记录UITextField删除状态

self.testTextField.leftView = [[UIView alloc] initWithFrame:CGRectMake(, , , )];
self.testTextField.leftViewMode = UITextFieldViewModeAlways;

这两机代码可以是textField的光标向右偏移40;

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项目中需要在UITextField在删除时候的做些事情，本身又没有方法。所以需要自己写

KeyInPutTextField.h

#import <UIKit/UIKit.h>

@protocol  KeyInPutTextFieldDelegate<NSObject>

@optional
- (void)deleteBackward;

@end

@interface KeyInPutTextField : UITextField

@property (nonatomic, assign)id<KeyInPutTextFieldDelegate>keyInputDelegate;

@end

KeyInPutTextField.m

#import "KeyInPutTextField.h"

@implementation KeyInPutTextField

- (void)deleteBackward
{
    [super deleteBackward];
    if ((_keyInputDelegate &&[_keyInputDelegate respondsToSelector:@selector(deleteBackward)]))
    {
        [_keyInputDelegate deleteBackward];
    }
}

@end

调用

#import "ViewController.h"
#import "KeyInPutTextField.h"
@interface ViewController ()<UITextFieldDelegate, KeyInPutTextFieldDelegate>

@property (nonatomic, strong) KeyInPutTextField *testTextField;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.testTextField = [[KeyInPutTextField alloc]initWithFrame:CGRectMake(, , , )];
    self.testTextField.borderStyle = UITextBorderStyleRoundedRect;
    self.testTextField.textColor = [UIColor redColor];
    self.testTextField.delegate = self;
    self.testTextField.keyInputDelegate = self;
    [self.view addSubview:self.testTextField];
    [self.testTextField becomeFirstResponder];

    self.testTextField.rightViewMode = UITextFieldViewModeAlways;

    self.testTextField.leftView = [[UIView alloc] initWithFrame:CGRectMake(, , , )];
    self.testTextField.leftViewMode = UITextFieldViewModeAlways;
}

- (void)deleteBackward
{
    NSLog(@"aa");
}