Kotlin: View Binding

最近工作有點不如意阿,壓力太大,總是遇到不好的人...

嘆~

Android app一般情況下的UI component :Button,textview...,使用前須透過 :

(最新方法:)
developer - View Binding
https://developer.android.com/topic/libraries/view-binding

(舊式,已可以全部改用view binding.)

ButterKnife

https://github.com/JakeWharton/butterknife

(原始方法,若程式元件不多,可直接用這方法取得ui元件)

findViewById

https://developer.android.com/reference/android/view/View#findViewById(int)

<Button     android:id="@+id/button_submit"     android:src="@drawable/image1"     android:layout_width="wrap_content"     android:layout_height="wrap_content"/> var btn_submit = findViewById(R.id.button_submit) as Button 或是: private lateinit var textView : TextView //in onCreate() textView = findViewById(R.id.textView) 這樣的宣告才可使用,否則未宣告就使用會導致直接app crash.

若是有超過10個以上的UI元件,程式碼就變成非常繁瑣,有一大部分都在寫這重複的code,所以就有view-binding的出現.

(In most cases, view binding replaces findViewById.)

----

View-Binding:

https://developer.android.com/topic/libraries/view-binding

 you need to use the below in your app gradle:

android {
    ...
    buildFeatures {
        viewBinding true
    }
}

In your class add import for import kotlinx.android.synthetic.main.<layout>.* where <layout> is the filename of your layout.

That's it, you can call any view item id in layout directly in your code.

private lateinit var binding: ResultProfileBinding

override fun onCreate(savedInstanceState: Bundle?) {

    super.onCreate(savedInstanceState)

    binding = ResultProfileBinding.inflate(layoutInflater)

    setContentView(binding.root)

}

增加上面這幾行,有了這幾行,就少了很大的一部分findViewById(...) Code.

程式碼變簡潔多了.

重點是  setContentView(binding.root) 要更改成這.