Android实现图片验证码

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最近项目上用到了随机生成图片验证码的功能，实现如下：

CodeUtils.java

package com.jackie.countdowntimer;import android.graphics.Bitmap;import android.graphics.Bitmap.Config;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import java.util.Random;/** * Created by Jackie on 2015/12/1. * 用于图片验证码的工具类 */public class CodeUtils {    private static final char[] CHARS = {            '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'    };    private static CodeUtils mCodeUtils;    private int mPaddingLeft, mPaddingTop;    private StringBuilder mBuilder = new StringBuilder();    private Random mRandom = new Random();    //Default Settings    private static final int DEFAULT_CODE_LENGTH = 4;//验证码的长度  这里是4位    private static final int DEFAULT_FONT_SIZE = 60;//字体大小    private static final int DEFAULT_LINE_NUMBER = 3;//多少条干扰线    private static final int BASE_PADDING_LEFT = 20; //左边距    private static final int RANGE_PADDING_LEFT = 35;//左边距范围值    private static final int BASE_PADDING_TOP = 42;//上边距    private static final int RANGE_PADDING_TOP = 15;//上边距范围值    private static final int DEFAULT_WIDTH = 200;//默认宽度.图片的总宽    private static final int DEFAULT_HEIGHT = 100;//默认高度.图片的总高    private static final int DEFAULT_COLOR = 0xDF;//默认背景颜色值    public static CodeUtils getInstance() {        if(mCodeUtils == null) {            mCodeUtils = new CodeUtils();        }        return mCodeUtils;    }    //生成验证码图片    public Bitmap createBitmap() {        mPaddingLeft = 0; //每次生成验证码图片时初始化        mPaddingTop = 0;        Bitmap bitmap = Bitmap.createBitmap(DEFAULT_WIDTH, DEFAULT_HEIGHT, Config.ARGB_8888);        Canvas canvas = new Canvas(bitmap);        //生成的验证码        String code = createCode();        canvas.drawColor(Color.rgb(DEFAULT_COLOR, DEFAULT_COLOR, DEFAULT_COLOR));        Paint paint = new Paint();        paint.setTextSize(DEFAULT_FONT_SIZE);        for (int i = 0; i < code.length(); i++) {            randomTextStyle(paint);            randomPadding();            canvas.drawText(code.charAt(i) + "" , mPaddingLeft, mPaddingTop, paint);        }        //干扰线        for (int i = 0; i < DEFAULT_LINE_NUMBER; i++) {            drawLine(canvas, paint);        }        canvas.save(Canvas.ALL_SAVE_FLAG);//保存        canvas.restore();        return bitmap;    }    //生成验证码    public String createCode() {        mBuilder.delete(0, mBuilder.length()); //使用之前首先清空内容        for (int i = 0; i < DEFAULT_CODE_LENGTH; i++) {            mBuilder.append(CHARS[mRandom.nextInt(CHARS.length)]);        }        return mBuilder.toString();    }    //生成干扰线    private void drawLine(Canvas canvas, Paint paint) {        int color = randomColor();        int startX = mRandom.nextInt(DEFAULT_WIDTH);        int startY = mRandom.nextInt(DEFAULT_HEIGHT);        int stopX = mRandom.nextInt(DEFAULT_WIDTH);        int stopY = mRandom.nextInt(DEFAULT_HEIGHT);        paint.setStrokeWidth(1);        paint.setColor(color);        canvas.drawLine(startX, startY, stopX, stopY, paint);    }    //随机颜色    private int randomColor() {        mBuilder.delete(0, mBuilder.length()); //使用之前首先清空内容        String haxString;        for (int i = 0; i < 3; i++) {            haxString = Integer.toHexString(mRandom.nextInt(0xFF));            if (haxString.length() == 1) {                haxString = "0" + haxString;            }            mBuilder.append(haxString);        }        return Color.parseColor("#" + mBuilder.toString());    }    //随机文本样式    private void randomTextStyle(Paint paint) {        int color = randomColor();        paint.setColor(color);        paint.setFakeBoldText(mRandom.nextBoolean());  //true为粗体，false为非粗体        float skewX = mRandom.nextInt(11) / 10;        skewX = mRandom.nextBoolean() ? skewX : -skewX;        paint.setTextSkewX(skewX); //float类型参数，负数表示右斜，整数左斜//        paint.setUnderlineText(true); //true为下划线，false为非下划线//        paint.setStrikeThruText(true); //true为删除线，false为非删除线    }    //随机间距    private void randomPadding() {        mPaddingLeft += BASE_PADDING_LEFT + mRandom.nextInt(RANGE_PADDING_LEFT);        mPaddingTop = BASE_PADDING_TOP + mRandom.nextInt(RANGE_PADDING_TOP);    }}

用法：

CodeUtils.getInstance().createBitmap();

效果图如下：

2 0