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前言

　　一个双向进度的自定义View，已经封装好，可以直接使用

效果图

代码

import android.content.Context
import android.graphics.*
import android.util.AttributeSet
import android.view.View
import androidx.annotation.ColorInt

/**
 * 双向进度View
 */
class TwoWayProgressView(context: Context?, attrs: AttributeSet?) : View(context, attrs) {
    private var mWidth = 0
    private var mHeight = 0
    private var mCurrentProgress = 100
    private var mPaint: Paint = Paint()
    private var mIsRound = true
    private var mStartColor = Color.parseColor("#48F3D0")
    private var mEndColor = Color.parseColor("#1DBBFF")
    private var mIsHorizontal = false

    init {
        mPaint.style = Paint.Style.FILL
        mPaint.isAntiAlias = true
    }

    /**
     * 是否是圆角
     */
    fun isRound(isRound: Boolean) {
        mIsRound = isRound
        invalidate()
    }

    /**
     * 设置颜色渐变
     * [orientation]渐变方向 true=横向 false=竖向
     * [startColor] 开始颜色
     * [endColor] 结束颜色
     */
    fun setLinearGradientColor(isHorizontal: Boolean, @ColorInt startColor: Int, @ColorInt endColor: Int) {
        mIsHorizontal = isHorizontal
        mStartColor = startColor
        mEndColor = endColor
        invalidate()
    }

    /**
     * 设置进度 0-100
     */
    fun setProgress(progress: Int) {
        mCurrentProgress = progress
        invalidate()
    }

    fun getProgress() = mCurrentProgress

    /**
     * 测量尺寸
     */
    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec)
        mWidth = MeasureSpec.getSize(widthMeasureSpec)
        mHeight = MeasureSpec.getSize(heightMeasureSpec)
        setMeasuredDimension(mWidth, mHeight)
    }

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

    fun drawProgress(canvas: Canvas) {
        val linearGradient = if (mIsHorizontal) {
            //从左到右
            LinearGradient(0f, 0f, mWidth.toFloat(), 0f, mStartColor, mEndColor, Shader.TileMode.CLAMP)
        } else {
            //从上到下渐变
            LinearGradient(0f, 0f, 0f, mHeight.toFloat(), mStartColor, mEndColor, Shader.TileMode.CLAMP)
        }
        mPaint.shader = linearGradient

        val widthScale = (mWidth.toFloat() / 2) / 100
        val left = mWidth / 2 - widthScale * mCurrentProgress
        val right = mWidth / 2 + widthScale * mCurrentProgress
        val rect = RectF()
        rect.top = 0f
        rect.left = left
        rect.right = right
        rect.bottom = mHeight.toFloat()
        if (mIsRound) {
            canvas.drawRoundRect(rect, mWidth / 2f, mWidth / 2f, mPaint)
        } else {
            canvas.drawRect(rect, mPaint)
        }
    }
}