Android程序員用控件玩彩票，告訴網友什麼叫真正的隨機

爲了買彩票，我寫了這個控件

0.

最近偶爾會買個雙色球，一週買個6塊錢的，也很少，就是湊個熱鬧，爲生活添加個小情趣

由於不會選號，每次都是機選，做爲一個陰謀論者，我以爲機選可能不夠"隨機"，爲此我決定本身寫個程序爲我選號，學過Java會Android的我模仿老虎機寫了一個控件。先上圖

1.

先設計一下

1.1支持從數字和數組獲取數據

1.2繪製兩個數字，當前數字和下一個數字

1.3設置便宜量，並實現加速

1.4開始和中止，中止時添加回調

1.5支持設置文字大小與顏色

2.

廢話少說，上代碼

package com.skateboard.numberrunningview

import android.content.Context

import android.graphics.Canvas

import android.graphics.Color

import android.graphics.Paint

import android.support.v4.view.ViewCompat

import android.util.AttributeSet

import android.view.View

class NumberRunningView(context: Context, attributes: AttributeSet?) : View(context, attributes) {

private var numberColor = Color.WHITE

private var numberSize = 15.0f

//開始時的數字或者數組下標

var min = 0

//最大的數字或者數組下標

var max = 0

//當前要繪製數字或者數組下標

private var now = min

//每次刷新移動的距離

private var offset = 0

private var paint = Paint(Paint.ANTI_ALIAS_FLAG)

private var isStart = false

var maxSpeed = 10f

//當前移動速度

private var curSpeed = 0f

//加速度增量

private var speedOffset = 0.1f

var dataList: List<Int>? = null

set(value) {

field = value

min = 0

max = (value?.size ?: 1) - 1

now = min

offset = 0

}

var onNumberSelectedListener: OnNumberSelectedListenern? = null

init {

if (attributes != null) {

parseAttrs(attributes)

}

initPaint()

}

constructor(context: Context) : this(context, null)

private fun parseAttrs(attributes: AttributeSet) {

val typedArray = context.obtainStyledAttributes(attributes, R.styleable.NumberRunningView)

min = typedArray.getInt(R.styleable.NumberRunningView_min, min)

max = typedArray.getInt(R.styleable.NumberRunningView_max, max)

maxSpeed = typedArray.getFloat(R.styleable.NumberRunningView_maxSpeed, maxSpeed)

numberColor = typedArray.getColor(R.styleable.NumberRunningView_numberColor, numberColor)

numberSize = typedArray.getDimension(R.styleable.NumberRunningView_numberSize, numberSize)

speedOffset = typedArray.getFloat(R.styleable.NumberRunningView_speedOffset, 0.1f)

typedArray.recycle()

now = min

}

private fun initPaint() {

paint.textSize = numberSize

paint.color = numberColor

}

override fun onDraw(canvas: Canvas?) {

super.onDraw(canvas)

canvas?.let {

drawNow(it)

drawNext(it)

calCurSpeed()

calOffset()

}

}

private fun calCurSpeed() {

curSpeed += speedOffset

if (curSpeed > maxSpeed) curSpeed = maxSpeed

}

private fun drawNow(canvas: Canvas) {

val curDataList = dataList

var nowNum = "0"

nowNum = if (curDataList != null) {

curDataList[now].toString()

} else {

now.toString()

}

val numWidth = paint.measureText(nowNum)

canvas.drawText(nowNum, width / 2 - numWidth / 2, height / 2 - offset + paint.textSize / 2, paint)

}

private fun drawNext(canvas: Canvas) {

val curDataList = dataList

var nextNum = ""

if (curDataList == null) {

nextNum = if (now + 1 > max) {

min.toString()

} else {

(now + 1).toString()

}

} else {

nextNum = if (now + 1 > max) {

curDataList[min].toString()

} else {

(curDataList[now + 1]).toString()

}

}

val numWidth = paint.measureText(nextNum)

canvas.drawText(nextNum, width / 2 - numWidth / 2, 1.5f * height - offset + paint.textSize / 2, paint)

}

private fun calOffset() {

if (isStart) {

if (offset == height) {

offset = 0

if (now + 1 > max) {

now = min

} else {

now += 1

}

} else if (offset + curSpeed > height) {

offset = height

} else {

offset = (offset + curSpeed).toInt()

}

postInvalidate()

} else {

if (offset != 0 && offset != height) {

offset = if (offset + curSpeed > height) {

height

} else {

(offset + curSpeed).toInt()

}

postInvalidate()

} else {

if (offset == 0) {

val curDataList = dataList

if (curDataList != null) {

onNumberSelectedListener?.onNumberSelected(curDataList[now])

} else {

onNumberSelectedListener?.onNumberSelected(now)

}

} else {

val curDataList = dataList

if (curDataList != null) {

onNumberSelectedListener?.onNumberSelected(if (now == max) curDataList[min] else curDataList[now + 1])

} else {

onNumberSelectedListener?.onNumberSelected(if (now == max) min else now + 1)

}

}

}

}

}

fun start() {

if (isStart) {

return

}

curSpeed = 0f

isStart = true

if (ViewCompat.isAttachedToWindow(this)) {

postInvalidate()

}

}

fun stop() {

isStart = false

}

interface OnNumberSelectedListenern {

fun onNumberSelected(num: Int)

}

}

---

• 代碼比較簡單，沒什麼難度，先看onDraw方法

• • *

private fun drawNow(canvas: Canvas) {

val curDataList = dataList

var nowNum = "0"

nowNum = if (curDataList != null) {

curDataList[now].toString()

} else {

now.toString()

}

val numWidth = paint.measureText(nowNum)

canvas.drawText(nowNum, width / 2 - numWidth / 2, height / 2 - offset + paint.textSize / 2, paint)

}

---

• 首先根據數據源的不一樣獲取的數據，而後計算文字繪製的位置，而後繪製 drawNext大同小異，無非就是一個下一個數字的判斷問題 calOffset方法

• • *

private fun calOffset() {

if (isStart) {

if (offset == height) {

offset = 0

if (now + 1 > max) {

now = min

} else {

now += 1

}

} else if (offset + curSpeed > height) {

offset = height

} else {

offset = (offset + curSpeed).toInt()

}

postInvalidate()

} else {

if (offset != 0 && offset != height) {

offset = if (offset + curSpeed > height) {

height

} else {

(offset + curSpeed).toInt()

}

postInvalidate()

} else {

if (offset == 0) {

val curDataList = dataList

if (curDataList != null) {

onNumberSelectedListener?.onNumberSelected(curDataList[now])

} else {

onNumberSelectedListener?.onNumberSelected(now)

}

} else {

val curDataList = dataList

if (curDataList != null) {

onNumberSelectedListener?.onNumberSelected(if (now == max) curDataList[min] else curDataList[now + 1])

} else {

onNumberSelectedListener?.onNumberSelected(if (now == max) min else now + 1)

}

}

}

}

}

---

1. 若是處於運行狀態，先判斷控件當前偏移量，若是等於控件高度，那麼就重置爲0，而後將now置爲下一個數，不然就加上速度從新計算偏移量。
2. 若是不處於運行狀態，那麼判斷當前的偏移量，若是既不等於0也不等於控件高度，說明處於一箇中間狀態，那麼就讓它移到下一個位置，並調用回調函數。其餘的也沒什麼關鍵了，各位有須要的看代碼就行了

3.

控件代碼就所有告訴你們了，感覺一把隨機的樂趣，至於彩票，這是薛定諤的彩票。也不要太沉迷，要否則，最後就是西湖的水，個人淚。

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