iOS-监听UITextView、UITextField键盘删除键

淡淡的烟草味﹌ 2023-10-16 23:59 39阅读 0赞

今天做了一个设置锁屏密码功能，其中我使用的是四个UITextField，上一个UITextField输入之后，下一个UITextField响应，这时的UITextField里面没有任何值，我想过使用UITextFieldTextDidChangeNotification通知，但是只有输入值时才能监听，此法行不通啊。

还找了一下如何获取深处这个按钮，UIButton \*clearButton = \[myTextField valueForKey:@"\_clearButton"\];

\[clearButton setImage:\[UIImagenew\] forState:UIControlStateNormal\];重写其中的点击方法也失败了。

参考其讲解[点击打开链接][Link 1]

我现在想做的是到下一个UITextField时，我点击键盘自带的删除按钮时，上一个UITextField响应删除方法，经研究发现一个办法，代码如下：

先说原理UITextField其实里面用的是UIKeyInput，先看UIKeyInput.h

@protocol UIKeyInput <UITextInputTraits>

\- (BOOL)hasText;

\- (void)insertText:(NSString \*)text;

\- (void)deleteBackward; <-------就是它删除方法

@end

使用首先继承 UITextField：

.h文件

\#import <UIKit/UIKit.h>

@classYNTextField;

@protocol YNTextFieldDelegate <NSObject>

\- (void)ynTextFieldDeleteBackward:(YNTextField \*)textField;

@end

@interface YNTextField : UITextField

@property (nonatomic, assign) id <YNTextFieldDelegate> yn\_delegate;

@end

再看.m文件

\#import "YNTextField.h"

@implementation YNTextField

\- (void)deleteBackward \{

！！！这里要调用super方法，要不然删不了东西

\[superdeleteBackward\];

if (\[self.yn\_delegaterespondsToSelector:@selector(ynTextFieldDeleteBackward:)\]) \{

\[self.yn\_delegateynTextFieldDeleteBackward:self\];

- (BOOL)keyboardInputShouldDelete:(YNTextField *)textField
    {
        BOOL shouldDelete =YES;
        if ([YNTextFieldinstancesRespondToSelector:_cmd])
        {
            BOOL (*keyboardInputShouldDelete)(id,SEL,UITextField *) = (BOOL (*)(id,SEL,UITextField *))[UITextFieldinstanceMethodForSelector:_cmd];
            if (keyboardInputShouldDelete)
            {
                shouldDelete = keyboardInputShouldDelete(self,_cmd, textField);
            }
        }
        if ([[[UIDevicecurrentDevice]systemVersion]intValue] >=8)
        {
            [selfdeleteBackward];
        }
            return shouldDelete;
    }
    
    @end

最后调用时设置代理

- (void)hqTextFieldDeleteBackward:(HQTextField *)textField
    {
    }

博主提供几篇具有帮助的文章

[iOS - 监听UITextField键盘删除键之分类][iOS - _UITextField]

[http://stackoverflow.com/questions/27921485/deletebackward-not-getting-called-for-custom-uitextfield][http_stackoverflow.com_questions_27921485_deletebackward-not-getting-called-for-custom-uitextfield]

[http://stackoverflow.com/questions/1977934/detect-backspace-in-uitextfield][http_stackoverflow.com_questions_1977934_detect-backspace-in-uitextfield]

[http://stackoverflow.com/questions/25371254/how-to-detect-delete-key-on-an-uitextfield-in-ios-8][http_stackoverflow.com_questions_25371254_how-to-detect-delete-key-on-an-uitextfield-in-ios-8]

[Link 1]: http://stackoverflow.com/questions/9239328/custom-uitextfield-clear-buttonhttp://
[iOS - _UITextField]: http://www.jianshu.com/p/d2c2f4aaef0d
[http_stackoverflow.com_questions_27921485_deletebackward-not-getting-called-for-custom-uitextfield]: http://stackoverflow.com/questions/27921485/deletebackward-not-getting-called-for-custom-uitextfield
[http_stackoverflow.com_questions_1977934_detect-backspace-in-uitextfield]: http://stackoverflow.com/questions/1977934/detect-backspace-in-uitextfield
[http_stackoverflow.com_questions_25371254_how-to-detect-delete-key-on-an-uitextfield-in-ios-8]: http://stackoverflow.com/questions/25371254/how-to-detect-delete-key-on-an-uitextfield-in-ios-8