iOS 金额输入框

//
//  HanNumberTextField.h
//  HanTTT
//
//  Created by Han on 2020/9/3.
//  Copyright © 2020 Han. All rights reserved.
//

#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface HanNumberTextField : UITextField

@end

NS_ASSUME_NONNULL_END

//
//  HanNumberTextField.m
//  HanTTT
//
//  Created by Han on 2020/9/3.
//  Copyright © 2020 Han. All rights reserved.
//

#import "HanNumberTextField.h"

@interface HanNumberTextField()<UITextFieldDelegate>
@end

@implementation HanNumberTextField



- (instancetype)init
{
    self = [super init];
    if (self) {
        self.delegate = self;
        self.keyboardType = UIKeyboardTypeDecimalPad;
    }
    return self;
}
-(void)awakeFromNib{
    [super awakeFromNib];
    self.delegate = self;
    self.keyboardType = UIKeyboardTypeDecimalPad;
}

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    
        BOOL isHaveDian;
        // 判断是否有小数点
        if ([textField.text containsString:@"."]) {
            isHaveDian = YES;
        }else{
            isHaveDian = NO;
        }
        
        if (string.length > 0) {
            
            //当前输入的字符
            unichar single = [string characterAtIndex:0];
            
            // 不能输入.0-9以外的字符
            if (!((single >= '0' && single <= '9') || single == '.'))
            {
                //SVHUD_HINT(@"您的输入格式不正确");
                return NO;
            }
            
            // 只能有一个小数点
            if (isHaveDian && single == '.') {
                //SVHUD_HINT(@"最多只能输入一个小数点");
                return NO;
            }
            
            // 如果第一位是.则前面加上0.
            if ((textField.text.length == 0) && (single == '.')) {
                textField.text = @"0";
            }
            
            // 如果第一位是0则后面必须输入点，否则不能输入。
            if ([textField.text hasPrefix:@"0"]) {
                if (textField.text.length > 1) {
                    NSString *secondStr = [textField.text substringWithRange:NSMakeRange(1, 1)];
                    if (![secondStr isEqualToString:@"."]) return NO;
                }else{
                    if (![string isEqualToString:@"."]) return NO;
                }
            }
            
            // 小数点后最多能输入两位
            if (isHaveDian) {
                NSRange ran = [textField.text rangeOfString:@"."];
                // 由于range.location是NSUInteger类型的，所以这里不能通过(range.location - ran.location)>2来判断
                if (range.location > ran.location) {
                    if ([textField.text pathExtension].length > 1) {
                        return NO;
                    }
                }
            }
        }
    
    return YES;
}
@end