iOS 编程 计算字符串文字宽度

//

//  ViewController.m

//  tableview复习

//

//  Created by tianshangrenjian on 15/7/7.

//  Copyright © 2015年 tianshangrenjian. All rights reserved.

//

#import "ViewController.h"

@interface ViewController ()

@property (weak, nonatomic) IBOutletUILabel *lbInfo;

@property (weak, nonatomic) IBOutletUIView *viewInfo;

@end

@implementation ViewController

- (void)viewDidLoad {

    [superviewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

    

}

- (void)touchesBegan:(nonnullNSSet<UITouch *> *)touches withEvent:(nullableUIEvent *)event

{

    NSString *str=@"  开源界总是有许多有趣的东东，这三个合起来就是一个完整的XMPP IM 实现。包括服务器端——Openfire，，XMPP传输协议的实现——Smack（记住，XMPP是一个协议，协议是需要实现的，Smack起到的就是这样的一个作用）。三者都是基于Java语言的实现。";

   CGSize size=CGSizeMake(270,MAXFLOAT);

   UIFont *font=[UIFontsystemFontOfSize:18];

    NSDictionary *attrs=@{NSFontAttributeName:font};

    

    CGSize s=[strboundingRectWithSize:size options:NSStringDrawingTruncatesLastVisibleLine |

              NSStringDrawingUsesLineFragmentOrigin |

              NSStringDrawingUsesFontLeadingattributes:attrs context:nil].size;

   CGSize s1=[str sizeWithAttributes:attrs];

   NSLog(@"%g   %g",s.height,s.width);

   NSLog(@"s1 :%g   %g",s1.height,s1.width);

    

   self.viewInfo.frame=CGRectMake(0 ,0, s.width+20, s.height+38);

    [self.viewInfosetNeedsDisplay];

   self.lbInfo.frame=CGRectMake(15,5,270, s.height);

    self.lbInfo.lineBreakMode=NSLineBreakByWordWrapping;

   self.lbInfo.font=font;

    self.lbInfo.numberOfLines=0;

   self.lbInfo.text=str;

}

- (void)didReceiveMemoryWarning {

    [superdidReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

@end