Sharing Content with Intents

Overview

Intents allow us to communicate data between Android apps and implicit intents can also accept actions. One of those actions is the ACTION_SEND command which indicates we want to send data across apps. To send data, all you need to do is specify the data and its type, and the system will identify compatible receiving activities and display them to the user.

Sending and receiving data between applications with intents is most commonly used for social sharing of content. Intents allow users to share information quickly and easily, using their favorite applications.

Sharing Local Content

You can send content by invoking an implicit intent with ACTION_SEND.

Sending HTML

Intent sharingIntent = new Intent(Intent.ACTION_SEND);
sharingIntent.setType("text/html");
sharingIntent.putExtra(android.content.Intent.EXTRA_TEXT, Html.fromHtml("<p>This is the text shared.</p>"));
startActivity(Intent.createChooser(sharingIntent, "Share using"));

Sending Images

To send images or binary data:

final Intent shareIntent = new Intent(Intent.ACTION_SEND);
shareIntent.setType("image/jpg");
final File photoFile = new File(getFilesDir(), "foo.jpg");
shareIntent.putExtra(Intent.EXTRA_STREAM, Uri.fromFile(photoFile));
startActivity(Intent.createChooser(shareIntent, "Share image using"));

Sending Links

Sending URL links should simply use text/plain type:

Intent shareIntent = new Intent(Intent.ACTION_SEND);
shareIntent.setType("text/plain"); 
shareIntent.putExtra(Intent.EXTRA_TEXT, "http://codepath.com");
startActivity(Intent.createChooser(shareIntent, "Share link using"));

Sharing Multiple Types

In certain cases, we might want to send an image along with text. This can be done with:

String text = "Look at my awesome picture";
Uri pictureUri = Uri.parse("file://my_picture");
Intent shareIntent = new Intent();
shareIntent.setAction(Intent.ACTION_SEND);
shareIntent.putExtra(Intent.EXTRA_TEXT, text);
shareIntent.putExtra(Intent.EXTRA_STREAM, imageUri);
shareIntent.setType("image/*");
shareIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
startActivity(Intent.createChooser(shareIntent, "Share images..."));

Sharing multiple images can be done with:

Intent shareIntent = new Intent(Intent.ACTION_SEND_MULTIPLE);
shareIntent.putParcelableArrayListExtra(Intent.EXTRA_STREAM, imageUris);
shareIntent.setType("image/*");

See this stackoverflow post for more details.

Note: Facebook does not properly recognize multiple shared elements. See this facebook specific bug for more details and share using their SDK.

Share in Facebook

Facebook doesn't work well with normal sharing intents when sharing multiple content elements as discussed in this bug. To share posts with facebook, we need to:

1. Create a new Facebook app here (follow the instructions)
2. Add the Facebook SDK to your Android project
3. Share using this code snippet:

   public void setupFacebookShareIntent() {
        ShareDialog shareDialog;
        FacebookSdk.sdkInitialize(getApplicationContext());
        shareDialog = new ShareDialog(this);

        ShareLinkContent linkContent = new ShareLinkContent.Builder()
                .setContentTitle("Title")
                .setContentDescription(
                        "\"Body Of Test Post\"")
                .setContentUrl(Uri.parse("http://someurl.com/here"))
                .build();
        
        shareDialog.show(linkContent);
    }

Sharing Remote Images

You may want to send an image that were loaded from a remote URL. Assuming you are using a third party library like Glide, here is how you might share an image that came from the network and was loaded into an ImageView. There are two ways to accomplish this. The first way, shown below, takes the bitmap from the view and loads it into a file.

// Get access to ImageView 
ImageView ivImage = (ImageView) findViewById(R.id.ivResult);
// Fire async request to load image
GlideApp.with(context).load(imageUrl).into(ivImage);

and then later assuming after the image has completed loading, this is how you can trigger a share:

// Can be triggered by a view event such as a button press
public void onShareItem(View v) {
    // Get access to bitmap image from view
    ImageView ivImage = (ImageView) findViewById(R.id.ivResult);
    // Get access to the URI for the bitmap
    Uri bmpUri = getLocalBitmapUri(ivImage);
    if (bmpUri != null) {
        // Construct a ShareIntent with link to image
        Intent shareIntent = new Intent();
        shareIntent.setAction(Intent.ACTION_SEND);
        shareIntent.putExtra(Intent.EXTRA_STREAM, bmpUri);
        shareIntent.setType("image/*");
        // Launch sharing dialog for image
        startActivity(Intent.createChooser(shareIntent, "Share Image"));	
    } else {
        // ...sharing failed, handle error
    }
}

