Go语言终端应用开发：利用Termbox-Go实现固定输入提示与动态内容更新

package main

import (
    "fmt"
    "log"
    "strings"
    "time"

    "github.com/nsf/termbox-go/termbox"
)

// Message represents a message to be displayed
type Message struct {
    Text string
    Time time.Time
}

var (
    inputBuffer  []rune        // Current user input buffer
    messages     []Message     // List of messages
    prompt       = ">> "       // Input prompt
    maxMessages  = 10          // Max messages to display
    messageCount = 0           // Counter for simulated incoming messages
)

// drawScreen clears the screen and redraws all elements
func drawScreen() {
    termbox.Clear(termbox.ColorDefault, termbox.ColorDefault)

    width, height := termbox.Size()

    // 1. Draw messages
    messageY := 0
    startMessageIndex := 0
    if len(messages) > maxMessages {
        startMessageIndex = len(messages) - maxMessages
    }

    for i := startMessageIndex; i < len(messages); i++ {
        msg := messages[i]
        line := fmt.Sprintf("[%s] %s", msg.Time.Format("15:04:05"), msg.Text)
        if messageY < height-1 { // Ensure messages don't overlap input line
            for x, r := range line {
                termbox.SetCell(x, messageY, r, termbox.ColorWhite, termbox.ColorDefault)
            }
            messageY++
        }
    }

    // 2. Draw input prompt and buffer at the bottom
    inputLineY := height - 1 // Last line for input
    promptLen := len(prompt)

    // Draw prompt
    for x, r := range prompt {
        termbox.SetCell(x, inputLineY, r, termbox.ColorGreen, termbox.ColorDefault)
    }

    // Draw input buffer
    for x, r := range inputBuffer {
        termbox.SetCell(promptLen+x, inputLineY, r, termbox.ColorWhite, termbox.ColorDefault)
    }

    // 3. Set cursor position
    termbox.SetCursor(promptLen+len(inputBuffer), inputLineY)

    termbox.Flush()
}

// simulateIncomingMessages adds a dummy message periodically
func simulateIncomingMessages(stopChan chan struct{}) {
    ticker := time.NewTicker(5 * time.Second)
    defer ticker.Stop()

    for {
        select {
        case <-ticker.C:
            messageCount++
            messages = append(messages, Message{
                Text: fmt.Sprintf("Incoming message %d from server!", messageCount),
                Time: time.Now(),
            })
            drawScreen() // Redraw when new message arrives
        case <-stopChan:
            return
        }
    }
}

func main() {
    err := termbox.Init()
    if err != nil {
        log.Fatalf("Failed to initialize termbox: %v", err)
    }
    defer termbox.Close()

    // Initial screen draw
    drawScreen()

    // Channel to stop the goroutine
    stopSimChan := make(chan struct{})
    go simulateIncomingMessages(stopSimChan)

    // Main event loop
    for {
        switch ev := termbox.PollEvent(); ev.Type {
        case termbox.EventKey:
            switch ev.Key {
            case termbox.KeyEsc: // Exit on ESC
                close(stopSimChan) // Signal goroutine to stop
                return
            case termbox.KeyEnter: // Send message on Enter
                if len(inputBuffer) > 0 {
                    messages = append(messages, Message{
                        Text: "You: " + string(inputBuffer),
                        Time: time.Now(),
                    })
                    inputBuffer = nil // Clear input
                }
            case termbox.KeyBackspace, termbox.KeyBackspace2: // Handle backspace
                if len(inputBuffer) > 0 {
                    inputBuffer = inputBuffer[:len(inputBuffer)-1]
                }
            case termbox.KeySpace: // Handle space
                inputBuffer = append(inputBuffer, ' ')
            default: // Handle other printable characters
                if ev.Ch != 0 {
                    inputBuffer = append(inputBuffer, ev.Ch)
                }
            }
        case termbox.EventResize: // Handle terminal resize
            // No specific action needed for this simple example,
            // drawScreen will automatically adapt to new size.
        }
        drawScreen() // Redraw screen after every event
    }
}