OnModelCheckedChangeListener (#725)

* added OnModelCheckedChangeListener with tests

* created ListenerUtils and moved common functions in it.

epoxy-adapter/src/main/java/com/airbnb/epoxy/ListenersUtils.java

@@ -0,0 +1,48 @@
+package com.airbnb.epoxy;
+
+import android.view.View;
+import android.view.ViewParent;
+
+import androidx.annotation.Nullable;
+import androidx.recyclerview.widget.RecyclerView;
+import androidx.recyclerview.widget.RecyclerView.ViewHolder;
+
+public class ListenersUtils {
+
+  @Nullable
+  static EpoxyViewHolder getEpoxyHolderForChildView(View v) {
+    RecyclerView recyclerView = findParentRecyclerView(v);
+    if (recyclerView == null) {
+      return null;
+    }
+
+    ViewHolder viewHolder = recyclerView.findContainingViewHolder(v);
+    if (viewHolder == null) {
+      return null;
+    }
+
+    if (!(viewHolder instanceof EpoxyViewHolder)) {
+      return null;
+    }
+
+    return (EpoxyViewHolder) viewHolder;
+  }
+
+  @Nullable
+  private static RecyclerView findParentRecyclerView(@Nullable View v) {
+    if (v == null) {
+      return null;
+    }
+
+    ViewParent parent = v.getParent();
+    if (parent instanceof RecyclerView) {
+      return (RecyclerView) parent;
+    }
+
+    if (parent instanceof View) {
+      return findParentRecyclerView((View) parent);
+    }
+
+    return null;
+  }
+}

epoxy-adapter/src/main/java/com/airbnb/epoxy/OnModelCheckedChangeListener.java

@@ -0,0 +1,18 @@
+package com.airbnb.epoxy;
+
+import android.widget.CompoundButton;
+
+public interface OnModelCheckedChangeListener<T extends EpoxyModel<?>, V> {
+  /**
+   * Called when the view bound to the model is checked.
+   *
+   * @param model       The model that the view is bound to.
+   * @param parentView  The view bound to the model which received the click.
+   * @param clickedView The view that received the click. This is either a child of the parentView
+   *                    or the parentView itself
+   * @param isChecked   The new value for isChecked property.
+   * @param position    The position of the model in the adapter.
+   */
+  void onChecked(T model, V parentView,
+      CompoundButton checkedView, boolean isChecked, int position);
+}

epoxy-adapter/src/main/java/com/airbnb/epoxy/WrappedEpoxyModelCheckedChangeListener.java

@@ -0,0 +1,61 @@
+package com.airbnb.epoxy;
+
+import android.widget.CompoundButton;
+import android.widget.CompoundButton.OnCheckedChangeListener;
+
+import androidx.recyclerview.widget.RecyclerView;
+
+/**
+ * Used in the generated models to transform normal checked change listener to model
+ * checked change.
+ */
+public class WrappedEpoxyModelCheckedChangeListener<T extends EpoxyModel<?>, V>
+    implements OnCheckedChangeListener {
+
+  private final OnModelCheckedChangeListener<T, V> originalCheckedChangeListener;
+
+  public WrappedEpoxyModelCheckedChangeListener(
+      OnModelCheckedChangeListener<T, V> checkedListener
+  ) {
+    if (checkedListener == null) {
+      throw new IllegalArgumentException("Checked change listener cannot be null");
+    }
+
+    this.originalCheckedChangeListener = checkedListener;
+  }
+
+  @Override
+  public void onCheckedChanged(CompoundButton button, boolean isChecked) {
+    EpoxyViewHolder epoxyHolder = ListenersUtils.getEpoxyHolderForChildView(button);
+    if (epoxyHolder == null) {
+      throw new IllegalStateException("Could not find RecyclerView holder for clicked view");
+    }
+
+    final int adapterPosition = epoxyHolder.getAdapterPosition();
+    if (adapterPosition != RecyclerView.NO_POSITION) {
+      originalCheckedChangeListener
+          .onChecked((T) epoxyHolder.getModel(), (V) epoxyHolder.objectToBind(), button,
+          isChecked, adapterPosition);
+    }
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (!(o instanceof WrappedEpoxyModelCheckedChangeListener)) {
+      return false;
+    }
+
+    WrappedEpoxyModelCheckedChangeListener<?, ?>
+        that = (WrappedEpoxyModelCheckedChangeListener<?, ?>) o;
+
+    return originalCheckedChangeListener.equals(that.originalCheckedChangeListener);
+  }
+
+  @Override
+  public int hashCode() {
+    return originalCheckedChangeListener.hashCode();
+  }
+}

epoxy-adapter/src/main/java/com/airbnb/epoxy/WrappedEpoxyModelClickListener.java

@@ -3,11 +3,8 @@
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.view.View.OnLongClickListener;
-import android.view.ViewParent;
 
