Implements BottomSheetBehavior.Callbacks observables

rxbinding-material/src/main/java/com/jakewharton/rxbinding3/material/BottomSheetBehaiorStateChangeEventObservable.kt

@@ -0,0 +1,80 @@
+@file:JvmName("RxBottomSheetBehavior")
+@file:JvmMultifileClass
+
+package com.jakewharton.rxbinding3.material
+
+import android.content.Context
+import android.view.View
+import androidx.annotation.CheckResult
+import androidx.coordinatorlayout.widget.CoordinatorLayout.LayoutParams
+import com.google.android.material.bottomsheet.BottomSheetBehavior
+import com.google.android.material.bottomsheet.BottomSheetBehavior.BottomSheetCallback
+import com.jakewharton.rxbinding3.internal.checkMainThread
+import io.reactivex.Observable
+import io.reactivex.Observer
+import io.reactivex.android.MainThreadDisposable
+
+/**
+ * Create an observable which emits the state change events from `view` on
+ * [BottomSheetBehavior]
+ *
+ * *Warning:* The created observable keeps a strong reference to `view`. Unsubscribe
+ * to free this reference.
+ *
+ * *Warning:* The created observable uses [BottomSheetBehavior.setBottomSheetCallback] to observe
+ * state changes. Only one observable can be used for a view at a time.
+ */
+@CheckResult
+fun View.stateChangeEvents(): Observable<BottomSheetBehaviorStateChangeEvent> {
+  return BottomSheetBehaviorStateChangeEventObservable(this)
+}
+
+/**
+ * A BottomSheetBehavior state change event on a view.
+ *
+ * **Warning:** Instances keep a strong reference to the view. Operators that cache
+ * instances have the potential to leak the associated [Context].
+ */
+data class BottomSheetBehaviorStateChangeEvent(
+    val view: View,
+    val newState: Int
+)
+
+private class BottomSheetBehaviorStateChangeEventObservable(
+    private val view: View
+) : Observable<BottomSheetBehaviorStateChangeEvent>() {
+
+  override fun subscribeActual(observer: Observer<in BottomSheetBehaviorStateChangeEvent>) {
+    if (!checkMainThread(observer)) {
+      return
+    }
+    val params = view.layoutParams as? LayoutParams
+        ?: throw IllegalArgumentException("The view is not in a Coordinator Layout.")
+    val behavior = params.behavior as BottomSheetBehavior<*>?
+        ?: throw IllegalStateException("There's no behavior set on this view.")
+
+    val listener = Listener(behavior, observer)
+    observer.onSubscribe(listener)
+    behavior.setBottomSheetCallback(listener.callback)
+  }
+
+  private class Listener(
+      private val behavior: BottomSheetBehavior<*>,
+      private val observer: Observer<in BottomSheetBehaviorStateChangeEvent>
+  ) : MainThreadDisposable() {
+
+    val callback = object : BottomSheetCallback() {
+      override fun onStateChanged(view: View, newState: Int) {
+        if (!isDisposed) {
+          observer.onNext(BottomSheetBehaviorStateChangeEvent(view, newState))
+        }
+      }
+
+      override fun onSlide(view: View, slideOffset: Float) {}
+    }
+
+    override fun onDispose() {
+      behavior.setBottomSheetCallback(null)
+    }
+  }
+}

rxbinding-material/src/main/java/com/jakewharton/rxbinding3/material/BottomSheetBehaviorSlideEventObservable.kt

