Ok, je pense avoir trouvé la solution ultime pour ça. En raison d'AppCompat et de ses amis, le dessin fourni est parfois gonflé sous différentes formes, il ne suffit donc pas de le fairegetResources().getBitmap(R.drawable.my_awesome_drawable) .
Donc, pour obtenir une instance dessinable du même type et de la même forme que celle fournie par la vue, on peut faire ceci:
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);
}
}
Ceci est utile lors des tests. Cependant, je ne recommanderais pas de faire cela en production. Si vous en avez besoin, une mise en cache supplémentaire serait souhaitable pour éviter de trop réfléchir.
Pour les tests Expresso, vous pouvez utiliser ceci très bien:
onView(withDrawable(R.drawable.awesome_drawable))
.check(matches(isDisplayed()));
ou
onView(withId(R.id.view_id))
.check(matches(withDrawable(R.drawable.awesome_drawable)));
Avant de devoir déclarer cette classe d'assistance:
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);
}
}
}
}