Android本地验证码的生成

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

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;}

实现onDraw()方法，绘画出验证码

@Overrideprotected 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

@Overridepublic 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https://github.com/myloften/VerificationCodeSample

继承view，重写构造方法，并初始化所需参数

重写onDraw()，绘制图形

添加触摸事件，点击切换验证码

添加公开使用方法

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