Ok, creo que he encontrado la solución definitiva para esto. Gracias a AppCompat y sus amigos, el dibujante proporcionado a veces se infla en diferentes formas, por lo que no es suficiente getResources().getBitmap(R.drawable.my_awesome_drawable).
Entonces, para obtener una instancia dibujable del mismo tipo y forma que proporciona la vista, uno puede hacer esto:
public static Drawable drawableFrom(View view, @DrawableRes int drawableId) {
Context context = view.getContext();
try {
View dummyView = view.getClass().getConstructor(Context.class).newInstance(context);
dummyView.setBackgroundResource(drawableId);
return dummyView.getBackground();
} catch (Exception e) {
return ResourcesCompat.getDrawable(context.getResources(), drawableId, null);
}
}
Esto es útil al realizar pruebas. Sin embargo, no recomendaría hacer esto en producción. Si es necesario, sería deseable almacenamiento en caché adicional para evitar hacer demasiada reflexión.
Para las pruebas de Expresso, puede usar esto bastante bien:
onView(withDrawable(R.drawable.awesome_drawable))
.check(matches(isDisplayed()));
o
onView(withId(R.id.view_id))
.check(matches(withDrawable(R.drawable.awesome_drawable)));
Antes tendrás que declarar esta clase auxiliar:
public class CustomMatchers {
public static Matcher<View> withDrawable(@DrawableRes final int drawableId) {
return new DrawableViewMatcher(drawableId);
}
private static class DrawableViewMatcher extends TypeSafeMatcher<View> {
private final int expectedId;
private String resourceName;
private enum DrawableExtractionPolicy {
IMAGE_VIEW {
@Override
Drawable findDrawable(View view) {
return view instanceof ImageView ? ((ImageView) view).getDrawable() : null;
}
},
TEXT_VIEW_COMPOUND {
@Override
Drawable findDrawable(View view) {
return view instanceof TextView ? findFirstCompoundDrawable((TextView) view) : null;
}
},
BACKGROUND {
@Override
Drawable findDrawable(View view) {
return view.getBackground();
}
};
@Nullable
private static Drawable findFirstCompoundDrawable(TextView view) {
for (Drawable drawable : view.getCompoundDrawables()) {
if (drawable != null) {
return drawable;
}
}
return null;
}
abstract Drawable findDrawable(View view);
}
private DrawableViewMatcher(@DrawableRes int expectedId) {
this.expectedId = expectedId;
}
@Override
protected boolean matchesSafely(View view) {
resourceName = resources(view).getResourceName(expectedId);
return haveSameState(actualDrawable(view), expectedDrawable(view));
}
private boolean haveSameState(Drawable actual, Drawable expected) {
return actual != null && expected != null && areEqual(expected.getConstantState(), actual.getConstantState());
}
private Drawable actualDrawable(View view) {
for (DrawableExtractionPolicy policy : DrawableExtractionPolicy.values()) {
Drawable drawable = policy.findDrawable(view);
if (drawable != null) {
return drawable;
}
}
return null;
}
private boolean areEqual(Object first, Object second) {
return first == null ? second == null : first.equals(second);
}
private Drawable expectedDrawable(View view) {
return drawableFrom(view, expectedId);
}
private static Drawable drawableFrom(View view, @DrawableRes int drawableId) {
Context context = view.getContext();
try {
View dummyView = view.getClass().getConstructor(Context.class).newInstance(context);
dummyView.setBackgroundResource(drawableId);
return dummyView.getBackground();
} catch (Exception e) {
return ResourcesCompat.getDrawable(context.getResources(), drawableId, null);
}
}
@NonNull
private Resources resources(View view) {
return view.getContext().getResources();
}
@Override
public void describeTo(Description description) {
description.appendText("with drawable from resource id: ");
description.appendValue(expectedId);
if (resourceName != null) {
description.appendValueList("[", "", "]", resourceName);
}
}
}
}