-import androidx.annotation.Nullable;
 import androidx.recyclerview.widget.RecyclerView;
-import androidx.recyclerview.widget.RecyclerView.ViewHolder;
 
 /**
  * Used in the generated models to transform normal view click listeners to model click
@@ -40,7 +37,7 @@ public WrappedEpoxyModelClickListener(OnModelLongClickListener<T, V> clickListen
 
   @Override
   public void onClick(View v) {
-    EpoxyViewHolder epoxyHolder = getEpoxyHolderForChildView(v);
+    EpoxyViewHolder epoxyHolder = ListenersUtils.getEpoxyHolderForChildView(v);
     if (epoxyHolder == null) {
       throw new IllegalStateException("Could not find RecyclerView holder for clicked view");
     }
@@ -55,7 +52,7 @@ public void onClick(View v) {
 
   @Override
   public boolean onLongClick(View v) {
-    EpoxyViewHolder epoxyHolder = getEpoxyHolderForChildView(v);
+    EpoxyViewHolder epoxyHolder = ListenersUtils.getEpoxyHolderForChildView(v);
     if (epoxyHolder == null) {
       throw new IllegalStateException("Could not find RecyclerView holder for clicked view");
     }
@@ -71,43 +68,6 @@ public boolean onLongClick(View v) {
     return false;
   }
 
-  @Nullable
-  private static EpoxyViewHolder getEpoxyHolderForChildView(View v) {
-    RecyclerView recyclerView = findParentRecyclerView(v);
-    if (recyclerView == null) {
-      return null;
-    }
-
-    ViewHolder viewHolder = recyclerView.findContainingViewHolder(v);
-    if (viewHolder == null) {
-      return null;
-    }
-
-    if (!(viewHolder instanceof EpoxyViewHolder)) {
-      return null;
-    }
-
-    return (EpoxyViewHolder) viewHolder;
-  }
-
-  @Nullable
-  private static RecyclerView findParentRecyclerView(@Nullable View v) {
-    if (v == null) {
-      return null;
-    }
-
-    ViewParent parent = v.getParent();
-    if (parent instanceof RecyclerView) {
-      return (RecyclerView) parent;
-    }
-
-    if (parent instanceof View) {
-      return findParentRecyclerView((View) parent);
-    }
-
-    return null;
-  }
-
   @Override
   public boolean equals(Object o) {
     if (this == o) {

epoxy-integrationtest/src/main/java/com/airbnb/epoxy/integrationtest/ModelWithCheckedChangeListener.java

@@ -0,0 +1,27 @@
+package com.airbnb.epoxy.integrationtest;
+
+import android.view.View;
+import android.widget.CompoundButton;
+import android.widget.CompoundButton.OnCheckedChangeListener;
+
+import com.airbnb.epoxy.EpoxyAttribute;
+import com.airbnb.epoxy.EpoxyModel;
+
+import androidx.annotation.NonNull;
+
+public class ModelWithCheckedChangeListener extends EpoxyModel<View> {
+
+  @EpoxyAttribute OnCheckedChangeListener checkedChangeListener;
+
+  @Override
+  protected int getDefaultLayout() {
+    return R.layout.model_with_checked_change;
+  }
+
+  @Override
+  public void bind(@NonNull View view) {
+    if (view instanceof CompoundButton) {
+      ((CompoundButton) view).setOnCheckedChangeListener(checkedChangeListener);
+    }
+  }
+}

epoxy-integrationtest/src/main/res/layout/model_with_checked_change.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<CheckBox xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+</CheckBox>

epoxy-integrationtest/src/test/java/com/airbnb/epoxy/BindDiffTest.kt

@@ -69,7 +69,7 @@ class BindDiffTest {
 
     @Test
     fun propGroupChangedFromOneAttributeToAnother() {
-        val clickListener = View.OnClickListener { v -> }
+        val clickListener = View.OnClickListener {}
         validateDiff(
                 model1Props = {
                     requiredText("hello")

epoxy-integrationtest/src/test/java/com/airbnb/epoxy/ModelClickListenerTest.java

@@ -2,8 +2,10 @@
 
 import android.view.View;
 import android.view.View.OnClickListener;
+import android.widget.CompoundButton;
 
 import com.airbnb.epoxy.integrationtest.BuildConfig;
+import com.airbnb.epoxy.integrationtest.ModelWithCheckedChangeListener_;
 import com.airbnb.epoxy.integrationtest.ModelWithClickListener_;
 import com.airbnb.epoxy.integrationtest.ModelWithLongClickListener_;
 
