iphone - 尝试执行某种串联

Question

我在进行某种串联时遇到了麻烦；

我收到了通过“[dico objectForKey:@"alertSerie"]”(例如)获得的 4 个不同数据。数据必须用在屏幕上引入数据的字符串来显示。我必须将这些数据放入一个 UITextField 中。

示例:

[dico objectForKey:@"alertfriend"] = Beth
[dico objectForKey:@"alertmom"] = Lise
[dico objectForKey:@"alertgirlf"] = Angela


text for Beth will be "This is my friend :"
text for Lise will be "This is my mom :"
text for Angela will be "This is my girlfriend :"

在 UITextField 中，我想显示:

This is my friend :Beth
This is my mom : Lise
This is my girlfriend : Angela

到目前为止一切正常，代码如下所示:

field.text = [NSString stringWithFormat:@"NThis is my friend : %@\nTHis is my mom : %@\nThis is my girlfriend : %@\n",[dico objectForKey:@"alertfriend"], [dico objectForKey:@"alertmom"], [dico objectForKey:@"alertgfriend"] ];

现在，一个人可能没有 friend 、没有妈妈、没有女朋友……

我该怎么办？？？

我尝试了很多可能性，但我们无法连接对象这一事实对我来说并不常见，这在这种情况下给我带来了问题......

非常感谢您的关注!!!

编辑:

我尝试了该代码，但有以下错误； ] 或者其他什么...

    if ([dico objectForKey:@"alertSerie"]) {
        NSString *serie = [NSString stringWithFormat:@"Numéro de série : %@\n", [dico objectForKey:@"alertSerie"] ];}
    else {
        NSString *serie = [NSString stringWithFormat:@" "] ];}

    if ([dico objectForKey:@"alertDate"]) {
        NSString *date = [NSString stringWithFormat:@"Date de mise en service : %@\n", [dico objectForKey:@"alertDate"] ];}
    else {
        NSString *date = [[NSString stringWithFormat:@" "] ];}

    if ([dico objectForKey:@"alertCli"]) {
        NSString *cli = [NSString stringWithFormat:@"Nom du client associé : %@\n", [dico objectForKey:@"alertCli"] ];}
    else {
        NSString *cli = [NSString stringWithFormat:@" "] ];}

Answer 1

你需要检查这个人是否有 friend 、女朋友和妈妈。这意味着您必须使用条件。这可以通过使用一些简单的 if 语句来完成。

NSMutableString *text = [[NSString alloc] init];

if([dico objectForKey:@"alertmom"] != nil)
{
   [text appendFormat:@"This is my Mom: %@ \n", [dico objectForKey:@"alertmom"]];
}
if([dico objectForKey:@"alertfriend"]!= nil)
{
   [text appendFormat:@"This is my friend: %@ \n", [dico objectForKey:@"alertfriend"]];
}
if([dico objectForKey:@"alertgirlf"] != nil)
{
   [text appendFormat:@"This is my girlfriend: %@ \n", [dico objectForKey:@"alertgirlf"]];
}

field.text = text;