@@ -0,0 +1,80 @@
+@file:JvmName("RxBottomSheetBehavior")
+@file:JvmMultifileClass
+
+package com.jakewharton.rxbinding3.material
+
+import android.content.Context
+import android.view.View
+import androidx.annotation.CheckResult
+import androidx.coordinatorlayout.widget.CoordinatorLayout.LayoutParams
+import com.google.android.material.bottomsheet.BottomSheetBehavior
+import com.google.android.material.bottomsheet.BottomSheetBehavior.BottomSheetCallback
+import com.jakewharton.rxbinding3.internal.checkMainThread
+import io.reactivex.Observable
+import io.reactivex.Observer
+import io.reactivex.android.MainThreadDisposable
+
+/**
+ * Create an observable which emits the slide events from `view` on
+ * [BottomSheetBehavior]
+ *
+ * *Warning:* The created observable keeps a strong reference to `view`. Unsubscribe
+ * to free this reference.
+ *
+ * *Warning:* The created observable uses [BottomSheetBehavior.setBottomSheetCallback] to observe
+ * slides. Only one observable can be used for a view at a time.
+ */
+@CheckResult
+fun View.slideEvents(): Observable<BottomSheetBehaviorSlideEvent> {
+  return BottomSheetBehaviorSlideEventObservable(this)
+}
+
+/**
+ * A BottomSheetBehavior slide event on a view.
+ *
+ * **Warning:** Instances keep a strong reference to the view. Operators that cache
+ * instances have the potential to leak the associated [Context].
+ */
+data class BottomSheetBehaviorSlideEvent(
+    val view: View,
+    val slideOffset: Float
+)
+
+private class BottomSheetBehaviorSlideEventObservable(
+    private val view: View
+) : Observable<BottomSheetBehaviorSlideEvent>() {
+
+  override fun subscribeActual(observer: Observer<in BottomSheetBehaviorSlideEvent>) {
+    if (!checkMainThread(observer)) {
+      return
+    }
+    val params = view.layoutParams as? LayoutParams
+        ?: throw IllegalArgumentException("The view is not in a Coordinator Layout.")
+    val behavior = params.behavior as BottomSheetBehavior<*>?
+        ?: throw IllegalStateException("There's no behavior set on this view.")
+
+    val listener = Listener(behavior, observer)
+    observer.onSubscribe(listener)
+    behavior.setBottomSheetCallback(listener.callback)
+  }
+
+  private class Listener(
+      private val behavior: BottomSheetBehavior<*>,
+      private val observer: Observer<in BottomSheetBehaviorSlideEvent>
+  ) : MainThreadDisposable() {
+
+    val callback = object : BottomSheetCallback() {
+      override fun onStateChanged(view: View, newState: Int) {}
+
+      override fun onSlide(view: View, slideOffset: Float) {
+        if (!isDisposed) {
+          observer.onNext(BottomSheetBehaviorSlideEvent(view, slideOffset))
+        }
+      }
+    }
+
+    override fun onDispose() {
+      behavior.setBottomSheetCallback(null)
+    }
+  }
+}

rxbinding-material/src/main/java/com/jakewharton/rxbinding3/material/BottomSheetBehaviorSlideObservable.kt

