How to Share an Image Using a Bitmap with Intent in Android Kotlin?

OK as you say you went to share image to another app and you all ready save bitmap in to cache.

then you need to Add File Provider in your AndroidManifest.xml

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

after you need to create one xml file in res/xml folder file_paths.xml

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

and last you went to share that image using share image funaction created below

fun shareImage(context: Context, bitmap: Bitmap) {
    val uri = saveBitmapToCache(bitmap, context) ?: return
    val shareIntent = Intent().apply {
    action = Intent.ACTION_SEND
    putExtra(Intent.EXTRA_STREAM, uri)
    type = "image/png"
    addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
    }
    context.startActivity(Intent.createChooser(shareIntent, "Share Image"))
}

FileProvider: Ensures URI accessibility by other apps.

FLAG_GRANT_READ_URI_PERMISSION: Grants temporary read access for the URI.

Here's the whole helper class for sharing image Bitmap with intent in kotlin

import android.content.Context
import android.content.Intent
import android.graphics.Bitmap
import android.graphics.drawable.Drawable
import android.net.Uri
import android.widget.Toast
import androidx.core.content.FileProvider
import com.bumptech.glide.Glide
import com.bumptech.glide.request.target.CustomTarget
import com.bumptech.glide.request.transition.Transition
import java.io.File
import java.io.FileOutputStream
import java.io.IOException


object WallpaperShare {

    fun shareWallpaperFromUrl(context: Context, imageUrl: String, fileName: String) {
        // Download the image using Glide and then share
        Glide.with(context).asBitmap().load(imageUrl).into(object : CustomTarget<Bitmap>() {
            override fun onResourceReady(resource: Bitmap, transition: Transition<in Bitmap>?) {
                // Save the downloaded bitmap to cache and get its URI
                val imageUri = saveImageToExternalStorage(context, resource, fileName)
                if (imageUri != null) {
                    val shareIntent = Intent().apply {
                        action = Intent.ACTION_SEND
                        putExtra(Intent.EXTRA_STREAM, imageUri)
                        putExtra(
                            Intent.EXTRA_TEXT,
                            "Get 4K wallpapers - To discover beautiful 3D Parallax, 4K, Live Wallpapers. "
                                    + "Download at: https://play.google.com/store/apps/details?id=${context.packageName}"
                        )
                        type = "image/png"
                        addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
                    }
                    context.startActivity(
                        Intent.createChooser(
                            shareIntent, "Share Wallpaper via"
                        )
                    )
                } else {
                    Toast.makeText(context, "Unable to share wallpaper", Toast.LENGTH_SHORT).show()
                }
            }

            override fun onLoadCleared(placeholder: Drawable?) {
                // Handle when the image load is canceled or fails
            }
        })
    }


    fun saveImageToExternalStorage(context: Context, bitmap: Bitmap, fileName: String): Uri? {
        val imagesFolder = File(context.cacheDir, "images")
        var uri: Uri? = null
        try {
            imagesFolder.mkdirs()
            val file = File(imagesFolder, "$fileName.png")
            val stream = FileOutputStream(file)
            bitmap.compress(Bitmap.CompressFormat.PNG, 100, stream)
            stream.flush()
            stream.close()
            uri = FileProvider.getUriForFile(context, "${context.packageName}.fileprovider", file)
        } catch (e: IOException) {
            e.printStackTrace()
        }
        return uri
    }

}