Request write permission when downloading circulars

app/src/main/java/net/underdesk/circolapp/MainActivity.kt

@@ -18,9 +18,13 @@
 
 package net.underdesk.circolapp
 
+import android.app.DownloadManager
 import android.content.Context
 import android.content.Intent
+import android.content.pm.PackageManager
+import android.net.Uri
 import android.os.Bundle
+import android.os.Environment
 import android.view.Menu
 import android.view.MenuItem
 import androidx.appcompat.app.AlertDialog
@@ -30,9 +34,19 @@ import androidx.navigation.ui.AppBarConfiguration
 import androidx.navigation.ui.setupActionBarWithNavController
 import androidx.navigation.ui.setupWithNavController
 import com.google.android.material.bottomnavigation.BottomNavigationView
+import com.google.android.material.snackbar.Snackbar
+import kotlinx.android.synthetic.main.activity_main.*
+import net.underdesk.circolapp.adapters.CircularLetterAdapter
+import net.underdesk.circolapp.data.Circular
 import net.underdesk.circolapp.works.PollWork
 
-class MainActivity : AppCompatActivity() {
+class MainActivity : AppCompatActivity(), CircularLetterAdapter.AdapterCallback {
+
+    companion object {
+        internal const val PERMISSIONS_REQUEST_WRITE_EXTERNAL_STORAGE = 10
+    }
+
+    override var circularToDownload: Circular? = null
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -80,6 +94,44 @@ class MainActivity : AppCompatActivity() {
         }
     }
 
+    override fun onRequestPermissionsResult(
+        requestCode: Int,
+        permissions: Array<String>, grantResults: IntArray
+    ) {
+        when (requestCode) {
+            PERMISSIONS_REQUEST_WRITE_EXTERNAL_STORAGE -> {
+                // If request is cancelled, the result arrays are empty.
+                if ((grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED)) {
+                    downloadCircular()
+                } else {
+                    Snackbar.make(
+                        container,
+                        resources.getString(R.string.snackbar_write_permission_not_granted),
+                        Snackbar.LENGTH_LONG
+                    ).show()
+                }
+                return
+            }
+        }
+    }
+
+    override fun downloadCircular() {
+        val request = DownloadManager.Request(Uri.parse(circularToDownload!!.url))
+        request.setTitle(circularToDownload!!.name)
+        request.setDestinationInExternalPublicDir(
+            Environment.DIRECTORY_DOWNLOADS,
+            "Circolapp/" + circularToDownload!!.id + ".pdf"
+        )
+
+        (getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager).enqueue(request)
+
+        Snackbar.make(
+            container,
+            resources.getString(R.string.snackbar_circular_downloaded),
+            Snackbar.LENGTH_LONG
+        ).show()
+    }
+
     private fun showInfoDialog() {
         val builder = AlertDialog.Builder(this)
         builder.apply {

app/src/main/java/net/underdesk/circolapp/adapters/CircularLetterAdapter.kt

@@ -18,29 +18,37 @@
 
 package net.underdesk.circolapp.adapters
 
-import android.app.DownloadManager
+import android.Manifest
 import android.app.PendingIntent
 import android.content.Context
 import android.content.Intent
+import android.content.pm.PackageManager
 import android.net.Uri
-import android.os.Environment
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import android.widget.ImageButton
 import android.widget.TextView
+import androidx.appcompat.app.AlertDialog
+import androidx.appcompat.app.AppCompatActivity
+import androidx.core.app.ActivityCompat
+import androidx.core.content.ContextCompat
 import androidx.fragment.app.FragmentActivity
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import kotlinx.android.synthetic.main.item_circular.view.*
 import net.underdesk.circolapp.AlarmBroadcastReceiver
+import net.underdesk.circolapp.MainActivity
 import net.underdesk.circolapp.R
 import net.underdesk.circolapp.data.AppDatabase
 import net.underdesk.circolapp.data.Circular
 import net.underdesk.circolapp.fragments.NewReminderFragment
 
 
-class CircularLetterAdapter(private val circulars: List<Circular>) :
+class CircularLetterAdapter(
+    private val circulars: List<Circular>,
+    private val adapterCallback: AdapterCallback
+) :
     RecyclerView.Adapter<CircularLetterAdapter.CircularLetterViewHolder>() {
     private lateinit var context: Context
     private var collapsedItems = -1
@@ -108,14 +116,36 @@ class CircularLetterAdapter(private val circulars: List<Circular>) :
         }
 
         holder.downloadButton.setOnClickListener {
-            val request = DownloadManager.Request(Uri.parse(circulars[position].url))
-            request.setTitle(circulars[position].name)
-            request.setDestinationInExternalPublicDir(
-                Environment.DIRECTORY_DOWNLOADS,
-                "Circolapp/" + circulars[position].id + ".pdf"
-            )
+            adapterCallback.circularToDownload = circulars[position]
 
