Kotlin conversion

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.0.5 - 2017-09-11
+
+- Convert to Kotlin library.
+
 ## 1.0.4 - 2017-09-11
 
 - Minor tweaks.

README.md

@@ -8,7 +8,7 @@ A simple utility class that allows you to track when your Android application ha
 
 ```groovy
 
-compile 'com.miguelgaeta.android-backgrounded:backgrounded:1.0.4'
+compile 'com.miguelgaeta.android-backgrounded:backgrounded:1.0.5'
 
 ```
 

app/build.gradle

@@ -1,15 +1,15 @@
 apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android'
 
 android {
-    compileSdkVersion 26
-    buildToolsVersion '25.0.0'
+    compileSdkVersion rootProject.ext.target_sdk_version
+    buildToolsVersion rootProject.ext.build_tools_version
 
     defaultConfig {
         applicationId "com.miguelgaeta.android_backgrounded"
-        minSdkVersion 14
-        targetSdkVersion 26
-        versionCode 1
-        versionName "1.0"
+
+        minSdkVersion rootProject.ext.min_sdk_version
+        targetSdkVersion rootProject.ext.target_sdk_version
     }
     buildTypes {
         release {
@@ -22,10 +22,13 @@ android {
 dependencies {
 
     //noinspection GradleDynamicVersion
-    compile 'com.android.support:appcompat-v7:26+'
+    compile "com.android.support:appcompat-v7:$target_sdk_version+"
 
     //noinspection GradleDynamicVersion
     compile 'io.reactivex:rxjava:1.+'
 
+    //noinspection GradleDynamicVersion
+    compile 'org.jetbrains.kotlin:kotlin-stdlib-jre7:1.+'
+
     compile project(':backgrounded')
 }

app/src/main/java/com/miguelgaeta/AppActivity.kt

@@ -0,0 +1,24 @@
+package com.miguelgaeta
+
+import android.os.Bundle
+import android.support.v7.app.AppCompatActivity
+import android.util.Log
+import com.miguelgaeta.backgrounded.Backgrounded
+
+class AppActivity : AppCompatActivity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+
+        Backgrounded.init(application)
+        Backgrounded.get().subscribe { backgrounded -> Log.e("Test", "Backgrounded status: " + backgrounded) }
+
+        Log.e("Test", "Currently backgrounded: " + Backgrounded.isBackgrounded())
+    }
+
+    override fun onDestroy() {
+        super.onDestroy()
+
+        Backgrounded.destroy(application)
+    }
+}

backgrounded/build.gradle

@@ -1,12 +1,13 @@
 apply plugin: 'com.android.library'
+apply plugin: 'kotlin-android'
 
 android {
-    compileSdkVersion 26
-    buildToolsVersion '25.0.0'
+    compileSdkVersion rootProject.ext.target_sdk_version
+    buildToolsVersion rootProject.ext.build_tools_version
 
     defaultConfig {
-        minSdkVersion 14
-        targetSdkVersion 26
+        minSdkVersion rootProject.ext.min_sdk_version
+        targetSdkVersion rootProject.ext.target_sdk_version
     }
 
     buildTypes {
@@ -21,6 +22,9 @@ dependencies {
 
     //noinspection GradleDynamicVersion
     provided 'io.reactivex:rxjava:1.+'
+
+    //noinspection GradleDynamicVersion
+    provided "org.jetbrains.kotlin:kotlin-stdlib-jre7:1.+"
 }
 
 apply from: '../build.release-aar.gradle'

backgrounded/src/main/java/com/miguelgaeta/backgrounded/Backgrounded.kt

@@ -0,0 +1,85 @@
+package com.miguelgaeta.backgrounded
+
+import android.app.Activity
+import android.app.Application
+import android.os.Bundle
+import android.util.Log
+import rx.Observable
+import rx.Subscription
+import rx.subjects.BehaviorSubject
+import rx.subjects.SerializedSubject
+import java.util.concurrent.TimeUnit
+
+/**
+ * Utility class that uses [Application.ActivityLifecycleCallbacks] to heuristically
+ * track whether or not the current application is in the foreground or background.
+ */
+object Backgrounded {
+
+    private val lifecycle: Lifecycle = Lifecycle()
+
+    @JvmStatic fun init(application: Application?) {
+        application?.registerActivityLifecycleCallbacks(lifecycle)
+    }
+
+    @JvmStatic fun destroy(application: Application?) {
+        application?.unregisterActivityLifecycleCallbacks(lifecycle)
+    }
+
+    @JvmStatic fun get(): Observable<Boolean> =
+            lifecycle.emitter.distinctUntilChanged()
+
+    @JvmStatic fun isBackgrounded(): Boolean =
+            lifecycle.emitter.toBlocking().mostRecent(true).iterator().next()
+
+    private class Lifecycle internal constructor() : Application.ActivityLifecycleCallbacks {
+
+        internal val emitter = SerializedSubject(BehaviorSubject.create<Boolean>())
+        internal var subscription: Subscription? = null
+
+        init {
+            checkBackgrounded(DELAY_SHORT)
+        }
+
+        override fun onActivityCreated(activity: Activity, bundle: Bundle) {
+        }
+
+        override fun onActivityStarted(activity: Activity) {
+        }
+
+        override fun onActivityResumed(activity: Activity) {
+            subscription?.unsubscribe()
+
+            emitter.onNext(false)
+        }
+
+        override fun onActivityPaused(activity: Activity) {
+            checkBackgrounded(DELAY)
+        }
+
+        override fun onActivityStopped(activity: Activity) {
+        }
+
+        override fun onActivitySaveInstanceState(activity: Activity, bundle: Bundle) {
+        }
+
+        override fun onActivityDestroyed(activity: Activity) {
+        }
+
+        private fun checkBackgrounded(delay: Long) {
+            subscription = Observable
+                    .just(true)
+                    .delay(delay, TimeUnit.MILLISECONDS)
+                    .subscribe(emitter::onNext) { Log.e(TAG, TAG_ERROR) }
+        }
+
+        companion object {
+
+            private val DELAY = 2000L
+            private val DELAY_SHORT = 500L
+
+            private val TAG = "Backgrounded"
+            private val TAG_ERROR = "Subscription error in backgrounded delay."
+        }
+    }
+}

build.gradle

@@ -1,9 +1,17 @@
 buildscript {
+    ext.kotlin_version = '1.1.51'
+    ext.build_tools_version = '26.0.1'
+    ext.gradle_tools_version = '2.3.3'
+    ext.min_sdk_version = 14
+    ext.target_sdk_version = 26
+
     repositories {
         jcenter()
     }
+
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.3.3'
+        classpath "com.android.tools.build:gradle:$gradle_tools_version"
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }