ZacharyZhang-NYandClaude Opus 5.5
bcce34cda1
MyGo v0.5.5 returns ui.Element as a checked value handle instead of a
pointer. Migrated with `mygo migrate-ui`, then fixed what the codemod
leaves to review:
- Element nil checks become .Valid(); absent elements are ui.Element{}.
- Input handlers and paint callbacks run outside the build pass, where
elements expire and Context methods are inert: read IsDisabled into a
local during the build, keep a ui.Handle for Focus, use c.Services()
for clipboard access, create ui.Local state during the build.
- Add core.AutoFocus: v0.5.5 records an overlay's opener after its
content builds, so same-frame autofocus lost focus restore on close.
It focuses one frame later; cascader rows defer their focus likewise.
- core.OverlayLayer identifies build passes by the root element, not
c.Now(), which repeats across passes and under the Tester clock.
- Context menus survive the opening press counted as PressedOutside;
split button tooltip no longer reorders its open menu; disabled
menubar rows pass presses to the panel; Form defers blur-started
async checks so the growing message no longer moves Submit away
from the release; Combobox drops its disabled copy now that MyGo
blocks typing under a disabled wrapper (canary flipped to a guard).
- The Tester clock is virtual: tests use Advance/Now instead of
time.Sleep/time.Now and read element state inside the view. The web
mirror advances the clock to wall time before each frame and input.
- AGENTS.md and docs describe the value Element API and the new pin.
Snapshot goldens are darwin-only and were not re-verified here.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
2.0 KiB
2.0 KiB
007 ScrollArea 滚动区域
用途
纵向、横向或双向滚动内容。支持滚轮、触控板、滚动条拖动与键盘；可读取、设置并保留滚动位置。基于 MyGo ui.Scroll。
最小示例
var offset ui.ScrollState
layout.ScrollArea(c, &offset, layout.ScrollAreaOptions{Label: "Log"}, func() {
for range 50 {
ui.Text(c, "A line of the log")
}
}).Height(200)
签名：func ScrollArea(c *ui.Context, state *ui.ScrollState, opts ScrollAreaOptions, children func()) ui.Element
参数
| 字段 | 类型 | 默认值 | 含义 |
|---|---|---|---|
state |
*ui.ScrollState |
nil | 滚动位置。设置 X/Y 即滚动到该处，math.MaxFloat32 表示末尾；组件写回 MaxX/MaxY。nil 时按区域在视图中的位置保留。 |
Direction |
ScrollDirection |
ScrollVertical |
ScrollVertical、ScrollHorizontal、ScrollBoth；非法值 panic。 |
Label |
string |
"" | 区域的无障碍名称。 |
children |
func() |
必填 | 内容；nil 时 panic。 |
需给区域尺寸（Height、Grow 等）。
状态
- 内容溢出时区域可获得焦点，键盘焦点环画在区域内侧：先留 2 DIP 间隔，再画 2 DIP Focus 色环线，避免被父级裁剪。溢出状态在布局后变化时组件立即重建，焦点停靠随之更新。
- 不溢出时不进入 Tab 序列。
- 滚动条为 MyGo 叠加式滑块，颜色取主题 Scrollbar（TextMuted 50%），指针悬停时显示，不占布局空间。
- 切换主题、折叠周围布局都不重置位置。
事件
无独立事件；比较 state.X/state.Y 的变化即可得知滚动。
键盘操作
焦点在区域或其内容上时：方向键滚动 40 DIP，Page Up/Down 与 Space/Shift+Space 翻页，Home/End 到顶部/底部（macOS 另有 Cmd+↑/↓）。文本输入等自行处理这些键的控件优先。
限制
- 滚动条只在悬停时显示，不提供常驻滚动条（MyGo 滚动条不占空间的设计）。
- 大量行请使用虚拟化列表，ScrollArea 会构建全部子项。