-            (context.getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager).enqueue(request)
+            if (ContextCompat.checkSelfPermission(
+                    context,
+                    Manifest.permission.WRITE_EXTERNAL_STORAGE
+                )
+                != PackageManager.PERMISSION_GRANTED
+            ) {
+
+                val builder: AlertDialog.Builder? = AlertDialog.Builder(context)
+
+                builder?.apply {
+                    setMessage(context.getString(R.string.dialog_message_permission_write))
+                    setTitle(context.getString(R.string.dialog_title_permission_required))
+                    setPositiveButton(
+                        context.getString(R.string.dialog_next)
+                    ) { _, _ ->
+                        ActivityCompat.requestPermissions(
+                            adapterCallback as AppCompatActivity,
+                            arrayOf(Manifest.permission.WRITE_EXTERNAL_STORAGE),
+                            MainActivity.PERMISSIONS_REQUEST_WRITE_EXTERNAL_STORAGE
+                        )
+                    }
+
+                }
+
+                builder?.create()?.show()
+            } else {
+                adapterCallback.downloadCircular()
+            }
         }
 
         holder.favouriteButton.setOnClickListener {
@@ -163,4 +193,9 @@ class CircularLetterAdapter(private val circulars: List<Circular>) :
     }
 
     override fun getItemCount() = circulars.size
+
+    interface AdapterCallback {
+        var circularToDownload: Circular?
+        fun downloadCircular()
+    }
 }

app/src/main/java/net/underdesk/circolapp/fragments/CircularLetterFragment.kt

@@ -29,6 +29,7 @@ import androidx.lifecycle.ViewModelProviders
 import androidx.recyclerview.widget.LinearLayoutManager
 import com.google.android.material.snackbar.Snackbar
 import kotlinx.android.synthetic.main.fragment_circular_letters.view.*
+import net.underdesk.circolapp.MainActivity
 import net.underdesk.circolapp.R
 import net.underdesk.circolapp.adapters.CircularLetterAdapter
 import net.underdesk.circolapp.viewmodels.CircularLetterViewModel
@@ -49,7 +50,7 @@ class CircularLetterFragment : Fragment() {
         circularLetterViewModel =
             ViewModelProviders.of(this).get(CircularLetterViewModel::class.java)
         circularLetterViewModel.circulars.observe(this, Observer {
-            root.circulars_list.adapter = CircularLetterAdapter(it)
+            root.circulars_list.adapter = CircularLetterAdapter(it, activity as MainActivity)
         })
         circularLetterViewModel.showMessage.observe(this, Observer {
             if (it) activity?.findViewById<ConstraintLayout>(R.id.container)?.let { view ->

app/src/main/java/net/underdesk/circolapp/fragments/FavouritesFragment.kt

@@ -27,6 +27,7 @@ import androidx.lifecycle.Observer
 import androidx.lifecycle.ViewModelProviders
 import androidx.recyclerview.widget.LinearLayoutManager
 import kotlinx.android.synthetic.main.fragment_circular_letters.view.*
+import net.underdesk.circolapp.MainActivity
 import net.underdesk.circolapp.R
 import net.underdesk.circolapp.adapters.CircularLetterAdapter
 import net.underdesk.circolapp.viewmodels.FavouritesViewModel
@@ -47,7 +48,7 @@ class FavouritesFragment : Fragment() {
         favouritesViewModel =
             ViewModelProviders.of(this).get(FavouritesViewModel::class.java)
         favouritesViewModel.circulars.observe(this, Observer {
-            root.circulars_list.adapter = CircularLetterAdapter(it)
+            root.circulars_list.adapter = CircularLetterAdapter(it, activity as MainActivity)
         })
         return root
     }

app/src/main/java/net/underdesk/circolapp/fragments/RemindersFragment.kt

@@ -27,6 +27,7 @@ import androidx.lifecycle.Observer
 import androidx.lifecycle.ViewModelProviders
 import androidx.recyclerview.widget.LinearLayoutManager
 import kotlinx.android.synthetic.main.fragment_circular_letters.view.*
+import net.underdesk.circolapp.MainActivity
 import net.underdesk.circolapp.R
 import net.underdesk.circolapp.adapters.CircularLetterAdapter
 import net.underdesk.circolapp.viewmodels.RemindersViewModel
@@ -47,7 +48,7 @@ class RemindersFragment : Fragment() {
         remindersViewModel =
             ViewModelProviders.of(this).get(RemindersViewModel::class.java)
         remindersViewModel.circulars.observe(this, Observer {
-            root.circulars_list.adapter = CircularLetterAdapter(it)
+            root.circulars_list.adapter = CircularLetterAdapter(it, activity as MainActivity)
         })
         return root
     }

app/src/main/res/values/strings.xml

@@ -32,5 +32,11 @@
     © 2019  Matteo Schiff\nThis program comes with ABSOLUTELY NO WARRANTY.\nThis is free software, and you are welcome to redistribute it
     under certain conditions.</string>
 
+    <string name="dialog_title_permission_required">Permission required</string>
+    <string name="dialog_message_permission_write">We need your permission to save this circular letter to local storage</string>
+
+    <string name="snackbar_write_permission_not_granted">Unable to save this circular letter to local storage. Permission not granted</string>
+    <string name="snackbar_circular_downloaded">The circular letter will be saved into the download folder</string>
+
     <string name="snackbar_connection_not_available">Network not available. Results may be outdated</string>
 </resources>