1.根據(jù)字體大小的計算出字符串的長和寬

  CGSize nameSize = [name sizeWithAttributes:[NSDictionary dictionaryWithObjectsAndKeys:[UIFont systemFontOfSize:14],NSFontAttributeName, nil]];

2.通過生日計算年齡

//  calculate age by birthday
//  birthday : YYYYMMDD
//  age: *歲*個月*天
- (NSString *)ageStringByBirthday:(NSString *)birthday{
    //年齢計算
    NSDateFormatter *inputFormatter = [[NSDateFormatter alloc] init];
    [inputFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"zh_CN"] ] ;
    [inputFormatter setDateFormat:@"yyyyMMdd"];
    NSDate* inputDate = [inputFormatter dateFromString:birthday];
    
    
    NSDate *today = [NSDate date];
    NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
    
    NSDateComponents *dayComponents = [gregorian components:NSCalendarUnitYear | NSCalendarUnitMonth| NSCalendarUnitDay fromDate:inputDate toDate:today options:0];
    
    long year = [dayComponents year];
    long month = [dayComponents month];
    long day = [dayComponents day];
    NSString *result = [NSString stringWithFormat:@"%li歲%li個月%li天",year,month,day];
    
    return result;
}

3.為右邊的導(dǎo)航按鈕設(shè)置彈簧距離

    UIButton* rightBtn= [UIButton buttonWithType:UIButtonTypeCustom];
    rightBtn.titleLabel.font = [UIFont systemFontOfSize:11];
    [rightBtn setTitleColor:[UIColor colorWithRed:255.0/255 green:93.0/255 blue:93.0/255 alpha:1] forState:(UIControlStateNormal)];
    rightBtn.frame = CGRectMake(self.view.bounds.size.width-70, 20, 60, 44);
    
    UIBarButtonItem* rightBtnItem = [[UIBarButtonItem alloc]initWithCustomView:rightBtn];
    
    [rightBtn addTarget:self action:@selector(attentionBtnClick:) forControlEvents:UIControlEventTouchUpInside];
    UIBarButtonItem *spaceItem = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:(UIBarButtonSystemItemFixedSpace) target:nil action:nil];
    spaceItem.width = -12;
    self.navigationItem.rightBarButtonItems = @[spaceItem, rightBtnItem];   

4.使得tableview在界面啟動后定位在某一行

 NSIndexPath *idxPath = [NSIndexPath indexPathForRow:5 inSection:0]; 
  [self.tableView scrollToRowAtIndexPath:idxPath  atScrollPosition:UITableViewScrollPositionMiddle  animated:NO]

5.給定寬度和字體大小計算字符串的高度

- (CGSize)getHeightText:(NSString*)text
{
    NSDictionary *attribute = @{NSFontAttributeName: [UIFont systemFontOfSize:14]};
    CGSize size = [text boundingRectWithSize:CGSizeMake(kWindowW-COMMON_CARD_MARGIN*2-105, MAXFLOAT) options: NSStringDrawingTruncatesLastVisibleLine | NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading attributes:attribute context:nil].size;
 
    return size;
}

6.檢測是否是手機號碼

-(BOOL)isMobileNumber:(NSString*)mobileNum
{
//手機號碼
//移動：134[0-8],135,136,137,138,139,150,151,157,158,159,182,187,188
//聯(lián)通：130,131,132,152,155,156,185,186
//電信：133,1349,153,180,189
NSString*MOBILE=@"^1(3[0-9]|5[0-35-9]|8[025-9])\\d{8}$";
    
 //中國移動：China Mobile
NSString*CM=@"^1(34[0-8]|(3[5-9]|5[017-9]|8[278])\\d)\\d{7}$";
    
    
    // 中國聯(lián)通：China Unicom
NSString*CU=@"^1(3[0-2]|5[256]|8[56])\\d{8}$";
    
    // 中國電信：China Telecom
NSString*CT=@"^1((33|53|8[09])[0-9]|349)\\d{7}$";
    
  // 大陸地區(qū)固話及小靈通
// NSString * PHS = @"^0(10|2[0-5789]|\\d{3})\\d{7,8}$";
    
    
    NSPredicate*regextestmobile=[NSPredicate predicateWithFormat:@"SELF MATCHES %@",MOBILE];
    NSPredicate*regextestcm=[NSPredicate predicateWithFormat:@"SELF MATCHES %@",CM];
    NSPredicate*regextestcu=[NSPredicate predicateWithFormat:@"SELF MATCHES %@",CU];
    NSPredicate*regextestct=[NSPredicate predicateWithFormat:@"SELF MATCHES %@",CT];
    if(([regextestmobile evaluateWithObject:mobileNum]==YES)||([regextestcm evaluateWithObject:mobileNum]==YES)||([regextestct evaluateWithObject:mobileNum]==YES)||([regextestcu evaluateWithObject:mobileNum]==YES)){
    return YES;
        }else{
    return NO;
    }
}

7.怎么畫虛線

 - (instancetype)initWithFrame:(CGRect)frame
{
    
    if (self = [super initWithFrame:frame]) {
        [self drawRect:frame];
    }
    return self;
    
