Android 验证码实现

先上效果图：

自定义VerificationCode 类。

 

public class VerificationCode {

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 VerificationCode bpUtil;

 

private VerificationCode() {

};

 

public static VerificationCode getInstance() {

if (bpUtil == null)

bpUtil = new VerificationCode();

return bpUtil;

}

 

private static final int DEFAULT_CODE_LENGTH = 4;

private static final int DEFAULT_FONT_SIZE = 60;

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;

private static final int DEFAULT_HEIGHT = 70;

private final int DEFAULT_COLOR = 0xdf;// 默认背景颜色值

 

private int width = DEFAULT_WIDTH;

private int height = DEFAULT_HEIGHT;

 

private int base_padding_left = BASE_PADDING_LEFT;

private int range_padding_left = RANGE_PADDING_LEFT;

private int base_padding_top = BASE_PADDING_TOP;

private int range_padding_top = RANGE_PADDING_TOP;

 

private int codeLength = DEFAULT_CODE_LENGTH;

private int line_number = DEFAULT_LINE_NUMBER;

private int font_size = DEFAULT_FONT_SIZE;

 

private String code;// 保存生成的验证码

private int padding_left, padding_top;

private Random random = new Random();

 

private Bitmap createBitmap() {

padding_left = 0;

Bitmap bp = Bitmap.createBitmap(width, height, Config.ARGB_8888);

Canvas c = new Canvas(bp);

code = createCode();

c.drawColor(Color.rgb(DEFAULT_COLOR, DEFAULT_COLOR, DEFAULT_COLOR));

Paint paint = new Paint();

paint.setTextSize(font_size);

for (int i = 0; i < code.length(); i++) {

randomTextStyle(paint);

randomPadding();

c.drawText(code.charAt(i) + "", padding_left, padding_top, paint);

}

for (int i = 0; i < line_number; i++) {

drawLine(c, paint);

}

c.save(Canvas.ALL_SAVE_FLAG);// 保存

c.restore();//

return bp;

}

 

public String getCode() {

return code.toLowerCase();

}

 

public Bitmap getBitmap() {

return createBitmap();

}

 

private String createCode() {

StringBuilder buffer = new StringBuilder();

for (int i = 0; i < codeLength; i++) {

buffer.append(CHARS[random.nextInt(CHARS.length)]);

}

return buffer.toString();

}

 

private void drawLine(Canvas canvas, Paint paint) {

int color = randomColor();

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);

}

 

private int randomColor() {

return randomColor(1);

}

 

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);

}

 

private void randomTextStyle(Paint paint) {

int color = randomColor();

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

}

 

private void randomPadding() {

padding_left += base_padding_left + random.nextInt(range_padding_left);

padding_top = base_padding_top + random.nextInt(range_padding_top);

}

 

}

如何使用：

调用 VerificationCode.getInstance().getBitmap() 赋予imageview便可显示验证码.

例如：

 

 

ImageView vc_image = (ImageView) findViewById(R.id.vc_image);

vc_image.setImageBitmap(VerificationCode.getInstance().getBitmap());