Android本地验证码的生成代码

android客户端生成本地验证码主要用来限制用户随意按请求按钮，其实该示例也是来对自定义view的练练手而已，先给出效果图吧

其中可定制：

＊干扰线数目
＊干扰点数目
＊背景颜色
＊验证码字体大小及字数

相信以上可以满足一般的需要了吧，不够的话可自行添加，下面就来讲实现的步骤了

继承view，重写构造方法，并初始化所需参数

public class ValidationCode extends View {

 private Paint mTextPaint;//文字画笔
 private Paint mPointPaint;//干扰点画笔
 private Paint mPathPaint;//干扰线画笔
 private Paint mBitmapPaint;//Bitmap图画笔
 private String mCodeString;//随机验证码
 private int mCodeCount;//验证码位数
 private float mTextSize;//验证码字符大小
 private int mPointNumber;//干扰点数目
 private int mLineNumber;//干扰线数目
 private int mBackGround;//背景颜色
 private float mTextWidth;//验证码字符串的显示宽度
 private static int mWidth;//控件的宽度
 private static int mHeight;//控件的高度
 private static Random mRandom = new Random();
 private Bitmap bitmap = null;//生成验证码图片

 public ValidationCode(Context context) {
  this(context, null);
 }

 public ValidationCode(Context context, AttributeSet attrs) {
  super(context, attrs);
  getAttrValues(context, attrs);
  init();
 }

 /**
  * 获取布局文件中的值
  */
 private void getAttrValues(Context context, AttributeSet attrs) {
  TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.ValidationCode);
  mCodeCount = typedArray.getInteger(R.styleable.ValidationCode_CodeCount, 4);
  mPointNumber = typedArray.getInteger(R.styleable.ValidationCode_PointNumber, 100);
  mLineNumber = typedArray.getInteger(R.styleable.ValidationCode_LineNumber, 2);
  mTextSize = typedArray.getDimension(R.styleable.ValidationCode_CodeTextSize, 20);
  mBackGround = typedArray.getColor(R.styleable.ValidationCode_BackGround,Color.WHITE);
  typedArray.recycle();
 }

 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  super.onMeasure(widthMeasureSpec, heightMeasureSpec);
  setMeasuredDimension(measureWidth(widthMeasureSpec), measureHeight(heightMeasureSpec));

 }

 /**
  * 初始化画笔
  */
 private void init() {
  //生成随机数字和字母组合
  mCodeString = getValidationCode(mCodeCount);
  //初始化文字画笔
  mTextPaint = new Paint();
  mTextPaint.setStrokeWidth(3);
  mTextPaint.setTextSize(mTextSize);
  //初始化干扰点画笔
  mPointPaint = new Paint();
  mPointPaint.setStrokeWidth(4);
  mPointPaint.setStrokeCap(Paint.Cap.ROUND);//设置断点处为圆形
  //初始化干扰线画笔
  mPathPaint = new Paint();
  mPathPaint.setStrokeWidth(5);
  mPathPaint.setColor(Color.GRAY);
  mPathPaint.setStyle(Paint.Style.STROKE);//设置画笔为空心
  mPathPaint.setStrokeCap(Paint.Cap.ROUND);//设置断点处为圆形
  //初始化Bitmap画笔
  mBitmapPaint = new Paint();
  mBitmapPaint.setColor(Color.RED);
  //取得验证码字符串显示的宽度值
  mTextWidth = mTextPaint.measureText(mCodeString);

 }
}

getAttrValues方法是用来配置自定义的属性，需要在 values 中新建 * attrs.xml * 文件，并加上自定义的属性，如下：

<?xml version="1.0" encoding="utf-8"?>
<resources>
 <declare-styleable name="ValidationCode">
  <attr name="CodeCount" format="integer"/>
  <attr name="PointNumber" format="integer"/>
  <attr name="LineNumber" format="integer"/>
  <attr name="CodeTextSize" format="dimension"/>
  <attr name="BackGround" format="color"/>
 </declare-styleable>
</resources>

onMeasure方法则是在你需要对自定义的view的大小做出处理时，通过setMeasuredDimension设置该控件大小，下面给出重新定义的宽高代码块

/**
* 对view的宽高进行重新定义
*/
private int measureWidth(int measureSpec) {
 int result = 0;
 int specMode = MeasureSpec.getMode(measureSpec);
 int specSize = MeasureSpec.getSize(measureSpec);

 if (specMode == MeasureSpec.EXACTLY) {
  result = specSize;
 } else {
  result = (int) (mTextWidth * 2.0f);
  if (specMode == MeasureSpec.AT_MOST) {
   result = Math.min(result, specSize);
  }
 }
 return result;
}

private int measureHeight(int measureSpec) {
 int result = 0;

 int specMode = MeasureSpec.getMode(measureSpec);
 int specSize = MeasureSpec.getSize(measureSpec);

 if (specMode == MeasureSpec.EXACTLY) {
  result = specSize;
 } else {
  result = (int) (mTextWidth / 1.5f);
  if (specMode == MeasureSpec.AT_MOST) {
   result = Math.min(result, specSize);
  }
 }
 return result;
}

