Android Styleable Custom View https://github.com/alphonzo79/AndroidStyleableViewExample

The Challenge ● The design team has established a strong design and theme for the app. ● Even though design elements keep the same or similar form, there are variations to communicate state or to differentiate sections of the app.

Step One: Custom View ● Extend a base View class – Most often one of the layouts: LinearLayout, FrameLayout, RelativeLayout ● Build your xml layout ● Remember to change the root to merge when you have it all set ● Create initView method (or similar) and call from all constructors to inflate the layout ● Expose needed methods in the Javas just like any other

Step Two: Make it Styleable ● Declare the View styleable in attrs.xml ● Define each attribute for the view ● Define the format(s) for each attribute ● Optionally, define flags for specific, limited possible values

Step Three: Consume the Attributes ● Inside initView, after inflating the layout, retrieve the attributes ● TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.ComplexEditText); ● Attributes may not be present ● Some attributes may be represented in different formats ● Don't forget to recycle the TypedArray

Step Four: Wire it all together ● Declare a namespace pointing to res-auto ● xmlns:app="http://schemas.android.com/apk/res­auto" ● Apply your attributes as you would any others, but prefixed with your own namespace

Tips ● Look through the Android source code, especially for the view that you're extending or views that you're incorporating ● http://trickyandroid.com/protip-inflating-layout-for-your- custom-view/