Android Share Intent for a Bitmap - is it possible not to save it prior sharing?
Asked Answered
B

5

83

I try to export a bitmap from my app using share intent without saving a file for a temporal location. All the examples I found are two-step 1) save to SD Card and create Uri for that file 2) start the intent with this Uri

Is it possible to make it without requiring WRITE_EXTERNAL_STORAGE permission, saving the file [and removing it afterwards]? How to address devices without ExternalStorage?

Between answered 28/1, 2012 at 22:20 Comment(0)
M
294

I had this same problem. I didn't want to have to ask for the read and write external storage permissions. Also, sometimes there are problems when phones don't have SD cards or the cards get unmounted.

The following method uses a ContentProvider called FileProvider. Technically, you are still saving the bitmap (in internal storage) prior to sharing, but you don't need to request any permissions. Also, every time you share the bitmap the image file gets overwritten. And since it is in the internal cache, it will be deleted when the user uninstalls the app. So in my opinion, it is just as good as not saving the image. This method is also more secure than saving it to external storage.

The documentation is pretty good (see the Further Reading below), but some parts are a little tricky. Here is a summary that worked for me.

Set up the FileProvider in the Manifest

<manifest>
    ...
    <application>
        ...
        <provider
            android:name="androidx.core.content.FileProvider"
            android:authorities="com.example.myapp.fileprovider"
            android:grantUriPermissions="true"
            android:exported="false">
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/filepaths" />
        </provider>
        ...
    </application>
</manifest>

Replace com.example.myapp with your app package name.

Create res/xml/filepaths.xml

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <cache-path name="shared_images" path="images/"/>
</paths>

This tells the FileProvider where to get the files to share (using the cache directory in this case).

Save the image to internal storage

// save bitmap to cache directory
try {

    File cachePath = new File(context.getCacheDir(), "images");
    cachePath.mkdirs(); // don't forget to make the directory
    FileOutputStream stream = new FileOutputStream(cachePath + "/image.png"); // overwrites this image every time
    bitmap.compress(Bitmap.CompressFormat.PNG, 100, stream);
    stream.close();

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

Share the image

File imagePath = new File(context.getCacheDir(), "images");
File newFile = new File(imagePath, "image.png");
Uri contentUri = FileProvider.getUriForFile(context, "com.example.myapp.fileprovider", newFile);

if (contentUri != null) {
    Intent shareIntent = new Intent();
    shareIntent.setAction(Intent.ACTION_SEND);
    shareIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION); // temp permission for receiving app to read this file
    shareIntent.setDataAndType(contentUri, getContentResolver().getType(contentUri));
    shareIntent.putExtra(Intent.EXTRA_STREAM, contentUri);
    startActivity(Intent.createChooser(shareIntent, "Choose an app"));
}

Further reading

Meddlesome answered 11/5, 2015 at 16:21 Comment(14)
Great solution! Any reason why you are using getCacheDir() instead of getFilesDir(), or even getExternalCacheDir()?Maryjomaryl
Also, this would require an AsyncTask or IntentService? What do you think works best for this case? Do you have (or know of) any full code that wraps up your solution in an AsyncTask or IntentService?Maryjomaryl
@Jamrelian, since the purpose is just to share the image and not to save it, I selected the cache directory. Things in the cache directory are not long lasting. I imagine, though, that it would work fine to use another directory.Meddlesome
cache memory size is increasing every time once i share the screen shot but as you said it will replace the previous image so it should not increase the cache memory size. Please explain this.Photoflood
@GvSharma. I don't know how to explain that. It sounds like a good candidate for a new question. If you get an answer, link back to it here.Meddlesome
Great answer! For future readers - Most apps save a thumbnail cache relative to the image file name. The cache isn't updated if the filename remains same. I solved this by deleting the contents of the directory and setting the filename to the current date in milliseconds.Crib
@GurupadMamadapur You are right. You need delete the cache and save with other file name...Kendall
Is there any risk of using cacheDir instead of externalFilesDir? For example, if I'm saving an image, am I at a higher risk of running out of space when saving to the cache?Engen
@JHowzer, The system automatically deletes data in the cache directory when it needs to (though you should do it yourself if you don't need the file anymore). Read this for more information.Meddlesome
What is minimalSDK requirement for this code? (as I know 21) What is alternate if minimalSDK requirement is 15 (4.0.3)?Seventeen
@vugar_saleh, I don't know what the minimum is but I think I have used it with API 14, the minimum for the current support library. Which part is telling you the min is 21? Are you using the support library?Meddlesome
Anybody knows how to create the filpaths.xml file in Xamarin?Rearward
@UsmanRana, I haven't done much of that but see this and thisMeddlesome
The Uri shared by i.e. whatsapp is of private directory and file is unable to be retrievedSeattle
W
11

I try to export a bitmap from my app using share intent without saving a file for a temporal location.

