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头文件

#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface UITextField (handleKeyboardShelter)

/**
 处理键盘遮挡
 
 @param vc 当前textfield所在的VC
 */
- (void)handleKeyboardShelterWithViewController:(UIViewController *)vc;

/**
 处理dealloc 要在当前textfield所在的VC中调用该方法
 */
- (void)handleDealloc;

@end

NS_ASSUME_NONNULL_END

.m 文件

#import "UITextField+handleKeyboardShelter.h"
#import <objc/runtime.h>

static NSString *kCurrentVC = @"UITextFieldHandleKeyboardShelterCurrentVC";
static NSString *kCurrentVCFrame = @"UITextFieldHandleKeyboardShelterCurrentVCFrame";

@implementation UITextField (handleKeyboardShelter)

- (void)handleKeyboardShelterWithViewController:(UIViewController *)vc {
    [self setCurrentVC:vc];
    //监听键盘展示和隐藏的通知
    [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
    
}


- (void)handleDealloc {
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

- (void)keyboardWillShow:(NSNotification *)notification{
    if (![self isFirstResponder]) {
        return;
    }
    UIViewController *vc = [self currentVC];
    CGRect rect = [self.superview convertRect:self.frame toView:vc.view];//获取相对于self.view的位置
    NSDictionary *userInfo = [notification userInfo];
    NSValue* aValue = [userInfo objectForKey:UIKeyboardFrameEndUserInfoKey];//获取弹出键盘的fame的value值
    CGRect keyboardRect = [aValue CGRectValue];
    keyboardRect = [vc.view convertRect:keyboardRect fromView:vc.view.window];//获取键盘相对于self.view的frame ，传window和传nil是一样的
    CGFloat keyboardTop = keyboardRect.origin.y;
    NSNumber * animationDurationValue = [userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey];//获取键盘弹出动画时间值
    NSTimeInterval animationDuration = [animationDurationValue doubleValue];
    if (keyboardTop < CGRectGetMaxY(rect)) {//如果键盘盖住了输入框
        CGFloat gap = keyboardTop - CGRectGetMaxY(rect) - 10;//计算需要网上移动的偏移量（输入框底部离键盘顶部为10的间距）
        __weak typeof(vc)weakSelf = vc;
        CGRect viewFrame = vc.view.frame;
        [self setCurrentVCFrame:viewFrame];
        viewFrame.origin.y = gap + viewFrame.origin.y;
        [UIView animateWithDuration:animationDuration animations:^{
            weakSelf.view.frame = viewFrame;
        }];
    }
}
- (void)keyboardWillHide:(NSNotification *)notification{
    if (![self isFirstResponder]) {
        return;
    }
    UIViewController *vc = [self currentVC];
    NSDictionary *userInfo = [notification userInfo];
    NSNumber * animationDurationValue = [userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey];//获取键盘隐藏动画时间值
    NSTimeInterval animationDuration = [animationDurationValue doubleValue];
    if (vc.view.frame.origin.y < 0) {//如果有偏移，当影藏键盘的时候就复原
        CGRect frame = [self currentVCFrame];
        __weak typeof(vc)weakSelf = vc;
        [UIView animateWithDuration:animationDuration animations:^{
            weakSelf.view.frame = frame;
        }];
    }
}


- (UIViewController *)currentVC {
    return objc_getAssociatedObject(self, &kCurrentVC);
}

- (void)setCurrentVC:(UIViewController *)vc {
    return objc_setAssociatedObject(self, &kCurrentVC, vc, OBJC_ASSOCIATION_ASSIGN);
}

- (CGRect)currentVCFrame {
    NSString *frameStr = objc_getAssociatedObject(self, &kCurrentVCFrame);
    return CGRectFromString(frameStr);
}

- (void)setCurrentVCFrame:(CGRect)frame {
    NSString *frameStr = NSStringFromCGRect(frame);
    return objc_setAssociatedObject(self, &kCurrentVCFrame, frameStr, OBJC_ASSOCIATION_COPY_NONATOMIC);
}
@end

使用方法:
1.在textField所在控制器的ViewDidLoad方法添加[self.phoneNumberTextField handleKeyboardShelterWithViewController:self];

- (void)viewDidLoad {
    [super viewDidLoad];
   //..........
    [self.phoneNumberTextField handleKeyboardShelterWithViewController:self];
}

2.在textField所在控制器的dealloc方法中释放

- (void)dealloc {
    [self.phoneNumberTextField handleDealloc];
}

两行代码搞定.