使用GXUI在Go中滚动窗口

I am trying to add scroll bars to my application windows in Go using GXUI.

Say I have this code:

package main

import (
    "fmt"

    "github.com/google/gxui"
    "github.com/google/gxui/drivers/gl"
    "github.com/google/gxui/samples/flags"
    "github.com/google/gxui/themes/dark"
)

func appMain(driver gxui.Driver) {
    theme := dark.CreateTheme(driver)

    window := theme.CreateWindow(800, 600, "Grid")
    window.SetScale(flags.DefaultScaleFactor)
    window.OnClose(driver.Terminate)

    row := theme.CreateLinearLayout()
    row.SetDirection(gxui.LeftToRight)
    for c := 0; c < 4; c++ {
        col := theme.CreateLinearLayout()
        col.SetDirection(gxui.TopToBottom)
        for r := 0; r < 100; r++ {
            cell := theme.CreateLabel()
            cell.SetText(fmt.Sprintf("%d", r*4+c))
            col.AddChild(cell)
        }
        row.AddChild(col)
    }

    window.AddChild(row)
}

func main() {
    gl.StartDriver(appMain)
}

When I run it, I get this window:

How can I get the window to have a scroll bar so that I can view all of the lines?

The following code uses ScrollLayout to add a scroll bar to the window. The trick is to make ScrollLayout the window's child and make the next widget (in this case a LinearLayout) a child of the ScrollLayout.

package main

import (
    "fmt"
    "github.com/google/gxui"
    "github.com/google/gxui/drivers/gl"
    "github.com/google/gxui/samples/flags"
    "github.com/google/gxui/themes/dark"
)

func appMain(driver gxui.Driver) {
    theme := dark.CreateTheme(driver)
    window := theme.CreateWindow(800, 600, "Grid")
    window.SetScale(flags.DefaultScaleFactor)
    window.OnClose(driver.Terminate)
    sl := theme.CreateScrollLayout()
    row := theme.CreateLinearLayout()
    row.SetDirection(gxui.LeftToRight)
    for c := 0; c < 4; c++ {
        col := theme.CreateLinearLayout()
        col.SetDirection(gxui.TopToBottom)
        for r := 0; r < 100; r++ {
            cell := theme.CreateLabel()
            cell.SetText(fmt.Sprintf("%d", r*4+c))
            col.AddChild(cell)
        }
        row.AddChild(col)
    }
    sl.SetChild(row)
    window.AddChild(sl)
}

func main() {
    gl.StartDriver(appMain)
}

Note that my computer gave me display issues when I increased the number of rows (the rightmost columns began to get cut off), but other people did not encounter this issue, so it is likely due to a bad installation on my end.

I wasn't able to do with help ScrollLayout, but I can propose this variant on the basis of examples from github.

package main

import (
    "fmt"
    "github.com/google/gxui"
    "github.com/google/gxui/drivers/gl"
    "github.com/google/gxui/math"
    "github.com/google/gxui/samples/flags"
    "github.com/google/gxui/themes/dark"
)

type customAdapter struct {
    gxui.AdapterBase
}

func (a *customAdapter) Count() int {
    return 1000
}

func (a *customAdapter) ItemAt(index int) gxui.AdapterItem {
    return index
}

func (a *customAdapter) ItemIndex(item gxui.AdapterItem) int {
    return item.(int)
}

func (a *customAdapter) Size(theme gxui.Theme) math.Size {
    return math.Size{W: 200, H: 25}
}

func (a *customAdapter) Create(theme gxui.Theme, index int) gxui.Control {

    layout1 := theme.CreateLinearLayout()
    layout1.SetDirection(gxui.LeftToRight)
    for c := 0; c < 4; c++ {
        col := theme.CreateLinearLayout()
        col.SetDirection(gxui.TopToBottom)
        cell := theme.CreateLabel()
        cell.SetText(fmt.Sprintf("%d", index*4+c))
        col.AddChild(cell)
        layout1.AddChild(col)
    }
    return layout1
}

func appMain(driver gxui.Driver) {
    theme := dark.CreateTheme(driver)
    window := theme.CreateWindow(600, 400, "Grid")
    window.BorderPen()
    window.SetScale(flags.DefaultScaleFactor)
    window.OnClose(driver.Terminate)
    adapter := &customAdapter{}
    list := theme.CreateList()
    list.SetAdapter(adapter)
    list.SetOrientation(gxui.Vertical)
    window.AddChild(list)
}

func main() {
    gl.StartDriver(appMain)
}

Each line is placed in the list,their number and size are specified in the overridden methods. The advantage is that in the list already have the scrollbar.