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android:textAppearance allows you to apply an additional layer of styling for certain attributes on text views. I'm wondering whether the flexibility of this feature outweighs its complexity.

  • Is android:textAppearance required for any technical or visual reason?
  • What might be the consequences of relying solely on style throughout a project and omitting the use of android:textAppearance in layouts?
  • What if it were omitted from styles too?

Here's two guides that recommend the use of android:textAppearance:

Styling Views on Android (Without Going Crazy)

TextAppearance allows you to merge two styles for some of the most commonly modified text attributes. Take a look at all your styles: how many of them only modify how the text looks? In those cases, you could instead just modify the TextAppearance.

Best practices for happy Android resources

To ensure consistent-looking TextViews, do not define any of the TextAppearance attributes in a normal style, but always set a TextAppearance from your library on that style’s android:textAppearance field.

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Looking at TextView.java, there don't appear to be any attributes that are defined by android:textAppearance that are not able to be set on a TextView directly. So there doesn't appear to be any technical reason that one needs to use them over defining attributes in styles directly, at least in one's ability to configure how a TextView looks.

This means that you can avoid using it in your layouts as well as your styles without any adverse effects, provided that you override all the associated attributes. The base theme defines many different standard android:textAppearances for the various widgets, so you should check that all the widgets are properly overridden.

Based on my experience, android:textAppearance is most useful if you wish your app to appear to integrate into the rest of the device. So if you need big text, you can use android:textAppearance="?android:attr/textAppearanceLarge" and now your text is large! No need to know how many sp that means for the given device/screen size/etc..

However if your app is highly styled and you'd otherwise be overriding all the text sizes anyhow, the value-add of android:textAppearance diminishes. You can certainly use it as referenced in the posts above, but if that doesn't fit into your styling system, then feel free to omit it. It's just another tool to help you get a good-looking app across all devices.

I would also recommend making extra-sure that you try your app across a variety of devices if you choose not to use it, just to make sure that you didn't neglect to override a default android:textAppearance.

于 2018-05-31T15:10:04.960 回答