How to read value of custom attribute of multiple formats?

Question

related SO question

We can define custom attribute of multiple types.

<declare-styleable name="RoundedImageView">
    <attr name="cornerRadius" format="dimension|fraction"/>
</declare-styleable>

And I want to use it in the following way

<RoundedImageView app:cornerRadius="30dp"/>
<RoundedImageView app:cornerRadius="20%"/>

How to read the value out of it?

---

API level 21 provided an API TypedArray.getType(index)

int type = a.getType(R.styleable.RoundedImageView_cornerRadius);
if (type == TYPE_DIMENSION) {
    mCornerRadius = a.getDimension(R.styleable.RoundedImageView_cornerRadius, 0);
} else if (type == TYPE_FRACTION) {
    mCornerRadius = a.getFraction(R.styleable.RoundedImageView_cornerRadius, 1, 1, 0);
}

I guess this is the recommended solution.

But how to do it with lower API level? Do I have to use try catch?

Or maybe just define two attributes... cornerRadius and cornerRadiusPercentage... I'm going to miss border-radius in CSS.

Answer 1

Thanks for @Selvin's comment. You can use TypedArray.getValue(...) + TypedValue.type. You can find the type constants here

TypedValue tv = new TypedValue();
a.getValue(R.styleable.RoundedImageView_cornerRadius, tv);
if (tv.type == TYPE_DIMENSION) {
    mCornerRadius = tv.getDimension(getContext().getResources().getDisplayMetrics());
} else if (tv.type == TYPE_FRACTION) {
    mCornerRadius = tv.getFraction(1, 1);
    mUsePercentage = true;
}