obj-c 保護你的delegate method calling

@protocol SearchViewDelegate<NSObject>

@optional

- (void)searchTextFieldDidBeginEditing;

- (void)onSearchTextFieldValueChanged:(NSString *)text;

@end

@interface SearchView()

@end

@implementation SearchView

typedef struct {

    unsigned int searchTextFieldDidBeginEditing:1;

    unsigned int onSearchTextFieldValueChanged:1;

} DelegateRespondsTo;

DelegateRespondsTo delegateRespondsTo;

- (void)setDelegate:(id <SearchViewDelegate>)aDelegate {

    if (_delegate != aDelegate) {

        _delegate = aDelegate;

        

        delegateRespondsTo.searchTextFieldDidBeginEditing = [_delegate respondsToSelector:@selector(searchTextFieldDidBeginEditing)];

        delegateRespondsTo.onSearchTextFieldValueChanged = [_delegate respondsToSelector:@selector(onSearchTextFieldValueChanged:)];

    }

}

textFieldShouldClear dismiss keyboard

func textFieldShouldClear(_ textField: UITextField) -> Bool {

    textField.resignFirstResponder()
        
    textField.text = nil
        
    return false
}

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改變UISegmentedControl的font

#import "UISegmentedControl+Font.h"

@implementation UISegmentedControl(Font)

- (void)setFont:(UIFont *)font color:(UIColor *)color {
    NSDictionary *attributes = [NSDictionary dictionaryWithObjectsAndKeys:font, NSFontAttributeName, [UIColor blackColor], NSForegroundColorAttributeName, nil];
    [self setTitleTextAttributes:attributes forState:UIControlStateNormal];
    NSDictionary *highlightedAttributes = [NSDictionary dictionaryWithObject:[UIColor whiteColor] forKey:NSForegroundColorAttributeName];
    [self setTitleTextAttributes:highlightedAttributes forState:UIControlStateSelected];
}

@end