iOS 常用知识点 汇集 整理

0. set方法赋值不上

• 无关其他，是用sd_layout框架设置frame有问题。

1.移除父控件上的说有子view

[self.view.subviews makeObjectsPerformSelector:@selector(removeFromSuperview)]; 

2.Xcode log 不完整

#ifdef DEBUG
#define CSLog(format, ...) printf("class: <%p %s:(%d) > method: %s \n%s\n", self, [[[NSString stringWithUTF8String:__FILE__] lastPathComponent] UTF8String], __LINE__, __PRETTY_FUNCTION__, [[NSString stringWithFormat:(format), ##__VA_ARGS__] UTF8String] )
#else
#define CSLog(format, ...)
#endif 

3. UIImage 图片拉伸方法

- (UIImage *)resizableImage:(NSString *)name
{
    UIImage *image = [UIImage imageNamed:name];
    return [image stretchableImageWithLeftCapWidth:image.size.width * 0.5 topCapHeight:image.size.height * 0.5];
}

4.字符串截取信息

NSUInteger loc = [string rangeOfString:@"\":\""].location + 3;
NSUInteger len = [string rangeOfString:@"\"}"].location - loc;
NSString *msg = [string substringWithRange:NSMakeRange(loc, len)];

5.URL 中的中文转化

NSString *encodedString = [urlString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
// 上面方法已经废弃
NSCharacterSet *set = [NSCharacterSet characterSetWithCharactersInString:name1];
NSString *abc = [name1 stringByAddingPercentEncodingWithAllowedCharacters:set];

• 解码：把str字符串以UTF-8规则进行解码 , UTF-8 转化中文

[str stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
// 上面的已经废弃 
str.stringByRemovingPercentEncoding
//////////
NSString *urlStr = [NSString stringWithFormat:@"http://localhost/login?username=喝喝&pwd=123"];  
urlStr = [urlStr stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]];  

6.数组顺序和添加的时候到过来

NSArray* reversedArray = [[self.keyRecordData reverseObjectEnumerator] allObjects];

7.退出键盘

 [self.view endEditing:YES];

 [self.messageField resignFirstResponder];

 [self.messageField endEditing:YES];

8.打电话

 NSMutableString *str=[[NSMutableString alloc] initWithFormat:@"telprompt://%@",twoModel.UserPhone];
 UIWebView *callWebview = [[UIWebView alloc] init];
 [callWebview loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:str]]];
 [self.view addSubview:callWebview];

9. 获取版本号

NSString *appVersion =[[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleShortVersionString"];

10. __weak

__weak UITextField * weakTf = textField;

11 获取文字高度

CGFloat h = [model.message boundingRectWithSize:CGSizeMake([UIScreen mainScreen].bounds.size.width - kGAP-kAvatar_Size - 2*kGAP, CGFLOAT_MAX) options:NSStringDrawingUsesLineFragmentOrigin attributes:attributes context:nil].size.height+0.5;

12 section

 _dataArray = @[@{ @"key":@"基本信息",
                          @"value":@[@"姓名",@"性别",@"年龄",@"身高(cm)",@"体重(kg)"],
                          },
                       @{ @"key":@"疾病信息",
                          @"value":@[@"诊断哮喘日期/年龄",@"首次诊断的日期"],
                          },
                       @{ @"key":@"过敏原结果",
                          @"value":@[@"尘螨过敏",@"吸入物过敏",@"食物过敏"],
                          },
                       @{ @"key":@"肺功能",
                          @"value":@[@"支气管舒张试验",@"支气管激发试验"],
                          }
                       ];

13 使用xib给label 换行快捷键

• option +reutrn

14 过滤空格

 //过滤掉输入框输入的文字前后的空格
    NSString *textString = [textField.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

15 absoluteString

NSURL *url = [NSURL URLWithString:@"http://www.baidu.com/search?id=1"];
2
    NSLog(@"scheme:%@", [url scheme]); //协议 http
3
    NSLog(@"host:%@", [url host]);     //域名 www.baidu.com
4
    NSLog(@"absoluteString:%@", [url absoluteString]); //完整的url字符串 http://www.baidu.com:8080/search?id=1   (刚才在真机上跑了一下，并没有打印出来端口 8080 啊)
5
    NSLog(@"relativePath: %@", [url relativePath]); //相对路径 search
6
    NSLog(@"port :%@", [url port]);  // 端口 8080
7
    NSLog(@"path: %@", [url path]);  // 路径 search
8
    NSLog(@"pathComponents:%@", [url pathComponents]); // search
9
    NSLog(@"Query:%@", [url query]);  //参数 id=1

16 UICollectionView flowlayout 固定item的设置

 
    CGFloat margin = (kScreenWidth - ZKCommonCollectionHW *3)/4.0;
    //每行之间竖直之间的最小间距 （可以大于） 设置垂直间距
    flowLayout.minimumLineSpacing = margin;
    //同行的cell与cell之间水平之间的最小间距（可以） 设置水平间距
    flowLayout.minimumInteritemSpacing = margin;
    flowLayout.itemSize = CGSizeMake(ZKCommonCollectionHW,ZKCommonCollectionHW);
   // 设置整个collectionView的内边距 相对于 上左下右的偏移量
    flowLayout.sectionInset = UIEdgeInsetsMake(margin, margin, margin*3 , margin);

// 或者可以使用sdlayout 设置frame 时 就可以不用底部insert 乘以3倍了。
既
 _collectionView.sd_layout.spaceToSuperView(UIEdgeInsetsZero);
则
   flowLayout.sectionInset = UIEdgeInsetsMake(margin, margin, margin , margin);

17 APP首次和更新后的启动

// NO 没有
- (BOOL)hasLaunched {
    
    NSString *version = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleShortVersionString"];
    NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
    if (![[userDefaults objectForKey:@"version"] isEqualToString:version]) {
        [userDefaults setObject:version forKey:@"version"];
        return NO;
    }else {
        return YES;
    }
}