In theory, this is possible. In practice, it is probably not possible.

In theory, all you need to share is a Uri that will resolve to the bitmap. The simplest approach is if that is a file that is directly accessible by the other application, such as on external storage.

To not write it to flash at all, you would need to implement your own ContentProvider, figure out how to implement openFile() to return your in-memory bitmap, and then pass a Uri representing that bitmap in the ACTION_SEND Intent. Since openFile() needs to return a ParcelFileDescriptor, I don't know how you would do that without an on-disk representation, but I have not spent much time searching.

Is it possible to make it without requiring WRITE_EXTERNAL_STORAGE permission, saving the file [and removing it afterwards]?

If you simply do not want it on external storage, you can go the ContentProvider route, using a file on internal storage. This sample project demonstrates a ContentProvider that serves up a PDF file via ACTION_VIEW to a PDF viewer on a device; the same approach could be used for ACTION_SEND.

Wonderstricken answered 28/1, 2012 at 22:32 Comment(4)
Couldn't one just use getCacheDir() as is suggested in this SO answer?Meddlesome
@Suragch: Creating world-readable files on your app's internal storage is not a good idea.Wonderstricken
That makes sense. After making that comment I read another one of your answers where you recommend using FileProvider so that is what I am working toward now.Meddlesome
cache memory size is increasing every time once i share the screen shot but as from the other answer, it will replace the previous image so it should not increase the cache memory size. Please explain this.Photoflood
L
8

If anyone still looking for easy and short solution without any storage permission (Supports nougat 7.0 as well). Here it is.

Add this in Manifest

<provider
     android:name="android.support.v4.content.FileProvider"
     android:authorities="${applicationId}.provider"
     android:exported="false"
     android:grantUriPermissions="true">
     <meta-data
          android:name="android.support.FILE_PROVIDER_PATHS"
          android:resource="@xml/provider_paths" />
 </provider>

Now create provider_paths.xml

<paths>
    <external-path name="external_files" path="."/>
</paths>

Finally Add this method to your activity/fragment (rootView is the view you want share)

 private void ShareIt(View rootView){
        if (rootView != null && context != null && !context.isFinishing()) {
            rootView.setDrawingCacheEnabled(true);
            Bitmap bitmap = Bitmap.createBitmap(rootView.getDrawingCache());
            if (bitmap != null ) {
                 //Save the image inside the APPLICTION folder
                File mediaStorageDir = new File(AppContext.getInstance().getExternalCacheDir() + "Image.png");

                try {
                    FileOutputStream outputStream = new FileOutputStream(String.valueOf(mediaStorageDir));
                    bitmap.compress(Bitmap.CompressFormat.PNG, 100, outputStream);
                    outputStream.close();

                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }

                if (ObjectUtils.isNotNull(mediaStorageDir)) {

                    Uri imageUri = FileProvider.getUriForFile(getActivity(), getActivity().getApplicationContext().getPackageName() + ".provider", mediaStorageDir);

                    if (ObjectUtils.isNotNull(imageUri)) {
                        Intent waIntent = new Intent(Intent.ACTION_SEND);
                        waIntent.setType("image/*");
                        waIntent.putExtra(Intent.EXTRA_STREAM, imageUri);
                        startActivity(Intent.createChooser(waIntent, "Share with"));
                    }
                }
            }
        }
    }

Update:

As @Kathir mentioned in comments,

DrawingCache is deprecated from API 28+. Use below code to use Canvas instead.

