iOS开发实战之Label全方位对齐的轻松实现

#import <UIKit/UIKit.h>
@class ARMaker;

typedef NS_ENUM(NSUInteger, textAlignType)
{
 textAlignType_top = 10, // 顶部对齐
 textAlignType_left,  // 左边对齐
 textAlignType_bottom,  // 底部对齐
 textAlignType_right,  // 右边对齐
 textAlignType_center  // 水平/垂直对齐（默认中心对齐）
};

@interface ARAlignLabel : UILabel

/**
 * 根据对齐方式进行文本对齐
 *
 * @param alignType 对齐block
 */
- (void)textAlign:(void(^)(ARMaker *make))alignType;

@end


//工具类
@interface ARMaker : NSObject

/* 存放对齐样式 */
@property(nonatomic, strong) NSMutableArray *typeArray;

/**
 * 添加对齐样式
 */
- (ARMaker *(^)(textAlignType type))addAlignType;

@end

#import "ARAlignLabel.h"

@interface ARAlignLabel ()

/* 对齐方式 */
@property(nonatomic, strong) NSArray *typeArray;
//上
@property(nonatomic, assign) BOOL hasTop;
//左
@property(nonatomic, assign) BOOL hasLeft;
//下
@property(nonatomic, assign) BOOL hasBottom;
//右
@property(nonatomic, assign) BOOL hasRight;

@end

@implementation ARAlignLabel

- (CGRect)textRectForBounds:(CGRect)bounds limitedToNumberOfLines:(NSInteger)numberOfLines {
 CGRect textRect = [super textRectForBounds:bounds limitedToNumberOfLines:numberOfLines];
 if (self.typeArray){
  for (int i=0; i<self.typeArray.count; i++) {
   textAlignType type = [self.typeArray[i] integerValue];
   switch (type) {
    case textAlignType_top: //顶部对齐
     self.hasTop = YES;
     textRect.origin.y = bounds.origin.y;
     break;
    case textAlignType_left: //左部对齐
     self.hasLeft = YES;
     textRect.origin.x = bounds.origin.x;
     break;
    case textAlignType_bottom: //底部对齐
     self.hasBottom = YES;
     textRect.origin.y = bounds.size.height - textRect.size.height;
     break;
    case textAlignType_right: //右部对齐
     self.hasRight = YES;
     textRect.origin.x = bounds.size.width - textRect.size.width;
     break;
    case textAlignType_center:
     if (self.hasTop) { //上中
      textRect.origin.x = (bounds.size.width - textRect.size.width)*0.5;
     }
     else if (self.hasLeft) { //左中
      textRect.origin.y = (bounds.size.height - textRect.size.height)*0.5;
     }
     else if (self.hasBottom) { //下中
      textRect.origin.x = (bounds.size.width - textRect.size.width)*0.5;
     }
     else if (self.hasRight) { //右中
      textRect.origin.y = (bounds.size.height - textRect.size.height)*0.5;
     }
     else{ //上下左右居中
      textRect.origin.x = (bounds.size.width - textRect.size.width)*0.5;
      textRect.origin.y = (bounds.size.height - textRect.size.height)*0.5;
     }
     break;
    default:
     break;
   }
  }
 }
 return textRect;
}

- (void)drawTextInRect:(CGRect)requestedRect {
 CGRect actualRect = requestedRect;
 if (self.typeArray) {
  actualRect = [self textRectForBounds:requestedRect limitedToNumberOfLines:self.numberOfLines];
 }
 [super drawTextInRect:actualRect];
}

- (void)textAlign:(void(^)(ARMaker *make))alignType {
 ARMaker *make = [[ARMaker alloc]init];
 alignType(make);
 self.typeArray = make.typeArray;
}

@end

//工具类
@implementation ARMaker

- (instancetype)init {
 self = [super init];
 if (self) {
  self.typeArray = [NSMutableArray array];
 }
 return self;
}

- (ARMaker *(^)(enum textAlignType type))addAlignType {
 __weak typeof (self) weakSelf = self;
 return ^(enum textAlignType type) {
  [weakSelf.typeArray addObject:@(type)];
  return weakSelf;
 };
}

