Fyne-Widget

软件包widget定义了许多小部件
```go
import "fyne.io/fyne/v2/widget"
```

## Accordion 下拉框

### 定义
```go
type Accordion struct {
	BaseWidget
	//  项目
	Items     []*AccordionItem
	//  是否同时打开多个项目
	MultiOpen bool
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/canvas"
	"fyne.io/fyne/v2/widget"
	"image/color"
	"strconv"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

a1 := widget.NewAccordion()
	for i := 0; i < 3; i++ {
		a3 := widget.NewAccordion()
		for j := 0; j < 4; j++ {
			s := strconv.Itoa(i) + strconv.Itoa(j)
			a3.Append(widget.NewAccordionItem(s, canvas.NewText(s, color.White)))
		}
		a2 := widget.NewAccordionItem(strconv.Itoa(i), a3)
		a1.Append(a2)
	}

Window.SetContent(a1)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget1.png)

## Button 按钮

### 定义
```go
type Button struct {
	DisableableWidget
	//  按钮的文本或图标
	Text string
	Icon fyne.Resource
	//  按钮突出程度
	Importance    ButtonImportance
	//  按钮对齐方式
	Alignment     ButtonAlign
	//  图标位置
	IconPlacement ButtonIconPlacement
	//  按钮绑定的函数
	OnTapped func() `json:"-"`
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/widget"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

l := widget.NewLabel("hello")
	b := widget.NewButton("world", func() {
		l.Text = "world"
		l.Refresh()
	})

box := container.NewVBox()
	box.Add(l)
	box.Add(b)

Window.SetContent(box)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget2.png)

## Card 卡片

### 定义
```go
type Card struct {
	BaseWidget
	//  标题
	Title, Subtitle string
	//  图片
	Image           *canvas.Image
	//  内容
	Content         fyne.CanvasObject
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/canvas"
	"fyne.io/fyne/v2/widget"
	"image/color"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

c := widget.NewCard("Hello", "World", canvas.NewCircle(color.White))

Window.SetContent(c)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget3.png)

## Check 选择框

### 定义
```go
type Check struct {
	DisableableWidget
	//  文本
	Text    string
	//  当前选择状态
	Checked bool
	//  触发时的函数
	OnChanged func(bool) `json:"-"`
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/widget"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

l := widget.NewLabel("Hello")
	c := widget.NewCheck("World", func(b bool) {
		if b {
			l.Text = "World"
			l.Refresh()
		} else {
			l.Text = "Hello"
			l.Refresh()
		}
	})
	box := container.NewVBox()
	box.Add(l)
	box.Add(c)

Window.SetContent(box)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget4.png)

## CheckGroup 多选框

### 定义
```go
type CheckGroup struct {
	DisableableWidget
	//  选项是否水平排列
	Horizontal bool
	//  是否至少选择一个
	Required   bool
	//  触发时的函数，传入被选择字符串的列表
	OnChanged  func([]string) `json:"-"`
	//  选项列表
	Options    []string
	//  被选择字符串的列表
	Selected   []string
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/widget"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

l := widget.NewLabel("")
	ss := []string{"A", "B", "C"}
	c := widget.NewCheckGroup(ss, func(s []string) {
		l.Text = ""
		for _, i := range s {
			l.Text += i
		}
		l.Refresh()
	})
	box := container.NewVBox()
	box.Add(l)
	box.Add(c)

Window.SetContent(box)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget5.png)

## Entry 输入框

### 定义
```go
type Entry struct {
	DisableableWidget
	//  文本
	Text string
	//  文本样式
	TextStyle   fyne.TextStyle

PlaceHolder string
	//  触发函数
	OnChanged   func(string) `json:"-"`
	OnSubmitted func(string) `json:"-"`
	//  输入框类型
	Password    bool
	MultiLine   bool
	//  其它参数
	Wrapping    fyne.TextWrap
	Validator fyne.StringValidator `json:"-"`
	CursorRow, CursorColumn int
	OnCursorChanged         func() `json:"-"`
	ActionItem fyne.CanvasObject `json:"-"`
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/widget"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

l := widget.NewLabel("")
	e := widget.NewEntry()
	e.OnChanged = func(s string) {
		l.Text = e.Text
		l.Refresh()
	}
	box := container.NewVBox()
	box.Add(l)
	box.Add(e)

Window.SetContent(box)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget6.png)

