Android自定义sleep图,android自定义view实现钟表效果
本文實例為大家分享了android view實現(xiàn)鐘表的具體代碼，供大家參考，具體內(nèi)容如下
先看效果圖：
自定義view大家肯定已經(jīng)不陌生了，所以直接今天直接步入正題：如何利用canvas去繪制出一個鐘表
當然繪制之前我們必須進行測量(重寫onMeasure)，根據(jù)自己的規(guī)則去測量，這暫時是將控件限制為一個正方形。
首先我們先把鐘表分解，看它由哪幾部分組成。如上圖：鐘表包括表盤(刻度)和表針還有文字構(gòu)成。
分清結(jié)構(gòu)之后我們再明確canvas需要畫什么，表盤的構(gòu)成其實就是外層一個圓，然后上面是有規(guī)律的線段，表針就是三個長短不一的線段，再加上12個鐘點文字。這樣一分析是不是發(fā)現(xiàn)調(diào)用canvas的drawCircle、drawLine和drawText就可以完成鐘表的繪制了。
既然明確了我們繪制所需要的方法，那么就開始重頭戲了，告訴canvas在哪繪制這些零件。
最外層的圓是最簡單的，我們只需要以控件的中心為圓心，控件的寬度一半為半徑畫一個圓就可以了。
接下來就是難點一了，這些刻度怎么辦呢，其實我們不難發(fā)現(xiàn)其中的規(guī)律，每個刻度之間的弧度是一樣的，那這樣我們是不是可以通過旋轉(zhuǎn)畫布就可以實現(xiàn)這些刻度的繪制呢，答案是肯定的。
難點二，文字又該如何繪制，難道也通過旋轉(zhuǎn)畫布嗎，但是你想一下，假如通過旋轉(zhuǎn)畫布去繪制文字，那有些文字可是會顛倒的，這并不是我們想要的結(jié)果，那該怎么辦，這時候我們只能通過數(shù)學計算老老實實的計算每個文字的起始坐標，這些坐標并沒有想象中的復雜，我們可以根據(jù)中心點的位置和偏移角度(當然還需要考慮文字的寬度)算出。
難點三，繪制表針，其實文字繪制出來，那么同樣可以根據(jù)中心點和偏移角度算出表針的起始坐標和結(jié)束坐標
表心就是一個實體的圓，這個就簡單了。
好像還沒說時分秒是怎么確定的，這當然是通過系統(tǒng)時間獲取的了。說到這里似乎一個靜態(tài)鐘表已經(jīng)繪制出來了，接下來讓它動起來就可以了。在這我們啟動一個線程，讓它隔一秒鐘進行一次重繪即可。
下面我直接貼一下代碼把，代碼是用kotlin實現(xiàn)(這不是重點)的
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 //默認寬度
}
private lateinit var mBlackPaint: Paint//黑色畫筆
private lateinit var mRedPaint: Paint //紅色畫筆
private lateinit var mBlackPaint2: Paint//黑色畫筆
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()
}
/**
* 初始化畫筆
*/
private fun initPaints() {
mBlackPaint = Paint()
with(mBlackPaint) {
color = Color.BLACK
strokeWidth = 5f
isAntiAlias = true
style = Paint.Style.STROKE
}
//用于畫表心
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)
//獲取當前時間
getCurrentTime()
//先畫最外層的圓圈
drawOuterCircle(canvas)
//畫刻度
drawScale(canvas)
//繪制文字
drawTimeText(canvas)
//繪制表針
drawHand(canvas)
//繪制表心
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()//文字構(gòu)成的圓的半徑
for (i in 0..11) {
//繪制文字的起始坐標
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())
}
//恢復原來狀態(tài)
canvas?.restore()
}
/**
* 繪制秒針
*/
private fun drawSecond(canvas: Canvas?, paint: Paint?) {
//秒針長半徑 (表針會穿過表心 所以需要根據(jù)兩個半徑計算起始和結(jié)束半徑)
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)
}
/**
* 繪制分針
*/
private fun drawMinute(canvas: Canvas?, paint: Paint?) {
//半徑比秒針小一點
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)
}
/**
* 繪制時針
*/
private fun drawHour(canvas: Canvas?, paint: Paint?) {
//半徑比秒針小一點
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)
}
/**
* 進行測量
*/
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()
//啟動線程 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)
//中斷線程
refreshThread?.interrupt()
}
}
在這送上幾點建議，1.盡量不要再ondraw里面創(chuàng)建對象，因為view可能會多次重繪，每次都創(chuàng)建新的對象會造成不必要的內(nèi)存浪費
2.onmeasure方法會調(diào)用多次，請保證你的邏輯覆蓋性，否則可能會出現(xiàn)沒有按照你的預期得到寬高
3.線程的謹慎使用
以上就是本文的全部內(nèi)容，希望對大家的學習有所幫助，也希望大家多多支持腳本之家。
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