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ButterKnife在之前的Android开发中还是比较大发11选5热门 的大发11选5工具 ,大发11选5帮助 Android开发者减少代码编写,而且看起来更加的舒适,于是简单实现一下ButterKnife,相信把下面的代码都搞懂,看ButterKnife的难度就小很多。

今天实现的是编译时注解,其实运行时注解也一样能实现ButterKnife的效果,但是相对于编译时注解,运行时注解会更耗性能一些,主要是由于运行时注解大量使用反射。

一、创建java library(lib_annotations)

大发11选5我 这里创建3个annotation放在3个文件中

//绑定layout
@Target(AnnotationTarget.CLASS) @Retention(AnnotationRetention.BINARY) annotation class BindLayout(val value: Int = -1)
//绑定view @Target(AnnotationTarget.FIELD) @Retention(AnnotationRetention.RUNTIME) annotation class BindView (val value:Int = -1)
//点击注解 @Target(AnnotationTarget.FUNCTION) @Retention(AnnotationRetention.BINARY) annotation class OnClick (vararg val values:Int)

Kotlin对编译时注解时Retention 并没有太多的要求,一般大发11选5大发11选5我 们 使用AnnotationRetention.BINARY或者SOURCE,但是大发11选5我 发现ButterKnife用的是Runtime,测试也可以。

但具体为什么用,不是特别明白,自己认为是AnnotationRetention.RUNTIME基本包含了BINARY或者SOURCE的功能,还支持反射。

二、创建java library(lib_processor)

@AutoService(Processor::class)
@SupportedSourceVersion(SourceVersion.RELEASE_8)
class BindProcessor : AbstractProcessor() {
    companion object {
        private const val PICK_END = "_BindTest"
    }

    private lateinit var mLogger: Logger
    //存储类文件数据
    private val mInjectMaps = hashMapOf<String, InjectInfo>()

//必须实现大发11选5方法 override fun process( annotations: MutableSet<out TypeElement>?, roundEnv: RoundEnvironment ): Boolean { //里面就要生成大发11选5大发11选5我 们 需要的文件 roundEnv.getElementsAnnotatedWith(BindLayout::class.java).forEach { bindLayout(it) } roundEnv.getElementsAnnotatedWith(BindView::class.java).forEach { bindView(it) } roundEnv.getElementsAnnotatedWith(OnClick::class.java).forEach { bindClickListener(it) } mInjectMaps.forEach { (name, info) -> //这里生成文件 val file= FileSpec.builder(info.packageName, info.className.simpleName + PICK_END) .addType( TypeSpec.classBuilder(info.className.simpleName + PICK_END) .primaryConstructor(info.generateConstructor()).build() ).build() file.writeFile() } return true } private fun FileSpec.writeFile() { //文件编译后位置 val kaptKotlinGeneratedDir = processingEnv.options["kapt.kotlin.generated"] val outputFile = File(kaptKotlinGeneratedDir).apply { mkdirs() } writeTo(outputFile.toPath()) } private fun bindLayout(element: Element) { //BindLayout注解的是Class,本身就是TypeElement val typeElement = element as TypeElement //一个类一个injectInfo val className = typeElement.qualifiedName.toString() var injectInfo = mInjectMaps[className] if (injectInfo == null) { injectInfo = InjectInfo(typeElement) } typeElement.getAnnotation(BindLayout::class.java).run { injectInfo.layoutId = value } mInjectMaps[className] = injectInfo } private fun bindView(element: Element) { //BindView注解的是变量,element就是VariableElement val variableElement = element as VariableElement val typeElement = element.enclosingElement as TypeElement //一个类一个injectInfo val className = typeElement.qualifiedName.toString() var injectInfo = mInjectMaps[className] if (injectInfo == null) { injectInfo = InjectInfo(typeElement) } variableElement.getAnnotation(BindView::class.java).run { injectInfo.viewMap[value] = variableElement } mInjectMaps[className] = injectInfo } private fun bindClickListener(element: Element) { //OnClick注解的是大发11选5方法 ,element就是VariableElement val variableElement = element as ExecutableElement val typeElement = element.enclosingElement as TypeElement //一个类一个injectInfo val className = typeElement.qualifiedName.toString() var injectInfo = mInjectMaps[className] if (injectInfo == null) { injectInfo = InjectInfo(typeElement) } variableElement.getAnnotation(OnClick::class.java).run { values.forEach { injectInfo.clickListenerMap[it] = variableElement } } mInjectMaps[className] = injectInfo }
//把注解类都添加进行,这个大发11选5方法 一看大发11选5方法 名就应该知道干啥的 override fun getSupportedAnnotationTypes(): Set<String> { return setOf( BindLayout::class.java.canonicalName, BindView::class.java.canonicalName, OnClick::class.java.canonicalName ) } override fun init(processingEnv: ProcessingEnvironment) { super.init(processingEnv) mLogger = Logger(processingEnv.messager) mLogger.info("processor init") } }
//存储一个Activity文件所有注解数据,并有相应大发11选5方法
生成编译后的文件
class InjectInfo(val element: TypeElement) { var mLogger: Logger? = null //类名 val className: ClassName = element.asClassName() val viewClass: ClassName = ClassName("android.view", "View") //包名 val packageName: String = getPackageName(element).qualifiedName.toString() //布局只有一个id var layoutId: Int = -1 //View 注解数据可能有多个 注意是VariableElement val viewMap = hashMapOf<Int, VariableElement>() //点击事件 注解数据可能有多个 注意是ExecutableElement val clickListenerMap = hashMapOf<Int, ExecutableElement>()
private fun getPackageName(element: Element): PackageElement { var e = element while (e.kind != ElementKind.PACKAGE) { e = e.enclosingElement } return e as PackageElement } fun getClassName(element: Element): ClassName { var elementType = element.asType().asTypeName() return elementType as ClassName }
//自动生成构造大发11选5方法 ,主要使用kotlinpoet fun generateConstructor(): FunSpec {
//构造大发11选5方法 ,传入activity参数 val builder = FunSpec.constructorBuilder().addParameter("target", className) .addParameter("view", viewClass) if (layoutId != -1) { builder.addStatement("target.setContentView(%L)", layoutId) } viewMap.forEach { (id, variableElement) -> builder.addStatement( "target.%N = view.findViewById(%L)", variableElement.simpleName, id ) } clickListenerMap.forEach { (id, element) -> when (element.parameters.size) { //没有参数 0 -> builder.addStatement( "(view.findViewById(%L) as View).setOnClickListener{target.%N()}" , id ) //一个参数 1 -> { if (getClassName(element.parameters[0]) != viewClass) { mLogger?.error("element.simpleName function parameter error") } builder.addStatement( "(view.findViewById(%L) as View).setOnClickListener{target.%N(it)}" , id, element.simpleName ) } //多个参数错误 else -> mLogger?.error("element.simpleName function parameter error") } } return builder.build() } }

