/** TextField 輸入長(zhǎng)度限制 */
#import <UIKit/UIKit.h>
NS_ASSUME_NONNULL_BEGIN
typedef void(^TextLengthMoreThanBlock)(void);
@interface UITextField (LimitLength)
/** 輸入限制長(zhǎng)度 */
@property (nonatomic, strong) NSNumber *limitLength;
/** 輸入長(zhǎng)度超過限制回調(diào) */
@property (nonatomic, copy) TextLengthMoreThanBlock lenghtBlock;
@end
NS_ASSUME_NONNULL_END
#import "UITextField+LimitLength.h"
#import <objc/runtime.h>
#import <objc/message.h>
static const void *limitLengthKey = &limitLengthKey;
static const void *textLengthMoreThanBlockKey = &textLengthMoreThanBlockKey;
@implementation UITextField (LimitLength)
#pragma mark - Setter/Getter
- (NSNumber *)limitLength
{
return objc_getAssociatedObject(self, limitLengthKey);
}
- (void)setLimitLength:(NSNumber *)limitLength
{
objc_setAssociatedObject(self, limitLengthKey, limitLength, OBJC_ASSOCIATION_COPY_NONATOMIC);
[self addTarget:self action:@selector(textFieldTextDidChange) forControlEvents:UIControlEventEditingChanged];
}
- (TextLengthMoreThanBlock)lenghtBlock
{
return objc_getAssociatedObject(self, textLengthMoreThanBlockKey);
}
- (void)setLenghtBlock:(TextLengthMoreThanBlock)lenghtBlock
{
objc_setAssociatedObject(self, textLengthMoreThanBlockKey, lenghtBlock, OBJC_ASSOCIATION_COPY_NONATOMIC);
}
- (void)textFieldTextDidChange
{
if (self.text.length >= self.limitLength.intValue)
{
self.text = [self.text substringToIndex:self.limitLength.intValue];
if (self.lenghtBlock)
{
self.lenghtBlock();
}
}
}
+ (void)load
{
Method origMethod = class_getInstanceMethod([self class], NSSelectorFromString(@"dealloc"));
Method newMethod = class_getInstanceMethod([self class], @selector(my_dealloc));
method_exchangeImplementations(origMethod, newMethod);
}
- (void)my_dealloc
{
// do your logic here
[[NSNotificationCenter defaultCenter] removeObserver:self name:UITextFieldTextDidChangeNotification object:self];
//this calls original dealloc method
[self my_dealloc];
}
@end
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