- (BOOL)isDigit:(NSString *)text

{

    NSCharacterSet *digitCharSet = [NSCharacterSet characterSetWithCharactersInString:@"0123456789"];

    NSScanner *aScanner = [NSScanner localizedScannerWithString:text];

    [aScanner setCharactersToBeSkipped:nil];

    [aScanner scanCharactersFromSet:digitCharSet intoString:NULL];

    return [aScanner isAtEnd];

}

チェックしたい場所で作成した関数を呼び出す。

    if (![self isDigit:text1.text]){

        UIAlertView *alert = [[UIAlertView alloc]

                              initWithTitle:@"入力値エラー"

                              message:@"比率には数値を設定してください。"

                              delegate:self

                              cancelButtonTitle:nil

                              otherButtonTitles:@"OK", nil];

        [alert show];

        return;

    }

    //画面サイズ取得

    CGRect screenSize = [[UIScreen mainScreen] applicationFrame];

    int screen_Width = screenSize.size.width;

    int screen_Height = screenSize.size.height;

    scrollView.contentSize = CGSizeMake(screen_Width, screen_Height);