// Returns the URI path to the Bitmap displayed in specified ImageView
    public Uri getLocalBitmapUri(ImageView imageView) {
        // Extract Bitmap from ImageView drawable
        Drawable drawable = imageView.getDrawable();
        Bitmap bmp = null;
        if (drawable instanceof BitmapDrawable){
            bmp = ((BitmapDrawable) imageView.getDrawable()).getBitmap();
        } else {
            return null;
        }
        // Store image to default external storage directory
        Uri bmpUri = null;
        try {
            // Use methods on Context to access package-specific directories on external storage.
            // This way, you don't need to request external read/write permission.
            // See https://youtu.be/5xVh-7ywKpE?t=25m25s
            File file =  new File(getExternalFilesDir(Environment.DIRECTORY_PICTURES), "share_image_" + System.currentTimeMillis() + ".png");
            FileOutputStream out = new FileOutputStream(file);
            bmp.compress(Bitmap.CompressFormat.PNG, 90, out);
            out.close();
            // **Warning:** This will fail for API >= 24, use a FileProvider as shown below instead.
            bmpUri = Uri.fromFile(file);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return bmpUri;
    }

// Method when launching drawable within Glide
public Uri getBitmapFromDrawable(Bitmap bmp){

    // Store image to default external storage directory
    Uri bmpUri = null;
    try {
        // Use methods on Context to access package-specific directories on external storage.
        // This way, you don't need to request external read/write permission.
        // See https://youtu.be/5xVh-7ywKpE?t=25m25s
        File file =  new File(getExternalFilesDir(Environment.DIRECTORY_PICTURES), "share_image_" + System.currentTimeMillis() + ".png");
        FileOutputStream out = new FileOutputStream(file);
        bmp.compress(Bitmap.CompressFormat.PNG, 90, out);
        out.close();

        // wrap File object into a content provider. NOTE: authority here should match authority in manifest declaration
        bmpUri = FileProvider.getUriForFile(BookDetailActivity.this, "com.codepath.fileprovider", file);  // use this version for API >= 24 

        // **Note:** For API < 24, you may use bmpUri = Uri.fromFile(file);

    } catch (IOException e) {
        e.printStackTrace();
    }
    return bmpUri;
}

Make sure to setup the "SD Card" within the emulator device settings:

Note that if you are using API 24 or above, see the section below on using a FileProvider to work around new file restrictions.

Sharing Files with API 24 or higher

If you are targeting Android API 24 or higher, private File URI resources (file:///) cannot be shared. You must instead wrap the File object as a content provider (content://) using the FileProvider class.

First, you must declare this FileProvider in your AndroidManifest.xml file within the <application> tag:

<application>

  <!-- make sure within the application tag, otherwise app will crash with XmlResourceParser errors -->
  <provider
    android:name="androidx.core.content.FileProvider"
    android:authorities="com.codepath.fileprovider"
    android:exported="false"
    android:grantUriPermissions="true">
      <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/fileprovider" />
  </provider>
</application>

Next, create a resource directory called xml and create a fileprovider.xml. Assuming you wish to grant access to the application's specific external storage directory, which requires requesting no additional permissions, you can declare this line as follows:

<?xml version="1.0" encoding="utf-8"?>
<paths>
    <!-- See table below.  The external-files-path DOES NOT require external storage permissions. -->
    <external-files-path
        name="images"
        path="Pictures" />

    <!--Uncomment below to share the entire application specific directory -->
    <!--<external-path name="all_dirs" path="."/>-->
</paths>

Finally, you will convert the File object into a content provider using the FileProvider class:

// getExternalFilesDir() + "/Pictures" should match the declaration in fileprovider.xml paths
File file = new File(getExternalFilesDir(Environment.DIRECTORY_PICTURES), "share_image_" + System.currentTimeMillis() + ".png");

// wrap File object into a content provider. NOTE: authority here should match authority in manifest declaration
bmpUri = FileProvider.getUriForFile(MyActivity.this, "com.codepath.fileprovider", file);

If you see a INSTALL_FAILED_CONFLICTING_PROVIDER error when attempting to run the app, change the string com.codepath.fileprovider in your Java and XML files to something more unique, such as com.codepath.fileprovider.YOUR_APP_NAME_HERE.

Note that there are other XML tags you can use in the fileprovider.xml, which map to the File directory specified. In the example above, we use Context.getExternalFilesDir(Environment.DIRECTORY_PICTURES), which corresponded to the <external-files-path> XML tag in the declaration with the Pictures path explicitly specified. Here are all the options you can use too:

XML tag	Corresponding storage call	When to use
<files-path>	Context.getFilesDir()	data can only be viewed by app, deleted when uninstalled (/data/data/[packagename]/files)
<external-files-path>	Context.getExternalFilesDir()	data can be read/write by the app, any apps granted with READ_STORAGE permission can read too, deleted when uninstalled (/Android/data/[packagename]/files)
<cache-path>	Context.getCacheDir()	temporary file storage
<external-path>	Environment.getExternalStoragePublicDirectory()	data can be read/write by the app, any apps can view, files not deleted when uninstalled
<external-cache-path>	Context.getExternalCacheDir()	temporary file storage with usually larger space

If you are using API 23 or above, then you'll need to request runtime permissions for Manifest.permission.READ_EXTERNAL_STORAGE and Manifest.permission.WRITE_EXTERNAL_STORAGE in order to share the image as shown above since newer versions require explicit permisions at runtime for accessing external storage.

