What is “DataBindingComponent” class in android databinding?

Question

I have seen the DataBindingComponent in the official API doc.

https://developer.android.com/reference/android/databinding/DataBindingUtil.html

Th

Answer 1

After reading the answer from @tynn , the DataBindingComponent class can also be as "object" scope of data binding method. Instead of setting all the method in static way, the following example can be used to be extendable and custom. For example, we setup 3 binding methods for ImageView, TextView and View type. You can setup the interface first ( like Retrofit 2 setup interface for API)

1. Setup 3 interface first

ImageViewBindingInterface.java

public interface ImageViewBindingInterface {
    @BindingAdapter({"bind:imageUrl", "bind:error"})
    public  void loadImage(ImageView view, String url, Drawable error);
}

TextViewBindingInterface.java

public interface TextViewBindingInterface {
    @BindingAdapter({"bind:font"})
      void setFont(TextView textView, String fontName);
}

ViewBindingInterface.java

public interface ViewBindingInterface {
    @BindingAdapter("android:paddingLeft")
    public  void setPaddingLeft(View view, int padding);
    @BindingAdapter("android:onViewAttachedToWindow")
    public  void setListener(View view, ViewBindingAdapter.OnViewAttachedToWindow attached);
}

2. The DataBindingComponent.java should be updated automatically as @tynn mentioned like the following.

If you have a look at the default DataBindingComponent class in Android Studio you find it located in build/generated/source/apt/dev.

public interface DataBindingComponent {
    example.com.testerapplication.binding.ViewBindingInterface getViewBindingInterface();
    example.com.testerapplication.binding.TextViewBindingInterface getTextViewBindingInterface();
    example.com.testerapplication.binding.ImageViewBindingInterface getImageViewBindingInterface();
}

3. Build your own implementation method for binding.

BaseImageViewBinding.java

public class BaseImageViewBinding implements ImageViewBindingInterface{
    @Override
    public void loadImage(ImageView view, String url, Drawable error) {
          Picasso.with(view.getContext()).load(url).error(error).into(view);
    }
}

BaseTextViewBinding.java

public class BaseTextViewBinding implements TextViewBindingInterface {
    @Override
    public void setFont(TextView textView, String fontName) {
        textView.setTypeface(Typeface.createFromAsset(textView.getContext().getAssets(), "fonts/" + fontName));
    }
}

BaseViewBinding.java

public class BaseViewBinding implements ViewBindingInterface {
    @Override
    public void setPaddingLeft(View view, int padding) {
        view.setPadding(padding,
                view.getPaddingTop(),
                view.getPaddingRight(),
                view.getPaddingBottom());
    }
    @Override
    public void setListener(View view, ViewBindingAdapter.OnViewAttachedToWindow attached) {

    }
}

4. Set your OwnDatabindingComponent

public class MyOwnDefaultDataBindingComponent implements android.databinding.DataBindingComponent {
    @Override
    public ViewBindingInterface getViewBindingInterface() {
        return new BaseViewBinding();
    }
    @Override
    public TextViewBindingInterface getTextViewBindingInterface() {
        return new BaseTextViewBinding();
    }
    @Override
    public ImageViewBindingInterface getImageViewBindingInterface() {
        return new BaseImageViewBinding();
    }
}

5. Setup your default DataBindingComponent in the Application

public class MyApplication extends Application {
    public void onCreate() {
        super.onCreate();
        DataBindingUtil.setDefaultComponent(new MyOwnDefaultDataBindingComponent());
    }
}

Using this method should be fine to make the custom data binding in a custom way and can be extensible.