android - 当我在自定义 View 类中使用 R.styleable 时，我得到一个红色的 Unresolved reference : styleable

Question

我是初学者。这几天开始学习自定义 View ，过程中几乎没有问题。

我去谷歌解决这个问题时，有人提出了解决方案，但都没有成功。我使用 Kotlin 编写的自定义 View 。

这是我的自定义 View 类，名字是MyView.kt

package com.example.demos

import android.R
import android.content.Context
import android.content.res.TypedArray
import android.graphics.Canvas
import android.graphics.Color
import android.graphics.Paint
import android.graphics.RectF
import android.util.AttributeSet
import android.view.View
import kotlin.math.min


class MyView : View {
    //    init
    private lateinit var arcPaint: Paint
    private lateinit var progressTextPaint: Paint
//    private lateinit var arcPaintColor: Color
    private var arcPaintColor = Color.BLACK
//    private lateinit var progressTextPaintColor: Color
    private var progressTextPaintColor = Color.BLACK
    private var angle = 0f
    private var progress: Float = angle / 3.6f


    //    get/set
    fun setArcPaintColor(color: Int) {
        arcPaintColor = color
    }

    fun getArcPaintColor(): Int {
        return arcPaintColor
    }

    fun setProgressTextPaintColor(color: Int) {
        progressTextPaintColor = color
    }

    fun getProgressTextPaintColor(): Int {
        return progressTextPaintColor
    }

    fun setAngle(float: Float) {
        angle = float
        progress = angle / 3.6f
        invalidate()
    }

    fun getAngle(): Float {
        return angle
    }

    fun setProgress(float: Float) {
        progress = float
        angle = progress * 3.6f
        invalidate()
    }

    fun getProgress(): Float {
        return progress
    }

    /*call method initPaint()*/
    constructor(context: Context) : super(context) {
        initPaint()
    }

    constructor(context: Context, attributeSet: AttributeSet?) : super(context, attributeSet) {
        initPaint()
    }

    constructor(context: Context, attributeSet: AttributeSet?, defStyleAttr: Int) : super(
        context,
        attributeSet,
        defStyleAttr
    ) {
        arcPaintColor = typedArray.getColor(R.styleable.arcPaintColor,)
        initPaint()
    }


    /*override onDraw()，draw view*/
    override fun onDraw(canvas: Canvas?) {
        super.onDraw(canvas)
        drawView(canvas)
    }

    //init paints
    private fun initPaint() {
        arcPaint = Paint(Paint.ANTI_ALIAS_FLAG).also {
            it.color = arcPaintColor
            it.strokeWidth = 5f
            it.strokeWidth = 40f
            it.style = Paint.Style.STROKE
            it.strokeCap = Paint.Cap.ROUND
        }
        progressTextPaint = Paint(Paint.ANTI_ALIAS_FLAG).also {
            it.color = progressTextPaintColor
//            it.color = Color.GREEN
//            it.setStrokeWidth(5f)
            it.style = Paint.Style.FILL
            it.textSize = 50f
        }
    }

    /*draw view*/
    private fun drawView(canvas: Canvas?) {
        val displayWidth = width
        val displayHeight = height
        /*get center of circle*/
        val centerX = (displayWidth / 2).toFloat()
        val centerY = (displayHeight / 2).toFloat()

        /*get radius*/
        val radius = min(displayWidth, displayHeight) / 4


        val rectF = RectF(
            centerX - radius,
            centerY - radius,
            centerX + radius,
            centerY + radius
        )


        canvas?.drawArc(
            rectF,
            0f,
            angle,
            false,
            arcPaint
        )

        canvas?.drawText(
            "${String.format("%.1f", progress)}%",
            centerX - progressTextPaint.measureText("${String.format("%.1f", progress)}%") / 2,
            centerY,
            progressTextPaint
        )
    }
}

这是我的自定义属性的xml文件

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="MyView">
        <attr name="arcPaintColor" format="color"/>
        <attr name="progressTextPaintColor" format="color"/>
    </declare-styleable>
</resources>

the xml file of my custom attribute

Answer 1

问题是您正在导入 android.R

您需要导入 [you package name].R 版本。