Android Data Binder bug

Android Data Binder bug

Following the official tutorial to learn how to use data binding, the function is indeed very powerful. This is a huge step for Android to become MVVM and a small step for Native development to move closer to the Web.

One of the binding methods is to directly use resource data, for example:

android:padding="@{large? @dimen/largePadding : @dimen/smallPadding}"

Official Tutorial:

The layout file of the full version is as follows:

largePaddingAndsmallPaddingAll are defined indimens.xmlFile.

  
   20dp
  
  
   5dp
  

Bind the large variable in the Java code and assign the valueture.

@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);   ResourceBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_resource);    binding.setLarge(true);} 

Theoretically, this should be fine, but an error occurs during the Run project. The error message is as follows:

cannot find the setter for attribute 'android:padding' on android.widget.TextView with parameter type float.

It seems like DataBinder@dimen/largePaddingResolvedfloatType, you can try type conversion:

android:padding="@{large? (int)@dimen/largePadding : (int)@dimen/smallPadding}"

After compilation is passed, the running result is correct. It should be a bug in DataBinder. The original resource binding has such advanced usage, and type conversion can be performed directly-(int)@dimen/largePadding.

It feels amazing. You must read the source code to understand how DataBinder works.