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。