 Bitmap bitmap = Bitmap.createBitmap(rootView.getWidth(), rootView.getHeight(), quality);
    Canvas canvas = new Canvas(bitmap);

    Drawable backgroundDrawable = view.getBackground();
    if (backgroundDrawable != null) {
        backgroundDrawable.draw(canvas);
    } else {
        canvas.drawColor(Color.WHITE);
    }
    view.draw(canvas);

    return bitmap;
Logion answered 19/7, 2018 at 10:25 Comment(1)
DrawingCache is deprecated from API 28+. Use Canvas or PixelCopy to accomplish this. Example for Canvas usage. And, do not forget to set the background colour (either to your view or Bitmap), else you will get a black backgroundValorie
M
3

This for sharing CardView as an Image then saving it in the cache subdirectory of the app's internal storage area. hope it will be helpful.

        @Override
        public void onClick(View view) {

            CardView.setDrawingCacheEnabled(true);
            CardView.buildDrawingCache();
            Bitmap bitmap = CardView.getDrawingCache();

            try{
                File file = new File(getContext().getCacheDir()+"/Image.png");
                bitmap.compress(Bitmap.CompressFormat.PNG,100,new FileOutputStream(file));
                Uri uri = FileProvider.getUriForFile(getContext(),"com.mydomain.app", file);

                Intent shareIntent = new Intent();
                shareIntent.setAction(Intent.ACTION_SEND);
                shareIntent.putExtra(Intent.EXTRA_STREAM, uri);
                shareIntent.setType("image/jpeg");
                getContext().startActivity(Intent.createChooser(shareIntent, "Share"));

            }catch (FileNotFoundException e) {e.printStackTrace();}

        }
    });
Mcentire answered 31/12, 2017 at 8:19 Comment(1)
this code is deprecated now. CardView.setDrawingCacheEnabled(true); CardView.buildDrawingCache(); Bitmap bitmap = CardView.getDrawingCache();Pitcher
G
1

Here is working method to make a screenshot of own app and share it as image via any messanger or email client.

To fix the bitmap not updating problem I improved Suragch's answer, using Gurupad Mamadapur's comment and added own modifications.


Here is code in Kotlin language:

private lateinit var myRootView:View // root view of activity
@SuppressLint("SimpleDateFormat")
private fun shareScreenshot() {
    // We need date and time to be added to image name to make it unique every time, otherwise bitmap will not update
    val sdf = SimpleDateFormat("yyyyMMdd_HHmmss")
    val currentDateandTime = sdf.format(Date())
    val imageName = "/image_$currentDateandTime.jpg"       

    // CREATE
    myRootView = window.decorView.rootView
    myRootView.isDrawingCacheEnabled = true
    myRootView.buildDrawingCache(true) // maybe You dont need this
    val bitmap = Bitmap.createBitmap(myRootView.drawingCache)
    myRootView.isDrawingCacheEnabled = false

    // SAVE
    try {
        File(this.cacheDir, "images").deleteRecursively() // delete old images
        val cachePath = File(this.cacheDir, "images")
        cachePath.mkdirs() // don't forget to make the directory
        val stream = FileOutputStream("$cachePath$imageName")
        bitmap.compress(Bitmap.CompressFormat.JPEG, 90, stream) // can be png and any quality level
        stream.close()
    } catch (ex: Exception) {
        Toast.makeText(this, ex.javaClass.canonicalName, Toast.LENGTH_LONG).show() // You can replace this with Log.e(...)
    }

    // SHARE
    val imagePath = File(this.cacheDir, "images")
    val newFile = File(imagePath, imageName)
    val contentUri = FileProvider.getUriForFile(this, "com.example.myapp.fileprovider", newFile)
    if (contentUri != null) {
        val shareIntent = Intent()
        shareIntent.action = Intent.ACTION_SEND
        shareIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION) // temp permission for receiving app to read this file
        shareIntent.type = "image/jpeg" // just assign type. we don't need to set data, otherwise intent will not work properly
        shareIntent.putExtra(Intent.EXTRA_STREAM, contentUri)
        startActivity(Intent.createChooser(shareIntent, "Choose app"))
    } 
}
Galvin answered 10/6, 2018 at 4:12 Comment(2)
Zakir, please explain your code to help other people to use it. Btw, it's good to say that Kotlin and Java codes can be used in the same Android Studio project. Some people might not consider your solution because they don't know that. Thanks!Shape
Hi zakir can you please provide java code. I need to capture scrollview data. Successfully capturing image and able to store in /storage but while sharing not getting file path. Will you please help me outCr

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