XXNumberButton 針對購物車商品進行加減操作，輸入框是動態改變大小的，可以修改輸入框字型顏色，加減按鈕文字背景圖，都是單獨拿出來可以設定資訊，可以設定TextField是否可輸入。

//
//  XXNumberButton.h
//
//  Created by Mac on 2018/8/28.
//  Copyright © 2018年 xiangxx. All rights reserved.
//

#import <UIKit/UIKit.h>

typedef void(^BlockCurrentNumber)(NSString *currentNumber);

@interface XXNumberButton : UIView

- (instancetype)initWithFrame:(CGRect)frame;

@property (nonatomic, copy) BlockCurrentNumber blockCurrentNumber;

/** 加按鈕背景圖片 */
@property (nonatomic, strong ) IBInspectable UIImage *increaseImage;
/** 減按鈕背景圖片 */
@property (nonatomic, strong ) IBInspectable UIImage *decreaseImage;
/** 加按鈕標題 */
@property (nonatomic, copy   ) IBInspectable NSString *increaseTitle;
/** 減按鈕標題 */
@property (nonatomic, copy   ) IBInspectable NSString *decreaseTitle;



/** 加減按鈕的字型大小 */
@property (nonatomic, assign ) IBInspectable CGFloat buttonTitleFont;

/** 輸入框中的字型大小 */
@property (nonatomic, assign ) IBInspectable CGFloat inputFieldFont;

/** 輸入框中的字型顏色 */
@property (nonatomic, strong) IBInspectable UIColor *inputFieldColor;



/** 最小值, default is 0 */
@property (nonatomic, assign ) IBInspectable CGFloat minValue;
/** 最大值 */
@property (nonatomic, assign ) CGFloat maxValue;
/** 遞增步長，預設步長為1 */
@property (nonatomic, assign ) CGFloat stepValue;




/** 為YES時,初始化時減號按鈕隱藏(餓了麼/百度外賣/美團外賣按鈕模式), default is NO*/
@property (nonatomic, assign ) IBInspectable BOOL decreaseHide;

/** 是否可以使用鍵盤輸入, default is YES*/
@property (nonatomic, assign, getter=isEditing) IBInspectable BOOL editing;


@end

#pragma mark - NSString分類
@interface NSString (XXNumberButton)
/**
 字串 nil, @"", @"  ", @"\n" Returns NO;
 其他 Returns YES.
 */
- (BOOL)isNotBlank;
@end
 

//
//  NumberButton.m
//  XXNumberButton
//
//  Created by Mac on 2018/8/28.
//  Copyright © 2018年 xiangxx. All rights reserved.
//

#import "XXNumberButton.h"

@interface XXNumberButton()<UITextFieldDelegate>

@property (nonatomic, assign) CGFloat width;  // 控制元件自身的寬
@property (nonatomic, assign) CGFloat height; // 控制元件自身的高


// 減按鈕
@property (nonatomic, strong) UIButton *decreaseBtn;

// 加按鈕
@property (nonatomic, strong) UIButton *increaseBtn;

// 數量展開輸入框
@property (nonatomic, strong) UITextField *textField;

@end

@implementation XXNumberButton

- (instancetype)initWithCoder:(NSCoder *)aDecoder{
    self = [super initWithCoder:aDecoder];
    if (self) {
        [self initUI];
    }
    return self;
}

- (instancetype)initWithFrame:(CGRect)frame{
    self = [super initWithFrame:frame];
    if (self) {
        [self initUI];
        if(CGRectIsEmpty(frame)) {self.frame = CGRectMake(0, 0, 110, 30);};
    }
    return self;
}

#pragma mark - layoutSubviews
- (void)layoutSubviews
{
    [super layoutSubviews];
    
    _width =  self.frame.size.width;
    _height = self.frame.size.height;
    _textField.frame = CGRectMake(_height, 0, _width - 2*_height, _height);
    _increaseBtn.frame = CGRectMake(_width - _height, 0, _height, _height);
    
    if (_decreaseHide && _textField.text.floatValue < _minValue) {
        _decreaseBtn.frame = CGRectMake(_width-_height, 0, _height, _height);
    } else {
        _decreaseBtn.frame = CGRectMake(0, 0, _height, _height);
    }
}

