objective-c - 使自动完成不区分大小写

Question

我正在为 OSX 应用程序在 cocoa 中实现自动完成功能，到目前为止我已经把它全部搞定了。一个挂断是自动完成是区分大小写的，这并不是我真正想要/需要的。理想情况下，自动完成将不区分大小写。相关代码如下:

    @implementation autocompleteController
- (void)viewDidLoad {
    [super viewDidLoad];
    self.textField.delegate = self;
}

-(void)controlTextDidChange:(NSNotification *)obj{
    NSTextView * fieldEditor = [[obj userInfo] objectForKey:@"NSFieldEditor"];
    if (self.isAutocompleting == NO  && !self.backspaceKey) {
        self.isAutocompleting = YES;
        self.lastEntry = [[[fieldEditor string] capitalizedString] copy];
        [fieldEditor complete:nil];
        self.isAutocompleting = NO;
    }
    if (self.backspaceKey) {
        self.backspaceKey = NO;
    }
}

-(NSArray *)control:(NSControl *)control textView:(NSTextView *)textView completions:(NSArray *)words forPartialWordRange:(NSRange)charRange indexOfSelectedItem:(NSInteger *)index{
    NSMutableArray * suggestions = [NSMutableArray array];
    NSArray * possibleStrings = @[@"TEST", @"ABC", @"abc", @"amauroy", @"AMA", @"amazing"];

    if (!self.lastEntry || !possibleStrings) {
        return nil;
    }
    for (NSString * string in possibleStrings) {
        if ([string hasPrefix:self.lastEntry]) {
            [suggestions addObject:string];
        }
    }
    return suggestions;
}

-(BOOL)control:(NSControl *)control textView:(NSTextView *)textView doCommandBySelector:(SEL)commandSelector{
    if (commandSelector == @selector(deleteBackward:)) {
        self.backspaceKey = YES;
    }
    return NO;
}

@end

Answer 1

正如 Pro Blaster 指出的那样，问题在于以下行:

if ([string hasPrefix:self.lastEntry]) {

您的自动完成功能区分大小写，因为 -hasPrefix: 区分大小写。一种方法是将所有内容转换为小写(当然，大写也可以)。另一种方法是编写一个不区分大小写的 -hasPrefix: 版本，并使用类别将其添加到 NSString 中，如下所示:

@interface NSString (autocomplete)

- (BOOL)hasPrefixIgnoringCase:(NSString*)aString;

@end;

@implementation NSString (autocomplete)

- (BOOL)hasPrefixIgnoringCase:(NSString*)aString
{
    NSRange *prefix = [self rangeOfString:aString options:NSCaseInsensitiveSearch];
    return prefix.location == 0 && prefix.length == aString.length;
}

@end

然后在代码中使用该方法:

if ([string hasPrefixIgnoringCase:self.lastEntry]) {

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注意:提供的代码未经测试。这个概念很合理，但您可能会发现一两个语法错误。