NSComboBox输入字符时自动打开下拉菜单并匹配

NSComboBox，此功能实现的效果图如下图所示：



1. 首先调用NSComboBox的父类NSTextField的delegate方法，实现实时输入监测。其中比较关键的方法是-(void)controlTextDidChange:(NSNotification*)notification,这个方法可以实现输入内容的实时监测。
-(void)controlTextDidChange:(NSNotification*)notification
{
id object = [notification object];
[object setComplete:YES];//这个函数可以实现自动匹配功能
}
2. 可以看到，在NSComboBox控件的右边有一个标有下三角的按钮，这个按钮在鼠标点击后才弹出下拉菜单来，但是我们在输入的时候没有实现鼠标事件，所以下来菜单无法弹出，因此需要模拟鼠标事件-(void)mouseDown:(NSEvent*)theEvent，但是这个按钮是NSComboBoxCell中的私有变量，所以我们重新创建一个类，这个类继承NSComboBoxCell，这样我们就可以应用它的私有变量了。
继承NSComboBox类：
@interface ComboBoxCell : NSComboBoxCell
{
}

- (void)popUpList;
- (void)closePopUpWindow;
- (BOOL)isPopUpWindowVisible;
@end

@implementation ComboBoxCell
- (void)popUpList
{
if ([self isPopUpWindowVisible])
{
return;
}
else
{
[_buttonCell performClick:nil];//模拟鼠标事件
}
}
- (void)closePopUpWindow

{

if ([self isPopUpWindowVisible])

{

[_popUp close];

}

}

- (BOOL)isPopUpWindowVisible

{

return [_popUp isVisible];

}

@end

3. 实现NSComboBox类的Datasource方法：

- (NSInteger)numberOfItemsInComboBox:(NSComboBox *)aComboBox;

- (id)comboBox:(NSComboBox *)aComboBox objectValueForItemAtIndex:(NSInteger)index;

- (NSUInteger)comboBox:(NSComboBox *)aComboBox indexOfItemWithStringValue:(NSString *)string;

这是Datasource方法，我们需要重写此方法。下面是三个方法的实现，方法中的结构体可以根据用户的需要自定义。

- (NSInteger)numberOfItemsInComboBox:(NSComboBox *)aComboBox

{

NSInteger row = 0;

if (currentBoxIndex_ == -1)

{

return row;

}

DBBoxManager *currentBox = [[DBManager defaultDBManager] boxAtIndex:currentBoxIndex_];

if ([vendorControl_ isEqual:aComboBox])

{

row = [currentBox userDefineVenderInfos].count;

}

else if ([categoryControl_ isEqual:aComboBox])

{

row = [currentBox userDefineCategoryInfos].count;

}

else if ([paymentControl_ isEqual:aComboBox])

{

row = [currentBox userDefinePaymentInfos].count;

}

else if ([purposeControl_ isEqual:aComboBox])

{

row = [currentBox userDefinePurposeInfos].count;

}

else if ([categorySelectBtn_ isEqual:aComboBox])

{

row = [currentBox userDefineCategoryInfos].count;

}

else if([vendorSelectBtn_ isEqual:aComboBox])

{

row = [currentBox userDefineVenderInfos].count;

}

row = row + 1;

return row;

}

- (id)comboBox:(NSComboBox *)aComboBox objectValueForItemAtIndex:(NSInteger)index

{

NSString *content = nil;

if (currentBoxIndex_ == -1)

{

return content;

}

NSMutableArray *array = nil;

DBBoxManager *currentBox = [[DBManager defaultDBManager] boxAtIndex:currentBoxIndex_];

if ([vendorControl_ isEqual:aComboBox])

{

array = [currentBox userDefineVenderInfos];

}

else if ([categoryControl_ isEqual:aComboBox])

{

array = [currentBox userDefineCategoryInfos];

}

else if ([paymentControl_ isEqual:aComboBox])

{

array = [currentBox userDefinePaymentInfos];

}

else if ([purposeControl_ isEqual:aComboBox])

{

array = [currentBox userDefinePurposeInfos];

}

else if ([categorySelectBtn_ isEqual:aComboBox])

{

array = [currentBox userDefineCategoryInfos];

}

else if ([vendorSelectBtn_ isEqual:aComboBox])

{

array = [currentBox userDefineVenderInfos];

}

if (index == 0)

{

content = @"";

}

else

{

NSDictionary *dic = [array objectAtIndex:index - 1];

content = (NSString *)[dicobjectForKey:kUserDefinedBoxValue];

}

return content;

}

- (NSUInteger)comboBox:(NSComboBox *)aComboBox indexOfItemWithStringValue:(NSString *)string

{

DBBoxManager *currentBox = [[DBManager defaultDBManager] boxAtIndex:currentBoxIndex_];

NSMutableArray *comboxList = nil;

if ([aComboBox isEqual:vendorControl_])

{

comboxList = [currentBox userDefineVenderInfos];

}

else if([aComboBox isEqual:categoryControl_])

{

comboxList = [currentBox userDefineCategoryInfos];

}

else if([aComboBox isEqual:paymentControl_])

{

comboxList = [currentBox userDefinePaymentInfos];

}

else if([aComboBox isEqual:purposeControl_])

{

comboxList = [currentBox userDefinePurposeInfos];

}

NSMutableArray *newList = [[[NSMutableArray alloc] initWithCapacity:0] autorelease];

[newList addObject:@""];

for (int i = 0; i < [comboxList count]; i++)

{

NSString *name = [[comboxList objectAtIndex:i] objectForKey:kUserDefinedBoxValue];

[newList addObject:name];

}

return [newList indexOfObject:string];

}

做到这里，这个功能就基本实现了，本文中的代码来自正在开发的工程，读者只需替换响应的结构体，即可实现功能。