Move from Java to Kotlin

app/build.gradle

@@ -39,7 +39,7 @@ def getVersionName = { ->
 }
 
 android {
-    compileSdkVersion 34
+    compileSdk 34
     defaultConfig {
         applicationId "com.vgaidarji.cimatters"
         minSdkVersion 24
@@ -58,8 +58,8 @@ android {
         }
     }
     compileOptions {
-        sourceCompatibility JavaVersion.VERSION_1_8
-        targetCompatibility JavaVersion.VERSION_1_8
+        sourceCompatibility JavaVersion.VERSION_17
+        targetCompatibility JavaVersion.VERSION_17
     }
     lintOptions {
         checkReleaseBuilds false

app/src/androidTest/java/com/vgaidarji/cimatters/LoginActivityTest.kt

@@ -0,0 +1,48 @@
+package com.vgaidarji.cimatters
+
+import android.support.test.espresso.Espresso
+import android.support.test.espresso.action.ViewActions
+import android.support.test.espresso.assertion.ViewAssertions
+import android.support.test.espresso.matcher.ViewMatchers
+import android.support.test.rule.ActivityTestRule
+import android.support.test.runner.AndroidJUnit4
+import org.hamcrest.CoreMatchers
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class LoginActivityTest {
+    @Rule
+    var activityTestRule = ActivityTestRule(
+        LoginActivity::class.java
+    )
+
+    @Test
+    @Throws(Exception::class)
+    fun onLoginClick_shouldOpenNextActivityForAllowedCredentials() {
+        Espresso.onView(ViewMatchers.withId(R.id.edit_text_email))
+            .perform(ViewActions.typeText("[email protected]"))
+        Espresso.onView(ViewMatchers.withId(R.id.edit_text_password))
+            .perform(ViewActions.typeText("1111"))
+        Espresso.onView(ViewMatchers.withId(R.id.button_login)).perform(ViewActions.click())
+        Espresso.onView(ViewMatchers.withText("OK"))
+            .check(ViewAssertions.matches(ViewMatchers.isDisplayed()))
+    }
+
+    @Test
+    @Throws(Exception::class)
+    fun onLoginClick_shouldShowErrorForIncorrectCredentials() {
+        Espresso.onView(ViewMatchers.withId(R.id.edit_text_email))
+            .perform(ViewActions.typeText("[email protected]"))
+        Espresso.onView(ViewMatchers.withId(R.id.edit_text_password))
+            .perform(ViewActions.typeText("not_a_password"))
+        Espresso.onView(ViewMatchers.withId(R.id.button_login)).perform(ViewActions.click())
+        Espresso.onView(
+            CoreMatchers.allOf(
+                ViewMatchers.withId(android.support.design.R.id.snackbar_text),
+                ViewMatchers.withText("Wrong credentials.")
+            )
+        ).check(ViewAssertions.matches(ViewMatchers.isDisplayed()))
+    }
+}

app/src/main/java/com/vgaidarji/cimatters/CiMattersApplication.kt

@@ -0,0 +1,10 @@
+package com.vgaidarji.cimatters
+
+import android.app.Application
+
+class CiMattersApplication : Application() {
+    override fun onCreate() {
+        super.onCreate()
+        // TODO: integrate with Crashlytics
+    }
+}

app/src/main/java/com/vgaidarji/cimatters/LoginActivity.kt

@@ -0,0 +1,51 @@
+package com.vgaidarji.cimatters
+
+import android.content.Intent
+import android.os.Bundle
+import android.support.design.widget.CoordinatorLayout
+import android.support.design.widget.Snackbar
+import android.support.v7.app.AppCompatActivity
+import android.widget.Button
+import android.widget.EditText
+import butterknife.ButterKnife
+import butterknife.InjectView
+import butterknife.OnClick
+
+class LoginActivity : AppCompatActivity(), LoginView {
+    @InjectView(R.id.coordinator)
+    var coordinatorLayout: CoordinatorLayout? = null
+
+    @InjectView(R.id.edit_text_email)
+    var editTextEmail: EditText? = null
+
+    @InjectView(R.id.edit_text_password)
+    var editTextPassword: EditText? = null
+
+    @InjectView(R.id.button_login)
+    var buttonLogin: Button? = null
+    private var presenter: LoginPresenter? = null
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_login)
+        title = getString(R.string.activity_login)
+        ButterKnife.inject(this)
+        presenter = LoginPresenter(this)
+    }
+
+    @OnClick(R.id.button_login)
+    fun onLoginClick() {
+        presenter!!.onLoginClick(
+            editTextEmail!!.text.toString(),
+            editTextPassword!!.text.toString()
+        )
+    }
+
+    override fun openNextActivity() {
+        startActivity(Intent(this@LoginActivity, MainActivity::class.java))
+        finish()
+    }
+
+    override fun showError(message: String?) {
+        message?.let { Snackbar.make(coordinatorLayout!!, it, Snackbar.LENGTH_LONG).show() }
+    }
+}

app/src/main/java/com/vgaidarji/cimatters/LoginPresenter.kt

@@ -0,0 +1,17 @@
+package com.vgaidarji.cimatters
+
+internal class LoginPresenter(private val view: LoginView) {
+    fun onLoginClick(email: String, password: String) {
+        if (email == EMAIL && password == PASSWORD) {
+            view.openNextActivity()
+        } else {
+            view.showError(WRONG_CREDENTIALS)
+        }
+    }
+
+    companion object {
+        private const val EMAIL = "[email protected]"
+        private const val PASSWORD = "1111"
+        private const val WRONG_CREDENTIALS = "Wrong credentials."
+    }
+}

app/src/main/java/com/vgaidarji/cimatters/LoginView.kt

@@ -0,0 +1,6 @@
+package com.vgaidarji.cimatters
+
+internal interface LoginView {
+    fun openNextActivity()
+    fun showError(message: String?)
+}

app/src/main/java/com/vgaidarji/cimatters/MainActivity.kt

@@ -0,0 +1,12 @@
+package com.vgaidarji.cimatters
+
+import android.os.Bundle
+import android.support.v7.app.AppCompatActivity
+
+class MainActivity : AppCompatActivity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_main)
+        title = getString(R.string.activity_main)
+    }
+}

app/src/test/java/com/vgaidarji/cimatters/LoginPresenterTest.kt

@@ -0,0 +1,31 @@
+package com.vgaidarji.cimatters
+
+import org.junit.Before
+import org.junit.Test
+import org.mockito.Matchers
+import org.mockito.Mockito
+
+class LoginPresenterTest {
+    private lateinit var view: LoginView
+    private var presenter: LoginPresenter? = null
+    @Before
+    @Throws(Exception::class)
+    fun setUp() {
+        view = Mockito.mock(LoginView::class.java)
+        presenter = LoginPresenter(view)
+    }
+
+    @Test
+    @Throws(Exception::class)
+    fun onLoginClick_shouldOpenNextActivityForAllowedCredentials() {
+        presenter!!.onLoginClick("[email protected]", "1111")
+        Mockito.verify(view)?.openNextActivity()
+    }
+
+    @Test
+    @Throws(Exception::class)
+    fun onLoginClick_shouldShowErrorForIncorrectCredentials() {
+        presenter!!.onLoginClick("[email protected]", "not_a_password")
+        Mockito.verify(view)?.showError(Matchers.anyString())
+    }
+}