com.facebook.litho.testing.viewtree

Class ViewTree

java.lang.Object

com.facebook.litho.testing.viewtree.ViewTree

public final class ViewTree
extends Object

This is a helper class to allow asserting on view trees and recursively verify predicates on its nodes within the narrow abilities that Robolectric affords us.

Method Summary

Modifier and Type	Method and Description
<any>	findChild(<any> predicate) Find a view in the hierarchy for which the given predicate is true
<any>	findChild(<any> predicate, <any> shouldCheckChildren) Find a view in the hierarchy for which the given predicate is true, while only check children of nodes as directed by the additional shouldCheckChildren predicate
View	getRoot()
String	makeString(<any> extraTextFunction) Generates a string describing the views tree using the views' toString methods and an extra information function.
static ViewTree	of(View view)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

of

public static ViewTree of(View view)

getRoot

public View getRoot()

Returns:

the view group used to generate this tree

findChild

public <any> findChild(<any> predicate)

Find a view in the hierarchy for which the given predicate is true

Parameters:

predicate - the predicate to find a view upholding

Returns:

null if no such view is found, or a list showing the path in the hierarchy to the view for which the predicate holds

findChild

public <any> findChild(<any> predicate,
                       <any> shouldCheckChildren)

Find a view in the hierarchy for which the given predicate is true, while only check children of nodes as directed by the additional shouldCheckChildren predicate

Parameters:

predicate - the predicate to find a view upholding

shouldCheckChildren - a predicate to decide whether to

Returns:

null if no such view is found, or a list showing the path in the hierarchy to the view for which the predicate holds

makeString

public String makeString(<any> extraTextFunction)

Generates a string describing the views tree using the views' toString methods and an extra information function.

The output is a string, with each view of the tree in its own line, indented according to its depth in the tree, and then the extra information supplied by teh function.

This can be used, for example, to print all views and their respective text and is useful for when assertions fail.

Parameters:

extraTextFunction - the function returning extra information to print per view, or null if not extra information should be printed

Returns:

a string describing the tree