// 初始化介面
- (void)initUI{
    
    _buttonTitleFont = 17;
    _inputFieldFont = 15;
    _minValue = 0;
    _maxValue = NSIntegerMax;
    self.stepValue = 1;
    
    _increaseBtn = [self createButton];
    _decreaseBtn = [self createButton];
    
    //數量展示/輸入框
    _textField = [[UITextField alloc] init];
    _textField.delegate = self;
    _textField.textAlignment = NSTextAlignmentCenter;
    _textField.keyboardType = UIKeyboardTypeDecimalPad;
    _textField.font = [UIFont systemFontOfSize:_inputFieldFont];
    _textField.text = [NSString stringWithFormat:@"%.0f",_minValue];
    _textField.textColor = [UIColor grayColor];
    
    [self addSubview:_increaseBtn];
    [self addSubview:_decreaseBtn];
    [self addSubview:_textField];
    
    self.clipsToBounds = YES;
    self.layer.cornerRadius = 3.0f;
    self.backgroundColor = [UIColor whiteColor];
}

// 設定加減 按鈕的公共方法
- (UIButton *)createButton{
    UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
    btn.titleLabel.font = [UIFont boldSystemFontOfSize:_buttonTitleFont];
    [btn setTitleColor:[UIColor grayColor] forState:UIControlStateNormal];
    [btn addTarget:self action:@selector(touchDown:) forControlEvents:UIControlEventTouchUpInside];
    return btn;
}

#pragma mark - 加減按鈕點選響應
- (void)touchDown:(UIButton *)sender
{
    [_textField resignFirstResponder];
    
    if (sender == _increaseBtn) {
        [self increase];
    } else {
        [self decrease];
    }
}

// 加運算
- (void)increase{
    
    CGFloat number = [_textField.text floatValue] + self.stepValue;
    
    if (number <= _maxValue) {
        // 當按鈕為"減號按鈕隱藏模式",且輸入框值==設定最小值,減號按鈕展開
        if (_decreaseHide && number==_minValue) {
            
            __weak typeof(self)weakSelf = self;
            [UIView animateWithDuration:0.3f animations:^{
                weakSelf.decreaseBtn.alpha = 1;
                weakSelf.decreaseBtn.frame = CGRectMake(0, 0, weakSelf.height, weakSelf.height);
            } completion:^(BOOL finished) {
                weakSelf.textField.hidden = NO;
            }];
        }
        _textField.text = [NSString stringWithFormat:@"%.0f",number];
        
        if (self.blockCurrentNumber) {
            self.blockCurrentNumber([NSString stringWithFormat:@"%@",_textField.text]);
        }

    } else {

        if (self.blockCurrentNumber) {
            self.blockCurrentNumber([NSString stringWithFormat:@"資料已超過最大數量%.0f",_maxValue]);
        }
    }
}

// 減運算
- (void)decrease{
    
    CGFloat number = [_textField.text floatValue] - self.stepValue;
    
    if (number >= _minValue) {
        _textField.text = [NSString stringWithFormat:@"%.0f",number];
    } else {
        // 當按鈕為"減號按鈕隱藏模式",且輸入框值 < 設定最小值,減號按鈕隱藏
        if (_decreaseHide && number<_minValue) {
            _textField.hidden = YES;
            _textField.text = [NSString stringWithFormat:@"%.0f",_minValue-1];
            
            __weak typeof(self)weakSelf = self;
            [UIView animateWithDuration:0.3f animations:^{
                weakSelf.decreaseBtn.alpha = 0;
                weakSelf.decreaseBtn.frame = CGRectMake(weakSelf.width - weakSelf.height, 0, weakSelf.height, weakSelf.height);
            }];
            return;
        }else{
            
            if (self.blockCurrentNumber) {
                self.blockCurrentNumber([NSString stringWithFormat:@"資料不能小於最小值%.0f",_minValue]);
            }
            return;
        }
    }
    
    if (self.blockCurrentNumber) {
        self.blockCurrentNumber([NSString stringWithFormat:@"%@",_textField.text]);
    }
}

