Cocoa NSTextField NSNumberFormatter和delegate

时间:2015-04-07 22:59:29

标签: xcode cocoa delegates nstextfield nsnumberformatter

我正在制作一个具有以下特征的NSTextField:
1)仅允许整数值(0-9)
2)长度为1或2位 3)min为1,最大为99
4)如果输入0,则值应更改回1
5)如果按下删除并且单元格完全清空,则该值应更改为1并自动选择(高亮显示),以便用户只需键入新值

我可以通过创建自定义格式化程序和委托来获得此行为,但我想仅在自定义格式化程序中实现此功能(以保持“简单”我认为)。

这是我的代码:

在委托文件中:

- (void)controlTextDidChange:(NSNotification *)aNotification
{
    if ([[txtfldSaveDuration stringValue] length]==0) {
        [txtfldSaveDuration setStringValue:@"1"];
    }
    if ([[txtfldSaveDuration stringValue] isEqualToString:@"0"]) {
        [txtfldSaveDuration setStringValue:@"1"];
    }
}
自定义格式化程序文件中的

@implementation OnlyIntegerValueFormatter

- (BOOL)isPartialStringValid:(NSString*)partialString newEditingString:    (NSString**)newString errorDescription:(NSString**)error
{
    // necessary otherwise can't delete (to select) the first character
    if([partialString length] == 0) {
        return YES;
    }  
    // two integer max length (99)
    if([partialString length] > 2) {
        return NO;
    }
    // integers only
    NSScanner* scanner = [NSScanner scannerWithString:partialString];
    if(!([scanner scanInt:0] && [scanner isAtEnd])) {
        NSBeep();
        return NO;
    }    
    return YES;
}
@end

我该如何简化?

1 个答案:

答案 0 :(得分:2)

如果改为实施-isPartialStringValid:proposedSelectedRange:originalString:originalSelectedRange:errorDescription:,您将获得更多控制权,包括在所选范围内。

可能类似于:

- (BOOL)isPartialStringValid:(NSString **)partialStringPtr
       proposedSelectedRange:(NSRangePointer)proposedSelRangePtr
              originalString:(NSString *)origString
       originalSelectedRange:(NSRange)origSelRange
            errorDescription:(NSString **)error
{
    if ([*partialStringPtr length] == 0)
    {
        *partialStringPtr = @"1";
        *proposedSelRangePtr = NSMakeRange(0, [*partialStringPtr length]);
        return NO;
    }

    // two integer max length (99)
    if ([*partialStringPtr length] > 2)
    {
        NSRange changed = NSMakeRange(origSelRange.location, [*partialStringPtr length] - (origString.length - origSelRange.length));
        NSRange excess;
        excess.length = [*partialStringPtr length] - 2;
        excess.location = changed.location + (changed.length - excess.length);
        *partialStringPtr = [*partialStringPtr stringByReplacingCharactersInRange:excess withString:@""];
        *proposedSelRangePtr = NSMakeRange(excess.location, 0);
        return NO;
    }
    // integers only
    NSScanner* scanner = [NSScanner scannerWithString:*partialStringPtr];
    scanner.charactersToBeSkipped = nil;
    if(!([scanner scanInt:0] && [scanner isAtEnd])) {
        *partialStringPtr = origString;
        *proposedSelRangePtr = origSelRange;
        NSBeep();
        return NO;
    }    
    return YES;
}