android自定义view实现钟表效果

package com.example.commonui.widget
 
import android.annotation.SuppressLint
import android.content.Context
import android.graphics.Canvas
import android.graphics.Color
import android.graphics.Paint
import android.os.Handler
import android.os.Message
import android.util.AttributeSet
import android.view.View
import java.util.*
 
/**
 * Created by zhang on 2017/12/20.
 */
class ClockView(context: Context?, attrs: AttributeSet? = null, defStyleAttr: Int = 0) : View(context, attrs, defStyleAttr) {
 
  companion object {
    private const val DEFAULT_WIDTH = 200 //默认宽度
  }
 
  private lateinit var mBlackPaint: Paint//黑色画笔
  private lateinit var mRedPaint: Paint //红色画笔
  private lateinit var mBlackPaint2: Paint//黑色画笔
  private lateinit var mTextPaint: Paint
  private var hour: Int? = null
  private var minute: Int? = null
  private var second: Int? = null
  private val textArray = arrayOf("12", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11")
  private var refreshThread: Thread? = null
  private var mHandler = @SuppressLint("HandlerLeak")
  object : Handler() {
    override fun handleMessage(msg: Message?) {
      super.handleMessage(msg)
      when (msg?.what) {
        0 -> {
          invalidate()
        }
      }
 
    }
  }
 
  init {
    initPaints()
  }
 
  /**
   * 初始化画笔
   */
  private fun initPaints() {
    mBlackPaint = Paint()
    with(mBlackPaint) {
      color = Color.BLACK
      strokeWidth = 5f
      isAntiAlias = true
      style = Paint.Style.STROKE
    }
    //用于画表心
    mBlackPaint2 = Paint()
    with(mBlackPaint2) {
      color = Color.BLACK
      isAntiAlias = true
      style = Paint.Style.FILL
    }
    mRedPaint = Paint()
    with(mRedPaint) {
      color = Color.RED
      strokeWidth = 5f
      isAntiAlias = true
    }
 
    mTextPaint = Paint()
    with(mTextPaint) {
      color = Color.BLACK
      textSize = 30f
      isAntiAlias = true
    }
  }
 
  override fun onDraw(canvas: Canvas?) {
    super.onDraw(canvas)
    //获取当前时间
    getCurrentTime()
 
    //先画最外层的圆圈
    drawOuterCircle(canvas)
 
    //画刻度
    drawScale(canvas)
 
    //绘制文字
    drawTimeText(canvas)
 
    //绘制表针
    drawHand(canvas)
 
    //绘制表心
    drawCenter(canvas)
  }
 
  private fun getCurrentTime() {
    val calendar = Calendar.getInstance()
    hour = calendar.get(Calendar.HOUR)
    minute = calendar.get(Calendar.MINUTE)
    second = calendar.get(Calendar.SECOND)
  }
 
  private fun drawOuterCircle(canvas: Canvas?) {
    mBlackPaint.strokeWidth = 5f
    canvas?.drawCircle(measuredWidth / 2.toFloat(), measuredHeight / 2.toFloat(), (measuredWidth / 2 - 5).toFloat(), mBlackPaint)
  }
 
  private fun drawCenter(canvas: Canvas?) {
    canvas?.drawCircle(measuredWidth / 2.toFloat(), measuredHeight / 2.toFloat(), 20f, mBlackPaint2)
  }
 
  private fun drawHand(canvas: Canvas?) {
    drawSecond(canvas, mRedPaint)
    mBlackPaint.strokeWidth = 10f
    drawMinute(canvas, mBlackPaint)
    mBlackPaint.strokeWidth = 15f
    drawHour(canvas, mBlackPaint)
  }
 
  private fun drawTimeText(canvas: Canvas?) {
    val textR = (measuredWidth / 2 - 50).toFloat()//文字构成的圆的半径
    for (i in 0..11) {
      //绘制文字的起始坐标
      val startX = (measuredWidth / 2 + textR * Math.sin(Math.PI / 6 * i) - mTextPaint.measureText(textArray[i]) / 2).toFloat()
      val startY = (measuredHeight / 2 - textR * Math.cos(Math.PI / 6 * i) + mTextPaint.measureText(textArray[i]) / 2).toFloat()
      canvas?.drawText(textArray[i], startX, startY, mTextPaint)
    }
  }
 