}

-(void)drawRect:(CGRect)rect{
    //    self.layer.cornerRadius = 10;
    
    UIView *lineView = [[UIView alloc]init];
    lineView.frame = CGRectMake(12, rect.size.height-1,rect.size.width-12*2, 1);
    
    [DashedLineView drawDashLine:lineView lineLength:4 lineSpacing:3
                 lineColor:kRTColorWithHEX(0xd0d0d0, 1.0)];
    [self addSubview:lineView];
    
    
}

/**
 ** lineView:      需要繪制成虛線的view
 ** lineLength:  虛線的寬度
 ** lineSpacing:    虛線的間距
 ** lineColor:    虛線的顏色
 **/
+ (void)drawDashLine:(UIView *)lineView lineLength:(int)lineLength lineSpacing:(int)lineSpacing lineColor:(UIColor *)lineColor
{
    CAShapeLayer *shapeLayer = [CAShapeLayer layer];
    [shapeLayer setBounds:lineView.bounds];
    [shapeLayer setPosition:CGPointMake(CGRectGetWidth(lineView.frame) / 2, CGRectGetHeight(lineView.frame))];
    [shapeLayer setFillColor:[UIColor clearColor].CGColor];
    //  設(shè)置虛線顏色為blackColor
    [shapeLayer setStrokeColor:lineColor.CGColor];
    //  設(shè)置虛線寬度
    [shapeLayer setLineWidth:CGRectGetHeight(lineView.frame)];
    [shapeLayer setLineJoin:kCALineJoinRound];
    //  設(shè)置線寬，線間距
    [shapeLayer setLineDashPattern:[NSArray arrayWithObjects:[NSNumber numberWithInt:lineLength], [NSNumber numberWithInt:lineSpacing], nil]];
    //  設(shè)置路徑
    CGMutablePathRef path = CGPathCreateMutable();
    CGPathMoveToPoint(path, NULL, 0, 0);
    CGPathAddLineToPoint(path, NULL, CGRectGetWidth(lineView.frame), 0);
    [shapeLayer setPath:path];
    CGPathRelease(path);
    //  把繪制好的虛線添加上來
    [lineView.layer addSublayer:shapeLayer];
}```   

8.把圖片保存到相冊中

- (void)save:(UIBarButtonItem *)sender {
  UIGraphicsBeginImageContext(self.hmView.bounds.size);
  CGContextRef ctx = UIGraphicsGetCurrentContext();
  [self.hmView.layer renderInContext:ctx];
  UIImage * image = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();
  UIImageWriteToSavedPhotosAlbum(image, NULL, NULL, NULL);

}

9.創(chuàng)建單一顏色的圖片然后設(shè)置UIControlStateHighlighted狀態(tài)

- (UImage *)imageWithColor:(UIColor *)color size:(CGSize)size {
  CGRect rect = CGRectMake(0, 0, size.width, size.height);
  UIGraphicsBeginImageContext(rect.size);
  CGContextRef context = UIGraphicsGetCurrentContext();
  CGContextSetFillColorWithColor(context, [color CGColor]);
   CGContextFillRect(context, rect);
  UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();
  return image;
  }

10.UIView中的坐標轉(zhuǎn)換

// 將像素point由point所在視圖轉(zhuǎn)換到目標視圖view中，返回在目標視圖view中的像素值  
  - (CGPoint)convertPoint:(CGPoint)point toView:(UIView *)view;  
    // 將像素point從view中轉(zhuǎn)換到當(dāng)前視圖中，返回在當(dāng)前視圖中的像素值  
    - (CGPoint)convertPoint:(CGPoint)point fromView:(UIView *)view;  
      
    // 將rect由rect所在視圖轉(zhuǎn)換到目標視圖view中，返回在目標視圖view中的rect  
    - (CGRect)convertRect:(CGRect)rect toView:(UIView *)view;  
    // 將rect從view中轉(zhuǎn)換到當(dāng)前視圖中，返回在當(dāng)前視圖中的rect  
    - (CGRect)convertRect:(CGRect)rect fromView:(UIView *)view;  
    // controllerA 中有一個UITableView, UITableView里有多行UITableVieCell，cell上放有一個button  
    // 在controllerA中實現(xiàn):  
    CGRect rc = [cell convertRect:cell.btn.frame toView:self.view];  
    或  
    CGRect rc = [self.view convertRect:cell.btn.frame fromView:cell];  
    // 此rc為btn在controllerA中的rect  
      
    或當(dāng)已知btn時：  
    CGRect rc = [btn.superview convertRect:btn.frame toView:self.view];  
    或  
    CGRect rc = [self.view convertRect:btn.frame fromView:btn.superview]; 

11.顏色：rgb，和16進制

    # define kRTColorWihRGB(R,G,B)     [UIColor colorWithRed:R/255.0 green:G/255.0 blue:B/255.0 alpha:1.0]
    
    # define kRTColorWithHEX(hex,opa)  [UIColor colorWithRed:((float)((hex & 0XFF0000)>>16))/255.0 green:((float)((hex & 0X00FF00)>>8))/255.0 blue:((float)(hex & 0X0000FF))/255.0 alpha:opa]