## Form 表单

### 定义
```go
type Form struct {
	BaseWidget
	//  表单内容
	Items      []*FormItem
	//  提交函数
	OnSubmit   func() `json:"-"`
	//  取消函数
	OnCancel   func() `json:"-"`
	//  提交按钮文本
	SubmitText string
	//  取消按钮文本
	CancelText string
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/widget"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

box := container.NewVBox()

l := widget.NewLabel("")
	f := widget.NewForm()

hello := widget.NewEntry()
	world := widget.NewEntry()
	f.AppendItem(widget.NewFormItem("hello", hello))
	f.Append("world", world)

f.OnSubmit = func() {
		s := hello.Text + world.Text
		l.Text = s
		l.Refresh()
	}
	f.Refresh()

box.Add(l)
	box.Add(f)

Window.SetContent(box)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget7.png)

## Hyperlink 超链接

### 定义
```go
type Hyperlink struct {
	BaseWidget
	//  文本
	Text      string
	//  连接
	URL       *url.URL
	//  对齐方式
	Alignment fyne.TextAlign
	//  文本包装
	Wrapping  fyne.TextWrap
	//  文本样式
	TextStyle fyne.TextStyle
	//  点击时触发
	OnTapped func() `json:"-"`
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/widget"
	"net/url"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

h := widget.NewHyperlink("Hello", &url.URL{Path: "http://leafbackaut.cn"})

Window.SetContent(h)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget8.png)

## Label 标签

### 定义
```go
type Label struct {
	BaseWidget
	//  文本
	Text      string
	//  对齐方式
	Alignment fyne.TextAlign
	//  文本包装
	Wrapping  fyne.TextWrap
	//  文本样式
	TextStyle fyne.TextStyle
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/widget"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

l := widget.NewLabel("Hello")

Window.SetContent(l)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget9.png)

## List 列表

### 定义
```go
type List struct {
	BaseWidget
	//  可以用来重写的函数
	Length       func() int                                  `json:"-"`
	CreateItem   func() fyne.CanvasObject                    `json:"-"`
	UpdateItem   func(id ListItemID, item fyne.CanvasObject) `json:"-"`
	OnSelected   func(id ListItemID)                         `json:"-"`
	OnUnselected func(id ListItemID)                         `json:"-"`
}
```

### 示例

使用NewList创建新的列表，参数分别代表创建列表长度，创建列表单个元素的内容，更新每个列表元素的函数
```go
func NewList(length func() int, createItem func() fyne.CanvasObject, updateItem func(ListItemID, fyne.CanvasObject)) *List
```

一个列表
```go
package main

import (
	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/widget"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

var data = []string{"a", "b", "c"}
	l := widget.NewList(func() int {
		return len(data)
	}, func() fyne.CanvasObject {
		return widget.NewLabel("Hello")
	}, func(id widget.ListItemID, object fyne.CanvasObject) {
		object.(*widget.Label).SetText(data[id])
	})

Window.SetContent(l)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget10.png)

## Menu 菜单

### 定义
```go
type Menu struct {
	BaseWidget
	//  菜单内容
	Items     []fyne.CanvasObject
	OnDismiss func()
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/widget"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

m := widget.NewMenu(fyne.NewMenu("Menu"))
	m.Items = append(m.Items, widget.NewLabel("hello"))
	m.Items = append(m.Items, widget.NewLabel("World"))

Window.SetContent(m)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget11.png)

## ProgressBar 进度条

### 定义
```go
type ProgressBar struct {
	BaseWidget
	//  最小值，最大值，当前值
	Min, Max, Value float64
	//  自定义文本样式
	TextFormatter func() string `json:"-"`
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/widget"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

p := widget.NewProgressBar()
	p.Max = 10
	p.Min = 0
	p.Value = 6

Window.SetContent(p)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget12.png)

## RadioGroup 单选列表

### 定义
```go
type RadioGroup struct {
	DisableableWidget
	//  排列方式
	Horizontal bool
	//  是否必选一个
	Required   bool
	//  选择时调用这个函数，传入一个字符串
	OnChanged  func(string) `json:"-"`
	//  选项列表
	Options    []string
	//  被选的字符串
	Selected   string
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/widget"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

box := container.NewVBox()

l := widget.NewLabel("")
	c := []string{"Hello", "World"}
	r := widget.NewRadioGroup(c, func(s string) {
		l.Text = s
		l.Refresh()
	})

box.Add(l)
	box.Add(r)

Window.SetContent(box)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget13.png)

## RichText 富文本

### 定义
```go
type RichText struct {
	BaseWidget
	//  富文本标记
	Segments []RichTextSegment
	Wrapping fyne.TextWrap
	Scroll   widget.ScrollDirection
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/widget"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

box := container.NewVBox()

m := widget.NewRichTextFromMarkdown("## Hello")
	t := widget.NewRichTextWithText("World")

box.Add(m)
	box.Add(t)

Window.SetContent(box)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget14.png)

