Simplify the base class usage

Author: DylanCaiCoding

sample/src/main/java/com/dylanc/viewbinding/sample/HomeFragment.kt

@@ -20,17 +20,14 @@ package com.dylanc.viewbinding.sample
 
 import android.os.Bundle
 import android.view.View
-import androidx.fragment.app.Fragment
 import androidx.fragment.app.setFragmentResult
-import com.dylanc.viewbinding.binding
+import com.dylanc.viewbinding.sample.base.reflection.kotlin.BaseBindingFragment
 import com.dylanc.viewbinding.sample.databinding.FragmentHomeBinding
 
 /**
  * @author Dylan Cai
  */
-class HomeFragment : Fragment(R.layout.fragment_home) {
-
-  private val binding :FragmentHomeBinding by binding()
+class HomeFragment : BaseBindingFragment<FragmentHomeBinding>() {
 
   override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
     super.onViewCreated(view, savedInstanceState)

sample/src/main/java/com/dylanc/viewbinding/sample/MainActivity.kt

@@ -17,22 +17,19 @@
 package com.dylanc.viewbinding.sample
 
 import android.os.Bundle
-import androidx.appcompat.app.AppCompatActivity
 import androidx.core.view.isVisible
 import androidx.fragment.app.Fragment
 import androidx.viewpager2.adapter.FragmentStateAdapter
 import com.dylanc.viewbinding.doOnCustomTabSelected
-import com.dylanc.viewbinding.nonreflection.binding
-import com.dylanc.viewbinding.nonreflection.setCustomView
+import com.dylanc.viewbinding.sample.base.reflection.kotlin.BaseBindingActivity
 import com.dylanc.viewbinding.sample.databinding.ActivityMainBinding
 import com.dylanc.viewbinding.sample.databinding.LayoutBottomTabBinding
 import com.dylanc.viewbinding.setCustomView
 import com.dylanc.viewbinding.updateCustomTab
 import com.google.android.material.tabs.TabLayoutMediator
 
-class MainActivity : AppCompatActivity() {
+class MainActivity : BaseBindingActivity<ActivityMainBinding>() {
 
-  private val binding by binding(ActivityMainBinding::inflate)
   private val tabs: List<CustomTab> by lazy {
     listOf(
       CustomTab(R.string.tab_home, R.drawable.ic_home_selector, HomeFragment()),

sample/src/main/java/com/dylanc/viewbinding/sample/base/reflection/kotlin/BaseBindingActivity.kt

@@ -21,26 +21,17 @@ package com.dylanc.viewbinding.sample.base.reflection.kotlin
 import android.os.Bundle
 import androidx.appcompat.app.AppCompatActivity
 import androidx.viewbinding.ViewBinding
-import com.dylanc.viewbinding.base.ViewBindingUtil
+import com.dylanc.viewbinding.base.BindingOwner
+import com.dylanc.viewbinding.base.BindingOwnerDelegate
 
 /**
- * How to modify the base class to use view binding, you need the following steps:
- * 1. Adds a generic of view binding to the base class.
- * 2. Declares a binding object.
- * 3. Uses [inflateBindingWithGeneric] method to create the binding object.
- * 4. Uses the root of the binding object instead of layout id to set content view.
- *
- * Here is the core code.
- *
  * @author Dylan Cai
  */
-abstract class BaseBindingActivity<VB : ViewBinding> : AppCompatActivity() {
-
-  lateinit var binding: VB
+abstract class BaseBindingActivity<VB : ViewBinding> : AppCompatActivity(),
+  BindingOwner<VB> by BindingOwnerDelegate() {
 
   override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
-    binding = ViewBindingUtil.inflateWithGeneric(this, layoutInflater)
-    setContentView(binding.root)
+    setContentViewWithBinding()
   }
 }

sample/src/main/java/com/dylanc/viewbinding/sample/base/reflection/kotlin/BaseBindingFragment.kt

@@ -14,41 +14,24 @@
  * limitations under the License.
  */
 
-@file:Suppress("unused", "MemberVisibilityCanBePrivate")
+@file:Suppress("unused")
 
 package com.dylanc.viewbinding.sample.base.reflection.kotlin
 
 import android.os.Bundle
 import android.view.LayoutInflater
-import android.view.View
 import android.view.ViewGroup
 import androidx.fragment.app.Fragment
 import androidx.viewbinding.ViewBinding
-import com.dylanc.viewbinding.base.ViewBindingUtil
+import com.dylanc.viewbinding.base.BindingOwner
+import com.dylanc.viewbinding.base.BindingOwnerDelegate
 
 /**
- * How to modify the base class to use view binding, you need the following steps:
- * 1. Adds a generic of view binding to the base class.
- * 2. Declares a binding object.
- * 3. Uses [inflateBindingWithGeneric] method to create the binding object.
- * 4. Uses the root of the binding object instead of view to return content view.
- *
- * Here is the core code.
- *
  * @author Dylan Cai
  */
-abstract class BaseBindingFragment<VB : ViewBinding> : Fragment() {
-
-  private var _binding: VB? = null
-  val binding: VB get() = _binding!!
-
-  override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
-    _binding = ViewBindingUtil.inflateWithGeneric(this, inflater, container, false)
-    return binding.root
-  }
+abstract class BaseBindingFragment<VB : ViewBinding> : Fragment(),
+  BindingOwner<VB> by BindingOwnerDelegate() {
 
-  override fun onDestroyView() {
-    super.onDestroyView()
-    _binding = null
-  }
+  override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?) =
+    createViewWithBinding(inflater, container)
 }

viewbinding-base/src/main/java/com/dylanc/viewbinding/base/BindingOwner.kt

@@ -0,0 +1,38 @@
+package com.dylanc.viewbinding.base
+
+import android.app.Activity
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.fragment.app.Fragment
+import androidx.viewbinding.ViewBinding
+
+interface BindingOwner<VB : ViewBinding> {
+  val Activity.binding: VB
+  val Fragment.binding: VB
+  fun Activity.setContentViewWithBinding()
+  fun Fragment.createViewWithBinding(inflater: LayoutInflater, container: ViewGroup?): View
+}
+
+class BindingOwnerDelegate<VB : ViewBinding> : BindingOwner<VB> {
+  private lateinit var _binding: VB
+
+  override val Activity.binding: VB get() = _binding
+
+  @Suppress("UNCHECKED_CAST")
+  override val Fragment.binding: VB
+    get() = requireNotNull(view) { "The property of binding has been destroyed." }
+      .getTag(R.id.tag_view_binding) as VB
+
+  override fun Activity.setContentViewWithBinding() {
+    _binding = ViewBindingUtil.inflateWithGeneric(this, layoutInflater)
+    setContentView(binding.root)
+  }
+
+  override fun Fragment.createViewWithBinding(inflater: LayoutInflater, container: ViewGroup?): View =
+    ViewBindingUtil.inflateWithGeneric<VB>(this, inflater, container, false)
+      .run {
+        root.setTag(R.id.tag_view_binding, this)
+        root
+      }
+}