DataBinding読みかけ

gistfile1.txt

# DataBinding

## repo

https://android.googlesource.com/platform/frameworks/data-binding

master is quite behind. studio-master-dev seems good.

## Parts

* baseLibrary - base library sources, to be embedded to .apk.
* compiler - APT, expression parser, 
* compilerCommon - parser for XML and binding expressions
* developmentPlugins - only 'localizeMavenPlugin' (ignorable?)
* extensions - adapters, and base library sources here too?
* gradlePlugin - only 'DataBindingExcludeGeneratedTask'


## Parsers

XmlParser (compilerCommon/src/main/xml-gen/android/databinding/parser/)
    implemented with ANTLR. WTF (実装が雑い...!)


### compiler/src/main/kotlin

android/databinding/tool

layout XMLからコードを生成する必要がある→Kotlinプロジェクトではktを生成



## Android Gradle Plugin integration

### DataBindingBuilder.java (in compilerCommon/..../android/databinding/tool) says:

    /**
    * This class is used by Android Gradle plugin.
    */

So...

In gradle-core-2.1.0-alphaX-sources.jar.
https://bintray.com/package/files/android/android-tools/com.android.tools.build.gradle-core?order=asc&sort=name&basePath=com%2Fandroid%2Ftools%2Fbuild%2Fgradle-core%2F2.1.0-alpha5&tab=files

- com/android/build/gradle/internal/*TaskManager.java

  ただし、用途はほとんどdata binding tool compiler version取得など

### DataBindingProcessLayoutsTask.java in Android Gradle Plugin

in com/android/build/gradle/internal/tasks/databinding/

DataBindingProcessLayoutsTask.processResources()
-> LayoutXmlProcessor.processResources()
  -> LayoutFileParser.parseXml()
    .stripFile()
      -> XmlEditor.strip() - remove <layout> root element.
    .parseOriginalXml()
      .parseData()
      .parseExpressions()
-> LayoutXmlProcessor.writeLayoutInfoFiles()



## その他

compiler/src/main/resources/api-versions.xml - なぜこんなところに?
-> ApiChecker.getMinApi()
-> used everywhere...!

## build intermediaries

- res/merged/debug/layout/* ... step 1.
- data-binding-layout-out/debug/layout/* - stripped out 'layout' and 'value' elements.
- data-binding-info/debug/* - XML like below:

	<Layout layout="content_main" modulePackage="name.astshieno.myapplication2" absoluteFilePath="/home/atsushi/Desktop/MyApplication2/app/src/main/res/layout/content_main.xml" directory="layout" isMerge="false">
		<Variables declared="true" type="name.astshieno.myapplication2.User" name="user">
			<location startLine="3" startOffset="8" endLine="3" endOffset="72"/>
		</Variables>
		<Targets>
			<Target tag="layout/content_main_0" view="LinearLayout">
				<Expressions/>
				<location startLine="6" startOffset="0" endLine="20" endOffset="14"/>
			</Target>
			<Target tag="binding_1" view="TextView">
				<Expressions>
					<Expression text="user.firstName" attribute="android:text">
						<Location startLine="18" startOffset="8" endLine="18" endOffset="39"/>
						<TwoWay>false</TwoWay>
						<ValueLocation startLine="18" startOffset="24" endLine="18" endOffset="37"/>
					</Expression>
				</Expressions>
				<location startLine="15" startOffset="4" endLine="18" endOffset="42"/>
			</Target>
		</Targets>
	</Layout>