在前面仿华为加载动画、仿网易音乐听歌识曲-麦克风动画中，我们通过绘图的基础知识完成了简单的绘制。在本例中，我们将绘制常见的验证码。

一、效果图

二、知识点与思路分析

通过上面的效果图观察，我们可以看到里面有绘制的随机线条，随机绘制的验证码。

绘制线条，直线或曲线

绘制文本，生成的验证码文本的绘制

绘制圆点。

三、代码编写

/** * Created by Iflytek_dsw on 2017/7/3. */public class IdentifyCodeUtil { private static final int CODE_NUMBER = 4; private static final int LINE_NUMBER = 5; private static final int POINT_NUMBER = 10; private StringBuffer stringBuffer = null; private Random random = new Random(); //随机数数组 private static final char[] CHARS = { '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k', 'm', 'n', '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', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' }; private static IdentifyCodeUtil instance; public static IdentifyCodeUtil getInstance(){ if(instance == null){ instance = new IdentifyCodeUtil(); } return instance; } public Bitmap createBitmapCode(int width, int height){ Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888); Canvas canvas = new Canvas(bitmap); canvas.drawColor(Color.LTGRAY); drawCodeText(canvas, width, height); drawLines(canvas, width, height); drawPoint(canvas, width, height); return bitmap; } /** * 返回验证码 * @return 验证码生成的字符串 */ public String getIdentifyCode(){ if(stringBuffer == null){ return ""; } return stringBuffer.toString(); } /** * 生成验证码 * @return */ private String buildIdentifyCode(){ StringBuffer stringBuffer = new StringBuffer(); for(int i=0; i < CODE_NUMBER;i++){ stringBuffer.append(CHARS[random.nextInt(CHARS.length)]); } Log.d("Code",stringBuffer.toString()); return stringBuffer.toString(); } /** * 绘制文本 * @param canvas 画布 * @param width 宽度 * @param height 高度 */ private void drawCodeText(Canvas canvas,int width, int height){ Paint paint = new Paint(); paint.setTextSize(50); /**构建验证码code*/ String text = buildIdentifyCode(); float textLength = paint.measureText(text); int startMaxLength = (int) ((width - textLength) / 2); /**随机计算验证码绘制每次开头的位置*/ int startPosition = random.nextInt(startMaxLength); //绘制文字 for(int index = 0; index < text.length(); index++){ /**生成旋转的角度*/ int offsetDegree = random.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 = random.nextInt(2) == 1 ? offsetDegree : -offsetDegree; canvas.save(); //设置旋转 canvas.rotate(offsetDegree, width / 2, height / 2); /**生成随机的颜色*/ paint.setARGB(255, random.nextInt(200) + 20, random.nextInt(200) + 20, random.nextInt(200) + 20); char tempChar = text.charAt(index); //给画笔设置随机颜色 canvas.drawText(String.valueOf(tempChar), startPosition +index * textLength / text.length() +15, height * 3 / 5f,paint); canvas.restore(); } } /** * 生成干扰线 * @param canvas * @param width * @param height */ private void drawLines(Canvas canvas,int width, int height){ Paint paint = new Paint(); paint.setStrokeWidth(3); for(int i = 0;i < LINE_NUMBER;i++){ paint.setARGB(255, random.nextInt(200) + 30, random.nextInt(200) + 30, random.nextInt(200) + 30); int startX = random.nextInt(width); int startY = random.nextInt(height); int endX = random.nextInt(width); int endY = random.nextInt(height); canvas.drawLine(startX, startY, endX, endY, paint); } } /** * 生成干扰点 */ private void drawPoint(Canvas canvas, int width, int height) { Paint paint = new Paint(); paint.setStrokeWidth(3); paint.setColor(Color.GRAY); for(int i=0; i< POINT_NUMBER; i++){ PointF pointF = new PointF(random.nextInt(width) + 10, random.nextInt(height) + 10); canvas.drawPoint(pointF.x, pointF.y, paint); } }}

以上所述是小编给大家介绍的Android绘制验证码的实例代码，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对网站的支持！