Intro

This project aims to be a much more powerful alternative to UIView's tag, viewWithTag, and subviews methods. Think jQuery selectors. It adds two parts. The first is is allowing a view to have unlimited NSString tags. The pertinent bits are

- (NSArray *)tags;
- (UIView *)addTags:(NSString *)tags;
- (UIView *)clearTags:(NSString *)tags;

Note: tags are a string containing one or more whitespace separated tags.

The second, and more powerful part, is a recursive super/subview query with a concise DSL that allows searching by tags, classes, arbitrary predicates, or any combination thereof.

- (NSArray *)viewQuery:(NSString *)query, ... ;

Query DSL

The query string starts with an optional prefix block indicating search direction/depth/height/max results. Prefixes start with 'h' for height, 'd' for depth, and 't' for take, each of which can be followed by an integer.

The query string itself use prefix notation and whitespace as separators. Logical operators are '!', '|' and '&'. @indicates the following text is a class to be used in an isKindOfClass test. %p indicates a predicate to passed as a vararg. All other text is interpreted as tags. The outermost set of parens are optional, and an empty query matches everything. Here are a few examples to make it clearer.

// get all subviews that have the 'my_view' tag
[self.view viewQuery:@"my_view"]

// get all subviews that have any of the tags 'my_view' 'my_other_view' 'pick_me'
[self.view viewQuery:@"| my_view my_other_view pick_me"]

// get all subviews to 3 deep that are UILabels
[self.view viewQuery:@"d3: @UILabel"]

// get all superviews that are UIImageViews
[self.view viewQuery:@"h: @UIImageView"]

// get all superviews to a height of 8 that have a width of 50
[self.view viewQuery:@"h8: %p", BK_PRED_VIEW(return view.width == 50;)]

// get all subviews to 3 deep that are both not of class UILabel and don't have the tag 'my_tag'
[self.view viewQuery:@"d3:& ! @UILabel ! my_tag"]

// get 1 subviews to depth 3 that is a label
[self.view viewQuery:@"t1 d3:@UILabel"]

// get one superview with the tag 'widget_root' 
[self.view viewQuery:@"h t1:widget_root"]

// get all superviews
[self.view viewQuery:@"h:"]

//get subviews to depth 3 that are either UILabels with tag 'x_is_0' or that have tag 'x_is_2' and red backgrounds
NSPredicate * redPred = BK_PRED_VIEW( return [self isRedView:view]; );
NSArray *views = [self.view viewQuery:@"d3: |   (& @UILabel x_is_0)\
                                                (& x_is_2   %p    )", redPred];


// get one view to any depth with the tag 'sometag' and hide it
[[self.view viewQuery:@"t1:sometag"][0] setHidden:YES];

Combine this with a decent enumeration library like YOLOKit and it becomes convenient to grab the views of interest and do things to them, like so:

[self.view viewQuery:@"sometag"].each(^(UIView *vw){
	vw.hidden = NO;
	//do more stuff
});

Misc.

By default there are unprefixed convenience methods, which is slightly unsafe. You can eliminate these by defining BK_TAG_SUBVIEW_NO_CONVENIENCE_METHODS. Likewise BK_TAG_SUBVIEW_NO_HELPER_PREDS will remove the helper macros.

Also, there's a small set of tests, and demo app if you want to give it a quick try.