NSScrollView 滚动不滚动？

Question

要显示 20 个按钮中的 8 个。但我不能滚动浏览其余部分？是否应该显示滚动条？

NSScrollView *nssvFonts = [[NSScrollView alloc] initWithFrame:CGRectMake(200, 200, 200, 400)];
[self.view addSubview:nssvFonts];

[nssvFonts.documentView setFrame: NSMakeRect(0,0,200, 400) ];
nssvFonts.hasVerticalScroller = YES;

for(int i = 0; i < 20; i++){
    NSButton *btnDown = [[NSButton alloc] initWithFrame:CGRectMake(0, 50 * i, 200, 50)];
    [nssvFonts addSubview:btnDown];
    [btnDown setButtonType:NSMomentaryPushInButton];
    [btnDown setTitle:[NSString stringWithFormat:@"Down: %d", i]];
}

---

所以我采纳了 Willeke 的建议并进行了添加和更改：

NSScrollView *nssvFonts = [[NSScrollView alloc] initWithFrame:CGRectMake(200, 200, 300, 400)];
[self.view addSubview:nssvFonts];

[nssvFonts.documentView setFrame: NSMakeRect(0,0,200, 1000)];
//[nssvFonts.contentView setFrame:NSMakeRect(0,  0, 200, 400)];
nssvFonts.hasVerticalScroller = YES;

for(int i = 0; i < 20; i++){
    NSButton *btnDown = [[NSButton alloc] initWithFrame:CGRectMake(50, 50 * i, 200, 50)];
    [nssvFonts addSubview:btnDown];
    [btnDown setButtonType:NSMomentaryPushInButton];
    [btnDown setTitle:[NSString stringWithFormat:@"Down: %d", i]];
}

但仍然没有显示垂直滚动条，我也无法使用鼠标滚动它...向下 1 个按钮或向下 2 个按钮以提供帮助。

Answer 1

滚动视图会显示视图中因太大而无法在窗口中显示的部分内容，并允许用户在滚动视图中移动文档视图。

换句话说：滚动视图显示其文档视图的一部分。如果文档视图与滚动视图大小相同，则它不会滚动。使文档视图足够大，以便所有按钮都适合。

编辑：

NSScrollView *nssvFonts = [[NSScrollView alloc] initWithFrame:NSMakeRect(200, 200, 300, 400)];
[self.view addSubview:nssvFonts];

NSView *documentView = [[NSScrollView alloc] initWithFrame:NSMakeRect(0, 0, 200, 1000)];
nssvFonts.documentView = documentView;

nssvFonts.hasVerticalScroller = YES;

for(int i = 0; i < 20; i++) {
    NSButton *btnDown = [[NSButton alloc] initWithFrame:NSMakeRect(50, 50 * i, 200, 50)];
    [documentView addSubview:btnDown];
    [btnDown setButtonType:NSMomentaryPushInButton];
    [btnDown setTitle:[NSString stringWithFormat:@"Down: %d", i]];
}