();
final String folder = externalDirectory.getAbsolutePath() + "/Android/data/" + packageName + "/files/";
This was explained in the Android Developer Reference.
I can get one photo to display by doing the following:
final Uri uri = Uri.fromFile(file);
final Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(uri, "image/*");
Util.startActivity(this, intent);
Where file is the file of a saved photo.
If it helps, I could save the images to any location available to my app, however I would prefer to not have the photos show up listed with the user's other personal photos as that may be annoying.
The Image Viewer has a menu option "Slideshow", so it must know about multiple photos.
I could create my own Image Viewer, but that seems like extra work and beyond what I would I reasonably expect. Even if I did this, I would like the user to be able to install a 3rd party Image Viewer and get a better experience with pan, zoom, share, ...
I tried using the directory of the cached photo files to create the Uri, but the Image Viewer shows a black page. If I pass in the file, it shows just that one file and no others.
I know this must be possible because I can see use the Gallery app and show the photos if I manually select the folder. Everytime I research this issue, the comments say it's not possible to show multiple images.
I suspect there's some magic incantation, but what?
回答1:
I think your goal is out of your control. If the viewer app is designed to handle mutiple images or a directory, you may ask it to show as you want, but you are defined to the viewer's pattern.
I have installed a third-party image viewer called QuickPic. I just tested your code snippet and the system popped up a chooser dialog to let me select the app to show the images in the folder. If I select native gallery, what I see is just an empty folder, while the Quickpic works as I want.
PS: I tell my app the Uri of the folder this way:
intent.setDataAndType(Uri.fromFile(new File("//mnt/sdcard/test/")), MimeTypeMap.getSingleton().getMimeTypeFromExtension("png"));
来源：https://stackoverflow.com/questions/9550557/android-action-view-multiple-images