Note: There is a common bug on emulators that will cause MediaStore.Images.Media.insertImage to fail with E/MediaStore﹕ Failed to insert image unless the media directory is first initialized as described in the link.

ShareActionProvider

This is how you can easily use an ActionBar share icon to activate a ShareIntent. The below focuses on the support ShareActionProvider for use with AppCompatActivity.

Note: This is an alternative to using a sharing intent as described in the previous section. You either can use a sharing intent or the provider as described below.

First, we need to add an ActionBar menu item in res/menu/ in the XML specifying the ShareActionProvider class.

<menu xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto">

    <item
        android:id="@+id/menu_item_share"
        app:showAsAction="ifRoom"
        android:title="Share"
        app:actionProviderClass="androidx.appcompat.widget.ShareActionProvider" />
    ...
</menu>

Next, get access to share provider menu item in the Activity so we can attach the share intent later:

private ShareActionProvider miShareAction;

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate menu resource file.
    getMenuInflater().inflate(R.menu.second_activity, menu);
    // Locate MenuItem with ShareActionProvider
    MenuItem item = menu.findItem(R.id.menu_item_share);
    // Fetch reference to the share action provider
    miShareAction = (ShareActionProvider) MenuItemCompat.getActionProvider(item);
    // Return true to display menu
    return true;
}

Note: ShareActionProvider does not respond to onOptionsItemSelected() events, so you set the share action provider as soon as it is possible.

Attach Share Intent for Remote Image

Now, once you've setup the ShareActionProvider menu item, construct and attach the share intent for the provider but only after image has been loaded as shown below using the RequestListener for Glide.

private Intent shareIntent;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // ...
    // Get access to ImageView
    ImageView ivImage = (ImageView) findViewById(R.id.ivResult);
    // Load image async from remote URL, setup share when completed
    GlideApp.with(this).load(result.getFullUrl())
        .listener(new RequestListener<Drawable>() {
            @Override
            public boolean onLoadFailed(@Nullable GlideException e, Object model, Target<Drawable> target, boolean isFirstResource) {
                return false;
            }

            @Override
            public boolean onResourceReady(Drawable resource, Object model, Target<Drawable> target, DataSource dataSource, boolean isFirstResource) {
                prepareShareIntent(((BitmapDrawable) resource).getBitmap());
                attachShareIntentAction();
                // Let Glide handle resource load
                return false; 
            }
        }
    )        
    .into(ivImage);
}

// Gets the image URI and setup the associated share intent to hook into the provider
public void prepareShareIntent(Bitmap drawableImage) {
    // Fetch Bitmap Uri locally
     Uri bmpUri = getBitmapFromDrawable(drawableImage);// see previous remote images section and notes for API > 23
    // Construct share intent as described above based on bitmap
    shareIntent = new Intent();
    shareIntent.setAction(Intent.ACTION_SEND);
    shareIntent.putExtra(Intent.EXTRA_STREAM, bmpUri);
    shareIntent.setType("image/*");   
}

// Attaches the share intent to the share menu item provider
public void attachShareIntentAction() {
    if (miShareAction != null && shareIntent != null)
        miShareAction.setShareIntent(shareIntent);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate menu resource file.
    getMenuInflater().inflate(R.menu.second_activity, menu);
    // Locate MenuItem with ShareActionProvider
    MenuItem item = menu.findItem(R.id.menu_item_share);
    // Fetch reference to the share action provider
    miShareAction = (ShareActionProvider) MenuItemCompat.getActionProvider(item);
    attachShareIntentAction(); // call here in case this method fires second
    // Return true to display menu
    return true;
}

Note: Be sure to call attachShareIntentAction method both inside onCreateOptionsMenu AND inside the onResourceReady for Glide to ensure that the share attaches properly.

Attach Share for a WebView URL

We can use a similar approach if we wish to create a share action for the current URL that is being loaded in a WebView:

@Override
public boolean onCreateOptionsMenu(Menu menu) {
  MenuInflater inflater = getMenuInflater();
  inflater.inflate(R.menu.menu_article, menu);

  MenuItem item = menu.findItem(R.id.menu_item_share);
  ShareActionProvider miShare = (ShareActionProvider) MenuItemCompat.getActionProvider(item);
  Intent shareIntent = new Intent(Intent.ACTION_SEND);
  shareIntent.setType("text/plain"); 

  // get reference to WebView
  WebView wvArticle = (WebView) findViewById(R.id.wvArticle);
  // pass in the URL currently being used by the WebView
  shareIntent.putExtra(Intent.EXTRA_TEXT, wvArticle.getUrl());

  miShare.setShareIntent(shareIntent);
  return super.onCreateOptionsMenu(menu);
}

Check out the official guide for easy sharing for more information.

References

• http://developer.android.com/training/sharing/send.html
• http://developer.android.com/training/sharing/shareaction.html
• http://developer.android.com/reference/android/widget/ShareActionProvider.html
• https://medium.com/@benexus/dealing-with-permissions-when-sharing-files-android-m-cee9ecc287bf