我试图弄清楚为什么这段代码没有显示相同的结果，以及为什么两个字符串不相等。正如您在日志中看到的那样，我插入UITextfield的值是“ a”。
- (void)resultsForSearchString:(NSString *)searchString
{
NSString *str = [NSString stringWithFormat:@"a"];
NSLog(@"searchString = %@", searchString);
NSLog(@"str = %@", str);
NSMutableArray *array = [NSMutableArray arrayWithObjects:@"Nick", @"Ben", @"Adam", @"Melissa", nil];
NSPredicate *aPredicate = [NSPredicate predicateWithFormat:@"SELF beginswith[c] %@", searchString];
NSArray *beginWithA = [array filteredArrayUsingPredicate:aPredicate];
NSLog(@"%@", beginWithA);
aPredicate = [NSPredicate predicateWithFormat:@"SELF beginswith[c] %@", str];
beginWithA = [array filteredArrayUsingPredicate:aPredicate];
NSLog(@"%@", beginWithA);
if ([str isEqualToString:searchString]) {
NSLog(@"true");
}
else {
NSLog(@"false");
}
}
像下面这样调用此方法作为UIControlEventEditingChanged的触发器：
- (void)textFieldDidChange:(UITextField *)sender
{
[self resultsForSearchString:sender.text];
}
这是输出：
2013-12-17 16:44:49.845 SevenOut[7381:70b] searchString = a
2013-12-17 16:44:49.846 SevenOut[7381:70b] str = a
2013-12-17 16:44:52.676 SevenOut[7381:70b] (
)
2013-12-17 16:44:53.956 SevenOut[7381:70b] (
Adam
)
2013-12-17 16:44:54.988 SevenOut[7381:70b] false
我刚刚测试了您的代码，效果很好。
2013-12-17 15:02:45.778 MessAbout[3856:70b] searchString = a | length = 1
2013-12-17 15:02:45.779 MessAbout[3856:70b] str = a | length = 1
2013-12-17 15:02:45.779 MessAbout[3856:70b] (
Adam
)
2013-12-17 15:02:45.779 MessAbout[3856:70b] (
Adam
)
2013-12-17 15:02:45.780 MessAbout[3856:70b] true
如果您将前两个日志更改为
NSLog(@"searchString = %@ | length = %u", searchString, [searchString length]);
NSLog(@"str = %@ | length = %u", str, [str length]);
然后，您可能会明白为什么它们不是相同的字符串。
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我来说两句