How to retrieve XML attribute for custom control

Question

I've created a combo box control with a edittext and spinner. I'm trying to let the android:prompt attribute be passed onto the spinner, which means I need to catch it in the constructor which passes my the AttributeSet and set it on the spinner. I can't figure out how to get the value of the prompt. I'm trying,

int[] ra = { android.R.attr.prompt };
TypedArray ta = context.getTheme().obtainStyledAttributes(ra); 
int id = ta.getResourceId(0, 0); 

I get back 0, which means it didn't find the attribute. I also did a ta.count() which returned 0. So I'm not getting anything back.

My XML simply defines an android:prompt value.

Thanks

Solution

I just wrote an answer explaining the whole process for using XML with custom UI elements. In your case, there is no need to declare a styleable, as you don't need custom attributes. Using android.R.attr.prompt as the int id will work fine. R.styleable.className_attributeName will only work if you defined your attributes in the styleable and you retrieved them by passing R.styleable.className into obtainStyledAttributes.

Comments

[MrSnowflake]

This, but you should not forget to define a new xml namespace for your custom settings in the layout xml: xmlns:app="schemas.android.com/apk/res/package.name". And use a.getString(R.stylable.option_name) to get the option.

[David]

Great thanks! a.getString(R.styleable.option_name) does not work. I get an index out of bounds exception. I presume the index is supposed to be the index within the array, not a resource id. Using android:prompt also works, android.R.attr.prompt. My problem was using the wrong signature on the obtainStyleAttributes method. I thought I had to use a Theme. These signatures work: TypedArray a = context.obtainStyledAttributes(attrs, new int[] { android.R.attr.prompt }); or context.obtainStyledAttributes(attrs, new int[] { android.R.attr.prompt}, 0, 0 ); Then a.getResourceId(0, 0);