如何比较两个RippleDrawables？

Question

我正在使用android Espresso。我想知道如何检查在视图中使用的drawable是否与规格中所述应该使用的相同。我试图比较view上使用drawable的ConstantStates和资源中的ConstantStates，但我没有得到任何地方。

有没有办法做到这一点？或者当它涉及到自动化测试时，这种检查完全不需要吗？

Answer 1

用于比较两个图像，我已经使用这个代码：

public class ImageComparator { 

public static Matcher<View> withImageResource(final int imageResourceId) { 
return new TypeSafeMatcher<View>() { 

@Override 
public void describeTo(Description description) { 
description.appendText("with drawable from resource id: " + imageResourceId); 
} 

@Override 
public boolean matchesSafely(View view) { 
Drawable actualDrawable = ((ImageView) view).getDrawable(); 
final Drawable correctDrawable = view.getResources().getDrawable(imageResourceId); 
if (actualDrawable == null) { 
return correctDrawable == null; 
} 
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) { 
return areImagesTheSameAfterSdk21(actualDrawable, correctDrawable); 
} else { 
return areImagesTheSameBeforeSdk21(actualDrawable, correctDrawable); 
} 
} 
}; 
} 

protected static boolean areImagesTheSameBeforeSdk21(Drawable actualDrawable, 
Drawable correctDrawable) { 
Drawable.ConstantState actualDrawableConstantState = actualDrawable.getConstantState(); 
Drawable.ConstantState correctDrawableConstantState = correctDrawable.getConstantState(); 
return actualDrawableConstantState.equals(correctDrawableConstantState); 
} 

@TargetApi(Build.VERSION_CODES.HONEYCOMB_MR1) 
protected static boolean areImagesTheSameAfterSdk21(Drawable actualDrawable, 
Drawable correctDrawable) { 
Bitmap correctBitmap = drawableToBitmap(correctDrawable); 
Bitmap actualBitmap = drawableToBitmap(actualDrawable); 

return correctBitmap.sameAs(actualBitmap); 
} 

private static Bitmap drawableToBitmap(Drawable drawable) { 
if (drawable instanceof BitmapDrawable) { 
return ((BitmapDrawable) drawable).getBitmap(); 
} 

Bitmap bitmap = Bitmap 
.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), 
Bitmap.Config.ARGB_8888); 
Canvas canvas = new Canvas(bitmap); 
drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight()); 
drawable.draw(canvas); 

return bitmap; 
} 
} 

希望这将有助于