CODEWITHSUNDEEP
androidandroid-layoutandroid-xmlandroid-resourcesandroid-screen-support
Jim
Jim

Reputation: 4405

Should we avoid the size definition inside the xml?

Is there any reason to avoid having dps defined directly in the xml files?
E.g. is there any reason to prefer:

android:layout_marginLeft="@dimen/left_margin"

over this:

android:layout_marginLeft=16dp

If I understand correctly, this would make sense only for tablets but in that case won't we have a relevant xml in land with the relevant values?
Also if is there anything to be careful in regards to adding something to dimen.xml? E.g. should left_margin be defined in all dimen.xml for all dimension?

Upvotes: 0

Views: 62

Answers (2)

TheWanderer
TheWanderer

Reputation: 17834

One good reason would be that maybe you have a whole lot of layouts where marginLeft needs to be the same. You could set them all to 16dp right in the layout files, but what if you need to change that dimension? If you have 16dp defined in every layout, you'll have to change every single instance of it, and you might forget some. If it's defined in dimens you only have to change it once.

Another reason would be themers. Someone might make a theme for your app. It's a lot easier to override extracted values than having to override and copy an entire layout just to change one value.

And as Gabe says, you really should use start and end instead of left and right, whenever possible. Otherwise, your app will look terrible on devices using RTL.

Upvotes: 1

Gabe Sechan
Gabe Sechan

Reputation: 93561

There's a good reason for using the first. Lets say that you decide on really big devices you want a bigger margin. With the first, you only have to override the dimens file and override the 1 dimension. In the second, you have to override the entire layout, which causes larger maintenance issues.

(Also you should almost always be using marginStart and marginEnd instead of left and right, so you handle RTL languages correctly).

Upvotes: 2

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