xn_hxp/app/src/main/java/xn/hxp/weidith/PageIndicatorView.kt

package xn.hxp.weidith

import android.content.Context
import android.graphics.Canvas
import android.graphics.Color
import android.graphics.Paint
import android.util.AttributeSet
import android.view.View

class PageIndicatorView @JvmOverloads constructor(
    context: Context,
    attrs: AttributeSet? = null,
    defStyleAttr: Int = 0
) : View(context, attrs, defStyleAttr) {
    private var currentPage = 0
    private var totalPages = 1
    private val activePaint: Paint
    private val inactivePaint: Paint

    init {
        activePaint = Paint().apply {
            color = Color.BLUE
            style = Paint.Style.FILL
        }

        inactivePaint = Paint().apply {
            color = Color.GRAY
            style = Paint.Style.FILL
        }
    }

    override fun onDraw(canvas: Canvas) {
        super.onDraw(canvas)

        val width = width
        val height = height

        val radius = height / 4
        val gap = height / 2

        val totalWidth = (totalPages - 1) * gap + 2 * radius * totalPages

        val startX = (width - totalWidth) / 2

        for (i in 0 until totalPages) {
            val paint = if (i == currentPage) activePaint else inactivePaint
            canvas.drawCircle(startX + i * (2 * radius + gap) + radius.toFloat(), height / 2.toFloat(), radius.toFloat(), paint)
        }
    }

    fun setCurrentPage(currentPage: Int) {
        this.currentPage = currentPage
        invalidate()
    }

    fun setTotalPages(totalPages: Int) {
        this.totalPages = totalPages
        invalidate()
    }
}