Optional SplashActivity

app/src/androidTest/java/com/example/android/dagger/ApplicationTest.kt

@@ -21,14 +21,14 @@ import androidx.test.espresso.Espresso.onView
 import androidx.test.espresso.action.ViewActions.*
 import androidx.test.espresso.assertion.ViewAssertions.matches
 import androidx.test.espresso.matcher.ViewMatchers.*
-import com.example.android.dagger.main.MainActivity
+import com.example.android.dagger.splash.SplashActivity
 import org.junit.Test
 
 class ApplicationTest {
 
     @Test
     fun runApp() {
-        ActivityScenario.launch(MainActivity::class.java)
+        ActivityScenario.launch(SplashActivity::class.java)
 
         // Should be in Registration/EnterDetails because the user is not registered
         onView(withText("Register to Dagger World!")).check(matches(isDisplayed()))

app/src/main/AndroidManifest.xml

@@ -27,14 +27,18 @@
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
         android:theme="@style/AppTheme">
-        <activity
-            android:name=".main.MainActivity"
+        <activity android:name=".splash.SplashActivity"
             android:screenOrientation="portrait">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
+
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
+        <activity
+            android:name=".main.MainActivity"
+            android:screenOrientation="portrait">
+        </activity>
         <activity
             android:name=".registration.RegistrationActivity"
             android:screenOrientation="portrait" />
@@ -46,4 +50,4 @@
             android:screenOrientation="portrait" />
     </application>
 
-</manifest>
+</manifest>

app/src/main/java/com/example/android/dagger/di/AppComponent.kt

@@ -19,6 +19,7 @@ package com.example.android.dagger.di
 import android.content.Context
 import com.example.android.dagger.login.LoginComponent
 import com.example.android.dagger.registration.RegistrationComponent
+import com.example.android.dagger.splash.SplashComponent
 import com.example.android.dagger.user.UserManager
 import dagger.BindsInstance
 import dagger.Component
@@ -42,4 +43,5 @@ interface AppComponent {
     fun registrationComponent(): RegistrationComponent.Factory
     fun loginComponent(): LoginComponent.Factory
     fun userManager(): UserManager
+    fun splashComponent(): SplashComponent.Factory
 }

app/src/main/java/com/example/android/dagger/di/AppSubcomponents.kt

@@ -18,6 +18,7 @@ package com.example.android.dagger.di
 
 import com.example.android.dagger.login.LoginComponent
 import com.example.android.dagger.registration.RegistrationComponent
+import com.example.android.dagger.splash.SplashComponent
 import com.example.android.dagger.user.UserComponent
 import dagger.Module
 
@@ -26,7 +27,8 @@ import dagger.Module
     subcomponents = [
         RegistrationComponent::class,
         LoginComponent::class,
-        UserComponent::class
+        UserComponent::class,
+        SplashComponent::class
     ]
 )
 class AppSubcomponents

app/src/main/java/com/example/android/dagger/main/MainActivity.kt

@@ -34,32 +34,17 @@ class MainActivity : AppCompatActivity() {
     @Inject
     lateinit var mainViewModel: MainViewModel
 
-    /**
-     * If the User is not registered, RegistrationActivity will be launched,
-     * If the User is not logged in, LoginActivity will be launched,
-     * else carry on with MainActivity.
-     */
     override fun onCreate(savedInstanceState: Bundle?) {
-        super.onCreate(savedInstanceState)
-
         // Grabs instance of UserManager from the application graph
         val userManager = (application as MyApplication).appComponent.userManager()
-        if (!userManager.isUserLoggedIn()) {
-            if (!userManager.isUserRegistered()) {
-                startActivity(Intent(this, RegistrationActivity::class.java))
-                finish()
-            } else {
-                startActivity(Intent(this, LoginActivity::class.java))
-                finish()
-            }
-        } else {
-            setContentView(R.layout.activity_main)
+        // If the MainActivity needs to be displayed, we get the UserComponent from the
+        // application graph and gets this Activity injected
+        userManager.userComponent!!.inject(this)
 
-            // If the MainActivity needs to be displayed, we get the UserComponent from the
-            // application graph and gets this Activity injected
-            userManager.userComponent!!.inject(this)
-            setupViews()
-        }
+        super.onCreate(savedInstanceState)
+
+        setContentView(R.layout.activity_main)
+        setupViews()
     }
 
