Android Captcha 防止機器人 生成隨機驗證碼
Android Captcha 防止機器人 生成隨機驗證碼，這個隨機驗證碼可以輕易的擋掉那些機器人來做一些事情，此方法是使用0~9和A~Z的所有組合，她可以有效的防止機器人攻擊你的伺服器，隨機驗證碼是你的好幫手來阻止伺服器被機器人攻破。
文章目錄
- 創建驗證碼類別
- 畫面布局
- 使用驗證碼
- 程式範例
- 效果展示
- GitHub
1.創建驗證碼
package com.example.test
import android.graphics.*
import java.lang.StringBuilder
import java.util.*
/**
* Author: Wade
* E-mail: tony91097@gmail.com
* Date: 2021/9/22
*/
class Captcha private constructor() {
companion object {
val CHARS_NUMBER = arrayListOf('0', '1', '2', '3', '4', '5', '6', '7', '8', '9')
val CHARS_LETTER = arrayListOf(
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w',
'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',
'X', 'Y', 'Z'
)
val CHARS_ALL = arrayListOf(
'0', '1', '2', '3', '4', '5', '6',
'7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w',
'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',
'X', 'Y', 'Z'
)
val instance: Captcha by lazy(LazyThreadSafetyMode.SYNCHRONIZED) { Captcha() }
}
/**
* 驗證碼寬度
*/
private var mWidth = 0
/**
* 驗證碼高度
*/
private var mHeight = 0
/**
* 驗證碼背景顏色
*/
private var mBackgroundColor = 0
/**
* 驗證碼長度
*/
private var mLength = 0
/**
* 干擾線的數量
*/
private var mLineNumber = 0
/**
* 驗證碼文字大小
*/
private var mFontSize = 0
/**
* 字體左邊距
*/
private var mFontPaddingLeft = 0
/**
* 字體左邊距範圍值
*/
private var mFontPaddingLeftRange = 0
/**
* 字體上邊距
*/
private var mFontPaddingTop = 0
/**
* 字體上邊距範圍值
*/
private var mFontPaddingTopRange = 0
/**
* 圖片倍率
*/
private var mScale = 0
private var mType: TYPE
private var mRandom: Random
private lateinit var mCode: String
sealed class TYPE {
object NUMBER : TYPE()
object LETTER : TYPE()
object CHARS : TYPE()
}
init {
mType = TYPE.CHARS
mScale = 1
mWidth = 200
mHeight = 100
mBackgroundColor = Color.WHITE
mLength = 4
mLineNumber = 5
mFontSize = 50
mFontPaddingLeft = 25
mFontPaddingLeftRange = 20
mFontPaddingTop = 60
mFontPaddingTopRange = 20
mRandom = Random()
}
fun setType(type: TYPE): Captcha {
mType = type
return instance
}
fun setScale(scale: Int): Captcha {
mScale = scale
return instance
}
fun setSize(width: Int, height: Int): Captcha {
mWidth = width * mScale
mHeight = height * mScale
return instance
}
fun setBackgroundColor(color: Int): Captcha {
mBackgroundColor = color
return instance
}
fun setLength(length: Int): Captcha {
mLength = length
return instance
}
fun setLineNumber(number: Int): Captcha {
mLineNumber = number
return instance
}
fun setFontSize(size: Int): Captcha {
mFontSize = size * mScale
return instance
}
fun setFontPadding(paddingLeft: Int, paddingTop: Int): Captcha {
mFontPaddingLeft = paddingLeft * mScale
mFontPaddingTop = paddingTop * mScale
return instance
}
fun setFontPadding(
paddingLeft: Int,
paddingLeftRange: Int,
paddingTop: Int,
paddingRange: Int
): Captcha {
mFontPaddingLeft = paddingLeft * mScale
mFontPaddingLeftRange = paddingLeftRange * mScale
mFontPaddingTop = paddingTop * mScale
mFontPaddingTopRange = paddingRange * mScale
return instance
}
/**
* 獲取驗證碼
*/
fun getCode() = mCode
fun create(): Bitmap {
mCode = createCode()
val bitmap = Bitmap.createBitmap(mWidth, mHeight, Bitmap.Config.ARGB_8888)
val canvas = Canvas(bitmap)
canvas.drawColor(mBackgroundColor)
val paint = Paint(Paint.ANTI_ALIAS_FLAG)
paint.textSize = mFontSize.toFloat()
var fontPaddingLeft = 0
for (code in mCode) {
getRandomTextStyle(paint)
fontPaddingLeft += getRandomFontPaddingLeft()
canvas.drawText(
code.toString(),
fontPaddingLeft.toFloat(),
getRandomFontPaddingTop().toFloat(),
paint
)
}
for (i in 0 until mLineNumber) {
drawLine(canvas, paint)
}
canvas.save()
canvas.restore()
return bitmap
}
private fun drawLine(canvas: Canvas, paint: Paint) {
val color = getRandomColor()
val startX = mRandom.nextInt(mWidth)
val startY = mRandom.nextInt(mHeight)
val stopX = mRandom.nextInt(mWidth)
val stopY = mRandom.nextInt(mHeight)
paint.strokeWidth = 1f
paint.color = color