  private fun drawScale(canvas: Canvas?) {
    var scaleLength: Float?
    canvas?.save()
    //0..59代表[0,59]
    for (i in 0..59) {
      if (i % 5 == 0) {
        //大刻度
        mBlackPaint.strokeWidth = 5f
        scaleLength = 20f
      } else {
        //小刻度
        mBlackPaint.strokeWidth = 3f
        scaleLength = 10f
      }
      canvas?.drawLine(measuredWidth / 2.toFloat(), 5f, measuredWidth / 2.toFloat(), (5 + scaleLength), mBlackPaint)
      canvas?.rotate(360 / 60.toFloat(), measuredWidth / 2.toFloat(), measuredHeight / 2.toFloat())
    }
    //恢复原来状态
    canvas?.restore()
  }
 
  /**
   * 绘制秒针
   */
  private fun drawSecond(canvas: Canvas?, paint: Paint?) {
    //秒针长半径 (表针会穿过表心 所以需要根据两个半径计算起始和结束半径)
    val longR = measuredWidth / 2 - 60
    val shortR = 60
    val startX = (measuredWidth / 2 - shortR * Math.sin(second!!.times(Math.PI / 30))).toFloat()
    val startY = (measuredWidth / 2 + shortR * Math.cos(second!!.times(Math.PI / 30))).toFloat()
    val endX = (measuredWidth / 2 + longR * Math.sin(second!!.times(Math.PI / 30))).toFloat()
    val endY = (measuredWidth / 2 - longR * Math.cos(second!!.times(Math.PI / 30))).toFloat()
    canvas?.drawLine(startX, startY, endX, endY, paint)
  }
 
  /**
   * 绘制分针
   */
  private fun drawMinute(canvas: Canvas?, paint: Paint?) {
    //半径比秒针小一点
    val longR = measuredWidth / 2 - 90
    val shortR = 50
    val startX = (measuredWidth / 2 - shortR * Math.sin(minute!!.times(Math.PI / 30))).toFloat()
    val startY = (measuredWidth / 2 + shortR * Math.cos(minute!!.times(Math.PI / 30))).toFloat()
    val endX = (measuredWidth / 2 + longR * Math.sin(minute!!.times(Math.PI / 30))).toFloat()
    val endY = (measuredWidth / 2 - longR * Math.cos(minute!!.times(Math.PI / 30))).toFloat()
    canvas?.drawLine(startX, startY, endX, endY, paint)
  }
 
 
  /**
   * 绘制时针
   */
  private fun drawHour(canvas: Canvas?, paint: Paint?) {
    //半径比秒针小一点
    val longR = measuredWidth / 2 - 120
    val shortR = 40
    val startX = (measuredWidth / 2 - shortR * Math.sin(hour!!.times(Math.PI / 6))).toFloat()
    val startY = (measuredWidth / 2 + shortR * Math.cos(hour!!.times(Math.PI / 6))).toFloat()
    val endX = (measuredWidth / 2 + longR * Math.sin(hour!!.times(Math.PI / 6))).toFloat()
    val endY = (measuredWidth / 2 - longR * Math.cos(hour!!.times(Math.PI / 6))).toFloat()
    canvas?.drawLine(startX, startY, endX, endY, paint)
  }
 
  /**
   * 进行测量
   */
  override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec)
    val widthSpecMode = MeasureSpec.getMode(widthMeasureSpec)
    val widthSpecSize = MeasureSpec.getSize(widthMeasureSpec)
    val heightSpecMode = MeasureSpec.getMode(heightMeasureSpec)
    val heightSpecSize = MeasureSpec.getSize(heightMeasureSpec)
    val result = if (widthSpecMode == MeasureSpec.AT_MOST && heightSpecMode == MeasureSpec.AT_MOST) {
      DEFAULT_WIDTH
    } else {
      Math.min(widthSpecSize, heightSpecSize)
    }
 
    setMeasuredDimension(result, result)
  }
 
  override fun onAttachedToWindow() {
    super.onAttachedToWindow()
    //启动线程 刷新界面
    refreshThread = Thread(Runnable {
      while (true) {
        try {
          Thread.sleep(1000)
          mHandler.sendEmptyMessage(0)
        } catch (e: InterruptedException) {
          break
        }
      }
    })
    refreshThread?.start()
  }
 
  override fun onDetachedFromWindow() {
    super.onDetachedFromWindow()
    mHandler.removeCallbacksAndMessages(null)
    //中断线程
    refreshThread?.interrupt()
  }
}