Creating custom view

I want开发者_高级运维 to create a custom view TestView class for which I can create object via new TestView(). A new view class however needs a AttributeSet object. From where do I get that AttributeSet and what does it have to include?

It's not mandatory, and most times you don't even have to worry about it as long as you provide constructors from View that pass them along to super().

public CustomView(Context context)  // No Attributes in this one.
{
  super(context);
  // Your code here
}

public CustomView(Context context, AttributeSet attrs)
{
  super(context, attrs);
  // Your code here
}

public CustomView(Context context, AttributeSet attrs, int default_style)
{
  super(context, attrs, default_style);
  // Your code here
}

View takes care of doing the heavy lifting for dealing with all of the android:* attributes that you'd usually pass in when adding the view to a layout. Your constructors could make use of those attributes or your own if you've defined them:

<com.blrfl.CustomView
 android:id="@+id/customid"
 android:layout_weight="1"
 android:layout_width="fill_parent"
 android:layout_height="fill_parent"
 android:layout_gravity="center"
 blrfl:foo="bar"
 blrfl:quux="bletch"
/>

Either of 3 constructor provided by view class can be implemented.. so providing constructor with attributeset is not mandatory.