canvas.drawLine(startX.toFloat(), startY.toFloat(), stopX.toFloat(), stopY.toFloat(), paint)
}
private fun getRandomFontPaddingLeft() =
mFontPaddingLeft + mRandom.nextInt(mFontPaddingLeftRange)
private fun getRandomFontPaddingTop() = mFontPaddingTop + mRandom.nextInt(mFontPaddingTopRange)
private fun getRandomTextStyle(paint: Paint) {
val color = getRandomColor()
paint.color = color
paint.isFakeBoldText = mRandom.nextBoolean()
var skewX = mRandom.nextInt(11) / 10
skewX = if (mRandom.nextBoolean()) skewX else -skewX
paint.textSkewX = skewX.toFloat()
}
private fun getRandomColor(): Int {
val red = mRandom.nextInt(256)
val green = mRandom.nextInt(256)
val blue = mRandom.nextInt(256)
return Color.rgb(red, green, blue)
}
private fun createCode(): String {
val buffer = StringBuilder()
when (mType) {
TYPE.NUMBER -> {
for (i in 0 until mLength) {
buffer.append(CHARS_NUMBER[mRandom.nextInt(CHARS_NUMBER.size)])
}
}
TYPE.LETTER -> {
for (i in 0 until mLength) {
buffer.append(CHARS_LETTER[mRandom.nextInt(CHARS_LETTER.size)])
}
}
TYPE.CHARS -> {
for (i in 0 until mLength) {
buffer.append(CHARS_ALL[mRandom.nextInt(CHARS_ALL.size)])
}
}
}
return buffer.toString()
}
}
2.畫面布局
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<androidx.appcompat.widget.AppCompatImageView
android:id="@+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
app:layout_constraintStart_toStartOf="@+id/code"
app:layout_constraintTop_toBottomOf="@+id/code"
tools:srcCompat="@tools:sample/avatars" />
<androidx.appcompat.widget.AppCompatEditText
android:hint="請輸入驗證碼"
android:maxLength="4"
android:id="@+id/code"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="36dp"
android:ems="10"
android:inputType="textPersonName"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<androidx.appcompat.widget.AppCompatButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="驗證"
android:onClick="validate"
app:layout_constraintBottom_toBottomOf="@+id/code"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="@+id/code"
app:layout_constraintTop_toTopOf="@+id/code" />
<androidx.appcompat.widget.AppCompatTextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:text="看不清楚可點擊圖片更換"
android:textColor="@color/black"
android:textSize="16sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="@+id/imageView"
app:layout_constraintTop_toTopOf="@+id/imageView" />
</androidx.constraintlayout.widget.ConstraintLayout>
3.使用驗證碼
val mCaptcha = Captcha.instance
.setType(Captcha.TYPE.CHARS)
.setScale(2)
.setSize(200, 100)
.setBackgroundColor(Color.WHITE)
.setLength(4)
.setLineNumber(5)
.setFontSize(50)
.setFontPadding(25, 20, 60, 20)
4.程式範例
package com.example.test
import android.graphics.Color
import android.os.Bundle
import android.view.View
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import androidx.appcompat.widget.AppCompatEditText
import androidx.appcompat.widget.AppCompatImageView
class MainActivity : AppCompatActivity() {
private lateinit var captcha: AppCompatImageView
private lateinit var code: AppCompatEditText
private lateinit var mCaptcha: Captcha
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
captcha = findViewById(R.id.imageView)
code = findViewById(R.id.code)
createCaptcha()
}
private fun createCaptcha() {
mCaptcha = Captcha.instance
.setType(Captcha.TYPE.CHARS)
.setScale(2)
.setSize(200, 100)
.setBackgroundColor(Color.WHITE)
.setLength(4)
.setLineNumber(5)
.setFontSize(50)
.setFontPadding(25, 20, 60, 20)
captcha.setImageBitmap(mCaptcha.create())
captcha.setOnClickListener {
captcha.setImageBitmap(mCaptcha.create())
}
}
fun validate(view: View) {
if (mCaptcha.getCode().equals(code.text.toString(), true)) {
Toast.makeText(this, "驗證成功", Toast.LENGTH_SHORT).show()
} else {
Toast.makeText(this, "驗證失敗", Toast.LENGTH_SHORT).show()
}
}
}
5.效果展示
6.Github
Android Captcha 防止機器人 生成隨機驗證碼 Github