@@ -69,6 +71,17 @@ public boolean onLongClick(ModelWithLongClickListener_ model, View view, View v,
     }
   }
 
+  static class ModelCheckedChangeListener
+      implements OnModelCheckedChangeListener<ModelWithCheckedChangeListener_, View> {
+    boolean checked;
+
+    @Override
+    public void onChecked(ModelWithCheckedChangeListener_ model, View parentView,
+        CompoundButton checkedView, boolean isChecked, int position) {
+      checked = true;
+    }
+  }
+
   static class ViewClickListener implements OnClickListener {
     boolean clicked;
 
@@ -137,6 +150,46 @@ public void basicModelLongClickListener() {
     verify(modelClickListener).onLongClick(eq(model), any(View.class), eq(viewMock), eq(1));
   }
 
+  @Test
+  public void basicModelCheckedChangeListener() {
+    final ModelWithCheckedChangeListener_ model = new ModelWithCheckedChangeListener_();
+    ModelCheckedChangeListener modelCheckedChangeListener = spy(new ModelCheckedChangeListener());
+    model.checkedChangeListener(modelCheckedChangeListener);
+
+    TestController controller = new TestController();
+    controller.setModel(model);
+
+    lifecycleHelper.buildModelsAndBind(controller);
+
+    CompoundButton compoundMock = mockCompoundButtonForClicking(model);
+
+    model.checkedChangeListener().onCheckedChanged(compoundMock, true);
+    assertTrue(modelCheckedChangeListener.checked);
+
+    verify(modelCheckedChangeListener).onChecked(eq(model), any(View.class), any(CompoundButton.class), eq(true), eq(1));
+  }
+
+  private CompoundButton mockCompoundButtonForClicking(EpoxyModel model) {
+    CompoundButton mockedView = mock(CompoundButton.class);
+    RecyclerView recyclerMock = mock(RecyclerView.class);
+    EpoxyViewHolder holderMock = mock(EpoxyViewHolder.class);
+
+    when(holderMock.getAdapterPosition()).thenReturn(1);
+    doReturn(recyclerMock).when(mockedView).getParent();
+    doReturn(holderMock).when(recyclerMock).findContainingViewHolder(mockedView);
+    doReturn(model).when(holderMock).getModel();
+
+    when(mockedView.getParent()).thenReturn(recyclerMock);
+    when(recyclerMock.findContainingViewHolder(mockedView)).thenReturn(holderMock);
+    when(holderMock.getAdapterPosition()).thenReturn(1);
+    when(holderMock.getModel()).thenReturn(model);
+
+    View parentView = mock(View.class);
+    when(holderMock.objectToBind()).thenReturn(parentView);
+    doReturn(parentView).when(holderMock).objectToBind();
+    return mockedView;
+  }
+
   @Test
   public void modelClickListenerOverridesViewClickListener() {
     final ModelWithClickListener_ model = new ModelWithClickListener_();

epoxy-processor/src/main/java/com/airbnb/epoxy/AttributeInfo.kt

@@ -3,6 +3,7 @@ package com.airbnb.epoxy
 import com.airbnb.epoxy.GeneratedModelInfo.AttributeGroup
 import com.airbnb.epoxy.Utils.EPOXY_MODEL_TYPE
 import com.airbnb.epoxy.Utils.isSubtypeOfType
+import com.airbnb.epoxy.Utils.isViewCheckedChangeListenerType
 import com.airbnb.epoxy.Utils.isViewClickListenerType
 import com.airbnb.epoxy.Utils.isViewLongClickListenerType
 import com.squareup.javapoet.AnnotationSpec
@@ -104,6 +105,9 @@ internal abstract class AttributeInfo {
     val isViewLongClickListener: Boolean
         get() = isViewLongClickListenerType(typeMirror)
 
+    val isViewCheckedChangeListener: Boolean
+        get() = isViewCheckedChangeListenerType(typeMirror)
+
     val isBoolean: Boolean
         get() = Utils.isBooleanType(typeMirror)