可能用到的方法

• StatusBarHeight x会返回44 普通返回20

• self.navigationItem.rightBarButtonItem

• 在任意位置（X，Y）展示只有文字的HUD

• 颜色转换为背景 图片

• 四舍五入保留小数位

• 遍历可变数组的同时删除数组元素

• 两种方法删除NSUserDefaults所有记录

• iOS跳转到App Store下载应用评分

• 更改iOS状态栏的颜色

• 退回上一界面的时候 判断当前控制器是push过来的 还是preset过来的，采取不同方式

• 数字放数组中 快速求总和 最大值 最小值 和 平均值

• 修改UITextField中Placeholder的文字颜色

• 阿拉伯数字转中文格式

• 通过监听textfield的变化 实现 字数限制

---

StatusBarHeight x会返回44 普通返回20

#define StatusBarHeight (IOS_VERSION >= 8.0 ? ([[UIApplication sharedApplication] statusBarFrame].size.height) : (IS_LANDSCAPE ? ([[UIApplication sharedApplication] statusBarFrame].size.width) : ([[UIApplication sharedApplication] statusBarFrame].size.height)))

// 操作系统版本号
#define IOS_VERSION ([[[UIDevice currentDevice] systemVersion] floatValue])

// 用户界面横屏了才会返回YES
#define IS_LANDSCAPE UIInterfaceOrientationIsLandscape([[UIApplication sharedApplication] statusBarOrientation])

self.navigationItem.rightBarButtonItem

    
    UIBarButtonItem *rightBarBtn = [[UIBarButtonItem alloc] initWithTitle:@"打印" style:UIBarButtonItemStylePlain target:self action:@selector(clickPrintBtn:)];
    
    self.navigationItem.rightBarButtonItem = rightBarBtn;

在任意位置（X，Y）展示只有文字的HUD

+ (void) showCustomMsg:(NSString *)msg X:(CGFloat )x Y:(CGFloat)y
{
   
   // 显示到主窗口中
   MBProgressHUD *hud =[MBProgressHUD showHUDAddedTo:[UIApplication sharedApplication].keyWindow animated:YES];
   
   // 显示模式,改成customView,即显示自定义图片(mode设置,必须写在customView赋值之前)
   hud.mode = MBProgressHUDModeCustomView;
   
   NSInteger delay = 1.5;

   // 设置要显示 的自定义的图片
   
   hud.labelText = msg;
   
   hud.xOffset = x;
   
   hud.yOffset = y;
   
   hud.opacity = 0.9;
   
   hud.margin = 7;
   
   hud.cornerRadius = 3;
   
   hud.labelFont = [UIFont systemFontOfSize:15];

   // 标志:必须为YES,才可以隐藏,  隐藏的时候从父控件中移除
   
   hud.removeFromSuperViewOnHide = YES;
   
   // 3秒后自动隐藏
   [hud hide:YES afterDelay:delay];
   
}

颜色转换为背景 图片

//  颜色转换为背景图片
+ (UIImage *)imageWithColor:(UIColor *)color {
    CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);
    UIGraphicsBeginImageContext(rect.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    
    CGContextSetFillColorWithColor(context, [color CGColor]);
    CGContextFillRect(context, rect);
    
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    return image;
}

四舍五入保留小数位

/**
四舍五入保留小数位

@param price 价格
@param position 保留几位小数
@return 保留position位小数后的字符串
*/
+ (NSString *)notRounding:(float)price afterPoint:(NSInteger)position{
   
   NSDecimalNumberHandler* roundingBehavior = [NSDecimalNumberHandler decimalNumberHandlerWithRoundingMode:NSRoundBankers scale:position raiseOnExactness:NO raiseOnOverflow:NO raiseOnUnderflow:NO raiseOnDivideByZero:NO];
   NSDecimalNumber *ouncesDecimal;
   NSDecimalNumber *roundedOunces;
   
   ouncesDecimal = [[NSDecimalNumber alloc] initWithString:[NSString stringWithFormat:@"%f",price]];
   roundedOunces = [ouncesDecimal decimalNumberByRoundingAccordingToBehavior:roundingBehavior];
   
   NSString *roundNOPoStr = [NSString stringWithFormat:@"%@",roundedOunces];
   
