Android编程生成验证码图片

2017-09-13 10:43:16来源:网络收集作者:纳米程序员人点击

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利用该类,可生成用于提示验证码的bitmap


代码块

代码块:Code.java


import java.util.Random;
import Android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Bitmap.Config;
public class Code {
private static final char[] CHARS = {
'2', '3', '4', '5', '6', '7', '8', '9',
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k', 'l', '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 Code bmpCode;
public static Code getInstance() {
if(bmpCode == null)
bmpCode = new Code();
return bmpCode;
}
//default settings
private static final int DEFAULT_CODE_LENGTH = 4;
private static final int DEFAULT_FONT_SIZE = 25;
private static final int DEFAULT_LINE_NUMBER = 2;
private static final int BASE_PADDING_LEFT = 5, RANGE_PADDING_LEFT = 15, BASE_PADDING_TOP = 15, RANGE_PADDING_TOP = 20;
private static final int DEFAULT_WIDTH = 80, DEFAULT_HEIGHT = 40;
//settings decided by the layout xml
//canvas width and height
private int width = DEFAULT_WIDTH, height = DEFAULT_HEIGHT;
//random word space and pading_top
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;
//number of chars, lines; font size
private int codeLength = DEFAULT_CODE_LENGTH, line_number = DEFAULT_LINE_NUMBER, font_size = DEFAULT_FONT_SIZE;
//variables
private String code;
private int padding_left, padding_top;
private Random random = new Random();
//验证码图片
public Bitmap createBitmap() {
padding_left = 0;
Bitmap bp = Bitmap.createBitmap(width, height, Config.ARGB_8888);
Canvas c = new Canvas(bp);
code = createCode();
c.drawColor(Color.WHITE);
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;
}
//验证码
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
//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
}
private void randomPadding() {
padding_left += base_padding_left + random.nextInt(range_padding_left);
padding_top = base_padding_top + random.nextInt(range_padding_top);
}
}



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