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TreeIterables

public final class TreeIterables
extends Object

java.lang.Object
   ↳ androidx.test.espresso.util.TreeIterables


Utility methods for iterating over tree structured items.

Since the view hierarchy is a tree - having a method of iterating over its contents is useful.

This is generalized for any object which can display tree like qualities - but this generalization was done for testability concerns (since creating View hierarchies is a pain).

Only public methods of this utility class are considered public API of the test framework.

Summary

Nested classes

class TreeIterables.ViewAndDistance

Represents the distance a given view is from the root view. 

Public methods

static Iterable<View> breadthFirstViewTraversal(View root)

Returns an iterable which iterates thru the provided view and its children in a breadth-first, row-level-order traversal.

static Iterable<View> depthFirstViewTraversal(View root)

Returns an iterable which iterates thru the provided view and its children in a depth-first, in-order traversal.

static Iterable<TreeIterables.ViewAndDistance> depthFirstViewTraversalWithDistance(View root)

Creates an iterable that traverses the tree formed by the given root.

Inherited methods

From class java.lang.Object

Public methods

breadthFirstViewTraversal

Iterable<View> breadthFirstViewTraversal (View root)

Returns an iterable which iterates thru the provided view and its children in a breadth-first, row-level-order traversal. That is to say that for a view such as: Root / | \ A R U /| |\ B D G N Will be iterated: Root, A, R, U, B, D, G, N

Parameters
root View: the non-null, root view.

Returns
Iterable<View>

depthFirstViewTraversal

Iterable<View> depthFirstViewTraversal (View root)

Returns an iterable which iterates thru the provided view and its children in a depth-first, in-order traversal. That is to say that for a view such as: Root / | \ A R U /| |\ B D G N Will be iterated: Root, A, B, D, R, G, N, U.

Parameters
root View: the non-null, root view.

Returns
Iterable<View>

depthFirstViewTraversalWithDistance

Iterable<TreeIterables.ViewAndDistance> depthFirstViewTraversalWithDistance (View root)

Creates an iterable that traverses the tree formed by the given root.

Along with iteration order, the distance from the root element is also tracked.

Parameters
root View: the root view to track from.

Returns
Iterable<TreeIterables.ViewAndDistance> An iterable of ViewAndDistance containing the view tree in a depth first order with the distance of a given node from the root.