Introduce LayoutInflaterFactory

This add the ability touch layout XML instantiates process. And most importantly, we can access AttributeSet, making custom view attribute possible.

Some other changes requires this.

app/src/main/java/com/topjohnwu/magisk/arch/BaseUIActivity.kt

@@ -17,6 +17,7 @@ import androidx.navigation.fragment.NavHostFragment
 import com.topjohnwu.magisk.BR
 import com.topjohnwu.magisk.core.Config
 import com.topjohnwu.magisk.core.base.BaseActivity
+import com.topjohnwu.magisk.ui.inflater.LayoutInflaterFactory
 import com.topjohnwu.magisk.ui.theme.Theme
 
 abstract class BaseUIActivity<VM : BaseViewModel, Binding : ViewDataBinding> :
@@ -44,6 +45,8 @@ abstract class BaseUIActivity<VM : BaseViewModel, Binding : ViewDataBinding> :
     }
 
     override fun onCreate(savedInstanceState: Bundle?) {
+        layoutInflater.factory2 = LayoutInflaterFactory(delegate)
+
         setTheme(themeRes)
         super.onCreate(savedInstanceState)
 

app/src/main/java/com/topjohnwu/magisk/ui/inflater/LayoutInflaterFactory.kt

@@ -0,0 +1,83 @@
+package com.topjohnwu.magisk.ui.inflater
+
+import android.content.Context
+import android.util.AttributeSet
+import android.view.InflateException
+import android.view.LayoutInflater
+import android.view.View
+import androidx.appcompat.app.AppCompatDelegate
+import androidx.collection.SimpleArrayMap
+import java.lang.reflect.Constructor
+
+open class LayoutInflaterFactory(private val delegate: AppCompatDelegate) : LayoutInflater.Factory2 {
+
+    override fun onCreateView(name: String, context: Context, attrs: AttributeSet): View? {
+        return onCreateView(null, name, context, attrs)
+    }
+
+    override fun onCreateView(parent: View?, name: String, context: Context, attrs: AttributeSet): View? {
+        val view = delegate.createView(parent, name, context, attrs)
+            ?: LayoutInflaterFactoryDefaultImpl.createViewFromTag(context, name, attrs)
+        onViewCreated(view, parent, name, context, attrs)
+        return view
+    }
+
+    open fun onViewCreated(view: View?, parent: View?, name: String, context: Context, attrs: AttributeSet) {
+        if (view == null) return
+    }
+}
+
+private object LayoutInflaterFactoryDefaultImpl {
+
+    private val constructorSignature = arrayOf(
+        Context::class.java, AttributeSet::class.java)
+
+    private val classPrefixList = arrayOf(
+        "android.widget.",
+        "android.view.",
+        "android.webkit."
+    )
+
+    private val constructorMap = SimpleArrayMap<String, Constructor<out View?>>()
+
+    fun createViewFromTag(context: Context, name: String, attrs: AttributeSet): View? {
+        var name = name
+        if (name == "view") {
+            name = attrs.getAttributeValue(null, "class")
+        }
+        return try {
+            if (-1 == name.indexOf('.')) {
+                for (prefix in classPrefixList) {
+                    val view: View? = createViewByPrefix(context, name, attrs, prefix)
+                    if (view != null) {
+                        return view
+                    }
+                }
+                null
+            } else {
+                createViewByPrefix(context, name, attrs, null)
+            }
+        } catch (e: Exception) {
+            null
+        }
+    }
+
+    @Throws(ClassNotFoundException::class, InflateException::class)
+    private fun createViewByPrefix(context: Context, name: String, attrs: AttributeSet, prefix: String?): View? {
+        var constructor = constructorMap[name]
+        return try {
+            if (constructor == null) { // Class not found in the cache, see if it's real, and try to add it
+                val clazz = Class.forName(
+                    if (prefix != null) prefix + name else name,
+                    false,
+                    context.classLoader).asSubclass(View::class.java)
+                constructor = clazz.getConstructor(*constructorSignature)
+                constructorMap.put(name, constructor)
+            }
+            constructor!!.isAccessible = true
+            constructor.newInstance(context, attrs)
+        } catch (e: Exception) {
+            null
+        }
+    }
+}