Model group building with Kotlin DSL (#1012)

* Add an empty constructor for `EpoxyModelGroup`, protected visibility only. * If the model implements `ModelCollector` make the build too so the DSL can be used. * Use the new model group DSL in the sample app * Add `implementsModelCollector` in memoizer * Fix memoizer implementation * Add `shouldSaveViewState` property to model group * Make `EpoxyModelGroup` a `ModelCollector` and create a `GroupModel` class with the `@EpoxyModelClass` annotation so it can be used in the DSL * Can be simnplified * force codegen on pr check * revert last change * Move ModelCollector code to GroupModel as EpoxyModelGroup can't be used directly in the DSL * Add a small doc/usage * Check class hierarchy for ModelCollector * Reset shouldSaveViewState to private Co-authored-by: Emmanuel Boudrant <eboudrant@netflix.com>
airbnb · Jul 23, 2020 · 1f14d64 · 1f14d64
1 parent 141894c
commit 1f14d64
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diff --git a/epoxy-adapter/src/main/java/com/airbnb/epoxy/EpoxyModelGroup.java b/epoxy-adapter/src/main/java/com/airbnb/epoxy/EpoxyModelGroup.java
@@ -12,6 +12,7 @@
 import androidx.annotation.CallSuper;
 import androidx.annotation.LayoutRes;
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 
 /**
  * An {@link EpoxyModel} that contains other models, and allows you to combine those models in
@@ -59,9 +60,12 @@
 @SuppressWarnings("rawtypes")
 public class EpoxyModelGroup extends EpoxyModelWithHolder<ModelGroupHolder> {
 
-  protected final List<? extends EpoxyModel<?>> models;
-  /** By default we save view state if any of the models need to save state. */
-  private final boolean shouldSaveViewState;
+  protected final List<EpoxyModel<?>> models;
+
+  private boolean shouldSaveViewStateDefault = false;
+
+  @Nullable
+  private Boolean shouldSaveViewState = null;
 
   /**
    * @param layoutRes The layout to use with these models.
@@ -83,7 +87,7 @@ public EpoxyModelGroup(@LayoutRes int layoutRes, EpoxyModel<?>... models) {
    * @param layoutRes The layout to use with these models.
    * @param models    The models that will be used to bind the views in the given layout.
    */
-  private EpoxyModelGroup(@LayoutRes int layoutRes, List<? extends EpoxyModel<?>> models) {
+  private EpoxyModelGroup(@LayoutRes int layoutRes, List<EpoxyModel<?>> models) {
     if (models.isEmpty()) {
       throw new IllegalArgumentException("Models cannot be empty");
     }
@@ -99,8 +103,22 @@ private EpoxyModelGroup(@LayoutRes int layoutRes, List<? extends EpoxyModel<?>>
         break;
       }
     }
+    // By default we save view state if any of the models need to save state.
+    shouldSaveViewStateDefault = saveState;
+  }
 
-    shouldSaveViewState = saveState;
+  /**
+   * Constructor use for DSL
+   */
+  protected EpoxyModelGroup() {
+    models = new ArrayList<>();
+    shouldSaveViewStateDefault = false;
+  }
+
+  protected void addModel(@NonNull EpoxyModel<?> model) {
+    // By default we save view state if any of the models need to save state.
+    shouldSaveViewStateDefault |= model.shouldSaveViewState();
+    models.add(model);
   }
 
   @CallSuper
@@ -217,11 +235,22 @@ protected final int getDefaultLayout() {
         "You should set a layout with layout(...) instead of using this.");
   }
 
+  @NonNull
+  public EpoxyModelGroup shouldSaveViewState(boolean shouldSaveViewState) {
+    onMutation();
+    this.shouldSaveViewState = shouldSaveViewState;
+    return this;
+  }
+
   @Override
   public boolean shouldSaveViewState() {
     // By default state is saved if any of the models have saved state enabled.
     // Override this if you need custom behavior.
-    return shouldSaveViewState;
+    if (shouldSaveViewState != null) {
+      return shouldSaveViewState;
+    } else {
+      return shouldSaveViewStateDefault;
+    }
   }
 
   /**

diff --git a/epoxy-adapter/src/main/java/com/airbnb/epoxy/GroupModel.kt b/epoxy-adapter/src/main/java/com/airbnb/epoxy/GroupModel.kt
@@ -0,0 +1,28 @@
+package com.airbnb.epoxy
+
+/**
+ * An [EpoxyModelGroup] usable in a DSL manner via the [group] extension.
+ * <p>
+ * Example:
+ * ```
+ * group {
+ *   id("photos")
+ *   layout(R.layout.photo_grid)
+ *
+ *   // add your models here, example:
+ *   for (photo in photos) {
+ *     imageView {
+ *       id(photo.id)
+ *       url(photo.url)
+ *     }
+ *   }
+ * }
+ * ```
+ */
+@EpoxyModelClass
+abstract class GroupModel : EpoxyModelGroup(), ModelCollector {
+
+    override fun add(model: EpoxyModel<*>) {
+        super.addModel(model)
+    }
+}
diff --git a/epoxy-processor/src/main/java/com/airbnb/epoxy/processor/Memoizer.kt b/epoxy-processor/src/main/java/com/airbnb/epoxy/processor/Memoizer.kt
@@ -359,6 +359,20 @@ class Memoizer(
             }
         }
     }
+
+    private val implementsModelCollectorMap = mutableMapOf<Name, Boolean>()
+    fun implementsModelCollector(classElement: TypeElement): Boolean {
+        return synchronized(typeMap) {
+            implementsModelCollectorMap.getOrPut(classElement.qualifiedName) {
+                classElement.interfaces.any {
+                    it.toString() == ClassNames.MODEL_COLLECTOR.toString()
+                } || classElement.superClassElement(types)?.let { superClassElement ->
+                    // Also check the class hierarchy
+                    implementsModelCollector(superClassElement)
+                } ?: false
+            }
+        }
+    }
 }
 