12.把數(shù)據(jù)變成三位加逗號的數(shù)據(jù)類型

• -(NSString *)formatNumber:(double)num{
  NSNumberFormatter *formatterCurrency = [[NSNumberFormatter alloc] init];
  formatterCurrency.numberStyle = NSNumberFormatterDecimalStyle;
  [formatterCurrency setMaximumFractionDigits:2];
  return [formatterCurrency stringFromNumber: @(num)];
  }
  

13. 把科學(xué)計數(shù)法變?yōu)槠胀〝?shù)

    NSString *str = @"1.2808245E7";
        NSRange eSite = [str rangeOfString:@"E"];
        double fund = [[str substringWithRange:NSMakeRange(0, eSite.location)] doubleValue];  //把E前面的數(shù)截取下來當(dāng)?shù)讛?shù)
        double top = [[str substringFromIndex:eSite.location + 1] doubleValue];   //把E后面的數(shù)截取下來當(dāng)指數(shù)
        double result = fund * pow(10.0, top);
    }

14.一些判斷的方法

-(BOOL) isKindOfClass: classObj 用來判斷是否是某個類或其子類的實例
-(BOOL) isMemberOfClass: classObj 用來判斷是否是某個類的實例
-(BOOL) respondsToSelector: selector 用來判斷是否有以某個名字命名的方法(被封裝在一個selector的對象里傳遞)
+(BOOL) instancesRespondToSelector: selector 用來判斷實例是否有以某個名字命名的方法. 和上面一個不同之處在于, 前面這個方法可以用在實例和類上，而此方法只能用在類上.

15.UIDatePicker的簡單使用

 UIDatePicker *dp = [[UIDatePicker alloc] init];
     [dp setDate:[NSDate date] animated:YES];    // 設(shè)置日期控件值
     [dp addTarget:self
            action:@selector(dateValueChange:)
  forControlEvents:UIControlEventValueChanged];  // 時間改變時觸發(fā)此事件
     設(shè)置日期選擇控件的地區(qū)
[dp setLocale:[[NSLocale alloc]initWithLocaleIdentifier:@"zh_CN"]];
     NSDateFormatter *form = [[NSDateFormatter alloc] init]; // 定義時間       格式
     [form setDateFormat:@"yyyy/MM/DD HH:mm"];
     NSString *dateString = [form stringFromDate:dp.date];
     dp.minuteInterval = 30; //  最小間隔30分鐘

 dp.minimumDate = [NSDate date];     // 最小值
 dp.maximumDate = [NSDate dateWithTimeIntervalSinceNow:60*60*24*31]; // 最大值
 dp.datePickerMode = UIDatePickerModeTime;               // 時間模式
 dp.datePickerMode = UIDatePickerModeDate;               // 日期模式
 dp.datePickerMode = UIDatePickerModeDateAndTime;        // 日期和時  間模式
  dp.datePickerMode = UIDatePickerModeCountDownTimer;     // 倒計時模式

16 ，計算據(jù)今天兩個月的日期

   //創(chuàng)建日歷
  NSCalendar *calendar = [NSCalendar currentCalendar];
        NSDateComponents *com = [calendar components:NSCalendarUnitYear|NSCalendarUnitMonth|NSCalendarUnitDay fromDate:[NSDate date]];
        com.year = 0;
        com.month = 2;
        com.day = 0;
  NSDate *date = [calendar dateByAddingComponents:com toDate:[NSDate date]options:0];

17 ，導(dǎo)航的問題

• - (void)initNavigationBar:(UINavigationBar *)navigationBar{
  
  // 設(shè)置導(dǎo)航欄的背景顏色
  UIColor* backgroundColor = [UIColor colorWithRed:(float)0x20/0xff green:(float)0x24/0xff blue:(float)0x2c/0xff alpha:1.0];
  [navigationBar setTranslucent:NO];
  [navigationBar setBarTintColor:backgroundColor];
  [navigationBar setBackgroundColor:backgroundColor];
  
  // 設(shè)置導(dǎo)航欄上的標題的顏色 
  navigationBar.titleTextAttributes = @{NSFontAttributeName:[UIFont systemFontOfSize:18],NSForegroundColorAttributeName:kRTColorWithHEX(0xffffff, 1)};   
  for (UINavigationItem *item in [navigationBar items]) {
      item.leftBarButtonItem.tintColor =[UIColor whiteColor];
  }
  
  // 去掉導(dǎo)航欄的邊界線
  [navigationBar setBackgroundImage:[[UIImage alloc] init] forBarMetrics:UIBarMetricsDefault];
  navigationBar.shadowImage = [[UIImage alloc] init];
  }
  

  創(chuàng)建block匿名函數(shù)之前一般需要對self進行weak化，否則造成循環(huán)引用無法釋放controller:

  __weak MyController *weakSelf = self 或者 __weak __typeof(self) weakSelf = self;