objective-c - NSOutlineView 示例

Question

拜托，你能给出一个简单完整的 Cocoa 应用程序示例吗？NSOutlineView 的分层数据表示不像 NSOutlineView and NSTreeController example 那样模棱两可。.

谢谢!

Answer 1

这个例子使用了一个简单的两层层次结构，两个父 Foo 和 Bar 分别有两个 child ，分别是 Foox、Fooz 和 Barx、Barz，大纲 View 是默认的，只有两列和第二列的标识符设置为“ child ”。

NSDictionary *firstParent = @{@"parent": @"Foo", @"children": @[@"Foox", @"Fooz"]};
NSDictionary *secondParent = @{@"parent": @"Bar", @"children": @[@"Barx", @"Barz"]};
NSArray *list = @[firstParent, secondParent];

- (BOOL)outlineView:(NSOutlineView *)outlineView isItemExpandable:(id)item
{        
    if ([item isKindOfClass:[NSDictionary class]]) {
        return YES;        
    }else {
        return NO;
    }
}

- (NSInteger)outlineView:(NSOutlineView *)outlineView numberOfChildrenOfItem:(id)item
{    

    if (item == nil) { //item is nil when the outline view wants to inquire for root level items
        return [list count];                 
    }   

    if ([item isKindOfClass:[NSDictionary class]]) {
        return [[item objectForKey:@"children"] count];
    }

    return 0;
}

- (id)outlineView:(NSOutlineView *)outlineView child:(NSInteger)index ofItem:(id)item
{

    if (item == nil) { //item is nil when the outline view wants to inquire for root level items
        return [list objectAtIndex:index];                   
    }

    if ([item isKindOfClass:[NSDictionary class]]) {
        return [[item objectForKey:@"children"] objectAtIndex:index];
    }     

    return nil;
}

- (id)outlineView:(NSOutlineView *)outlineView objectValueForTableColumn:(NSTableColumn *)theColumn byItem:(id)item
{          

    if ([[theColumn identifier] isEqualToString:@"children"]) {
        if ([item isKindOfClass:[NSDictionary class]]) {
            return [NSString stringWithFormat:@"%i kids",[[item objectForKey:@"children"] count]];
        }  
        return item;
    }else{
        if ([item isKindOfClass:[NSDictionary class]]) {
            return [item objectForKey:@"parent"];                         
        }           
    }

    return nil;
}