使用Anko从活动访问视图 [英] Accessing views from the Activity with Anko

问题描述

我知道我可以在Anko中使用id属性来识别视图:

I know I can use an id attribute with Anko to identify a view:

class MainActivityUI : AnkoComponent<MainActivity> {

    override fun createView(ui: AnkoContext<MainActivity>) = with(ui) {
        frameLayout {
            textView {
                id = R.id.text
            }
        }
    }

}

然后使用find()函数(或使用Kotlin Android扩展程序)在Activity中获取它:

Then obtain it in the Activity using the find() function (or by using Kotlin Android Extensions):

class MainActivity : AppCompatActivity() {

    private val textView by lazy {
        find<TextView>(R.id.text)
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        MainActivityUI().setContentView(this)

        textView.text = "Hello World"
    }

}

但是我觉得我缺少了一些东西. 自述文件唯一提及find函数或Kotlin Android扩展的地方在标题为支持现有代码的部分中:

But I feel like I am missing something; the only place the README mentions the find function or Kotlin Android Extensions is in the section titled Supporting Existing Code:

您不必使用Anko重写所有UI.你可以保持老 用Java编写的类.而且，如果您仍然想要(或必须) 编写Kotlin活动类，并为某些应用添加XML布局 因此，您可以使用View属性，这会使事情变得更容易:

You don't have to rewrite all your UI with Anko. You can keep your old classes written in Java. Moreover, if you still want (or have) to write a Kotlin activity class and inflate an XML layout for some reason, you can use View properties, which would make things easier:

// Same as findViewById(), simpler to use
val name = find<TextView>(R.id.name)
name.hint = "Enter your name"
name.onClick { /*do something*/ }

通过使用Kotlin Android，您可以使代码更加紧凑 扩展程序.

You can make your code even more compact by using Kotlin Android Extensions.

这使得find函数似乎仅用于支持旧" XML代码.

Which makes it seem like the find function is only meant for supporting "old" XML code.

所以我的问题是这个；使用id和find函数是使用Anko从Activity访问View的正确方法吗?还有更多的"Anko"处理方式吗?还是我错过了Anko的其他好处，而这些好处使从Activity中访问View无关紧要?

So my question is this; is using an id along with the find function the correct way of accessing a View from the Activity using Anko? Is there a more "Anko" way of handling this? Or am I missing some other benefit of Anko that makes accessing the View from the Activity irrelevant?

还有第二个相关问题；如果此是从Activity访问View的正确方法，是否可以从AnkoComponent内部创建id资源(即"@+id/")?而不是在ids.xml文件中创建每个id.

And a second related question; if this is the correct way of accessing a View from the Activity, is there a way of creating an id resource (i.e. "@+id/") from within an AnkoComponent? Rather than creating each id in the ids.xml file.

推荐答案

那么，为什么还要使用XML id来定位视图?因为我们已经使用Anko而不是XML.

So, why still use XML id to locate the View? since we already use the Anko instead of the XML.

我认为，我们可以将view元素存储在AnkoComponent中，而不是find view的id方法中.检查代码打击:

In my opinion, we can store the view elements inside the AnkoComponent instead of the find view's id method. Check the code blow:

class MainActivityUI : AnkoComponent<MainActivity> {

    lateinit var txtView: TextView

    override fun createView(ui: AnkoContext<MainActivity>) = with(ui) {
        frameLayout {
            txtView = textView {
                id = R.id.text // the id here is useless, we can delete this line.
            }
        }
    }

}

class MainActivity : AppCompatActivity() {

    lateinit var mainUI : MainActivityUI

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        mainUI = MainActivityUI()
        mainUI.setContentView(this)

        mainUI.txtView.text = "Hello World"
    }

}

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