给textField添加粘贴的回调

平时项目中,我们可能会遇到区分用户输入和粘贴的情况.例如当用户粘贴时,清空textField原有的内容.本文通过创建一个UITextField的子类来实现次功能.

子类代码

头文件

@protocol YJTextFieldDelegate <UITextFieldDelegate>

/**
 *  给textField粘贴时,不再调用- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string方法
 *  会调用此方法
 */
- (BOOL)textField:(YJTextField *)textField shouldPasteCharactersInRange:(NSRange)range replacementString:(NSString *)string;

@end



@interface YJTextField : UITextField
@property (nonatomic, weak) id<YJTextFieldDelegate, UITextFieldDelegate> delegate;

@end

实现文件

#import "YJTextField.h"

@implementation YJTextField

- (void)paste:(id)sender {
    UITextPosition *begin = self.beginningOfDocument;
    UITextPosition *start = self.selectedTextRange.start;
    UITextPosition *end = self.selectedTextRange.end;
    NSRange range = NSMakeRange([self offsetFromPosition:begin toPosition:start], [self offsetFromPosition:start toPosition:end]);
    if ([self.delegate respondsToSelector:@selector(textField:shouldPasteCharactersInRange:replacementString:)] &&
        [self.delegate textField:self shouldPasteCharactersInRange:range replacementString:[UIPasteboard generalPasteboard].string]) {
        [self replaceRange:self.selectedTextRange withText:[UIPasteboard generalPasteboard].string];
    }
}

@end

在需要识别粘贴的地方,用YJTextField,实现- (BOOL)textField:(YJTextField *)textField shouldPasteCharactersInRange:(NSRange)range replacementString:(NSString *)string;代理方法即可.