写代码的四点:
1.明确需求。要做什么?
2.分析思路。要怎么做?(1,2,3……)
3.确定步骤。每一个思路要用到哪些语句、方法和对象。
4.代码实现。用具体的语言代码将思路实现出来。
学习新技术的四点:
1.该技术是什么?
2.该技术有什么特点?(使用需注意的方面)
3.该技术怎么使用?(写Demo)
4.该技术什么时候用?(在Project中的使用场景 )
----------------------早计划,早准备,早完成。-------------------------
代码如下:
package com.wy.test.other; import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import java.util.Random; /** * 用于生成图片验证码 * 使用方式: * 第一步:获取类的实例 * 第二步:生成图片验证码 * 第三步:获取当前生成的验证码字符串,与用户输入的做对比 */ public class PhotoVerificationCodeUtil { //模板字符 private static final char[] TEMPLATE = { '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'}; //默认设置(常量) private static final int DEFAULT_CODE_LENGTH = 3; private static final int DEFAULT_FONT_SIZE = 25; private static final int DEFAULT_LINE_NUMBER = 2; private static final int BASE_PADDING_LEFT = 10, RANGE_PADDING_LEFT = 15, BASE_PADDING_TOP = 20, RANGE_PADDING_TOP = 5; private static final int DEFAULT_WIDTH = 80, DEFAULT_HEIGHT = 30; //画布的宽高 private int width = DEFAULT_WIDTH, height = DEFAULT_HEIGHT; //基本的padding值与随机的padding值的范围 private int base_padding_left = BASE_PADDING_LEFT, range_padding_left = RANGE_PADDING_LEFT, base_padding_top = BASE_PADDING_TOP, range_padding_top = RANGE_PADDING_TOP; //验证码的长度、线条数与字体大小 private int codeLength = DEFAULT_CODE_LENGTH, line_number = DEFAULT_LINE_NUMBER, font_size = DEFAULT_FONT_SIZE; private String code; private int padding_left, padding_top; private Random random = new Random(); private static PhotoVerificationCodeUtil instance; /** * 获取类的实例 * * @return 类的实例 */ public static PhotoVerificationCodeUtil getInstance() { if (instance == null) { instance = new PhotoVerificationCodeUtil(); } return instance; } /** * 生成图片验证码 * * @return 图片验证码 */ public Bitmap createBitmap() { padding_left = 0; Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888); Canvas canvas = new Canvas(bitmap); code = createCode(); canvas.drawColor(Color.GRAY); Paint paint = new Paint(); paint.setTextSize(font_size); for (int i = 0; i < code.length(); i++) { randomTextStyle(paint); randomPadding(); canvas.drawText(code.charAt(i) + "", padding_left, padding_top, paint); } for (int i = 0; i < line_number; i++) { drawLine(canvas, paint); } canvas.save(Canvas.ALL_SAVE_FLAG);//保存 canvas.restore();// return bitmap; } /** * 生成验证码字符串 * * @return 验证码 */ private String createCode() { StringBuilder buffer = new StringBuilder(); for (int i = 0; i < codeLength; i++) { buffer.append(TEMPLATE[random.nextInt(TEMPLATE.length)]); } return buffer.toString(); } /** * 获取当前生成的验证码字符串 * * @return 验证码 */ public String getCode() { return code; } /** * 画线 * 用于增加机器识别难度 * * @param canvas 画布 * @param paint 画笔 */ private void drawLine(Canvas canvas, Paint paint) { int color = randomColor(1); int startX = random.nextInt(width); int startY = random.nextInt(height); int stopX = random.nextInt(width); int stopY = random.nextInt(height); paint.setStrokeWidth(1); paint.setColor(color); canvas.drawLine(startX, startY, stopX, stopY, paint); } /** * 随机颜色 * * @return 色值 */ private int randomColor(int rate) { int red = random.nextInt(256) / rate; int green = random.nextInt(256) / rate; int blue = random.nextInt(256) / rate; return Color.rgb(red, green, blue); } /** * 随机字体样式 * * @param paint 画笔 */ private void randomTextStyle(Paint paint) { int color = randomColor(1); paint.setColor(color); paint.setFakeBoldText(random.nextBoolean()); //true为粗体,false为非粗体 float skewX = random.nextInt(11) / 10; skewX = random.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padding值 * 尽量避免字符重叠 */ private void randomPadding() { padding_left += base_padding_left + random.nextInt(range_padding_left); padding_top = base_padding_top + random.nextInt(range_padding_top); } }
在项目中的应用:
首先生成图片验证码,并设置到ImageView控件上;
然后获取当前生成的验证码字符串,与用户输入的做对比。
注:替换图片验证码,即生成新的图片验证码并设置到ImageView控件上。
Bitmap bitmap = PhotoVerificationCodeUtil.getInstance().createBitmap(); ivCode.setImageBitmap(bitmap); String code = PhotoVerificationCodeUtil.getInstance().getCode(); ToastUtil.makeText(getApplicationContext(),code);