@@ -0,0 +1,68 @@
+@file:JvmName("RxBottomSheetBehavior")
+@file:JvmMultifileClass
+
+package com.jakewharton.rxbinding3.material
+
+import android.view.View
+import androidx.annotation.CheckResult
+import androidx.coordinatorlayout.widget.CoordinatorLayout.LayoutParams
+import com.google.android.material.bottomsheet.BottomSheetBehavior
+import com.google.android.material.bottomsheet.BottomSheetBehavior.BottomSheetCallback
+import com.jakewharton.rxbinding3.internal.checkMainThread
+import io.reactivex.Observable
+import io.reactivex.Observer
+import io.reactivex.android.MainThreadDisposable
+
+/**
+ * Create an observable which emits the slide offsets from `view` on
+ * [BottomSheetBehavior]
+ *
+ * *Warning:* The created observable keeps a strong reference to `view`. Unsubscribe
+ * to free this reference.
+ *
+ * *Warning:* The created observable uses [BottomSheetBehavior.setBottomSheetCallback] to observe
+ * slides. Only one observable can be used for a view at a time.
+ */
+@CheckResult
+fun View.slides(): Observable<Float> {
+  return BottomSheetBehaviorSlideObservable(this)
+}
+
+private class BottomSheetBehaviorSlideObservable(
+    private val view: View
+) : Observable<Float>() {
+
+  override fun subscribeActual(observer: Observer<in Float>) {
+    if (!checkMainThread(observer)) {
+      return
+    }
+    val params = view.layoutParams as? LayoutParams
+        ?: throw IllegalArgumentException("The view is not in a Coordinator Layout.")
+    val behavior = params.behavior as BottomSheetBehavior<*>?
+        ?: throw IllegalStateException("There's no behavior set on this view.")
+
+    val listener = Listener(behavior, observer)
+    observer.onSubscribe(listener)
+    behavior.setBottomSheetCallback(listener.callback)
+  }
+
+  private class Listener(
+      private val behavior: BottomSheetBehavior<*>,
+      private val observer: Observer<in Float>
+  ) : MainThreadDisposable() {
+
+    val callback = object : BottomSheetCallback() {
+      override fun onStateChanged(view: View, newState: Int) {}
+
+      override fun onSlide(view: View, slideOffset: Float) {
+        if (!isDisposed) {
+          observer.onNext(slideOffset)
+        }
+      }
+    }
+
+    override fun onDispose() {
+      behavior.setBottomSheetCallback(null)
+    }
+  }
+}

rxbinding-material/src/main/java/com/jakewharton/rxbinding3/material/BottomSheetBehaviorStateChangeObservable.kt

@@ -0,0 +1,68 @@
+@file:JvmName("RxBottomSheetBehavior")
+@file:JvmMultifileClass
+
+package com.jakewharton.rxbinding3.material
+
+import android.view.View
+import androidx.annotation.CheckResult
+import androidx.coordinatorlayout.widget.CoordinatorLayout.LayoutParams
+import com.google.android.material.bottomsheet.BottomSheetBehavior
+import com.google.android.material.bottomsheet.BottomSheetBehavior.BottomSheetCallback
+import com.jakewharton.rxbinding3.internal.checkMainThread
+import io.reactivex.Observable
+import io.reactivex.Observer
+import io.reactivex.android.MainThreadDisposable
+
+/**
+ * Create an observable which emits the state changes from `view` on
+ * [BottomSheetBehavior]
+ *
+ * *Warning:* The created observable keeps a strong reference to `view`. Unsubscribe
+ * to free this reference.
+ *
+ * *Warning:* The created observable uses [BottomSheetBehavior.setBottomSheetCallback] to observe
+ * state changes. Only one observable can be used for a view at a time.
+ */
+@CheckResult
+fun View.stateChanges(): Observable<Int> {
+  return BottomSheetBehaviorStateChangeObservable(this)
+}
+
+private class BottomSheetBehaviorStateChangeObservable(
+    private val view: View
+) : Observable<Int>() {
+
+  override fun subscribeActual(observer: Observer<in Int>) {
+    if (!checkMainThread(observer)) {
+      return
+    }
+    val params = view.layoutParams as? LayoutParams
+        ?: throw IllegalArgumentException("The view is not in a Coordinator Layout.")
+    val behavior = params.behavior as BottomSheetBehavior<*>?
+        ?: throw IllegalStateException("There's no behavior set on this view.")
+
+    val listener = Listener(behavior, observer)
+    observer.onSubscribe(listener)
+    behavior.setBottomSheetCallback(listener.callback)
+  }
+
+  private class Listener(
+      private val behavior: BottomSheetBehavior<*>,
+      private val observer: Observer<in Int>
+  ) : MainThreadDisposable() {
+
+    val callback = object : BottomSheetCallback() {
+      override fun onStateChanged(view: View, newState: Int) {
+        if (!isDisposed) {
+          observer.onNext(newState)
+        }
+      }
+
+      override fun onSlide(view: View, slideOffset: Float) {}
+    }
+
+    override fun onDispose() {
+      behavior.setBottomSheetCallback(null)
+    }
+  }
+}