Android: how to get attribute from custom view super class

Question

I have a custom view A that has a TextView. I created a method that returns resourceID for a TextView. If no text is specified, the method will return -1 by default. I also have a custom view B that inherits from view A My custom view has the text hello. When I call the method to get the attribute of the super class, I get -1 back.

There is also an example in the code of how I can get the value, but it feels like a hack.

attrs.xml

 <declare-styleable name="A"> <attr name="mainText" format="reference" /> </declare-styleable> <declare-styleable name="B" parent="A"> <attr name="subText" format="reference" /> </declare-styleable> 

Class A

 protected static final int UNDEFINED = -1; protected void init(Context context, AttributeSet attrs, int defStyle) { TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.A, defStyle, 0); int mainTextId = getMainTextId(a); a.recycle(); if (mainTextId != UNDEFINED) { setMainText(mainTextId); } } protected int getMainTextId(TypedArray a) { return a.getResourceId(R.styleable.A_mainText, UNDEFINED); } 

Class B

 protected void init(Context context, AttributeSet attrs, int defStyle) { super.init(context, attrs, defStyle); TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.B, defStyle, 0); int mainTextId = getMainTextId(a); // this returns -1 (UNDEFINED) //this will return the value but feels kind of hacky //TypedArray b = context.obtainStyledAttributes(attrs, R.styleable.A, defStyle, 0); //int mainTextId = getMainTextId(b); int subTextId = getSubTextId(a); a.recycle(); if (subTextId != UNDEFINED) { setSubText(subTextId); } } 

Another solution that I have found so far is the following. I also think this is hacky.

 <attr name="mainText" format="reference" /> <declare-styleable name="A"> <attr name="mainText" /> </declare-styleable> <declare-styleable name="B" parent="A"> <attr name="mainText" /> <attr name="subText" format="reference" /> </declare-styleable> 

How to get attribute from superclass of custom view? I cannot find good examples of how inheritance works with custom views.

Answer 1

This seems to be the right way to do this:

 protected void init(Context context, AttributeSet attrs, int defStyle) { super.init(context, attrs, defStyle); TypedArray b = context.obtainStyledAttributes(attrs, R.styleable.B, defStyle, 0); int subTextId = getSubTextId(b); b.recycle(); TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.A, defStyle, 0); int mainTextId = getMainTextId(a); a.recycle(); if (subTextId != UNDEFINED) { setSubText(subTextId); } } 

There is an example in the source TextView.java. in line 1098