Why extends ImageView marked as error?

MarcGV picture MarcGV · Mar 23, 2017 · Viewed 10.9k times · Source

Android Studio marks as error this line:

public class ParallaxView extends ImageView

Here the error:

This custom view should extend android.support.v7.widget.AppCompatImageView instead less... (Ctrl+F1) 

In order to support features such as tinting, the appcompat library will automatically load special appcompat replacements for the builtin widgets.

However, this does not work for your own custom views.  Instead of extending the android.widget classes directly, you should instead extend one of the delegate classes in android.support.v7.widget.AppCompat.

It recommends me to extend AppCompatImageView but then my JUnit test don't pass because AppCompatImageView needs a mock Context with resources and Imageview doesn't need this.

Here the question to solve the other problem:
NullPointerException creating an AppCompatImageView with mock Context

Can I ignore this error and use ImageView? Any other solution?

Answer

dev.bmax picture dev.bmax · Mar 23, 2017

Using AppCompat widgets allows you to have some material design (and other new) features on devices with pre-Lollipop versions of Android.

At this point AppCompatImageView only provides the support for background tint and vector drawables. If you don't use them, then extending the regular ImageView will be fine.