Question

当我尝试加载另一个视图时，我收到此错误：

2012-02-21 20:31:38.477 App Demo[1671:f803] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSPlaceholderString initWithString:]: nil argument'

我无法确切地找到错误的位置。

任何帮助？

更新

NSString *pn1 = player1name.text;
NSString *pn2 = player2name.text;
NSString *pn3 = player3name.text;
NSString *pn4 = player4name.text;
NSString *k = kingdomLevel.text;

Kscores *kscores = [[Kscores alloc] initWithNibName:nil bundle:nil];
kscores.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentModalViewController:kscores animated:YES];


[[kscores player1name] setText:[NSString stringWithString:(NSString *)pn1]];
[[kscores player2name] setText:[NSString stringWithString:(NSString *)pn2]];
[[kscores player3name] setText:[NSString stringWithString:(NSString *)pn3]];
[[kscores player4name] setText:[NSString stringWithString:(NSString *)pn4]];
[[kscores king] setText:[NSString stringWithString:(NSString *)k]];

断点停在此代码

[[kscores player1name] setText:[NSString stringWithString:(NSString *)pn1]];

Answer 1

做stringWithString:的重点是什么？您可以像[[kscores player1name] setText:pn1];

一样直接设置它

您收到错误是因为pn1为零，并且您无法将nil传递给stringWithString:。

Answer 2

这意味着行中的pn1为nil：

[[kscores player1name] setText:[NSString stringWithString:(NSString *)pn1]];

这意味着该行中的player1name或player1name.text为nil：

NSString *pn1 = player1name.text;

Answer 3

您正在尝试传递 nil 参数：[[kscores player1name] setText:nil];，因为[NSString stringWithString:(NSString *)pn1] NULL 。

相反，请尝试：[[kscores player1name] setText: pn1]

xCode 4.2错误

3 个答案: