「無條件進位」、「無條件捨去」、「四捨五入」、「滿千加逗號」

// 四捨五入
round(number);
// 無條件捨去
down = floor(number);
// 無條件進位

up = ceil(number);

//所有的數字轉文字的格式，都可以在NSNumberFormatter class中找到。

//滿千加逗號

+ (NSString *)formatNumberWithComma:(NSNumber *)number

{

    NSNumberFormatter *formatter = [[NSNumberFormatter alloc]init];

    //設顯示小數點下第二位

    [formatter setMaximumFractionDigits:2];

    //設千分位的逗點

    [formatter setUsesGroupingSeparator:YES];

    [formatter setNumberStyle:NSNumberFormatterDecimalStyle];

        

    double entryFieldFloat = [number doubleValue];

    if ([number.stringValue rangeOfString:@"."].length == 1) {

        formatter.alwaysShowsDecimalSeparator = YES;

        return [formatter stringFromNumber:[NSNumber numberWithDouble:entryFieldFloat]];

    }

    

    formatter.alwaysShowsDecimalSeparator = NO;

    return [formatter stringFromNumber:[NSNumber numberWithDouble:entryFieldFloat]];

}

取用特定的Subview實體

//我們想要指定一個View去取用

UIImageView *iv = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"btn"]];

            [iv setTag:978];

//直接用viewWithTag就可以針對我們想取用的View去抓到實體

UIView *_subview = [cell.contentView viewWithTag:978];

                if( _subview )

                {

                    [_subview removeFromSuperview];

                }

在switch中要加上判斷的code，要用{ }大刮號

NSString *title, *subtitle;

        switch (indexPath.row) {

            case PROFILE_NAME:

                title = @"User name";

                subtitle = _userEntity.name;

                break;

            case PROFILE_BIRTHDAY:

                title = @"Birthday";

                subtitle = [_userEntity.birthday yyyy__MM__dd];

                break;

            case PROFILE_HEIGHT:

                title = @"Height";

                if (unitUSA) {

                    NSInteger feet, inch;

                    [UserEntity translateMeter:_userEntity.height.integerValue toFeet:&feet inch:&inch];

                    subtitle = [NSString stringWithFormat:@"%d'%d\"", feet, inch];

                } else

                    subtitle = [NSString stringWithFormat:@"%d cm", _userEntity.height.integerValue];

                break;

            case PROFILE_WEIGHT:

                title = @"Weight";

                subtitle =unitUSA ? [NSString stringWithFormat:@"%.1f lbs", [UserEntity translateLbFromKg:_userEntity.weight.integerValue]] : [NSString stringWithFormat:@"%d kg", _userEntity.weight.integerValue];

                break;

            case PROFILE_STRIDE:

                title = @"Stride";

                subtitle = unitUSA ? [NSString stringWithFormat:@"%d\"", (int)(_userEntity.stride.integerValue / 2.54)] : [NSString stringWithFormat:@"%d cm", _userEntity.stride.integerValue];

                break;

            case PROFILE_EMAIL:

                title = @"Email";

                subtitle = [apis getUserEmail];

            {

                UIView *_subview = [cell.contentView viewWithTag:978];

                if( _subview )

                {

                    [_subview removeFromSuperview];

                }

                

            }

                break;

            default:

                break;

        }

一次移除所有subview的方式

[[someUIView subviews]
 makeObjectsPerformSelector:@selector(removeFromSuperview)];

UIAlertView的慣用法

//UploadViewController.h

@interface UploadViewController : UIViewController <UIAlertViewDelegate>

//UploadViewController.m

- (IBAction)logoutPressed:(id)sender

{

    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Logout" message:@"Are you sure you want to logout?" delegate:self cancelButtonTitle:@"NO" otherButtonTitles:@"YES", nil];

    [alert show];

}

- (void)logout

{

    //TODO:Implement Logout code here...

}

#pragma mark - UIAlertView Delegate

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex

{

    if (buttonIndex == alertView.firstOtherButtonIndex) {

        [self logout];

    }

}

NSMutableArray的addObject是直接加入pointer而不是copy一份進去

NSMutableArray *array = [NSMutableArray new];

NSNumber *number = [[NSNumber new];

For (int i = 0, i<10 , i++){

   number = [NSNumber numberWithInt:i];

   [array addObject:number];

}

這樣的結果會是

10

10

10

10

10

10

10

10

10

10

NSMutableArray *array = [NSMutableArray new];

For (int i = 0, i<10 , i++){

   NSNumber *number = [[NSNumber new];

   number = [NSNumber numberWithInt:i];

   [array addObject:number];

}

而這樣的結果才會是

1

2

3

4

5

6

7

8

9

10

抓取另一個storyboard上的view controller

YourViewControllerClass *viewController = [[UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil] instantiateViewControllerWithIdentifier:@"ViewController"];