#pragma mark - 加減按鈕的屬性設定  為YES時,初始化時減號按鈕隱藏
- (void)setDecreaseHide:(BOOL)decreaseHide
{
    // 當按鈕為"減號按鈕隱藏模式(餓了麼/百度外賣/美團外賣按鈕樣式)"
    if (decreaseHide) {
        if (_textField.text.floatValue <= _minValue) {
            _textField.hidden = YES;
            _decreaseBtn.alpha = 0;
            
            _textField.text = [NSString stringWithFormat:@"%.0f",_minValue-1];
            _decreaseBtn.frame = CGRectMake(_width-_height, 0, _height, _height);
        }
        self.backgroundColor = [UIColor clearColor];
    } else {
        _decreaseBtn.frame = CGRectMake(0, 0, _height, _height);
    }
    _decreaseHide = decreaseHide;
}

#pragma mark set get 方法
- (void)setIncreaseImage:(UIImage *)increaseImage{
    _increaseImage = increaseImage;
    [_increaseBtn setBackgroundImage:increaseImage forState:UIControlStateNormal];
}

- (void)setDecreaseImage:(UIImage *)decreaseImage{
    _decreaseImage = decreaseImage;
    [_decreaseBtn setBackgroundImage:decreaseImage forState:UIControlStateNormal];
}

- (void)setIncreaseTitle:(NSString *)increaseTitle{
    _increaseTitle = increaseTitle;
    [_increaseBtn setTitle:increaseTitle forState:UIControlStateNormal];
}

- (void)setDecreaseTitle:(NSString *)decreaseTitle{
    _decreaseTitle = decreaseTitle;
    [_decreaseBtn setTitle:decreaseTitle forState:UIControlStateNormal];
}

- (void)setButtonTitleFont:(CGFloat)buttonTitleFont{
    
    _buttonTitleFont = buttonTitleFont;
    _increaseBtn.titleLabel.font = [UIFont systemFontOfSize:buttonTitleFont];
    _decreaseBtn.titleLabel.font = [UIFont systemFontOfSize:buttonTitleFont];
}

- (void)setInputFieldFont:(CGFloat)inputFieldFont{
    _inputFieldFont = inputFieldFont;
    _textField.font = [UIFont systemFontOfSize:inputFieldFont];
}

- (void)setInputFieldColor:(UIColor *)inputFieldColor{
    _inputFieldColor = inputFieldColor;
    _textField.textColor = inputFieldColor;
}

- (void)setEditing:(BOOL)editing{
    _editing = editing;
    _textField.enabled = editing;
}

- (void)setMinValue:(CGFloat)minValue{
    _minValue = minValue;
}

- (void)setMaxValue:(CGFloat)maxValue{
    _maxValue = maxValue;
}

- (void)setStepValue:(CGFloat)stepValue{
    _stepValue = stepValue;
}

#pragma mark TextFieldDelegate
- (void)textFieldDidEndEditing:(UITextField *)textField{
    [self checkTextFieldNumberWithUpdate];
}

// 檢查TextField中數字的合法性,並修正
- (void)checkTextFieldNumberWithUpdate
{
    NSString *minValueString = [NSString stringWithFormat:@"%.0f",_minValue];
    NSString *maxValueString = [NSString stringWithFormat:@"%.0f",_maxValue];
    
    if ([_textField.text isNotBlank] == NO || [_textField.text floatValue] < _minValue) {
        _textField.text = _decreaseHide ? [NSString stringWithFormat:@"%.0f",minValueString.floatValue-self.stepValue]:minValueString;
    }

    [_textField.text floatValue] > _maxValue ? _textField.text = maxValueString : nil;
    [_textField.text floatValue] < _minValue ? _textField.text = minValueString : nil;
    
    if (self.blockCurrentNumber) {
        self.blockCurrentNumber([NSString stringWithFormat:@"%@",_textField.text]);
    }
}


@end


#pragma mark - NSString分類
@implementation NSString (XXNumberButton)
//判斷 字串 nil, @"", @"  ", @"\n" Returns NO;
- (BOOL)isNotBlank
{
    NSCharacterSet *blank = [NSCharacterSet whitespaceAndNewlineCharacterSet];
    for (NSInteger i = 0; i < self.length; ++i) {
        unichar c = [self characterAtIndex:i];
        if (![blank characterIsMember:c]) {
            return YES;
        }
    }
    return NO;
}

@end
 

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