Iphone 目标C：简单的if x==y | | y | | y命令的问题

我有一个字符串（包含一个月），希望检查它是“短”月（就名称的长度而言）还是“月”名。根据名称的长度，我想确定其位置：

    NSString* dateMonth = @"SEPTEMPER";
if (dateMonth == @"MARCH" || @"APRIL" || @"MAY" || @"JUNE" || @"JULY") {

    CGRect calendarFrame = CGRectMake(170+100, 8, 200, 50);
    calendar1 = [[UIView alloc] initWithFrame:calendarFrame];
    calendar1.clipsToBounds = true;

} else {

    CGRect calendarFrame = CGRectMake(170,     8, 200, 50);
    calendar1 = [[UIView alloc] initWithFrame:calendarFrame];
    calendar1.clipsToBounds = true;

}

这种情况应该在ELSE函数中结束，但它不。。。我最终得到了170+100的位置

我做错了什么？如果（[dateMonth IsequalString:@“MARCH”]| |[dateMonth IsequalString…

当然，也许你应该用

UIFont *font = [UIFont boldSystemFontOfSize:11.0];
CGSize size = [dateMonth sizeWithFont:font constrainedToSize:CGSizeMake(200, 50)];

此代码

if (dateMonth == @"MARCH" || @"APRIL") {

实际评估为

if ((dateMonth == @"MARCH") || (@"APRIL")) {

由于

@“APRIL”

不是零或零，因此它的计算结果为

TRUE

可以做些什么

• 步骤1（部分固定）

• 步骤2（这已经起作用了）
  使用

  isEqual

  方法来比较字符串（或任何其他对象），而不是

  =

  。

  isEqualToString

  也有效，正如其他人所建议的那样

• 第三步（额外里程）
  通过使用set，您可以使它更可读（更简单）

  NSSet *shortMonths = [NSSet setWithObjects:@"MARCH", @"APRIL", @"MAY", nil];
  if ([shortMonths containsObject:@"APRIL"]) {
  

---

使用适当的比较语法。它应该类似于：-

 NSString* dateMonth = @"SEPTEMPER";

if (dateMonth == @"MARCH" || dateMonth == @"APRIL" || dateMonth == @"MAY" || dateMonth == @"JUNE" || dateMonth == @"JULY")

{
    CGRect calendarFrame = CGRectMake(170+100, 8, 200, 50);
    calendar1 = [[UIView alloc] initWithFrame:calendarFrame];
    calendar1.clipsToBounds = true;

} else {

    CGRect calendarFrame = CGRectMake(170,     8, 200, 50);
    calendar1 = [[UIView alloc] initWithFrame:calendarFrame];
    calendar1.clipsToBounds = true;

}

---

您不能用这种方式编写代码，这是不正确的语法

if (dateMonth == @"MARCH" || @"APRIL" || @"MAY" || @"JUNE" || @"JULY") 
if (dateMonth == @"MARCH" || dateMonth  == @"APRIL" || dateMonth  == @"MAY" || dateMonth  == @"JUNE" || dateMonth  ==@"JULY")

解决这个问题的正确方法是

NSString* dateMonth = @"SEPTEMPER";
    if ([dateMonth isEqualToString:@"MARCH"] || [dateMonth isEqualToString:@"APRIL"] || [dateMonth isEqualToString:@"MAY"] || [dateMonth isEqualToString:@"JUNE"] || [dateMonth isEqualToString:@"JULY"]) {

    CGRect calendarFrame = CGRectMake(170+100, 8, 200, 50);
    calendar1 = [[UIView alloc] initWithFrame:calendarFrame];
    calendar1.clipsToBounds = true;

} else {

    CGRect calendarFrame = CGRectMake(170,     8, 200, 50);
    calendar1 = [[UIView alloc] initWithFrame:calendarFrame];
    calendar1.clipsToBounds = true;

}

---

使用

NSString

的

IsequalString:

或

compare:

方法

NSString* dateMonth = @"SEPTEMPER";

if ([dateMonth isEqualToString:@"MARCH"] || [dateMonth isEqualToString:@"APRIL"] || [dateMonth isEqualToString:@"MAY"] || [dateMonth isEqualToString:@"JUNE"] || [dateMonth isEqualToString:@"JULY"]) {
CGRect calendarFrame = CGRectMake(170+100, 8, 200, 50);
calendar1 = [[UIView alloc] initWithFrame:calendarFrame];
calendar1.clipsToBounds = true;
} 
else
{
CGRect calendarFrame = CGRectMake(170,     8, 200, 50);
calendar1 = [[UIView alloc] initWithFrame:calendarFrame];
calendar1.clipsToBounds = true;
}

试试这个。希望对你有所帮助。你也可以用这个

NSString* dateMonth = @"SEPTEMPER";

NSString* dateMonths = @"MARCH,APRIL,MAY,JUNE,JULY";

if ([dateMonths rangeOfString:dateMonth].location != NSNotFound){

    CGRect calendarFrame = CGRectMake(170+100, 8, 200, 50);
    calendar1 = [[UIView alloc] initWithFrame:calendarFrame];
    calendar1.clipsToBounds = true;

} else {

    CGRect calendarFrame = CGRectMake(170,     8, 200, 50);
    calendar1 = [[UIView alloc] initWithFrame:calendarFrame];
    calendar1.clipsToBounds = true;

}

---

if语句中的逻辑运算符对于所需的操作不正确

你应该写的是：

if（[dateMonth IsequalString:@“MARCH”]| |[dateMonth IsequalString:@“APRIL”]| |…）

---

if（）

语句中的原始表达式会导致每次执行代码，因为表达式的一部分（例如“APRIL”| |@“MAY”）会导致布尔值为TRUE。

这不是工作代码！！！if（dateMonth=@“MARCH”| dateMonth==@“APRIL”| dateMonth==@“MAY”| dateMonth==@“MAY”| dateMonth==@“MAY”| JUNE”| | dateMonth=@“JULY”）你不能这样写！！！

NSString* dateMonth = @"SEPTEMPER";

NSString* dateMonths = @"MARCH,APRIL,MAY,JUNE,JULY";

if ([dateMonths rangeOfString:dateMonth].location != NSNotFound){

    CGRect calendarFrame = CGRectMake(170+100, 8, 200, 50);
    calendar1 = [[UIView alloc] initWithFrame:calendarFrame];
    calendar1.clipsToBounds = true;

} else {

    CGRect calendarFrame = CGRectMake(170,     8, 200, 50);
    calendar1 = [[UIView alloc] initWithFrame:calendarFrame];
    calendar1.clipsToBounds = true;

}