重写onDraw()，绘制图形

1、绘制验证码文本字符串，干扰点，干扰线，生成验证码的bitmap图

/**
 * 获取验证码
 *
 * @param length 生成随机数的长度
 * @return
 */
public static String getValidationCode(int length) {
 String val = "";
 Random random = new Random();
 for (int i = 0; i < length; i++) {
  //字母或数字
  String code = random.nextInt(2) % 2 == 0 ? "char" : "num";
  //字符串
  if ("char".equalsIgnoreCase(code)) {
   //大写或小写字母
   int choice = random.nextInt(2) % 2 == 0 ? 65 : 97;
   val += (char) (choice + random.nextInt(26));
  } else if ("num".equalsIgnoreCase(code)) {
   val += String.valueOf(random.nextInt(10));
  }
 }
 return val;
}

/**
 * 生成干扰点
 */
private static void drawPoint(Canvas canvas, Paint paint) {
 PointF pointF = new PointF(mRandom.nextInt(mWidth) + 10, mRandom.nextInt(mHeight) + 10);
 canvas.drawPoint(pointF.x, pointF.y, paint);
}

/**
 * 生成干扰线
 */
private static void drawLine(Canvas canvas, Paint paint) {
 int startX = mRandom.nextInt(mWidth);
 int startY = mRandom.nextInt(mHeight);
 int endX = mRandom.nextInt(mWidth);
 int endY = mRandom.nextInt(mHeight);
 canvas.drawLine(startX, startY, endX, endY, paint);
}

/**
 1. 绘制验证码并返回
 */
private Bitmap generateValidate(){
 if(bitmap != null && !bitmap.isRecycled()){
  //回收并且置为null
  bitmap.recycle();
  bitmap = null;
 }
 //创建图片和画布
 Bitmap sourceBitmap = Bitmap.createBitmap(mWidth,mHeight, Bitmap.Config.ARGB_8888);
 Canvas canvas = new Canvas(sourceBitmap);

 //画背景颜色
 canvas.drawColor(mBackGround);

 //画上验证码
 int length = mCodeString.length();
 float charLength = mTextWidth / length;
 for (int i = 1; i <= length; i++) {
  int offsetDegree = mRandom.nextInt(15);
  //这里只会产生0和1，如果是1那么正旋转正角度，否则旋转负角度
  offsetDegree = mRandom.nextInt(2) == 1 ? offsetDegree : -offsetDegree;
  canvas.save();
  canvas.rotate(offsetDegree, mWidth / 2, mHeight / 2);
  //给画笔设置随机颜色
  mTextPaint.setARGB(255, mRandom.nextInt(200) + 20, mRandom.nextInt(200) + 20,
    mRandom.nextInt(200) + 20);
  canvas.drawText(String.valueOf(mCodeString.charAt(i - 1)), (i - 1) * charLength * 1.6f + 30,
    mHeight * 2 / 3f, mTextPaint);
  canvas.restore();
 }

 //产生干扰效果1 －－ 干扰点
 for (int i = 0; i < mPointNumber; i++) {
  mPointPaint.setARGB(255, mRandom.nextInt(200) + 20, mRandom.nextInt(200) + 20,
    mRandom.nextInt(200) + 20);
  drawPoint(canvas, mPointPaint);
 }

 //生成干扰效果2 －－ 干扰线
 for (int i = 0; i < mLineNumber; i++) {
  mPathPaint.setARGB(255, mRandom.nextInt(200) + 20, mRandom.nextInt(200) + 20,
    mRandom.nextInt(200) + 20);
  drawLine(canvas, mPathPaint);
 }

 canvas.save();
 return sourceBitmap;
}

2、实现onDraw()方法，绘画出验证码

@Override
protected void onDraw(Canvas canvas) {
 super.onDraw(canvas);

 //获取控件的宽和高
 mHeight = getHeight();
 mWidth = getWidth();

 if(bitmap == null){
  bitmap = generateValidate();
 }
 canvas.drawBitmap(bitmap,0,0,mBitmapPaint);
}

添加触摸事件，点击切换验证码

@Override
public boolean onTouchEvent(MotionEvent event) {
 switch (event.getAction()) {
  case MotionEvent.ACTION_DOWN:
   mCodeString = getValidationCode(mCodeCount);
   bitmap = generateValidate();
   invalidate();
   break;
  default:
   break;
 }
 return super.onTouchEvent(event);
}

添加公开使用方法

我们总是需要提供给用户调用的方法，判断验证码是否一致之类的，方便用户进一步的操作，这里提供个几个方法

/**
 * 判断验证码是否一致
 *
 * @String CodeString
 * 这里忽略大小写
 */
public Boolean isEqualsIgnoreCase(String CodeString) {
 return mCodeString.equalsIgnoreCase(CodeString);
}

/**
 * 判断验证码是否一致
 * 不忽略大小写
 */
public Boolean isEquals(String CodeString) {
 return mCodeString.equals(CodeString);
}

/**
 * 外界控件调用刷新验证码图片
 */
public void refresh(){
 mCodeString = getValidationCode(mCodeCount);
 bitmap = generateValidate();
 invalidate();
}

以上就是生成本地验证码的一个简单的自定义view步骤，这里就给出源码地址，有需要的就去看看。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。