feat: complete 'Multi Step' sample app

Author: thelicato

multi-step/app/src/main/AndroidManifest.xml

@@ -14,7 +14,7 @@
         tools:targetApi="31">
         <activity
             android:name=".StateMachineActivity"
-            android:exported="false" />
+            android:exported="true" />
         <activity
             android:name=".MainActivity"
             android:exported="true">

multi-step/app/src/main/java/com/droidground/multistep/StateMachineActivity.kt

@@ -1,6 +1,9 @@
 package com.droidground.multistep
 
+import android.content.Context
+import android.content.Intent
 import android.os.Bundle
+import android.widget.TextView
 import androidx.activity.enableEdgeToEdge
 import androidx.appcompat.app.AppCompatActivity
 import androidx.core.view.ViewCompat
@@ -18,5 +21,51 @@ class StateMachineActivity : AppCompatActivity() {
             v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom)
             insets
         }
+
+        stateMachine(intent);
+    }
+
+
+    private fun getCurrentState(): Int {
+        val sharedPref = getPreferences(Context.MODE_PRIVATE) ?: return 0
+        val currentState = sharedPref.getInt("currentState", 0)
+        return currentState
+    }
+
+    private fun setCurrentState(state: Number) {
+        val sharedPref = getPreferences(Context.MODE_PRIVATE) ?: return
+        with (sharedPref.edit()) {
+            putInt("currentState", state.toInt())
+            apply()
+        }
+    }
+
+    private fun setText(txt: String) {
+        val myTextView = findViewById<TextView>(R.id.state_machine_txt)
+        myTextView.text = txt
+    }
+
+    fun stateMachine(intent: Intent) {
+        val action = intent.action
+        val ordinal = getCurrentState()
+        if (ordinal != 0) {
+            if (ordinal != 1) {
+                if (ordinal == 2) {
+                    setCurrentState(0)
+                    setText(flag)
+                    return
+                }
+            } else if ("GET_FLAG" == action) {
+                setCurrentState(2)
+                setText("Transitioned from PREPARE to GET_FLAG.")
+                return
+            }
+        }  else if ("PREPARE_FLAG" == action) {
+            setCurrentState(1)
+            setText("Transitioned from INIT to PREPARE.")
+            return
+        }
+
+        setCurrentState(0)
     }
 }

multi-step/app/src/main/res/layout/activity_state_machine.xml

@@ -7,4 +7,13 @@
     android:layout_height="match_parent"
     tools:context=".StateMachineActivity">
 
+    <TextView
+        android:id="@+id/state_machine_txt"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="69dp"
+        android:layout_marginTop="356dp"
+        android:text="Hi! I'm a state machine. I'm in the INIT state."
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
 </androidx.constraintlayout.widget.ConstraintLayout>