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>
77 lines
3.4 KiB
Markdown
77 lines
3.4 KiB
Markdown
# 087 DropdownMenu 下拉菜单
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## 用途
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按钮触发的应用内菜单，由 MujicaUI 自绘（不是系统菜单）。支持分组、子菜单、勾选项与禁用项；选择后按规则关闭。
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## 最小示例
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```go
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pinned := false
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view := func(c *ui.Context) {
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core.Use(c, core.Settings{})
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overlay.DropdownMenu(c, "Actions", overlay.DropdownMenuOptions{}, func(m *overlay.PopupMenu) {
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m.Group("Letter", func() {
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if m.Item("Rename", overlay.PopupMenuItemOptions{}) {
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fmt.Println("rename")
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}
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m.Check("Pinned", &pinned, overlay.PopupMenuItemOptions{KeepOpen: true})
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})
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m.Submenu("Move to", overlay.PopupMenuItemOptions{}, func(m *overlay.PopupMenu) {
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m.Item("Archive", overlay.PopupMenuItemOptions{})
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})
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m.Separator()
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m.Item("Burn", overlay.PopupMenuItemOptions{Disabled: true})
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})
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}
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ui.Render(view, 400, 300, 1)
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```
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签名：`func DropdownMenu(c *ui.Context, label string, opts DropdownMenuOptions, build func(m *PopupMenu)) ui.Element`，返回触发按钮。`build` 为 nil、或 `label` 与 `opts.Label` 都为空时 panic。
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## 参数
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| 字段 | 类型 | 默认值 | 含义 |
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| --- | --- | --- | --- |
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| `Icon` | `*ui.SVG` | `nil` | 标签前的图标。 |
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| `Disabled` | `bool` | `false` | 禁用触发按钮并关闭已打开的菜单。 |
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| `Label` | `string` | `""` | 仅图标按钮的无障碍名称。 |
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`PopupMenu` 方法：
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| 方法 | 说明 |
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| --- | --- |
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| `Item(label, opts) bool` | 普通项；本帧被选择时返回 true。 |
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| `Check(label, *bool, opts) bool` | 勾选项，切换 `*bool`；本帧变化时返回 true。 |
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| `Submenu(label, opts, build)` | 子菜单项；`build` 为 nil 时 panic。 |
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| `Group(label, fn)` | 带说明文字的分组，前面有内容时自动加分隔线。 |
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| `Separator()` | 分隔线。 |
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`PopupMenuItemOptions`：`Disabled bool`（不可选、不进入方向键序列），`KeepOpen bool`（选择后不关闭菜单）。
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## 状态
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- 触发按钮：次按钮外观加下拉箭头，打开时保持按下底色。
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- 菜单项：悬停或键盘焦点时显示 Selection 底色和左侧 2 DIP 强调条；勾选项显示勾号；禁用项变暗。
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- 菜单面板最高为可用空间，超出时滚动；子菜单在右侧打开，右侧放不下时翻到左侧，仍放不下时贴窗口边缘，宽度不超过窗口；下方放不下时上移。
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## 事件
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`Item` / `Check` 的返回值；每次选择只报告一次。
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## 键盘操作
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| 按键 | 行为 |
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| --- | --- |
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| Enter / Space / ↓ | 在触发按钮上打开菜单，焦点在第一项。 |
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| ↑ / ↓ / Home / End | 在当前层移动，跳过禁用项，首尾循环。 |
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| → / Enter | 在子菜单项上打开子菜单并进入。 |
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| ← / Escape | 在子菜单中关闭子菜单，回到父项。 |
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| Escape / Tab | 关闭菜单，焦点回到触发按钮。 |
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## 限制
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- MyGo 没有 menu / menuitem 无障碍角色（`ui/access.go:22` Role 列表），菜单面板报告为 popup，普通项为 button，勾选项为 checkbox，触发按钮为 menu button。
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- 打开期间外部点击只用于关闭，不传给下方控件：`PopoverBase` 用覆盖整窗的背板接收点击（`ui/base.go:373`）。
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- Escape 只关闭最上层的 MujicaUI 浮层（窗口内按打开顺序记录）。MyGo 自带的 `ui.Popover`、`ui.Select` 弹层不在这份记录中；它们打开在非模态 MujicaUI 浮层之上时，Escape 可能先关闭下面的 MujicaUI 浮层。
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