   NSString* lastStr;
   
   if (![roundNOPoStr containsString:@"."]) {
       
       NSString *addStr = @".";
       
       for (int i = 0; i < position; i ++) {
          addStr = [addStr stringByAppendingFormat:@"0"];
       }
       
       lastStr = [NSString stringWithFormat:@"%@%@",roundNOPoStr,addStr];
       
   }else{
       
       NSDecimalNumberHandler* roundingBehavior = [NSDecimalNumberHandler decimalNumberHandlerWithRoundingMode:NSRoundBankers scale:position raiseOnExactness:NO raiseOnOverflow:NO raiseOnUnderflow:NO raiseOnDivideByZero:NO];
       NSDecimalNumber *ouncesDecimal;
       NSDecimalNumber *roundedOunces;
       
       ouncesDecimal = [[NSDecimalNumber alloc] initWithString:[NSString stringWithFormat:@"%f",price]];
       roundedOunces = [ouncesDecimal decimalNumberByRoundingAccordingToBehavior:roundingBehavior];
       
       NSString *roundHasPoStr = [NSString stringWithFormat:@"%@",roundedOunces];
       
       NSArray *array1 = [roundHasPoStr componentsSeparatedByString:@"."];

       NSString *tempStr = array1[1];
       
       NSInteger count = tempStr.length ;
       
       if (count <= position) {

           NSString *addStr = @"";
           
           for (int i = 0; i < position - tempStr.length; i ++) {
              addStr = [addStr stringByAppendingFormat:@"0"];
           }
           
           lastStr = [NSString stringWithFormat:@"%@%@",roundHasPoStr,addStr];
           
       }else{
           
           NSArray *array2 = [ [NSString stringWithFormat:@"%f",price] componentsSeparatedByString:@"."];
           
           NSString *tempStr = array2[1];
           NSString *tailStr = [tempStr substringToIndex:position+1];

           NSString *totalStr = [NSString stringWithFormat:@"%@.%@",array2[0],tailStr];
           
           NSDecimalNumberHandler* roundingBehavior = [NSDecimalNumberHandler decimalNumberHandlerWithRoundingMode:NSRoundBankers scale:position raiseOnExactness:NO raiseOnOverflow:NO raiseOnUnderflow:NO raiseOnDivideByZero:NO];
           NSDecimalNumber *ouncesDecimal;
           NSDecimalNumber *roundedOunces;
           
           ouncesDecimal = [[NSDecimalNumber alloc] initWithString:totalStr];
           roundedOunces = [ouncesDecimal decimalNumberByRoundingAccordingToBehavior:roundingBehavior];
           
           lastStr = [NSString stringWithFormat:@"%@",roundedOunces];
           
       }

   }

   if (position <= 0) {
       lastStr = roundNOPoStr;
   }
   
   return lastStr;
}

遍历可变数组的同时删除数组元素

NSMutableArray *copyArray = [NSMutableArray arrayWithArray:array];  
NSString *str1 = @“zhangsan”;  

for (AddressPerson *perModel in copyArray) {  

    if ([[perModel name] isEqualToString:str1]) {  
        /*
         copyArray 和 array 里头的元素内存地址的一样的，
         所以遍历copyArray 直接删 array 中的 这个Model 是可以成功删掉的        
         */
        [array removeObject:perModel];
   }  

}

两种方法删除NSUserDefaults所有记录

//方法一
NSString *appDomain = [[NSBundle mainBundle] bundleIdentifier];
[[NSUserDefaults standardUserDefaults] removePersistentDomainForName:appDomain];


//方法二
- (void)resetDefaults
{
    NSUserDefaults * defs = [NSUserDefaults standardUserDefaults];
    NSDictionary * dict = [defs dictionaryRepresentation];
    for (id key in dict)
    {
        [defs removeObjectForKey:key];
    }
    [defs synchronize];
}

iOS跳转到App Store下载应用评分

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"itms-apps://itunes.apple.com/WebObjects/MZStore.woa/wa/viewContentsUserReviews?type=Purple+Software&id=APPID"]];

更改iOS状态栏的颜色

- (void)setStatusBarBackgroundColor:(UIColor *)color
{
    UIView *statusBar = [[[UIApplication sharedApplication] valueForKey:@"statusBarWindow"] valueForKey:@"statusBar"];

    if ([statusBar respondsToSelector:@selector(setBackgroundColor:)])
    {
        statusBar.backgroundColor = color;    
    }
}