     /**

app/src/main/java/com/example/android/dagger/splash/SplashActivity.kt

@@ -0,0 +1,29 @@
+package com.example.android.dagger.splash
+
+import android.content.Intent
+import androidx.appcompat.app.AppCompatActivity
+import android.os.Bundle
+import com.example.android.dagger.MyApplication
+import javax.inject.Inject
+
+class SplashActivity : AppCompatActivity() {
+
+    // @Inject annotated fields will be provided by Dagger
+    @Inject
+    lateinit var splashViewModel: SplashViewModel
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+
+        // Creates an instance of Splash component by grabbing the factory from the app graph
+        // and injects this activity to that Component
+        (application as MyApplication).appComponent.splashComponent().create().inject(this)
+        super.onCreate(savedInstanceState)
+        showActivity()
+    }
+
+    private fun showActivity() {
+        val activity = splashViewModel.getActivityClass()
+        startActivity(Intent(this, activity))
+        finish()
+    }
+}

app/src/main/java/com/example/android/dagger/splash/SplashComponent.kt

@@ -0,0 +1,19 @@
+package com.example.android.dagger.splash
+
+import com.example.android.dagger.di.ActivityScope
+import dagger.Subcomponent
+
+// Scope annotation that the SplashComponent uses
+// Classes annotated with @ActivityScope will have a unique instance in this Component
+@ActivityScope
+// Definition of a Dagger subcomponent
+@Subcomponent
+interface SplashComponent {
+    @Subcomponent.Factory
+    interface Factory {
+        fun create(): SplashComponent
+    }
+
+    // Classes that can be injected by this Component
+    fun inject(activity: SplashActivity)
+}

app/src/main/java/com/example/android/dagger/splash/SplashViewModel.kt

@@ -0,0 +1,36 @@
+package com.example.android.dagger.splash
+
+import androidx.appcompat.app.AppCompatActivity
+import com.example.android.dagger.di.ActivityScope
+import com.example.android.dagger.login.LoginActivity
+import com.example.android.dagger.main.MainActivity
+import com.example.android.dagger.registration.RegistrationActivity
+import com.example.android.dagger.user.UserManager
+import javax.inject.Inject
+
+/**
+ * SplashViewModel is the ViewModel that [SplashActivity] uses to
+ * obtain information of what Activity to show on the screen.
+ *
+ * @Inject tells Dagger how to provide instances of this type. Dagger also knows
+ * that UserManager is a dependency.
+ */
+@ActivityScope
+class SplashViewModel @Inject constructor(private val userManager: UserManager) {
+
+    /**
+     * If the User is not registered, RegistrationActivity will be returned,
+     * If the User is not logged in, LoginActivity will be returned,
+     * else MainActivity.
+     */
+    fun getActivityClass(): Class<out AppCompatActivity> =
+        if (!userManager.isUserLoggedIn()) {
+            if (!userManager.isUserRegistered()) {
+                RegistrationActivity::class.java
+            } else {
+                LoginActivity::class.java
+            }
+        } else {
+            MainActivity::class.java
+        }
+}

app/src/test/java/com/example/android/dagger/splash/SplashViewModelTest.kt

@@ -0,0 +1,45 @@
+package com.example.android.dagger.splash
+
+import com.example.android.dagger.login.LoginActivity
+import com.example.android.dagger.main.MainActivity
+import com.example.android.dagger.registration.RegistrationActivity
+import com.example.android.dagger.user.UserManager
+import org.junit.Assert.assertEquals
+import org.junit.Before
+import org.junit.Test
+import org.mockito.Mockito.mock
+import org.mockito.Mockito.`when` as whenever
+
+class SplashViewModelTest {
+
+    private lateinit var userManager: UserManager
+    private lateinit var viewModel: SplashViewModel
+
+    @Before
+    fun setup() {
+        userManager = mock(UserManager::class.java)
+        viewModel = SplashViewModel(userManager)
+    }
+
+    @Test
+    fun `If the user is not registered then getActivityClass returns RegistrationActivity`() {
+        whenever(userManager.isUserRegistered()).thenReturn(false)
+
+        assertEquals(RegistrationActivity::class.java, viewModel.getActivityClass())
+    }
+
+    @Test
+    fun `If the user is registered but not logged in then getActivityClass returns LoginActivity`() {
+        whenever(userManager.isUserRegistered()).thenReturn(true)
+        whenever(userManager.isUserLoggedIn()).thenReturn(false)
+
+        assertEquals(LoginActivity::class.java, viewModel.getActivityClass())
+    }
+
+    @Test
+    fun `If the user is logged in then getActivityClass returns MainActivity`() {
+        whenever(userManager.isUserLoggedIn()).thenReturn(true)
+
+        assertEquals(MainActivity::class.java, viewModel.getActivityClass())
+    }
+}