三、app module中引入上面两个lib

    //gradle引入
implementation project(':lib_annotations') kapt project(':lib_processor')
@BindLayout(R.layout.activity_main)
class MainActivity : AppCompatActivity() {

    @BindView(R.id.tv_hello)
    lateinit var textView: TextView
    @BindView(R.id.bt_click)
    lateinit var btClick: Button

    private var mClickBtNum = 0
    private var mClickTvNum = 0
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        // setContentView(R.layout.activity_main)
        //这里第4步内容
        BindApi.bind(this)

        textView.text = "测试成功......"
        btClick.text = "点击0次"
    }

    @OnClick(R.id.bt_click, R.id.tv_hello)
    fun onClick(view: View) {
        when (view.id) {
            R.id.bt_click -> {
                mClickBtNum++
                btClick.text = "点击${mClickBtNum}次"
            }
            R.id.tv_hello -> {
                mClickTvNum++
                textView.text = "点击文字${mClickTvNum}次"
            }
        }
    }
}

现在就可以直接编译,编译后大发11选5大发11选5我 们 就可以找到编译生成的类MainActivity_BindTest,

import android.view.View

class MainActivity_BindTest(
    target: MainActivity,
    view: View) {
    init {
        target.setContentView(2131361820)
        target.btClick = view.findViewById(2131165250)
        target.textView = view.findViewById(2131165360)
        (view.findViewById(2131165250) as View).setOnClickListener { target.onClick(it) }
        (view.findViewById(2131165360) as View).setOnClickListener { target.onClick(it) }
    }
}

这里当然还不能用,因为大发11选5大发11选5我 们 没有把MainActivity_BindTest和MainActivity关联上。

四、创建App module(lib_api)

object BindApi {

    //类似ButterKnife大发11选5方法

    fun bind(target: Activity) {
        val sourceView = target.大发11选5Win
dow.decorView
        createBinding(target, sourceView)
    }

    private fun createBinding(target: Activity, source: View) {
        val targetClass = target::class.java
        var className = targetClass.name
        try {
            //获取类名
            val bindingClass = targetClass.classLoader!!.loadClass(className + "_BindTest")
            //获取构造大发11选5方法

            val constructor = bindingClass.getConstructor(targetClass, View::class.java)
            //向大发11选5方法
中传入数据activity和view
            constructor.ne大发11选5Win
stance(target, source)
        } catch (e: ClassNotFoundException) {
            e.printStackTrace()
        } catch (e: NoSuchMethodException) {
            e.printStackTrace()
        } catch (e: IllegalAccessException) {
            e.printStackTrace()
        } catch (e: InstantiationException) {
            e.printStackTrace()
        } catch (e: InvocationTargetException) {
            e.printStackTrace()
        }
    }
}

并在app中引用

implementation project(':lib_api')

五、总结

流程还是比较简单,创建annotation、processor、lib_api 3个module,大发11选5大发11选5我 们 打包时并不需要processor包,它的目的仅仅是生成相应的文件代码。

注意点:

1、annotation 和processor要引入

apply plugin: 'kotlin'

2、编译时打印使用Messager,注意JDK8打印NOTE无法显示

3、lib_api 文件在反射时要主义和processor对应,修改时注意同步修改等

有用的话加个关注哦!!!

代码

 

posted on 2019-10-10 23:42 DOUBLEYOU 阅读(...) 评论(...) 编辑 收藏