fix: support DataBinding expressions in ImageView android:src attribute

Problem:
- When using android:src="@{icon}" with DataBinding, the icon was not displayed
- The generated executeBindings() method only contained text binding, missing icon binding

Root Cause:
- ImageSourceAttributeHandler.supportsValue() rejected DataBinding expressions like "@{icon}"
  because isSupportedDrawableReference("@{icon}") returned false
- This caused android:src to be marked as 'unsupported' instead of 'dataBinding'
- As a result, collectDataBindingExpressions() didn't collect the icon binding

Solution:
- Added isDataBindingExpression() helper to detect @{} and @={} expressions
- Modified ImageSourceAttributeHandler.supportsValue() to accept DataBinding expressions
- DataBinding expressions are validated at runtime via executeBindings(), not at compile time

Impact:
- android:src="@{icon}" now correctly generates viewIcon.setImageResource(icon ?: 0)
- Other drawable-based attributes can benefit from this pattern if needed

Author: donglua

compiler-core/src/main/kotlin/com/github/donglua/layoutx2c/registry/ViewRegistry.kt

@@ -1009,6 +1009,10 @@ open class ResourceAwareViewRegistry(
         }
 
         override fun supportsValue(node: LayoutNode, parentTagName: String?, attrName: String, value: String): Boolean {
+            // DataBinding 表达式会在运行时通过 executeBindings() 处理，不需要在这里验证
+            if (isDataBindingExpression(value)) {
+                return true
+            }
             return isSupportedDrawableReference(value) && supportsResourceReference(value)
         }
 
@@ -1924,6 +1928,11 @@ private fun isSupportedThemeAttr(value: String): Boolean {
     return value.startsWith("?attr/") || value.startsWith("?android:attr/")
 }
 
+private fun isDataBindingExpression(value: String): Boolean {
+    return (value.startsWith("@{") && value.endsWith("}")) ||
+           (value.startsWith("@={") && value.endsWith("}"))
+}
+
 private fun isSupportedLiteralOrStringReference(value: String): Boolean {
     return !value.startsWith("?") &&
         (value.startsWith("@string/") || !value.startsWith("@"))

compiler-core/src/test/kotlin/com/github/donglua/layoutx2c/codegen/ImageViewSrcBindingTest.kt

@@ -0,0 +1,67 @@
+package com.github.donglua.layoutx2c.codegen
+
+import com.github.donglua.layoutx2c.analyzer.LayoutAnalyzerV2
+import com.github.donglua.layoutx2c.parser.XmlLayoutParser
+import com.google.common.truth.Truth.assertThat
+import org.junit.Test
+
+class ImageViewSrcBindingTest {
+
+    private val parser = XmlLayoutParser()
+    private val analyzer = LayoutAnalyzerV2()
+    private val generator = BindingFacadeGeneratorV2(
+        packageName = "com.example.generated",
+        rPackageName = "com.example"
+    )
+
+    @Test
+    fun `generates ImageView src binding with Integer variable`() {
+        val tree = parser.parse(
+            """
+                <layout xmlns:android="http://schemas.android.com/apk/res/android">
+                    <data>
+                        <variable name="icon" type="Integer" />
+                        <variable name="text" type="String" />
+                    </data>
+                    <FrameLayout
+                        android:layout_width="match_parent"
+                        android:layout_height="match_parent">
+                        <ImageView
+                            android:id="@+id/view_icon"
+                            android:layout_width="24dp"
+                            android:layout_height="24dp"
+                            android:src="@{icon}" />
+                        <TextView
+                            android:id="@+id/view_text"
+                            android:layout_width="wrap_content"
+                            android:layout_height="wrap_content"
+                            android:text="@{text}" />
+                    </FrameLayout>
+                </layout>
+            """.trimIndent(),
+            "test_icon_binding"
+        )
+
+        val analyzed = analyzer.analyze(tree.root)
+
+        // 验证 android:src 被识别为 dataBindingAttribute
+        val imageViewNode = analyzed.children[0].children[0] // FrameLayout -> ImageView
+        assertThat(imageViewNode.dataBindingAttributes).contains("android:src")
+        assertThat(imageViewNode.unsupportedAttributes).doesNotContain("android:src")
+
+        val generated = generator.generate(
+            analyzedRoot = analyzed,
+            layoutName = "test_icon_binding",
+            layoutResId = "R.layout.test_icon_binding",
+            useFastPath = true,
+            dataBindingVariables = tree.rootMetadata.dataBindingVariables
+        ).toString()
+
+        println("=== Generated code ===")
+        println(generated)
+
+        // Should generate both text and icon bindings in executeBindings()
+        assertThat(generated).contains("viewText.setText(text ?: \"\")")
+        assertThat(generated).contains("viewIcon.setImageResource(icon ?: 0)")
+    }
+}

test_icon_binding.xml

@@ -0,0 +1,20 @@
+<layout xmlns:android="http://schemas.android.com/apk/res/android">
+    <data>
+        <variable name="icon" type="Integer" />
+        <variable name="text" type="String" />
+    </data>
+    <FrameLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent">
+        <ImageView
+            android:id="@+id/view_icon"
+            android:layout_width="24dp"
+            android:layout_height="24dp"
+            android:src="@{icon}" />
+        <TextView
+            android:id="@+id/view_text"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="@{text}" />
+    </FrameLayout>
+</layout>