iOS 自定义UITextField

在项目需求上遇到一个验证码输入的需求，具体UI参看下图：

image.png

image.png

实现时使用了自定义UITextFiled相关知识，啥也不说贴代码吧。

#import 

@interface YQSecurityCodeTextField : UITextField
@property (nonatomic ,weak) idSCDelegate;
- (instancetype)initWithDelegate:(id)SCDelegate;
@end

#import "YQSecurityCodeTextField.h"
static CGFloat margin = 28;
#define linePathWidth (SCREEN_WIDTH - 28*2)/11
@interface YQSecurityCodeTextField ()
@property (nonatomic ,strong) NSMutableArray *linesArray;
@property (nonatomic ,strong) NSMutableArray *deleteArray;
@property (nonatomic ,assign) NSInteger lastLength;
@end


@implementation YQSecurityCodeTextField


- (instancetype)initWithDelegate:(id)SCDelegate
{
    self = [super init];
    if (self) {
        _SCDelegate = SCDelegate;
        [self initialize];
    }
    return self;
}

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


-(CGRect)textRectForBounds:(CGRect)bounds {
    return CGRectMake(linePathWidth/2, 0, bounds.size.width-linePathWidth/4, bounds.size.height);
}

-(CGRect)editingRectForBounds:(CGRect)bounds {
    return CGRectMake(linePathWidth/2, 0, bounds.size.width-linePathWidth/4, bounds.size.height);
}

//初始化时设定好一些基本属性，然后注册UITextFieldTextDidChangeNotification通知，在这个通知的接受事件方法里改变下划线的绘制
- (void)initialize {
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(didChange:) name:UITextFieldTextDidChangeNotification object:self];
    self.linesArray = [[NSMutableArray alloc] initWithCapacity:6];
    self.deleteArray = [[NSMutableArray alloc] initWithCapacity:6];
    self.lastLength = 0;
    self.font = [UIFont fontWithName:@"PingFang-SC-Medium" size:26];
    
    self.delegate = self;
    self.tintColor = [UIColor clearColor];

    self.defaultTextAttributes = @{NSFontAttributeName :[UIFont fontWithName:@"PingFang-SC-Medium" size:26],
                                   NSKernAttributeName :@((SCREEN_WIDTH-margin*2-16*6-linePathWidth*2)/5)  //字间距
                                   };
    [self drawLine];
}

#pragma mark - 先准备六条贝塞尔曲线
- (void)drawLine {
    for (NSInteger index = 0 ; index<6; index++) {
        UIBezierPath *path = [UIBezierPath bezierPath];
        
        //6条曲线均是绘制在textField上的，每条曲线线宽及间隔都是linePathWidth
        
        [path moveToPoint:CGPointMake(2*index*linePathWidth, 20)];
        [path addLineToPoint:CGPointMake((2*index+1)*linePathWidth, 20)];
        path.lineWidth = 2.5;
        [UICOLOR_WITH_RGBINT(0x3d3d3d) setStroke];
        [self.linesArray addObject:path];
    }
}

- (void)deleteLine
{
    if (self.linesArray.count == 0) {
        return;
    }
    [self.deleteArray addObject:self.linesArray.firstObject];
    [self.linesArray removeObjectAtIndex:0];
    [self setNeedsDisplay];
}

- (void)addLine {
    if (self.deleteArray.count ==0) {
        return;
    }
    [self.linesArray insertObject:self.deleteArray.lastObject atIndex:0];
    [self.deleteArray removeLastObject];
    [self setNeedsDisplay];
}


// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
    [super drawRect:rect];
    for (NSInteger index = 0 ; index0) {
        for (NSInteger index = 0 ; index