## Select 选择框

### 定义
```go
type Select struct {
	DisableableWidget
	//  对齐方式
	Alignment   fyne.TextAlign
	//  当前选择的字符串
	Selected    string
	//  选项列表
	Options     []string
	PlaceHolder string
	//  单击选项调用函数
	OnChanged   func(string) `json:"-"`
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/widget"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

box := container.NewVBox()

l := widget.NewLabel("")
	var o = []string{"A", "B", "c"}
	s := widget.NewSelect(o, func(s string) {
		l.Text = s
		l.Refresh()
	})
	s.PlaceHolder = "Hello World"

box.Add(l)
	box.Add(s)

Window.SetContent(box)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget15.png)

## SelectEntry 输入选择框

### 定义
```go
type SelectEntry struct {
	//  输入框
	Entry
	dropDown *fyne.Menu
	popUp    *PopUpMenu
	//  选项列表
	options  []string
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/widget"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

box := container.NewVBox()

var o = []string{"A", "B", "C"}
	s := widget.NewSelectEntry(o)

box.Add(s)

Window.SetContent(box)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget16.png)

## Slider 滑块

### 定义
```go
type Slider struct {
	BaseWidget
	//  一些值
	Value float64
	Min   float64
	Max   float64
	Step  float64
	//  方向，垂直或水平
	Orientation Orientation
	//  数据改变时触发函数
	OnChanged   func(float64)
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/widget"
	"strconv"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

box := container.NewVBox()

l := widget.NewLabel("")
	s := widget.NewSlider(1, 10)
	s.Step = 0.01
	s.OnChanged = func(f float64) {
		l.Text = strconv.FormatFloat(f, 'f', 3, 64)
		l.Refresh()
	}

box.Add(l)
	box.Add(s)

Window.SetContent(box)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget17.png)

## Table 表格

### 定义
```go
type Table struct {
	BaseWidget
	//  一些参数
	Length       func() (int, int)                                `json:"-"`
	CreateCell   func() fyne.CanvasObject                         `json:"-"`
	UpdateCell   func(id TableCellID, template fyne.CanvasObject) `json:"-"`
	OnSelected   func(id TableCellID)                             `json:"-"`
	OnUnselected func(id TableCellID)                             `json:"-"`
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/widget"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

var data = [][]string{{"A", "B", "C"}, {"D", "E", "F"}, {"G", "H", "I"}}
	t := widget.NewTable(func() (int, int) {
		return len(data), len(data[0])
	}, func() fyne.CanvasObject {
		return widget.NewLabel("")
	}, func(id widget.TableCellID, object fyne.CanvasObject) {
		object.(*widget.Label).SetText(data[id.Col][id.Row])
	})

Window.SetContent(t)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget18.png)

## TextGrid 文本网格

### 定义
```go
type TextGrid struct {
	BaseWidget
	//  每一行的元素
	Rows []TextGridRow
	//  是否显示行数
	ShowLineNumbers bool
	//  是否在空格处打点
	ShowWhitespace  bool
	//  Tab键的宽度
	TabWidth
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/widget"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

t := widget.NewTextGrid()

var cell1 []widget.TextGridCell
	var hello = []rune("Hello")
	for _, s := range hello {
		cell1 = append(cell1, widget.TextGridCell{Rune: s})
	}

var cell2 []widget.TextGridCell
	var world = []rune("    World")
	for _, s := range world {
		cell2 = append(cell2, widget.TextGridCell{Rune: s})
	}

row1 := widget.TextGridRow{
		Cells: cell1,
		Style: nil,
	}
	row2 := widget.TextGridRow{
		Cells: cell2,
		Style: nil,
	}

t.SetRow(0, row1)
	t.SetRow(1, row2)
	t.ShowLineNumbers = true
	t.ShowWhitespace = true

Window.SetContent(t)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget19.png)

## Toolbar 工具栏

### 定义
```go
type Toolbar struct {
	BaseWidget
	//  工具栏选项
	Items []ToolbarItem
}
```

### 示例
```go
package main

import (
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/theme"
	"fyne.io/fyne/v2/widget"
)

func main() {
	App := app.New()
	Window := App.NewWindow("test")

box := container.NewBorder(t, nil, nil, nil, nil)

t := widget.NewToolbar()
	t.Append(widget.NewToolbarAction(theme.HomeIcon(), func() {}))
	t.Append(widget.NewToolbarSeparator())
	t.Append(widget.NewToolbarAction(theme.AccountIcon(), func() {}))
	t.Append(widget.NewToolbarAction(theme.HelpIcon(), func() {}))

Window.SetContent(box)
	Window.ShowAndRun()
}
```

![](https://blog.coolcooltomato.com/uploads/article/demoWidget20.png)

Fyne-Widget

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