Helper for sending ACTION_IMAGE_CAPTURE intent and retrieve its results. Handles all low level operations

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          xmlns:tools="http://schemas.android.com/tools"
          package="your.awesome.app">

    <application>
      
        <!-- need provider tag in application tag -->
        <provider
            android:name="android.support.v4.content.FileProvider"
            android:authorities="${applicationId}.provider"
            android:exported="false"
            android:grantUriPermissions="true">
            <!-- ressource file to create -->
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/file_paths">
            </meta-data>
        </provider>
      
    </application>
</manifest>

file_paths.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- locate res/xml/file_paths.xml -->
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <external-path name="external_files" path="." />
</paths>

ImageCaptureHelper.kt

package your.awesome.app

//MIT License
//Copyright (c) 2015 Karol Wrótniak, Droids On Roids


import android.app.Activity
import android.content.ActivityNotFoundException
import android.content.ContentResolver
import android.content.ContentValues
import android.content.Context
import android.content.Intent
import android.net.Uri
import android.os.Environment
import android.provider.MediaStore
import android.provider.MediaStore.Images.ImageColumns
import android.provider.MediaStore.MediaColumns
import android.support.v4.content.FileProvider
import net.nepula.nippan_android.BuildConfig
import java.io.File
import java.util.regex.Pattern

/**
 * Helper for sending ACTION_IMAGE_CAPTURE intent and retrieve its results. Handles all low level operations
 * <br></br>
 * Usage:<br></br>
 *
 *  1. Launch camera app by calling [.launchCameraApp], save resulting Uri, handle (or ignore) exceptions.
 *  1. In your onActivityResult(int requestCode, int resultCode, Intent data) call [) ][.retrievePhotoResult]. You may want to inform user if photo cannot be read despite the result is RESULT_OK.
 *
 * @author koral--
 */
object ImageCaptureHelper {

    private val PROJECTION = arrayOf(MediaColumns.DATA)
    private val CONTENT_VALUES = ContentValues(1)
    private val PHOTO_SHARED_PREFS_NAME = "photo_shared"
    private val PHOTO_URI = "photo_uri"
    /**
     * Description text inserted into @link{ImageColumns.DESCRIPTION} column
     */
    val DESCRIPTION = "Photo taken with example application"

    init {
        CONTENT_VALUES.put(ImageColumns.DESCRIPTION, DESCRIPTION)
    }

    /**
     * Tries to obtain File containing taken photo. Perform cleanups if photo was not taken or it is empty.
     * @param caller caller Activity
     * @param photoKey key in Shared Preferences for taken image, can be null
     * @return File containing photo or null if no or empty photo was saved by camera app.
     */
    fun retrievePhotoResult(caller: Activity, photoKey: String?): File? {
        var photoKey = photoKey
        try {
            if (photoKey == null) {
                photoKey = PHOTO_URI
            }
            val prefs = caller.getSharedPreferences(PHOTO_SHARED_PREFS_NAME, Context.MODE_PRIVATE)
            val takenPhotoUriString = prefs.getString(photoKey, null)
            prefs.edit().remove(photoKey).commit()

            if (takenPhotoUriString == null) {
                return null
            }

            val takenPhotoUri = Uri.parse(takenPhotoUriString)
            val cr = caller.contentResolver
            val out = File(getPhotoFilePath(takenPhotoUri, cr)!!)
            if (!out.isFile || out.length() == 0L) {
                cr.delete(takenPhotoUri, null, null)
            } else {
                return out
            }
        } catch (ex: Exception) {
            // no-op
        }

        return null
    }

    /**
     * Tries to create photo placeholder and launch camera app
     * @param requestCode your unique code that will be returned in onActivityResult
     * @param caller caller Activity
     * @param photoKey key in Shared Preferences for taken image, can be null
     * @throws ActivityNotFoundException if no camera app was found
     * @throws Exception if there is a problem with create photo eg. SDcard is not mounted. It may be eg. [IllegalStateException] or [UnsupportedOperationException] depending on [ContentResolver].
     */
    @Throws(ActivityNotFoundException::class, Exception::class)
    fun launchCameraApp(requestCode: Int, caller: Activity, photoKey: String?) {
        var photoKey = photoKey
        if (photoKey == null) {
            photoKey = PHOTO_URI
        }

        val cr = caller.contentResolver
        val takenPhotoUri = cr.insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, CONTENT_VALUES)
                ?: throw IllegalStateException("Photo insertion failed")
        val intent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
        intent.putExtra(MediaStore.EXTRA_OUTPUT, getIntentUri(caller, takenPhotoUri, cr))
        caller.startActivityForResult(intent, requestCode)

        val prefs = caller.getSharedPreferences(PHOTO_SHARED_PREFS_NAME, Context.MODE_PRIVATE)

        prefs.edit().putString(photoKey, takenPhotoUri.toString()).commit()
    }

    private fun getIntentUri(context: Context, takenPhotoUri: Uri, cr: ContentResolver): Uri {
        val path = getPhotoFilePath(takenPhotoUri, cr)
                ?: throw IllegalStateException("Photo resolution failed")

        return FileProvider.getUriForFile(
                context,
                "${BuildConfig.APPLICATION_ID}.provider", //(use your app signature + ".provider" )
                File(path));
//        return Uri.fromFile(File(path))
    }

    private fun getPhotoFilePath(takenPhotoUri: Uri, cr: ContentResolver): String? {
        val cursor = cr.query(takenPhotoUri, PROJECTION, null, null, null)
        var res: String? = null
        if (cursor != null) {
            val dataIdx = cursor.getColumnIndex(MediaColumns.DATA)
            if (dataIdx >= 0 && cursor.moveToFirst())
                res = cursor.getString(dataIdx)
            cursor.close()
        }
        return res
    }

    /**
     * Dirty hack for API level <8 to get a top-level public external storage directory where Camera photos should be placed.<br></br>
     * Empty photo is inserted, path of its parent directory is retrieved and then photo is deleted.<br></br>
     * If photo cannot be inserted eg. external storage is not mounted, then "DCIM" folder in root of the external storage is used as a fallback.
     * @param cr [ContentResolver] used to resolve image Uris
     * @return path to directory where camera app places photos (may be fallback)
     */
    fun getPhotoDirPath(cr: ContentResolver): String {
        val fallback = Environment.getExternalStorageDirectory().toString() + "/DCIM"
        var takenPhotoUri: Uri? = null
        var photoFilePath: String? = null
        try {
            takenPhotoUri = cr.insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, CONTENT_VALUES)
            if (takenPhotoUri == null)
                return fallback
            photoFilePath = getPhotoFilePath(takenPhotoUri, cr)
            cr.delete(takenPhotoUri, null, null)
        } catch (ex: Exception) {
            //igonred
        }

        if (photoFilePath == null)
            return fallback
        var parent = File(photoFilePath).parent
        val m = Pattern.compile("/DCIM(/|$)").matcher(parent)
        if (m.find())
            parent = parent.substring(0, m.end())

        return parent
    }
}