@end

- (void)viewDidLoad {
 [super viewDidLoad];
 self.view.backgroundColor = [UIColor whiteColor];
 
 if (_index == 9) {
  //富文本底部对齐
  [self attributedTextAgainOfBottom];
 }else {
  ARAlignLabel *label = [[ARAlignLabel alloc] initWithFrame:CGRectMake(kScreenWidth/2.0 - 150, 300, 300, 80)];
  label.backgroundColor = [UIColor orangeColor];
  label.textColor = [UIColor blackColor];
  label.font = [UIFont systemFontOfSize:18];
  label.text = @"爱学习，爱编程，爱咖啡可乐";
  label.numberOfLines = 1;
  [self.view addSubview:label];
  
  switch (_index) {
   case 0:
    [label textAlign:^(ARMaker *make) {
     make.addAlignType(textAlignType_left).addAlignType(textAlignType_top);
    }];
    break;
   case 1:
    [label textAlign:^(ARMaker *make) {
     make.addAlignType(textAlignType_left).addAlignType(textAlignType_center);
    }];
    break;
   case 2:
    [label textAlign:^(ARMaker *make) {
     make.addAlignType(textAlignType_left).addAlignType(textAlignType_bottom);
    }];
    break;
   case 3:
    [label textAlign:^(ARMaker *make) {
     make.addAlignType(textAlignType_center).addAlignType(textAlignType_top);
    }];
    break;
   case 4:
    [label textAlign:^(ARMaker *make) {
     make.addAlignType(textAlignType_center);
    }];
    break;
   case 5:
    [label textAlign:^(ARMaker *make) {
     make.addAlignType(textAlignType_center).addAlignType(textAlignType_bottom);
    }];
    break;
   case 6:
    [label textAlign:^(ARMaker *make) {
     make.addAlignType(textAlignType_right).addAlignType(textAlignType_top);
    }];
    break;
   case 7:
    [label textAlign:^(ARMaker *make) {
     make.addAlignType(textAlignType_right).addAlignType(textAlignType_center);
    }];
    break;
   case 8:
    [label textAlign:^(ARMaker *make) {
     make.addAlignType(textAlignType_right).addAlignType(textAlignType_bottom);
    }];
    break;
   default:
    break;
  }
 }
}

//富文本底部对齐
- (void)attributedTextAgainOfBottom {
 
 CGFloat space = 10.0;
 
 ARAlignLabel *leftLB = [[ARAlignLabel alloc] initWithFrame:CGRectMake(20, 200, kScreenWidth/2.0 - 20 - space/2.0, 80)];
 leftLB.backgroundColor = [UIColor lightGrayColor];
 leftLB.textColor = [UIColor blackColor];
 leftLB.numberOfLines = 1;
 [self.view addSubview:leftLB];
 //右下
 [leftLB textAlign:^(ARMaker *make) {
  make.addAlignType(textAlignType_center);
 }];
 
 NSMutableAttributedString *attributedArr = [[NSMutableAttributedString alloc] initWithString:@"单价 $123"];
 [attributedArr setAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:40], NSForegroundColorAttributeName:[UIColor blackColor]} range:NSMakeRange(0, 1)];
 [attributedArr setAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:25], NSForegroundColorAttributeName:[UIColor blackColor]} range:NSMakeRange(1, 1)];
 [attributedArr setAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:20], NSForegroundColorAttributeName:[UIColor blueColor]} range:NSMakeRange(3, 1)];
 [attributedArr setAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:35], NSForegroundColorAttributeName:[UIColor redColor]} range:NSMakeRange(4, attributedArr.length - 4)];
 
 leftLB.attributedText = attributedArr;
 
 
 //对齐之后
 ARAlignLabel *rightLB = [[ARAlignLabel alloc] initWithFrame:CGRectMake(kScreenWidth/2.0 + space/2.0, 200, leftLB.frame.size.width, 80)];
 rightLB.backgroundColor = [UIColor lightGrayColor];
 rightLB.textColor = [UIColor blackColor];
 rightLB.numberOfLines = 1;
 [self.view addSubview:rightLB];
 //左下
 [rightLB textAlign:^(ARMaker *make) {
  make.addAlignType(textAlignType_center);
 }];
 
 //设置部分文字的偏移量 (0是让文字保持原来的位置, 负值是让文字下移，正值是让文字上移)
 [attributedArr addAttribute:NSBaselineOffsetAttributeName value:@(1) range:NSMakeRange(0, 1)];
 [attributedArr addAttribute:NSBaselineOffsetAttributeName value:@(0) range:NSMakeRange(1, 1)];
 [attributedArr addAttribute:NSBaselineOffsetAttributeName value:@(-2) range:NSMakeRange(3, 1)];
 [attributedArr addAttribute:NSBaselineOffsetAttributeName value:@(-3) range:NSMakeRange(4, attributedArr.length - 4)];
 
 rightLB.attributedText = attributedArr;
 
}