 private val viewModelAnnotations = listOf(

diff --git a/epoxy-processor/src/main/java/com/airbnb/epoxy/processor/ModelBuilderInterfaceWriter.kt b/epoxy-processor/src/main/java/com/airbnb/epoxy/processor/ModelBuilderInterfaceWriter.kt
@@ -74,6 +74,11 @@ class ModelBuilderInterfaceWriter(
             addTypeVariables(modelInfo.typeVariables)
             addMethods(interfaceMethods)
 
+            if (modelInfo.memoizer.implementsModelCollector(modelInfo.superClassElement)) {
+                // If the model implements "ModelCollector" we want the builder too
+                addSuperinterface(ClassNames.MODEL_COLLECTOR)
+            }
+
             addOriginatingElement(modelInfo.superClassElement)
         }
 

diff --git a/epoxy-processortest/src/test/resources/EpoxyModelGroupWithAnnotations_.java b/epoxy-processortest/src/test/resources/EpoxyModelGroupWithAnnotations_.java
@@ -134,6 +134,12 @@ public int value() {
     return value;
   }
 
+  @Override
+  public EpoxyModelGroupWithAnnotations_ shouldSaveViewState(boolean shouldSaveViewState) {
+    super.shouldSaveViewState(shouldSaveViewState);
+    return this;
+  }
+
   @Override
   public EpoxyModelGroupWithAnnotations_ id(long id) {
     super.id(id);

diff --git a/kotlinsample/src/main/java/com/airbnb/epoxy/kotlinsample/MainActivity.kt b/kotlinsample/src/main/java/com/airbnb/epoxy/kotlinsample/MainActivity.kt
@@ -8,10 +8,12 @@ import android.widget.Toast
 import androidx.appcompat.app.AppCompatActivity
 import com.airbnb.epoxy.EpoxyRecyclerView
 import com.airbnb.epoxy.EpoxyVisibilityTracker
+import com.airbnb.epoxy.group
 import com.airbnb.epoxy.kotlinsample.helpers.carouselNoSnapBuilder
 import com.airbnb.epoxy.kotlinsample.models.ItemDataClass
 import com.airbnb.epoxy.kotlinsample.models.ItemViewBindingDataClass
 import com.airbnb.epoxy.kotlinsample.models.carouselItemCustomView
+import com.airbnb.epoxy.kotlinsample.models.coloredSquareView
 import com.airbnb.epoxy.kotlinsample.models.itemCustomView
 import com.airbnb.epoxy.kotlinsample.models.itemEpoxyHolder
 import com.airbnb.epoxy.kotlinsample.models.itemViewBindingEpoxyHolder
@@ -32,6 +34,26 @@ class MainActivity : AppCompatActivity() {
 
         recyclerView.withModels {
 
+            group {
+                id("epoxyModelGroupDsl")
+                layout(R.layout.vertical_linear_group)
+
+                coloredSquareView {
+                    id("coloredSquareView 1")
+                    color(Color.DKGRAY)
+                }
+
+                coloredSquareView {
+                    id("coloredSquareView 2")
+                    color(Color.GRAY)
+                }
+
+                coloredSquareView {
+                    id("coloredSquareView 3")
+                    color(Color.LTGRAY)
+                }
+            }
+
             for (i in 0 until 100) {
                 dataBindingItem {
                     id("data binding $i")

diff --git a/kotlinsample/src/main/java/com/airbnb/epoxy/kotlinsample/models/ColoredSquareView.kt b/kotlinsample/src/main/java/com/airbnb/epoxy/kotlinsample/models/ColoredSquareView.kt
@@ -0,0 +1,24 @@
+package com.airbnb.epoxy.kotlinsample.models
+
+import android.content.Context
+import android.graphics.Color
+import android.util.AttributeSet
+import android.view.View
+import androidx.annotation.ColorInt
+import com.airbnb.epoxy.ModelProp
+import com.airbnb.epoxy.ModelView
+import com.airbnb.epoxy.kotlinsample.R
+
+@ModelView(defaultLayout = R.layout.colored_square_view)
+class ColoredSquareView @JvmOverloads constructor(
+    context: Context,
+    attrs: AttributeSet? = null,
+    defStyleAttr: Int = 0
+) : View(context, attrs, defStyleAttr) {
+
+    @JvmOverloads
+    @ModelProp
+    fun color(@ColorInt color: Int = Color.RED) {
+        setBackgroundColor(color)
+    }
+}
diff --git a/kotlinsample/src/main/res/layout/colored_square_view.xml b/kotlinsample/src/main/res/layout/colored_square_view.xml
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<com.airbnb.epoxy.kotlinsample.models.ColoredSquareView xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="56dp"
+    android:layout_height="56dp" />
diff --git a/kotlinsample/src/main/res/layout/vertical_linear_group.xml b/kotlinsample/src/main/res/layout/vertical_linear_group.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:orientation="horizontal" />