退回上一界面的时候 判断当前控制器是push过来的 还是preset过来的，采取不同方式

NSArray *viewcontrollers=self.navigationController.viewControllers;

if (viewcontrollers.count > 1)
{
    if ([viewcontrollers objectAtIndex:viewcontrollers.count - 1] == self)
    {
        //push方式
       [self.navigationController popViewControllerAnimated:YES];
    }
}
else
{
    //present方式
    [self dismissViewControllerAnimated:YES completion:nil];
}

数字放数组中 快速求总和 最大值 最小值 和 平均值

NSArray *array = [NSArray arrayWithObjects:@"2.0", @"2.3", @"3.0", @"4.0", @"10", nil];
CGFloat sum = [[array valueForKeyPath:@"@sum.floatValue"] floatValue];
CGFloat avg = [[array valueForKeyPath:@"@avg.floatValue"] floatValue];
CGFloat max =[[array valueForKeyPath:@"@max.floatValue"] floatValue];
CGFloat min =[[array valueForKeyPath:@"@min.floatValue"] floatValue];
NSLog(@"%f\n%f\n%f\n%f",sum,avg,max,min);

修改UITextField中Placeholder的文字颜色

[textField setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"];

阿拉伯数字转中文格式

+(NSString *)translation:(NSString *)arebic
{  
    NSString *str = arebic;
    NSArray *arabic_numerals = @[@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",@"0"];
    NSArray *chinese_numerals = @[@"一",@"二",@"三",@"四",@"五",@"六",@"七",@"八",@"九",@"零"];
    NSArray *digits = @[@"个",@"十",@"百",@"千",@"万",@"十",@"百",@"千",@"亿",@"十",@"百",@"千",@"兆"];
    NSDictionary *dictionary = [NSDictionary dictionaryWithObjects:chinese_numerals forKeys:arabic_numerals];

    NSMutableArray *sums = [NSMutableArray array];
    for (int i = 0; i < str.length; i ++) {
        NSString *substr = [str substringWithRange:NSMakeRange(i, 1)];
        NSString *a = [dictionary objectForKey:substr];
        NSString *b = digits[str.length -i-1];
        NSString *sum = [a stringByAppendingString:b];
        if ([a isEqualToString:chinese_numerals[9]])
        {
            if([b isEqualToString:digits[4]] || [b isEqualToString:digits[8]])
            {
                sum = b;
                if ([[sums lastObject] isEqualToString:chinese_numerals[9]])
                {
                    [sums removeLastObject];
                }
            }else
            {
                sum = chinese_numerals[9];
            }

            if ([[sums lastObject] isEqualToString:sum])
            {
                continue;
            }
        }

        [sums addObject:sum];
    }

    NSString *sumStr = [sums componentsJoinedByString:@""];
    NSString *chinese = [sumStr substringToIndex:sumStr.length-1];
    NSLog(@"%@",str);
    NSLog(@"%@",chinese);
    return chinese;
}

通过监听textfield的变化 实现 字数限制

#define MAX_STARWORDS_LENGTH 60
//在viewDidLoad中注册<UITextFieldTextDidChangeNotification>通知
[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(textFiledEditChanged:)
                                            name:@"UITextFieldTextDidChangeNotification" object:myTextField];
//实现监听方法
#pragma mark - Notification Method
-(void)textFieldEditChanged:(NSNotification *)obj
{
    UITextField *textField = (UITextField *)obj.object;
    NSString *toBeString = textField.text;
    
    //获取高亮部分
    UITextRange *selectedRange = [textField markedTextRange];
    UITextPosition *position = [textField positionFromPosition:selectedRange.start offset:0];
    
    // 没有高亮选择的字，则对已输入的文字进行字数统计和限制
    if (!position)
    {
        if (toBeString.length > MAX_STARWORDS_LENGTH)
        {
            NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:MAX_STARWORDS_LENGTH];
            if (rangeIndex.length == 1)
            {
                textField.text = [toBeString substringToIndex:MAX_STARWORDS_LENGTH];
            }
            else
            {
                NSRange rangeRange = [toBeString rangeOfComposedCharacterSequencesForRange:NSMakeRange(0, MAX_STARWORDS_LENGTH)];
                textField.text = [toBeString substringWithRange:rangeRange];
            }
        }
    }
}