Added App Introduction Screens

Added three screens explaining Meshtastic and how to use the app. This is only shown on the first launch of the app.

app/src/main/java/com/geeksville/mesh/AppIntroduction.kt

@@ -0,0 +1,68 @@
+package com.geeksville.mesh
+
+import android.content.Context
+import android.content.Intent
+import android.content.SharedPreferences
+import android.os.Bundle
+import androidx.fragment.app.Fragment
+import com.github.appintro.AppIntro
+import com.github.appintro.AppIntroFragment
+
+class AppIntroduction : AppIntro() {
+
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        // Make sure you don't call setContentView!
+
+        // Call addSlide passing your Fragments.
+        // You can use AppIntroFragment to use a pre-built fragment
+        addSlide(
+            AppIntroFragment.createInstance(
+            title = resources.getString(R.string.intro_welcome_title),
+            description = resources.getString(R.string.intro_meshtastic_desc),
+            imageDrawable = R.mipmap.ic_launcher2_round,
+            backgroundColorRes = R.color.colourGrey,
+            descriptionColorRes = R.color.colorOnPrimary
+        ))
+        addSlide(AppIntroFragment.createInstance(
+            title = resources.getString(R.string.intro_get_started),
+            description = resources.getString(R.string.intro_started_text),
+            imageDrawable = R.drawable.icon_meanings,
+            backgroundColorRes = R.color.colourGrey,
+            descriptionColorRes = R.color.colorOnPrimary
+        ))
+        addSlide(AppIntroFragment.createInstance(
+            title = resources.getString(R.string.intro_ecryption_title),
+            description = resources.getString(R.string.intro_encryption_text),
+            imageDrawable = R.drawable.channel_name_image,
+            backgroundColorRes = R.color.colourGrey,
+            descriptionColorRes = R.color.colorOnPrimary
+        ))
+        //addSlide(SlideTwoFragment())
+    }
+
+    override fun onSkipPressed(currentFragment: Fragment?) {
+        super.onSkipPressed(currentFragment)
+        // Decide what to do when the user clicks on "Skip"
+        finish()
+        val preferences = getSharedPreferences("PREFERENCES", Context.MODE_PRIVATE)
+        var editor = preferences.edit()
+        editor.putBoolean("app_intro_completed", true)
+        editor.apply()
+
+        startActivity(Intent(this, MainActivity::class.java))
+    }
+
+    override fun onDonePressed(currentFragment: Fragment?) {
+        super.onDonePressed(currentFragment)
+        // Decide what to do when the user clicks on "Done"
+        finish()
+        val preferences = getSharedPreferences("PREFERENCES", Context.MODE_PRIVATE)
+        var editor = preferences.edit()
+        editor.putBoolean("app_intro_completed", true)
+        editor.apply()
+
+        startActivity(Intent(this, MainActivity::class.java))
+    }
+}

app/src/main/java/com/geeksville/mesh/MainActivity.kt

@@ -404,9 +404,16 @@ class MainActivity : BaseActivity(), Logging,
     }
 
     override fun onCreate(savedInstanceState: Bundle?) {
+        val preferences = getSharedPreferences("PREFERENCES", Context.MODE_PRIVATE)
+
         installSplashScreen()
         super.onCreate(savedInstanceState)
 
+        if (preferences.getBoolean("app_intro_completed", false) == false) {
+            startActivity(Intent(this, AppIntroduction::class.java))
+        }
+
+
         binding = ActivityMainBinding.inflate(layoutInflater)
 
         val prefs = UIViewModel.getPreferences(this)
@@ -1070,6 +1077,10 @@ class MainActivity : BaseActivity(), Logging,
                 chooseMapStyle()
                 return true
             }
+            R.id.show_intro -> {
+                startActivity(Intent(this, AppIntroduction::class.java))
+                return true
+            }
             else -> super.onOptionsItemSelected(item)
         }
     }

app/src/main/java/com/geeksville/mesh/android/ContextServices.kt

@@ -21,9 +21,11 @@ val Context.bluetoothManager: BluetoothManager? get() = getSystemService(Context
 val Context.deviceManager: CompanionDeviceManager?
     @SuppressLint("InlinedApi")
     get() {
-        val activity: MainActivity? = GeeksvilleApplication.currentActivity as MainActivity?
-        return if (hasCompanionDeviceApi()) activity?.getSystemService(Context.COMPANION_DEVICE_SERVICE) as? CompanionDeviceManager?
-        else null
+        if (GeeksvilleApplication.currentActivity is MainActivity) {
+            val activity = GeeksvilleApplication.currentActivity
+            if (hasCompanionDeviceApi()) return activity?.getSystemService(Context.COMPANION_DEVICE_SERVICE) as? CompanionDeviceManager?
+        }
+        return null
     }
 
 val Context.usbManager: UsbManager get() = requireNotNull(getSystemService(Context.USB_SERVICE) as? UsbManager?) { "USB_SERVICE is not available"}